gitadmin
/
tuoheng_airport_stream_discard_20240715
Следить 1
В избранное 0
Форкнуть 0
Код Задачи 0 Pull Request'ы 0 Релизы 0 Вики Активность
Вы не можете выбрать более 25 тем Темы должны начинаться с буквы или цифры, могут содержать дефисы(-) и должны содержать не более 35 символов.
11 коммитов
3 Ветки
ветка: master
Ветки Теги
${ item.name }
Создать ветку ${ searchTerm }
из 'master'
${ noResults }
tuoheng_airport_stream_disc.../ffmpeg/doc/ffmpeg-codecs.html

7071 line
280KB
Исходник Постоянная ссылка Blame История 

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

  2. <html>

  3. <!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ -->

  4.   <head>

  5.     <meta charset="utf-8">

  6.     <title>

  7.       FFmpeg Codecs Documentation

  8.     </title>

  9.     <meta name="viewport" content="width=device-width,initial-scale=1.0">

  10.     <link rel="stylesheet" type="text/css" href="bootstrap.min.css">

  11.     <link rel="stylesheet" type="text/css" href="style.min.css">

  12.   </head>

  13.   <body>

  14.     <div class="container">

  15.       <h1>

  16.       FFmpeg Codecs Documentation

  17.       </h1>

  18. <div align="center">

  19. </div>

  20. 

  21. 

  22. <a name="SEC_Top"></a>

  23. 

  24. <div class="Contents_element" id="SEC_Contents">

  25. <h2 class="contents-heading">Table of Contents</h2>

  26. 

  27. <div class="contents">

  28. 

  29. <ul class="no-bullet">

  30.   <li><a id="toc-Description" href="#Description">1 Description</a></li>

  31.   <li><a id="toc-Codec-Options" href="#Codec-Options">2 Codec Options</a></li>

  32.   <li><a id="toc-Decoders" href="#Decoders">3 Decoders</a></li>

  33.   <li><a id="toc-Video-Decoders" href="#Video-Decoders">4 Video Decoders</a>

  34.   <ul class="no-bullet">

  35.     <li><a id="toc-av1" href="#av1">4.1 av1</a>

  36.     <ul class="no-bullet">

  37.       <li><a id="toc-Options" href="#Options">4.1.1 Options</a></li>

  38.     </ul></li>

  39.     <li><a id="toc-rawvideo" href="#rawvideo">4.2 rawvideo</a>

  40.     <ul class="no-bullet">

  41.       <li><a id="toc-Options-1" href="#Options-1">4.2.1 Options</a></li>

  42.     </ul></li>

  43.     <li><a id="toc-libdav1d" href="#libdav1d">4.3 libdav1d</a>

  44.     <ul class="no-bullet">

  45.       <li><a id="toc-Options-2" href="#Options-2">4.3.1 Options</a></li>

  46.     </ul></li>

  47.     <li><a id="toc-libdavs2" href="#libdavs2">4.4 libdavs2</a></li>

  48.     <li><a id="toc-libuavs3d" href="#libuavs3d">4.5 libuavs3d</a>

  49.     <ul class="no-bullet">

  50.       <li><a id="toc-Options-3" href="#Options-3">4.5.1 Options</a></li>

  51.     </ul></li>

  52.     <li><a id="toc-QSV-Decoders" href="#QSV-Decoders">4.6 QSV Decoders</a>

  53.     <ul class="no-bullet">

  54.       <li><a id="toc-Common-Options" href="#Common-Options">4.6.1 Common Options</a></li>

  55.       <li><a id="toc-HEVC-Options" href="#HEVC-Options">4.6.2 HEVC Options</a></li>

  56.     </ul></li>

  57.     <li><a id="toc-v210" href="#v210">4.7 v210</a>

  58.     <ul class="no-bullet">

  59.       <li><a id="toc-Options-4" href="#Options-4">4.7.1 Options</a></li>

  60.     </ul></li>

  61.   </ul></li>

  62.   <li><a id="toc-Audio-Decoders" href="#Audio-Decoders">5 Audio Decoders</a>

  63.   <ul class="no-bullet">

  64.     <li><a id="toc-ac3" href="#ac3">5.1 ac3</a>

  65.     <ul class="no-bullet">

  66.       <li><a id="toc-AC_002d3-Decoder-Options" href="#AC_002d3-Decoder-Options">5.1.1 AC-3 Decoder Options</a></li>

  67.     </ul></li>

  68.     <li><a id="toc-flac-1" href="#flac-1">5.2 flac</a>

  69.     <ul class="no-bullet">

  70.       <li><a id="toc-FLAC-Decoder-options" href="#FLAC-Decoder-options">5.2.1 FLAC Decoder options</a></li>

  71.     </ul></li>

  72.     <li><a id="toc-ffwavesynth" href="#ffwavesynth">5.3 ffwavesynth</a></li>

  73.     <li><a id="toc-libcelt" href="#libcelt">5.4 libcelt</a></li>

  74.     <li><a id="toc-libgsm" href="#libgsm">5.5 libgsm</a></li>

  75.     <li><a id="toc-libilbc" href="#libilbc">5.6 libilbc</a>

  76.     <ul class="no-bullet">

  77.       <li><a id="toc-Options-5" href="#Options-5">5.6.1 Options</a></li>

  78.     </ul></li>

  79.     <li><a id="toc-libopencore_002damrnb" href="#libopencore_002damrnb">5.7 libopencore-amrnb</a></li>

  80.     <li><a id="toc-libopencore_002damrwb" href="#libopencore_002damrwb">5.8 libopencore-amrwb</a></li>

  81.     <li><a id="toc-libopus" href="#libopus">5.9 libopus</a></li>

  82.   </ul></li>

  83.   <li><a id="toc-Subtitles-Decoders" href="#Subtitles-Decoders">6 Subtitles Decoders</a>

  84.   <ul class="no-bullet">

  85.     <li><a id="toc-libaribb24" href="#libaribb24">6.1 libaribb24</a>

  86.     <ul class="no-bullet">

  87.       <li><a id="toc-libaribb24-Decoder-Options" href="#libaribb24-Decoder-Options">6.1.1 libaribb24 Decoder Options</a></li>

  88.     </ul></li>

  89.     <li><a id="toc-dvbsub" href="#dvbsub">6.2 dvbsub</a>

  90.     <ul class="no-bullet">

  91.       <li><a id="toc-Options-6" href="#Options-6">6.2.1 Options</a></li>

  92.     </ul></li>

  93.     <li><a id="toc-dvdsub" href="#dvdsub">6.3 dvdsub</a>

  94.     <ul class="no-bullet">

  95.       <li><a id="toc-Options-7" href="#Options-7">6.3.1 Options</a></li>

  96.     </ul></li>

  97.     <li><a id="toc-libzvbi_002dteletext" href="#libzvbi_002dteletext">6.4 libzvbi-teletext</a>

  98.     <ul class="no-bullet">

  99.       <li><a id="toc-Options-8" href="#Options-8">6.4.1 Options</a></li>

  100.     </ul></li>

  101.   </ul></li>

  102.   <li><a id="toc-Encoders" href="#Encoders">7 Encoders</a></li>

  103.   <li><a id="toc-Audio-Encoders" href="#Audio-Encoders">8 Audio Encoders</a>

  104.   <ul class="no-bullet">

  105.     <li><a id="toc-aac" href="#aac">8.1 aac</a>

  106.     <ul class="no-bullet">

  107.       <li><a id="toc-Options-9" href="#Options-9">8.1.1 Options</a></li>

  108.     </ul></li>

  109.     <li><a id="toc-ac3-and-ac3_005ffixed" href="#ac3-and-ac3_005ffixed">8.2 ac3 and ac3_fixed</a>

  110.     <ul class="no-bullet">

  111.       <li><a id="toc-AC_002d3-Metadata" href="#AC_002d3-Metadata">8.2.1 AC-3 Metadata</a>

  112.       <ul class="no-bullet">

  113.         <li><a id="toc-Metadata-Control-Options" href="#Metadata-Control-Options">8.2.1.1 Metadata Control Options</a></li>

  114.         <li><a id="toc-Downmix-Levels" href="#Downmix-Levels">8.2.1.2 Downmix Levels</a></li>

  115.         <li><a id="toc-Audio-Production-Information" href="#Audio-Production-Information">8.2.1.3 Audio Production Information</a></li>

  116.         <li><a id="toc-Other-Metadata-Options" href="#Other-Metadata-Options">8.2.1.4 Other Metadata Options</a></li>

  117.       </ul></li>

  118.       <li><a id="toc-Extended-Bitstream-Information" href="#Extended-Bitstream-Information">8.2.2 Extended Bitstream Information</a>

  119.       <ul class="no-bullet">

  120.         <li><a id="toc-Extended-Bitstream-Information-_002d-Part-1" href="#Extended-Bitstream-Information-_002d-Part-1">8.2.2.1 Extended Bitstream Information - Part 1</a></li>

  121.         <li><a id="toc-Extended-Bitstream-Information-_002d-Part-2" href="#Extended-Bitstream-Information-_002d-Part-2">8.2.2.2 Extended Bitstream Information - Part 2</a></li>

  122.       </ul></li>

  123.       <li><a id="toc-Other-AC_002d3-Encoding-Options" href="#Other-AC_002d3-Encoding-Options">8.2.3 Other AC-3 Encoding Options</a></li>

  124.       <li><a id="toc-Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options" href="#Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options">8.2.4 Floating-Point-Only AC-3 Encoding Options</a></li>

  125.     </ul></li>

  126.     <li><a id="toc-flac-2" href="#flac-2">8.3 flac</a>

  127.     <ul class="no-bullet">

  128.       <li><a id="toc-Options-10" href="#Options-10">8.3.1 Options</a></li>

  129.     </ul></li>

  130.     <li><a id="toc-opus" href="#opus">8.4 opus</a>

  131.     <ul class="no-bullet">

  132.       <li><a id="toc-Options-11" href="#Options-11">8.4.1 Options</a></li>

  133.     </ul></li>

  134.     <li><a id="toc-libfdk_005faac" href="#libfdk_005faac">8.5 libfdk_aac</a>

  135.     <ul class="no-bullet">

  136.       <li><a id="toc-Options-12" href="#Options-12">8.5.1 Options</a></li>

  137.       <li><a id="toc-Examples" href="#Examples">8.5.2 Examples</a></li>

  138.     </ul></li>

  139.     <li><a id="toc-libmp3lame-1" href="#libmp3lame-1">8.6 libmp3lame</a>

  140.     <ul class="no-bullet">

  141.       <li><a id="toc-Options-13" href="#Options-13">8.6.1 Options</a></li>

  142.     </ul></li>

  143.     <li><a id="toc-libopencore_002damrnb-1" href="#libopencore_002damrnb-1">8.7 libopencore-amrnb</a>

  144.     <ul class="no-bullet">

  145.       <li><a id="toc-Options-14" href="#Options-14">8.7.1 Options</a></li>

  146.     </ul></li>

  147.     <li><a id="toc-libopus-1" href="#libopus-1">8.8 libopus</a>

  148.     <ul class="no-bullet">

  149.       <li><a id="toc-Option-Mapping" href="#Option-Mapping">8.8.1 Option Mapping</a></li>

  150.     </ul></li>

  151.     <li><a id="toc-libshine-1" href="#libshine-1">8.9 libshine</a>

  152.     <ul class="no-bullet">

  153.       <li><a id="toc-Options-15" href="#Options-15">8.9.1 Options</a></li>

  154.     </ul></li>

  155.     <li><a id="toc-libtwolame" href="#libtwolame">8.10 libtwolame</a>

  156.     <ul class="no-bullet">

  157.       <li><a id="toc-Options-16" href="#Options-16">8.10.1 Options</a></li>

  158.     </ul></li>

  159.     <li><a id="toc-libvo_002damrwbenc" href="#libvo_002damrwbenc">8.11 libvo-amrwbenc</a>

  160.     <ul class="no-bullet">

  161.       <li><a id="toc-Options-17" href="#Options-17">8.11.1 Options</a></li>

  162.     </ul></li>

  163.     <li><a id="toc-libvorbis" href="#libvorbis">8.12 libvorbis</a>

  164.     <ul class="no-bullet">

  165.       <li><a id="toc-Options-18" href="#Options-18">8.12.1 Options</a></li>

  166.     </ul></li>

  167.     <li><a id="toc-mjpeg" href="#mjpeg">8.13 mjpeg</a>

  168.     <ul class="no-bullet">

  169.       <li><a id="toc-Options-19" href="#Options-19">8.13.1 Options</a></li>

  170.     </ul></li>

  171.     <li><a id="toc-wavpack" href="#wavpack">8.14 wavpack</a>

  172.     <ul class="no-bullet">

  173.       <li><a id="toc-Options-20" href="#Options-20">8.14.1 Options</a>

  174.       <ul class="no-bullet">

  175.         <li><a id="toc-Shared-options" href="#Shared-options">8.14.1.1 Shared options</a></li>

  176.         <li><a id="toc-Private-options" href="#Private-options">8.14.1.2 Private options</a></li>

  177.       </ul></li>

  178.     </ul></li>

  179.   </ul></li>

  180.   <li><a id="toc-Video-Encoders" href="#Video-Encoders">9 Video Encoders</a>

  181.   <ul class="no-bullet">

  182.     <li><a id="toc-a64_005fmulti_002c-a64_005fmulti5" href="#a64_005fmulti_002c-a64_005fmulti5">9.1 a64_multi, a64_multi5</a></li>

  183.     <li><a id="toc-Cinepak" href="#Cinepak">9.2 Cinepak</a>

  184.     <ul class="no-bullet">

  185.       <li><a id="toc-Options-21" href="#Options-21">9.2.1 Options</a></li>

  186.     </ul></li>

  187.     <li><a id="toc-GIF" href="#GIF">9.3 GIF</a>

  188.     <ul class="no-bullet">

  189.       <li><a id="toc-Options-22" href="#Options-22">9.3.1 Options</a></li>

  190.     </ul></li>

  191.     <li><a id="toc-Hap" href="#Hap">9.4 Hap</a>

  192.     <ul class="no-bullet">

  193.       <li><a id="toc-Options-23" href="#Options-23">9.4.1 Options</a></li>

  194.     </ul></li>

  195.     <li><a id="toc-jpeg2000" href="#jpeg2000">9.5 jpeg2000</a>

  196.     <ul class="no-bullet">

  197.       <li><a id="toc-Options-24" href="#Options-24">9.5.1 Options</a></li>

  198.     </ul></li>

  199.     <li><a id="toc-librav1e" href="#librav1e">9.6 librav1e</a>

  200.     <ul class="no-bullet">

  201.       <li><a id="toc-Options-25" href="#Options-25">9.6.1 Options</a></li>

  202.     </ul></li>

  203.     <li><a id="toc-libaom_002dav1" href="#libaom_002dav1">9.7 libaom-av1</a>

  204.     <ul class="no-bullet">

  205.       <li><a id="toc-Options-26" href="#Options-26">9.7.1 Options</a></li>

  206.     </ul></li>

  207.     <li><a id="toc-libsvtav1" href="#libsvtav1">9.8 libsvtav1</a>

  208.     <ul class="no-bullet">

  209.       <li><a id="toc-Options-27" href="#Options-27">9.8.1 Options</a></li>

  210.     </ul></li>

  211.     <li><a id="toc-libjxl" href="#libjxl">9.9 libjxl</a>

  212.     <ul class="no-bullet">

  213.       <li><a id="toc-Options-28" href="#Options-28">9.9.1 Options</a></li>

  214.     </ul></li>

  215.     <li><a id="toc-libkvazaar" href="#libkvazaar">9.10 libkvazaar</a>

  216.     <ul class="no-bullet">

  217.       <li><a id="toc-Options-29" href="#Options-29">9.10.1 Options</a></li>

  218.     </ul></li>

  219.     <li><a id="toc-libopenh264" href="#libopenh264">9.11 libopenh264</a>

  220.     <ul class="no-bullet">

  221.       <li><a id="toc-Options-30" href="#Options-30">9.11.1 Options</a></li>

  222.     </ul></li>

  223.     <li><a id="toc-libtheora" href="#libtheora">9.12 libtheora</a>

  224.     <ul class="no-bullet">

  225.       <li><a id="toc-Options-31" href="#Options-31">9.12.1 Options</a></li>

  226.       <li><a id="toc-Examples-1" href="#Examples-1">9.12.2 Examples</a></li>

  227.     </ul></li>

  228.     <li><a id="toc-libvpx" href="#libvpx">9.13 libvpx</a>

  229.     <ul class="no-bullet">

  230.       <li><a id="toc-Options-32" href="#Options-32">9.13.1 Options</a></li>

  231.     </ul></li>

  232.     <li><a id="toc-libwebp" href="#libwebp">9.14 libwebp</a>

  233.     <ul class="no-bullet">

  234.       <li><a id="toc-Pixel-Format" href="#Pixel-Format">9.14.1 Pixel Format</a></li>

  235.       <li><a id="toc-Options-33" href="#Options-33">9.14.2 Options</a></li>

  236.     </ul></li>

  237.     <li><a id="toc-libx264_002c-libx264rgb" href="#libx264_002c-libx264rgb">9.15 libx264, libx264rgb</a>

  238.     <ul class="no-bullet">

  239.       <li><a id="toc-Supported-Pixel-Formats" href="#Supported-Pixel-Formats">9.15.1 Supported Pixel Formats</a></li>

  240.       <li><a id="toc-Options-34" href="#Options-34">9.15.2 Options</a></li>

  241.     </ul></li>

  242.     <li><a id="toc-libx265" href="#libx265">9.16 libx265</a>

  243.     <ul class="no-bullet">

  244.       <li><a id="toc-Options-35" href="#Options-35">9.16.1 Options</a></li>

  245.     </ul></li>

  246.     <li><a id="toc-libxavs2" href="#libxavs2">9.17 libxavs2</a>

  247.     <ul class="no-bullet">

  248.       <li><a id="toc-Options-36" href="#Options-36">9.17.1 Options</a></li>

  249.     </ul></li>

  250.     <li><a id="toc-libxvid" href="#libxvid">9.18 libxvid</a>

  251.     <ul class="no-bullet">

  252.       <li><a id="toc-Options-37" href="#Options-37">9.18.1 Options</a></li>

  253.     </ul></li>

  254.     <li><a id="toc-MediaFoundation" href="#MediaFoundation">9.19 MediaFoundation</a></li>

  255.     <li><a id="toc-mpeg2" href="#mpeg2">9.20 mpeg2</a>

  256.     <ul class="no-bullet">

  257.       <li><a id="toc-Options-38" href="#Options-38">9.20.1 Options</a></li>

  258.     </ul></li>

  259.     <li><a id="toc-png" href="#png">9.21 png</a>

  260.     <ul class="no-bullet">

  261.       <li><a id="toc-Private-options-1" href="#Private-options-1">9.21.1 Private options</a></li>

  262.     </ul></li>

  263.     <li><a id="toc-ProRes" href="#ProRes">9.22 ProRes</a>

  264.     <ul class="no-bullet">

  265.       <li><a id="toc-Private-Options-for-prores_002dks" href="#Private-Options-for-prores_002dks">9.22.1 Private Options for prores-ks</a></li>

  266.       <li><a id="toc-Speed-considerations" href="#Speed-considerations">9.22.2 Speed considerations</a></li>

  267.     </ul></li>

  268.     <li><a id="toc-QSV-Encoders" href="#QSV-Encoders">9.23 QSV Encoders</a>

  269.     <ul class="no-bullet">

  270.       <li><a id="toc-Ratecontrol-Method" href="#Ratecontrol-Method">9.23.1 Ratecontrol Method</a></li>

  271.       <li><a id="toc-Global-Options-_002d_003e-MSDK-Options" href="#Global-Options-_002d_003e-MSDK-Options">9.23.2 Global Options -&gt; MSDK Options</a></li>

  272.       <li><a id="toc-Common-Options-1" href="#Common-Options-1">9.23.3 Common Options</a></li>

  273.       <li><a id="toc-Runtime-Options" href="#Runtime-Options">9.23.4 Runtime Options</a></li>

  274.       <li><a id="toc-H264-options" href="#H264-options">9.23.5 H264 options</a></li>

  275.       <li><a id="toc-HEVC-Options-1" href="#HEVC-Options-1">9.23.6 HEVC Options</a></li>

  276.       <li><a id="toc-MPEG2-Options" href="#MPEG2-Options">9.23.7 MPEG2 Options</a></li>

  277.       <li><a id="toc-VP9-Options" href="#VP9-Options">9.23.8 VP9 Options</a></li>

  278.       <li><a id="toc-AV1-Options" href="#AV1-Options">9.23.9 AV1 Options</a></li>

  279.     </ul></li>

  280.     <li><a id="toc-snow" href="#snow">9.24 snow</a>

  281.     <ul class="no-bullet">

  282.       <li><a id="toc-Options-39" href="#Options-39">9.24.1 Options</a></li>

  283.     </ul></li>

  284.     <li><a id="toc-VAAPI-encoders" href="#VAAPI-encoders">9.25 VAAPI encoders</a></li>

  285.     <li><a id="toc-vbn" href="#vbn">9.26 vbn</a>

  286.     <ul class="no-bullet">

  287.       <li><a id="toc-Options-40" href="#Options-40">9.26.1 Options</a></li>

  288.     </ul></li>

  289.     <li><a id="toc-vc2" href="#vc2">9.27 vc2</a>

  290.     <ul class="no-bullet">

  291.       <li><a id="toc-Options-41" href="#Options-41">9.27.1 Options</a></li>

  292.     </ul></li>

  293.   </ul></li>

  294.   <li><a id="toc-Subtitles-Encoders" href="#Subtitles-Encoders">10 Subtitles Encoders</a>

  295.   <ul class="no-bullet">

  296.     <li><a id="toc-dvdsub-1" href="#dvdsub-1">10.1 dvdsub</a>

  297.     <ul class="no-bullet">

  298.       <li><a id="toc-Options-42" href="#Options-42">10.1.1 Options</a></li>

  299.     </ul></li>

  300.   </ul></li>

  301.   <li><a id="toc-See-Also" href="#See-Also">11 See Also</a></li>

  302.   <li><a id="toc-Authors" href="#Authors">12 Authors</a></li>

  303. </ul>

  304. </div>

  305. </div>

  306. 

  307. <a name="Description"></a>

  308. <h2 class="chapter">1 Description<span class="pull-right"><a class="anchor hidden-xs" href="#Description" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Description" aria-hidden="true">TOC</a></span></h2>

  309. 

  310. <p>This document describes the codecs (decoders and encoders) provided by

  311. the libavcodec library.

  312. </p>

  313. 

  314. <span id="codec_002doptions"></span><a name="Codec-Options"></a>

  315. <h2 class="chapter">2 Codec Options<span class="pull-right"><a class="anchor hidden-xs" href="#Codec-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Codec-Options" aria-hidden="true">TOC</a></span></h2>

  316. 

  317. <p>libavcodec provides some generic global options, which can be set on

  318. all the encoders and decoders. In addition each codec may support

  319. so-called private options, which are specific for a given codec.

  320. </p>

  321. <p>Sometimes, a global option may only affect a specific kind of codec,

  322. and may be nonsensical or ignored by another, so you need to be aware

  323. of the meaning of the specified options. Also some options are

  324. meant only for decoding or encoding.

  325. </p>

  326. <p>Options may be set by specifying -<var>option</var> <var>value</var> in the

  327. FFmpeg tools, or by setting the value explicitly in the

  328. <code>AVCodecContext</code> options or using the <samp>libavutil/opt.h</samp> API

  329. for programmatic use.

  330. </p>

  331. <p>The list of supported options follow:

  332. </p>

  333. <dl compact="compact">

  334. <dt><span><samp>b <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  335. <dd><p>Set bitrate in bits/s. Default value is 200K.

  336. </p>

  337. </dd>

  338. <dt><span><samp>ab <var>integer</var> (<em>encoding,audio</em>)</samp></span></dt>

  339. <dd><p>Set audio bitrate (in bits/s). Default value is 128K.

  340. </p>

  341. </dd>

  342. <dt><span><samp>bt <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  343. <dd><p>Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate

  344. tolerance specifies how far ratecontrol is willing to deviate from the

  345. target average bitrate value. This is not related to min/max

  346. bitrate. Lowering tolerance too much has an adverse effect on quality.

  347. </p>

  348. </dd>

  349. <dt><span><samp>flags <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp></span></dt>

  350. <dd><p>Set generic flags.

  351. </p>

  352. <p>Possible values:

  353. </p><dl compact="compact">

  354. <dt><span>&lsquo;<samp>mv4</samp>&rsquo;</span></dt>

  355. <dd><p>Use four motion vector by macroblock (mpeg4).

  356. </p></dd>

  357. <dt><span>&lsquo;<samp>qpel</samp>&rsquo;</span></dt>

  358. <dd><p>Use 1/4 pel motion compensation.

  359. </p></dd>

  360. <dt><span>&lsquo;<samp>loop</samp>&rsquo;</span></dt>

  361. <dd><p>Use loop filter.

  362. </p></dd>

  363. <dt><span>&lsquo;<samp>qscale</samp>&rsquo;</span></dt>

  364. <dd><p>Use fixed qscale.

  365. </p></dd>

  366. <dt><span>&lsquo;<samp>pass1</samp>&rsquo;</span></dt>

  367. <dd><p>Use internal 2pass ratecontrol in first pass mode.

  368. </p></dd>

  369. <dt><span>&lsquo;<samp>pass2</samp>&rsquo;</span></dt>

  370. <dd><p>Use internal 2pass ratecontrol in second pass mode.

  371. </p></dd>

  372. <dt><span>&lsquo;<samp>gray</samp>&rsquo;</span></dt>

  373. <dd><p>Only decode/encode grayscale.

  374. </p></dd>

  375. <dt><span>&lsquo;<samp>psnr</samp>&rsquo;</span></dt>

  376. <dd><p>Set error[?] variables during encoding.

  377. </p></dd>

  378. <dt><span>&lsquo;<samp>truncated</samp>&rsquo;</span></dt>

  379. <dd><p>Input bitstream might be randomly truncated.

  380. </p></dd>

  381. <dt><span>&lsquo;<samp>drop_changed</samp>&rsquo;</span></dt>

  382. <dd><p>Don&rsquo;t output frames whose parameters differ from first decoded frame in stream.

  383. Error AVERROR_INPUT_CHANGED is returned when a frame is dropped.

  384. </p>

  385. </dd>

  386. <dt><span>&lsquo;<samp>ildct</samp>&rsquo;</span></dt>

  387. <dd><p>Use interlaced DCT.

  388. </p></dd>

  389. <dt><span>&lsquo;<samp>low_delay</samp>&rsquo;</span></dt>

  390. <dd><p>Force low delay.

  391. </p></dd>

  392. <dt><span>&lsquo;<samp>global_header</samp>&rsquo;</span></dt>

  393. <dd><p>Place global headers in extradata instead of every keyframe.

  394. </p></dd>

  395. <dt><span>&lsquo;<samp>bitexact</samp>&rsquo;</span></dt>

  396. <dd><p>Only write platform-, build- and time-independent data. (except (I)DCT).

  397. This ensures that file and data checksums are reproducible and match between

  398. platforms. Its primary use is for regression testing.

  399. </p></dd>

  400. <dt><span>&lsquo;<samp>aic</samp>&rsquo;</span></dt>

  401. <dd><p>Apply H263 advanced intra coding / mpeg4 ac prediction.

  402. </p></dd>

  403. <dt><span>&lsquo;<samp>ilme</samp>&rsquo;</span></dt>

  404. <dd><p>Apply interlaced motion estimation.

  405. </p></dd>

  406. <dt><span>&lsquo;<samp>cgop</samp>&rsquo;</span></dt>

  407. <dd><p>Use closed gop.

  408. </p></dd>

  409. <dt><span>&lsquo;<samp>output_corrupt</samp>&rsquo;</span></dt>

  410. <dd><p>Output even potentially corrupted frames.

  411. </p></dd>

  412. </dl>

  413. 

  414. </dd>

  415. <dt><span><samp>time_base <var>rational number</var></samp></span></dt>

  416. <dd><p>Set codec time base.

  417. </p>

  418. <p>It is the fundamental unit of time (in seconds) in terms of which

  419. frame timestamps are represented. For fixed-fps content, timebase

  420. should be <code>1 / frame_rate</code> and timestamp increments should be

  421. identically 1.

  422. </p>

  423. </dd>

  424. <dt><span><samp>g <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  425. <dd><p>Set the group of picture (GOP) size. Default value is 12.

  426. </p>

  427. </dd>

  428. <dt><span><samp>ar <var>integer</var> (<em>decoding/encoding,audio</em>)</samp></span></dt>

  429. <dd><p>Set audio sampling rate (in Hz).

  430. </p>

  431. </dd>

  432. <dt><span><samp>ac <var>integer</var> (<em>decoding/encoding,audio</em>)</samp></span></dt>

  433. <dd><p>Set number of audio channels.

  434. </p>

  435. </dd>

  436. <dt><span><samp>cutoff <var>integer</var> (<em>encoding,audio</em>)</samp></span></dt>

  437. <dd><p>Set cutoff bandwidth. (Supported only by selected encoders, see

  438. their respective documentation sections.)

  439. </p>

  440. </dd>

  441. <dt><span><samp>frame_size <var>integer</var> (<em>encoding,audio</em>)</samp></span></dt>

  442. <dd><p>Set audio frame size.

  443. </p>

  444. <p>Each submitted frame except the last must contain exactly frame_size

  445. samples per channel. May be 0 when the codec has

  446. CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not

  447. restricted. It is set by some decoders to indicate constant frame

  448. size.

  449. </p>

  450. </dd>

  451. <dt><span><samp>frame_number <var>integer</var></samp></span></dt>

  452. <dd><p>Set the frame number.

  453. </p>

  454. </dd>

  455. <dt><span><samp>delay <var>integer</var></samp></span></dt>

  456. <dt><span><samp>qcomp <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  457. <dd><p>Set video quantizer scale compression (VBR). It is used as a constant

  458. in the ratecontrol equation. Recommended range for default rc_eq:

  459. 0.0-1.0.

  460. </p>

  461. </dd>

  462. <dt><span><samp>qblur <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  463. <dd><p>Set video quantizer scale blur (VBR).

  464. </p>

  465. </dd>

  466. <dt><span><samp>qmin <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  467. <dd><p>Set min video quantizer scale (VBR). Must be included between -1 and

  468. 69, default value is 2.

  469. </p>

  470. </dd>

  471. <dt><span><samp>qmax <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  472. <dd><p>Set max video quantizer scale (VBR). Must be included between -1 and

  473. 1024, default value is 31.

  474. </p>

  475. </dd>

  476. <dt><span><samp>qdiff <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  477. <dd><p>Set max difference between the quantizer scale (VBR).

  478. </p>

  479. </dd>

  480. <dt><span><samp>bf <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  481. <dd><p>Set max number of B frames between non-B-frames.

  482. </p>

  483. <p>Must be an integer between -1 and 16. 0 means that B-frames are

  484. disabled. If a value of -1 is used, it will choose an automatic value

  485. depending on the encoder.

  486. </p>

  487. <p>Default value is 0.

  488. </p>

  489. </dd>

  490. <dt><span><samp>b_qfactor <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  491. <dd><p>Set qp factor between P and B frames.

  492. </p>

  493. </dd>

  494. <dt><span><samp>codec_tag <var>integer</var></samp></span></dt>

  495. <dt><span><samp>bug <var>flags</var> (<em>decoding,video</em>)</samp></span></dt>

  496. <dd><p>Workaround not auto detected encoder bugs.

  497. </p>

  498. <p>Possible values:

  499. </p><dl compact="compact">

  500. <dt><span>&lsquo;<samp>autodetect</samp>&rsquo;</span></dt>

  501. <dt><span>&lsquo;<samp>xvid_ilace</samp>&rsquo;</span></dt>

  502. <dd><p>Xvid interlacing bug (autodetected if fourcc==XVIX)

  503. </p></dd>

  504. <dt><span>&lsquo;<samp>ump4</samp>&rsquo;</span></dt>

  505. <dd><p>(autodetected if fourcc==UMP4)

  506. </p></dd>

  507. <dt><span>&lsquo;<samp>no_padding</samp>&rsquo;</span></dt>

  508. <dd><p>padding bug (autodetected)

  509. </p></dd>

  510. <dt><span>&lsquo;<samp>amv</samp>&rsquo;</span></dt>

  511. <dt><span>&lsquo;<samp>qpel_chroma</samp>&rsquo;</span></dt>

  512. <dt><span>&lsquo;<samp>std_qpel</samp>&rsquo;</span></dt>

  513. <dd><p>old standard qpel (autodetected per fourcc/version)

  514. </p></dd>

  515. <dt><span>&lsquo;<samp>qpel_chroma2</samp>&rsquo;</span></dt>

  516. <dt><span>&lsquo;<samp>direct_blocksize</samp>&rsquo;</span></dt>

  517. <dd><p>direct-qpel-blocksize bug (autodetected per fourcc/version)

  518. </p></dd>

  519. <dt><span>&lsquo;<samp>edge</samp>&rsquo;</span></dt>

  520. <dd><p>edge padding bug (autodetected per fourcc/version)

  521. </p></dd>

  522. <dt><span>&lsquo;<samp>hpel_chroma</samp>&rsquo;</span></dt>

  523. <dt><span>&lsquo;<samp>dc_clip</samp>&rsquo;</span></dt>

  524. <dt><span>&lsquo;<samp>ms</samp>&rsquo;</span></dt>

  525. <dd><p>Workaround various bugs in microsoft broken decoders.

  526. </p></dd>

  527. <dt><span>&lsquo;<samp>trunc</samp>&rsquo;</span></dt>

  528. <dd><p>trancated frames

  529. </p></dd>

  530. </dl>

  531. 

  532. </dd>

  533. <dt><span><samp>strict <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp></span></dt>

  534. <dd><p>Specify how strictly to follow the standards.

  535. </p>

  536. <p>Possible values:

  537. </p><dl compact="compact">

  538. <dt><span>&lsquo;<samp>very</samp>&rsquo;</span></dt>

  539. <dd><p>strictly conform to an older more strict version of the spec or reference software

  540. </p></dd>

  541. <dt><span>&lsquo;<samp>strict</samp>&rsquo;</span></dt>

  542. <dd><p>strictly conform to all the things in the spec no matter what consequences

  543. </p></dd>

  544. <dt><span>&lsquo;<samp>normal</samp>&rsquo;</span></dt>

  545. <dt><span>&lsquo;<samp>unofficial</samp>&rsquo;</span></dt>

  546. <dd><p>allow unofficial extensions

  547. </p></dd>

  548. <dt><span>&lsquo;<samp>experimental</samp>&rsquo;</span></dt>

  549. <dd><p>allow non standardized experimental things, experimental

  550. (unfinished/work in progress/not well tested) decoders and encoders.

  551. Note: experimental decoders can pose a security risk, do not use this for

  552. decoding untrusted input.

  553. </p></dd>

  554. </dl>

  555. 

  556. </dd>

  557. <dt><span><samp>b_qoffset <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  558. <dd><p>Set QP offset between P and B frames.

  559. </p>

  560. </dd>

  561. <dt><span><samp>err_detect <var>flags</var> (<em>decoding,audio,video</em>)</samp></span></dt>

  562. <dd><p>Set error detection flags.

  563. </p>

  564. <p>Possible values:

  565. </p><dl compact="compact">

  566. <dt><span>&lsquo;<samp>crccheck</samp>&rsquo;</span></dt>

  567. <dd><p>verify embedded CRCs

  568. </p></dd>

  569. <dt><span>&lsquo;<samp>bitstream</samp>&rsquo;</span></dt>

  570. <dd><p>detect bitstream specification deviations

  571. </p></dd>

  572. <dt><span>&lsquo;<samp>buffer</samp>&rsquo;</span></dt>

  573. <dd><p>detect improper bitstream length

  574. </p></dd>

  575. <dt><span>&lsquo;<samp>explode</samp>&rsquo;</span></dt>

  576. <dd><p>abort decoding on minor error detection

  577. </p></dd>

  578. <dt><span>&lsquo;<samp>ignore_err</samp>&rsquo;</span></dt>

  579. <dd><p>ignore decoding errors, and continue decoding.

  580. This is useful if you want to analyze the content of a video and thus want

  581. everything to be decoded no matter what. This option will not result in a video

  582. that is pleasing to watch in case of errors.

  583. </p></dd>

  584. <dt><span>&lsquo;<samp>careful</samp>&rsquo;</span></dt>

  585. <dd><p>consider things that violate the spec and have not been seen in the wild as errors

  586. </p></dd>

  587. <dt><span>&lsquo;<samp>compliant</samp>&rsquo;</span></dt>

  588. <dd><p>consider all spec non compliancies as errors

  589. </p></dd>

  590. <dt><span>&lsquo;<samp>aggressive</samp>&rsquo;</span></dt>

  591. <dd><p>consider things that a sane encoder should not do as an error

  592. </p></dd>

  593. </dl>

  594. 

  595. </dd>

  596. <dt><span><samp>has_b_frames <var>integer</var></samp></span></dt>

  597. <dt><span><samp>block_align <var>integer</var></samp></span></dt>

  598. <dt><span><samp>rc_override_count <var>integer</var></samp></span></dt>

  599. <dt><span><samp>maxrate <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  600. <dd><p>Set max bitrate tolerance (in bits/s). Requires bufsize to be set.

  601. </p>

  602. </dd>

  603. <dt><span><samp>minrate <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  604. <dd><p>Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR

  605. encode. It is of little use elsewise.

  606. </p>

  607. </dd>

  608. <dt><span><samp>bufsize <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  609. <dd><p>Set ratecontrol buffer size (in bits).

  610. </p>

  611. </dd>

  612. <dt><span><samp>i_qfactor <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  613. <dd><p>Set QP factor between P and I frames.

  614. </p>

  615. </dd>

  616. <dt><span><samp>i_qoffset <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  617. <dd><p>Set QP offset between P and I frames.

  618. </p>

  619. </dd>

  620. <dt><span><samp>dct <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  621. <dd><p>Set DCT algorithm.

  622. </p>

  623. <p>Possible values:

  624. </p><dl compact="compact">

  625. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  626. <dd><p>autoselect a good one (default)

  627. </p></dd>

  628. <dt><span>&lsquo;<samp>fastint</samp>&rsquo;</span></dt>

  629. <dd><p>fast integer

  630. </p></dd>

  631. <dt><span>&lsquo;<samp>int</samp>&rsquo;</span></dt>

  632. <dd><p>accurate integer

  633. </p></dd>

  634. <dt><span>&lsquo;<samp>mmx</samp>&rsquo;</span></dt>

  635. <dt><span>&lsquo;<samp>altivec</samp>&rsquo;</span></dt>

  636. <dt><span>&lsquo;<samp>faan</samp>&rsquo;</span></dt>

  637. <dd><p>floating point AAN DCT

  638. </p></dd>

  639. </dl>

  640. 

  641. </dd>

  642. <dt><span><samp>lumi_mask <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  643. <dd><p>Compress bright areas stronger than medium ones.

  644. </p>

  645. </dd>

  646. <dt><span><samp>tcplx_mask <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  647. <dd><p>Set temporal complexity masking.

  648. </p>

  649. </dd>

  650. <dt><span><samp>scplx_mask <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  651. <dd><p>Set spatial complexity masking.

  652. </p>

  653. </dd>

  654. <dt><span><samp>p_mask <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  655. <dd><p>Set inter masking.

  656. </p>

  657. </dd>

  658. <dt><span><samp>dark_mask <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  659. <dd><p>Compress dark areas stronger than medium ones.

  660. </p>

  661. </dd>

  662. <dt><span><samp>idct <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  663. <dd><p>Select IDCT implementation.

  664. </p>

  665. <p>Possible values:

  666. </p><dl compact="compact">

  667. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  668. <dt><span>&lsquo;<samp>int</samp>&rsquo;</span></dt>

  669. <dt><span>&lsquo;<samp>simple</samp>&rsquo;</span></dt>

  670. <dt><span>&lsquo;<samp>simplemmx</samp>&rsquo;</span></dt>

  671. <dt><span>&lsquo;<samp>simpleauto</samp>&rsquo;</span></dt>

  672. <dd><p>Automatically pick a IDCT compatible with the simple one

  673. </p>

  674. </dd>

  675. <dt><span>&lsquo;<samp>arm</samp>&rsquo;</span></dt>

  676. <dt><span>&lsquo;<samp>altivec</samp>&rsquo;</span></dt>

  677. <dt><span>&lsquo;<samp>sh4</samp>&rsquo;</span></dt>

  678. <dt><span>&lsquo;<samp>simplearm</samp>&rsquo;</span></dt>

  679. <dt><span>&lsquo;<samp>simplearmv5te</samp>&rsquo;</span></dt>

  680. <dt><span>&lsquo;<samp>simplearmv6</samp>&rsquo;</span></dt>

  681. <dt><span>&lsquo;<samp>simpleneon</samp>&rsquo;</span></dt>

  682. <dt><span>&lsquo;<samp>xvid</samp>&rsquo;</span></dt>

  683. <dt><span>&lsquo;<samp>faani</samp>&rsquo;</span></dt>

  684. <dd><p>floating point AAN IDCT

  685. </p></dd>

  686. </dl>

  687. 

  688. </dd>

  689. <dt><span><samp>slice_count <var>integer</var></samp></span></dt>

  690. <dt><span><samp>ec <var>flags</var> (<em>decoding,video</em>)</samp></span></dt>

  691. <dd><p>Set error concealment strategy.

  692. </p>

  693. <p>Possible values:

  694. </p><dl compact="compact">

  695. <dt><span>&lsquo;<samp>guess_mvs</samp>&rsquo;</span></dt>

  696. <dd><p>iterative motion vector (MV) search (slow)

  697. </p></dd>

  698. <dt><span>&lsquo;<samp>deblock</samp>&rsquo;</span></dt>

  699. <dd><p>use strong deblock filter for damaged MBs

  700. </p></dd>

  701. <dt><span>&lsquo;<samp>favor_inter</samp>&rsquo;</span></dt>

  702. <dd><p>favor predicting from the previous frame instead of the current

  703. </p></dd>

  704. </dl>

  705. 

  706. </dd>

  707. <dt><span><samp>bits_per_coded_sample <var>integer</var></samp></span></dt>

  708. <dt><span><samp>aspect <var>rational number</var> (<em>encoding,video</em>)</samp></span></dt>

  709. <dd><p>Set sample aspect ratio.

  710. </p>

  711. </dd>

  712. <dt><span><samp>sar <var>rational number</var> (<em>encoding,video</em>)</samp></span></dt>

  713. <dd><p>Set sample aspect ratio. Alias to <var>aspect</var>.

  714. </p>

  715. </dd>

  716. <dt><span><samp>debug <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp></span></dt>

  717. <dd><p>Print specific debug info.

  718. </p>

  719. <p>Possible values:

  720. </p><dl compact="compact">

  721. <dt><span>&lsquo;<samp>pict</samp>&rsquo;</span></dt>

  722. <dd><p>picture info

  723. </p></dd>

  724. <dt><span>&lsquo;<samp>rc</samp>&rsquo;</span></dt>

  725. <dd><p>rate control

  726. </p></dd>

  727. <dt><span>&lsquo;<samp>bitstream</samp>&rsquo;</span></dt>

  728. <dt><span>&lsquo;<samp>mb_type</samp>&rsquo;</span></dt>

  729. <dd><p>macroblock (MB) type

  730. </p></dd>

  731. <dt><span>&lsquo;<samp>qp</samp>&rsquo;</span></dt>

  732. <dd><p>per-block quantization parameter (QP)

  733. </p></dd>

  734. <dt><span>&lsquo;<samp>dct_coeff</samp>&rsquo;</span></dt>

  735. <dt><span>&lsquo;<samp>green_metadata</samp>&rsquo;</span></dt>

  736. <dd><p>display complexity metadata for the upcoming frame, GoP or for a given duration.

  737. </p>

  738. </dd>

  739. <dt><span>&lsquo;<samp>skip</samp>&rsquo;</span></dt>

  740. <dt><span>&lsquo;<samp>startcode</samp>&rsquo;</span></dt>

  741. <dt><span>&lsquo;<samp>er</samp>&rsquo;</span></dt>

  742. <dd><p>error recognition

  743. </p></dd>

  744. <dt><span>&lsquo;<samp>mmco</samp>&rsquo;</span></dt>

  745. <dd><p>memory management control operations (H.264)

  746. </p></dd>

  747. <dt><span>&lsquo;<samp>bugs</samp>&rsquo;</span></dt>

  748. <dt><span>&lsquo;<samp>buffers</samp>&rsquo;</span></dt>

  749. <dd><p>picture buffer allocations

  750. </p></dd>

  751. <dt><span>&lsquo;<samp>thread_ops</samp>&rsquo;</span></dt>

  752. <dd><p>threading operations

  753. </p></dd>

  754. <dt><span>&lsquo;<samp>nomc</samp>&rsquo;</span></dt>

  755. <dd><p>skip motion compensation

  756. </p></dd>

  757. </dl>

  758. 

  759. </dd>

  760. <dt><span><samp>cmp <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  761. <dd><p>Set full pel me compare function.

  762. </p>

  763. <p>Possible values:

  764. </p><dl compact="compact">

  765. <dt><span>&lsquo;<samp>sad</samp>&rsquo;</span></dt>

  766. <dd><p>sum of absolute differences, fast (default)

  767. </p></dd>

  768. <dt><span>&lsquo;<samp>sse</samp>&rsquo;</span></dt>

  769. <dd><p>sum of squared errors

  770. </p></dd>

  771. <dt><span>&lsquo;<samp>satd</samp>&rsquo;</span></dt>

  772. <dd><p>sum of absolute Hadamard transformed differences

  773. </p></dd>

  774. <dt><span>&lsquo;<samp>dct</samp>&rsquo;</span></dt>

  775. <dd><p>sum of absolute DCT transformed differences

  776. </p></dd>

  777. <dt><span>&lsquo;<samp>psnr</samp>&rsquo;</span></dt>

  778. <dd><p>sum of squared quantization errors (avoid, low quality)

  779. </p></dd>

  780. <dt><span>&lsquo;<samp>bit</samp>&rsquo;</span></dt>

  781. <dd><p>number of bits needed for the block

  782. </p></dd>

  783. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  784. <dd><p>rate distortion optimal, slow

  785. </p></dd>

  786. <dt><span>&lsquo;<samp>zero</samp>&rsquo;</span></dt>

  787. <dd><p>0

  788. </p></dd>

  789. <dt><span>&lsquo;<samp>vsad</samp>&rsquo;</span></dt>

  790. <dd><p>sum of absolute vertical differences

  791. </p></dd>

  792. <dt><span>&lsquo;<samp>vsse</samp>&rsquo;</span></dt>

  793. <dd><p>sum of squared vertical differences

  794. </p></dd>

  795. <dt><span>&lsquo;<samp>nsse</samp>&rsquo;</span></dt>

  796. <dd><p>noise preserving sum of squared differences

  797. </p></dd>

  798. <dt><span>&lsquo;<samp>w53</samp>&rsquo;</span></dt>

  799. <dd><p>5/3 wavelet, only used in snow

  800. </p></dd>

  801. <dt><span>&lsquo;<samp>w97</samp>&rsquo;</span></dt>

  802. <dd><p>9/7 wavelet, only used in snow

  803. </p></dd>

  804. <dt><span>&lsquo;<samp>dctmax</samp>&rsquo;</span></dt>

  805. <dt><span>&lsquo;<samp>chroma</samp>&rsquo;</span></dt>

  806. </dl>

  807. 

  808. </dd>

  809. <dt><span><samp>subcmp <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  810. <dd><p>Set sub pel me compare function.

  811. </p>

  812. <p>Possible values:

  813. </p><dl compact="compact">

  814. <dt><span>&lsquo;<samp>sad</samp>&rsquo;</span></dt>

  815. <dd><p>sum of absolute differences, fast (default)

  816. </p></dd>

  817. <dt><span>&lsquo;<samp>sse</samp>&rsquo;</span></dt>

  818. <dd><p>sum of squared errors

  819. </p></dd>

  820. <dt><span>&lsquo;<samp>satd</samp>&rsquo;</span></dt>

  821. <dd><p>sum of absolute Hadamard transformed differences

  822. </p></dd>

  823. <dt><span>&lsquo;<samp>dct</samp>&rsquo;</span></dt>

  824. <dd><p>sum of absolute DCT transformed differences

  825. </p></dd>

  826. <dt><span>&lsquo;<samp>psnr</samp>&rsquo;</span></dt>

  827. <dd><p>sum of squared quantization errors (avoid, low quality)

  828. </p></dd>

  829. <dt><span>&lsquo;<samp>bit</samp>&rsquo;</span></dt>

  830. <dd><p>number of bits needed for the block

  831. </p></dd>

  832. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  833. <dd><p>rate distortion optimal, slow

  834. </p></dd>

  835. <dt><span>&lsquo;<samp>zero</samp>&rsquo;</span></dt>

  836. <dd><p>0

  837. </p></dd>

  838. <dt><span>&lsquo;<samp>vsad</samp>&rsquo;</span></dt>

  839. <dd><p>sum of absolute vertical differences

  840. </p></dd>

  841. <dt><span>&lsquo;<samp>vsse</samp>&rsquo;</span></dt>

  842. <dd><p>sum of squared vertical differences

  843. </p></dd>

  844. <dt><span>&lsquo;<samp>nsse</samp>&rsquo;</span></dt>

  845. <dd><p>noise preserving sum of squared differences

  846. </p></dd>

  847. <dt><span>&lsquo;<samp>w53</samp>&rsquo;</span></dt>

  848. <dd><p>5/3 wavelet, only used in snow

  849. </p></dd>

  850. <dt><span>&lsquo;<samp>w97</samp>&rsquo;</span></dt>

  851. <dd><p>9/7 wavelet, only used in snow

  852. </p></dd>

  853. <dt><span>&lsquo;<samp>dctmax</samp>&rsquo;</span></dt>

  854. <dt><span>&lsquo;<samp>chroma</samp>&rsquo;</span></dt>

  855. </dl>

  856. 

  857. </dd>

  858. <dt><span><samp>mbcmp <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  859. <dd><p>Set macroblock compare function.

  860. </p>

  861. <p>Possible values:

  862. </p><dl compact="compact">

  863. <dt><span>&lsquo;<samp>sad</samp>&rsquo;</span></dt>

  864. <dd><p>sum of absolute differences, fast (default)

  865. </p></dd>

  866. <dt><span>&lsquo;<samp>sse</samp>&rsquo;</span></dt>

  867. <dd><p>sum of squared errors

  868. </p></dd>

  869. <dt><span>&lsquo;<samp>satd</samp>&rsquo;</span></dt>

  870. <dd><p>sum of absolute Hadamard transformed differences

  871. </p></dd>

  872. <dt><span>&lsquo;<samp>dct</samp>&rsquo;</span></dt>

  873. <dd><p>sum of absolute DCT transformed differences

  874. </p></dd>

  875. <dt><span>&lsquo;<samp>psnr</samp>&rsquo;</span></dt>

  876. <dd><p>sum of squared quantization errors (avoid, low quality)

  877. </p></dd>

  878. <dt><span>&lsquo;<samp>bit</samp>&rsquo;</span></dt>

  879. <dd><p>number of bits needed for the block

  880. </p></dd>

  881. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  882. <dd><p>rate distortion optimal, slow

  883. </p></dd>

  884. <dt><span>&lsquo;<samp>zero</samp>&rsquo;</span></dt>

  885. <dd><p>0

  886. </p></dd>

  887. <dt><span>&lsquo;<samp>vsad</samp>&rsquo;</span></dt>

  888. <dd><p>sum of absolute vertical differences

  889. </p></dd>

  890. <dt><span>&lsquo;<samp>vsse</samp>&rsquo;</span></dt>

  891. <dd><p>sum of squared vertical differences

  892. </p></dd>

  893. <dt><span>&lsquo;<samp>nsse</samp>&rsquo;</span></dt>

  894. <dd><p>noise preserving sum of squared differences

  895. </p></dd>

  896. <dt><span>&lsquo;<samp>w53</samp>&rsquo;</span></dt>

  897. <dd><p>5/3 wavelet, only used in snow

  898. </p></dd>

  899. <dt><span>&lsquo;<samp>w97</samp>&rsquo;</span></dt>

  900. <dd><p>9/7 wavelet, only used in snow

  901. </p></dd>

  902. <dt><span>&lsquo;<samp>dctmax</samp>&rsquo;</span></dt>

  903. <dt><span>&lsquo;<samp>chroma</samp>&rsquo;</span></dt>

  904. </dl>

  905. 

  906. </dd>

  907. <dt><span><samp>ildctcmp <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  908. <dd><p>Set interlaced dct compare function.

  909. </p>

  910. <p>Possible values:

  911. </p><dl compact="compact">

  912. <dt><span>&lsquo;<samp>sad</samp>&rsquo;</span></dt>

  913. <dd><p>sum of absolute differences, fast (default)

  914. </p></dd>

  915. <dt><span>&lsquo;<samp>sse</samp>&rsquo;</span></dt>

  916. <dd><p>sum of squared errors

  917. </p></dd>

  918. <dt><span>&lsquo;<samp>satd</samp>&rsquo;</span></dt>

  919. <dd><p>sum of absolute Hadamard transformed differences

  920. </p></dd>

  921. <dt><span>&lsquo;<samp>dct</samp>&rsquo;</span></dt>

  922. <dd><p>sum of absolute DCT transformed differences

  923. </p></dd>

  924. <dt><span>&lsquo;<samp>psnr</samp>&rsquo;</span></dt>

  925. <dd><p>sum of squared quantization errors (avoid, low quality)

  926. </p></dd>

  927. <dt><span>&lsquo;<samp>bit</samp>&rsquo;</span></dt>

  928. <dd><p>number of bits needed for the block

  929. </p></dd>

  930. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  931. <dd><p>rate distortion optimal, slow

  932. </p></dd>

  933. <dt><span>&lsquo;<samp>zero</samp>&rsquo;</span></dt>

  934. <dd><p>0

  935. </p></dd>

  936. <dt><span>&lsquo;<samp>vsad</samp>&rsquo;</span></dt>

  937. <dd><p>sum of absolute vertical differences

  938. </p></dd>

  939. <dt><span>&lsquo;<samp>vsse</samp>&rsquo;</span></dt>

  940. <dd><p>sum of squared vertical differences

  941. </p></dd>

  942. <dt><span>&lsquo;<samp>nsse</samp>&rsquo;</span></dt>

  943. <dd><p>noise preserving sum of squared differences

  944. </p></dd>

  945. <dt><span>&lsquo;<samp>w53</samp>&rsquo;</span></dt>

  946. <dd><p>5/3 wavelet, only used in snow

  947. </p></dd>

  948. <dt><span>&lsquo;<samp>w97</samp>&rsquo;</span></dt>

  949. <dd><p>9/7 wavelet, only used in snow

  950. </p></dd>

  951. <dt><span>&lsquo;<samp>dctmax</samp>&rsquo;</span></dt>

  952. <dt><span>&lsquo;<samp>chroma</samp>&rsquo;</span></dt>

  953. </dl>

  954. 

  955. </dd>

  956. <dt><span><samp>dia_size <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  957. <dd><p>Set diamond type &amp; size for motion estimation.

  958. </p><dl compact="compact">

  959. <dt><span>&lsquo;<samp>(1024, INT_MAX)</samp>&rsquo;</span></dt>

  960. <dd><p>full motion estimation(slowest)

  961. </p></dd>

  962. <dt><span>&lsquo;<samp>(768, 1024]</samp>&rsquo;</span></dt>

  963. <dd><p>umh motion estimation

  964. </p></dd>

  965. <dt><span>&lsquo;<samp>(512, 768]</samp>&rsquo;</span></dt>

  966. <dd><p>hex motion estimation

  967. </p></dd>

  968. <dt><span>&lsquo;<samp>(256, 512]</samp>&rsquo;</span></dt>

  969. <dd><p>l2s diamond motion estimation

  970. </p></dd>

  971. <dt><span>&lsquo;<samp>[2,256]</samp>&rsquo;</span></dt>

  972. <dd><p>var diamond motion estimation

  973. </p></dd>

  974. <dt><span>&lsquo;<samp>(-1,  2)</samp>&rsquo;</span></dt>

  975. <dd><p>small diamond motion estimation

  976. </p></dd>

  977. <dt><span>&lsquo;<samp>-1</samp>&rsquo;</span></dt>

  978. <dd><p>funny diamond motion estimation

  979. </p></dd>

  980. <dt><span>&lsquo;<samp>(INT_MIN, -1)</samp>&rsquo;</span></dt>

  981. <dd><p>sab diamond motion estimation

  982. </p></dd>

  983. </dl>

  984. 

  985. </dd>

  986. <dt><span><samp>last_pred <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  987. <dd><p>Set amount of motion predictors from the previous frame.

  988. </p>

  989. </dd>

  990. <dt><span><samp>precmp <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  991. <dd><p>Set pre motion estimation compare function.

  992. </p>

  993. <p>Possible values:

  994. </p><dl compact="compact">

  995. <dt><span>&lsquo;<samp>sad</samp>&rsquo;</span></dt>

  996. <dd><p>sum of absolute differences, fast (default)

  997. </p></dd>

  998. <dt><span>&lsquo;<samp>sse</samp>&rsquo;</span></dt>

  999. <dd><p>sum of squared errors

  1000. </p></dd>

  1001. <dt><span>&lsquo;<samp>satd</samp>&rsquo;</span></dt>

  1002. <dd><p>sum of absolute Hadamard transformed differences

  1003. </p></dd>

  1004. <dt><span>&lsquo;<samp>dct</samp>&rsquo;</span></dt>

  1005. <dd><p>sum of absolute DCT transformed differences

  1006. </p></dd>

  1007. <dt><span>&lsquo;<samp>psnr</samp>&rsquo;</span></dt>

  1008. <dd><p>sum of squared quantization errors (avoid, low quality)

  1009. </p></dd>

  1010. <dt><span>&lsquo;<samp>bit</samp>&rsquo;</span></dt>

  1011. <dd><p>number of bits needed for the block

  1012. </p></dd>

  1013. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  1014. <dd><p>rate distortion optimal, slow

  1015. </p></dd>

  1016. <dt><span>&lsquo;<samp>zero</samp>&rsquo;</span></dt>

  1017. <dd><p>0

  1018. </p></dd>

  1019. <dt><span>&lsquo;<samp>vsad</samp>&rsquo;</span></dt>

  1020. <dd><p>sum of absolute vertical differences

  1021. </p></dd>

  1022. <dt><span>&lsquo;<samp>vsse</samp>&rsquo;</span></dt>

  1023. <dd><p>sum of squared vertical differences

  1024. </p></dd>

  1025. <dt><span>&lsquo;<samp>nsse</samp>&rsquo;</span></dt>

  1026. <dd><p>noise preserving sum of squared differences

  1027. </p></dd>

  1028. <dt><span>&lsquo;<samp>w53</samp>&rsquo;</span></dt>

  1029. <dd><p>5/3 wavelet, only used in snow

  1030. </p></dd>

  1031. <dt><span>&lsquo;<samp>w97</samp>&rsquo;</span></dt>

  1032. <dd><p>9/7 wavelet, only used in snow

  1033. </p></dd>

  1034. <dt><span>&lsquo;<samp>dctmax</samp>&rsquo;</span></dt>

  1035. <dt><span>&lsquo;<samp>chroma</samp>&rsquo;</span></dt>

  1036. </dl>

  1037. 

  1038. </dd>

  1039. <dt><span><samp>pre_dia_size <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1040. <dd><p>Set diamond type &amp; size for motion estimation pre-pass.

  1041. </p>

  1042. </dd>

  1043. <dt><span><samp>subq <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1044. <dd><p>Set sub pel motion estimation quality.

  1045. </p>

  1046. </dd>

  1047. <dt><span><samp>me_range <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1048. <dd><p>Set limit motion vectors range (1023 for DivX player).

  1049. </p>

  1050. </dd>

  1051. <dt><span><samp>global_quality <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  1052. <dt><span><samp>slice_flags <var>integer</var></samp></span></dt>

  1053. <dt><span><samp>mbd <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1054. <dd><p>Set macroblock decision algorithm (high quality mode).

  1055. </p>

  1056. <p>Possible values:

  1057. </p><dl compact="compact">

  1058. <dt><span>&lsquo;<samp>simple</samp>&rsquo;</span></dt>

  1059. <dd><p>use mbcmp (default)

  1060. </p></dd>

  1061. <dt><span>&lsquo;<samp>bits</samp>&rsquo;</span></dt>

  1062. <dd><p>use fewest bits

  1063. </p></dd>

  1064. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  1065. <dd><p>use best rate distortion

  1066. </p></dd>

  1067. </dl>

  1068. 

  1069. </dd>

  1070. <dt><span><samp>rc_init_occupancy <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1071. <dd><p>Set number of bits which should be loaded into the rc buffer before

  1072. decoding starts.

  1073. </p>

  1074. </dd>

  1075. <dt><span><samp>flags2 <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp></span></dt>

  1076. <dd>

  1077. <p>Possible values:

  1078. </p><dl compact="compact">

  1079. <dt><span>&lsquo;<samp>fast</samp>&rsquo;</span></dt>

  1080. <dd><p>Allow non spec compliant speedup tricks.

  1081. </p></dd>

  1082. <dt><span>&lsquo;<samp>noout</samp>&rsquo;</span></dt>

  1083. <dd><p>Skip bitstream encoding.

  1084. </p></dd>

  1085. <dt><span>&lsquo;<samp>ignorecrop</samp>&rsquo;</span></dt>

  1086. <dd><p>Ignore cropping information from sps.

  1087. </p></dd>

  1088. <dt><span>&lsquo;<samp>local_header</samp>&rsquo;</span></dt>

  1089. <dd><p>Place global headers at every keyframe instead of in extradata.

  1090. </p></dd>

  1091. <dt><span>&lsquo;<samp>chunks</samp>&rsquo;</span></dt>

  1092. <dd><p>Frame data might be split into multiple chunks.

  1093. </p></dd>

  1094. <dt><span>&lsquo;<samp>showall</samp>&rsquo;</span></dt>

  1095. <dd><p>Show all frames before the first keyframe.

  1096. </p></dd>

  1097. <dt><span>&lsquo;<samp>export_mvs</samp>&rsquo;</span></dt>

  1098. <dd><p>Export motion vectors into frame side-data (see <code>AV_FRAME_DATA_MOTION_VECTORS</code>)

  1099. for codecs that support it. See also <samp>doc/examples/export_mvs.c</samp>.

  1100. </p></dd>

  1101. <dt><span>&lsquo;<samp>skip_manual</samp>&rsquo;</span></dt>

  1102. <dd><p>Do not skip samples and export skip information as frame side data.

  1103. </p></dd>

  1104. <dt><span>&lsquo;<samp>ass_ro_flush_noop</samp>&rsquo;</span></dt>

  1105. <dd><p>Do not reset ASS ReadOrder field on flush.

  1106. </p></dd>

  1107. <dt><span>&lsquo;<samp>icc_profiles</samp>&rsquo;</span></dt>

  1108. <dd><p>Generate/parse embedded ICC profiles from/to colorimetry tags.

  1109. </p></dd>

  1110. </dl>

  1111. 

  1112. </dd>

  1113. <dt><span><samp>export_side_data <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp></span></dt>

  1114. <dd>

  1115. <p>Possible values:

  1116. </p><dl compact="compact">

  1117. <dt><span>&lsquo;<samp>mvs</samp>&rsquo;</span></dt>

  1118. <dd><p>Export motion vectors into frame side-data (see <code>AV_FRAME_DATA_MOTION_VECTORS</code>)

  1119. for codecs that support it. See also <samp>doc/examples/export_mvs.c</samp>.

  1120. </p></dd>

  1121. <dt><span>&lsquo;<samp>prft</samp>&rsquo;</span></dt>

  1122. <dd><p>Export encoder Producer Reference Time into packet side-data (see <code>AV_PKT_DATA_PRFT</code>)

  1123. for codecs that support it.

  1124. </p></dd>

  1125. <dt><span>&lsquo;<samp>venc_params</samp>&rsquo;</span></dt>

  1126. <dd><p>Export video encoding parameters through frame side data (see <code>AV_FRAME_DATA_VIDEO_ENC_PARAMS</code>)

  1127. for codecs that support it. At present, those are H.264 and VP9.

  1128. </p></dd>

  1129. <dt><span>&lsquo;<samp>film_grain</samp>&rsquo;</span></dt>

  1130. <dd><p>Export film grain parameters through frame side data (see <code>AV_FRAME_DATA_FILM_GRAIN_PARAMS</code>).

  1131. Supported at present by AV1 decoders.

  1132. </p></dd>

  1133. </dl>

  1134. 

  1135. </dd>

  1136. <dt><span><samp>threads <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1137. <dd><p>Set the number of threads to be used, in case the selected codec

  1138. implementation supports multi-threading.

  1139. </p>

  1140. <p>Possible values:

  1141. </p><dl compact="compact">

  1142. <dt><span>&lsquo;<samp>auto, 0</samp>&rsquo;</span></dt>

  1143. <dd><p>automatically select the number of threads to set

  1144. </p></dd>

  1145. </dl>

  1146. 

  1147. <p>Default value is &lsquo;<samp>auto</samp>&rsquo;.

  1148. </p>

  1149. </dd>

  1150. <dt><span><samp>dc <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1151. <dd><p>Set intra_dc_precision.

  1152. </p>

  1153. </dd>

  1154. <dt><span><samp>nssew <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1155. <dd><p>Set nsse weight.

  1156. </p>

  1157. </dd>

  1158. <dt><span><samp>skip_top <var>integer</var> (<em>decoding,video</em>)</samp></span></dt>

  1159. <dd><p>Set number of macroblock rows at the top which are skipped.

  1160. </p>

  1161. </dd>

  1162. <dt><span><samp>skip_bottom <var>integer</var> (<em>decoding,video</em>)</samp></span></dt>

  1163. <dd><p>Set number of macroblock rows at the bottom which are skipped.

  1164. </p>

  1165. </dd>

  1166. <dt><span><samp>profile <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  1167. <dd>

  1168. <p>Set encoder codec profile. Default value is &lsquo;<samp>unknown</samp>&rsquo;. Encoder specific

  1169. profiles are documented in the relevant encoder documentation.

  1170. </p>

  1171. </dd>

  1172. <dt><span><samp>level <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  1173. <dd>

  1174. <p>Possible values:

  1175. </p><dl compact="compact">

  1176. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  1177. </dl>

  1178. 

  1179. </dd>

  1180. <dt><span><samp>lowres <var>integer</var> (<em>decoding,audio,video</em>)</samp></span></dt>

  1181. <dd><p>Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.

  1182. </p>

  1183. </dd>

  1184. <dt><span><samp>mblmin <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1185. <dd><p>Set min macroblock lagrange factor (VBR).

  1186. </p>

  1187. </dd>

  1188. <dt><span><samp>mblmax <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1189. <dd><p>Set max macroblock lagrange factor (VBR).

  1190. </p>

  1191. </dd>

  1192. <dt><span><samp>skip_loop_filter <var>integer</var> (<em>decoding,video</em>)</samp></span></dt>

  1193. <dt><span><samp>skip_idct        <var>integer</var> (<em>decoding,video</em>)</samp></span></dt>

  1194. <dt><span><samp>skip_frame       <var>integer</var> (<em>decoding,video</em>)</samp></span></dt>

  1195. <dd>

  1196. <p>Make decoder discard processing depending on the frame type selected

  1197. by the option value.

  1198. </p>

  1199. <p><samp>skip_loop_filter</samp> skips frame loop filtering, <samp>skip_idct</samp>

  1200. skips frame IDCT/dequantization, <samp>skip_frame</samp> skips decoding.

  1201. </p>

  1202. <p>Possible values:

  1203. </p><dl compact="compact">

  1204. <dt><span>&lsquo;<samp>none</samp>&rsquo;</span></dt>

  1205. <dd><p>Discard no frame.

  1206. </p>

  1207. </dd>

  1208. <dt><span>&lsquo;<samp>default</samp>&rsquo;</span></dt>

  1209. <dd><p>Discard useless frames like 0-sized frames.

  1210. </p>

  1211. </dd>

  1212. <dt><span>&lsquo;<samp>noref</samp>&rsquo;</span></dt>

  1213. <dd><p>Discard all non-reference frames.

  1214. </p>

  1215. </dd>

  1216. <dt><span>&lsquo;<samp>bidir</samp>&rsquo;</span></dt>

  1217. <dd><p>Discard all bidirectional frames.

  1218. </p>

  1219. </dd>

  1220. <dt><span>&lsquo;<samp>nokey</samp>&rsquo;</span></dt>

  1221. <dd><p>Discard all frames excepts keyframes.

  1222. </p>

  1223. </dd>

  1224. <dt><span>&lsquo;<samp>nointra</samp>&rsquo;</span></dt>

  1225. <dd><p>Discard all frames except I frames.

  1226. </p>

  1227. </dd>

  1228. <dt><span>&lsquo;<samp>all</samp>&rsquo;</span></dt>

  1229. <dd><p>Discard all frames.

  1230. </p></dd>

  1231. </dl>

  1232. 

  1233. <p>Default value is &lsquo;<samp>default</samp>&rsquo;.

  1234. </p>

  1235. </dd>

  1236. <dt><span><samp>bidir_refine <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1237. <dd><p>Refine the two motion vectors used in bidirectional macroblocks.

  1238. </p>

  1239. </dd>

  1240. <dt><span><samp>keyint_min <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1241. <dd><p>Set minimum interval between IDR-frames.

  1242. </p>

  1243. </dd>

  1244. <dt><span><samp>refs <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1245. <dd><p>Set reference frames to consider for motion compensation.

  1246. </p>

  1247. </dd>

  1248. <dt><span><samp>trellis <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  1249. <dd><p>Set rate-distortion optimal quantization.

  1250. </p>

  1251. </dd>

  1252. <dt><span><samp>mv0_threshold <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1253. <dt><span><samp>compression_level <var>integer</var> (<em>encoding,audio,video</em>)</samp></span></dt>

  1254. <dt><span><samp>bits_per_raw_sample <var>integer</var></samp></span></dt>

  1255. <dt><span><samp>channel_layout <var>integer</var> (<em>decoding/encoding,audio</em>)</samp></span></dt>

  1256. <dd>

  1257. <p>Possible values:

  1258. </p></dd>

  1259. <dt><span><samp>request_channel_layout <var>integer</var> (<em>decoding,audio</em>)</samp></span></dt>

  1260. <dd>

  1261. <p>Possible values:

  1262. </p></dd>

  1263. <dt><span><samp>rc_max_vbv_use <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  1264. <dt><span><samp>rc_min_vbv_use <var>float</var> (<em>encoding,video</em>)</samp></span></dt>

  1265. <dt><span><samp>ticks_per_frame <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp></span></dt>

  1266. <dt><span><samp>color_primaries <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1267. <dd><p>Possible values:

  1268. </p><dl compact="compact">

  1269. <dt><span>&lsquo;<samp>bt709</samp>&rsquo;</span></dt>

  1270. <dd><p>BT.709

  1271. </p></dd>

  1272. <dt><span>&lsquo;<samp>bt470m</samp>&rsquo;</span></dt>

  1273. <dd><p>BT.470 M

  1274. </p></dd>

  1275. <dt><span>&lsquo;<samp>bt470bg</samp>&rsquo;</span></dt>

  1276. <dd><p>BT.470 BG

  1277. </p></dd>

  1278. <dt><span>&lsquo;<samp>smpte170m</samp>&rsquo;</span></dt>

  1279. <dd><p>SMPTE 170 M

  1280. </p></dd>

  1281. <dt><span>&lsquo;<samp>smpte240m</samp>&rsquo;</span></dt>

  1282. <dd><p>SMPTE 240 M

  1283. </p></dd>

  1284. <dt><span>&lsquo;<samp>film</samp>&rsquo;</span></dt>

  1285. <dd><p>Film

  1286. </p></dd>

  1287. <dt><span>&lsquo;<samp>bt2020</samp>&rsquo;</span></dt>

  1288. <dd><p>BT.2020

  1289. </p></dd>

  1290. <dt><span>&lsquo;<samp>smpte428</samp>&rsquo;</span></dt>

  1291. <dt><span>&lsquo;<samp>smpte428_1</samp>&rsquo;</span></dt>

  1292. <dd><p>SMPTE ST 428-1

  1293. </p></dd>

  1294. <dt><span>&lsquo;<samp>smpte431</samp>&rsquo;</span></dt>

  1295. <dd><p>SMPTE 431-2

  1296. </p></dd>

  1297. <dt><span>&lsquo;<samp>smpte432</samp>&rsquo;</span></dt>

  1298. <dd><p>SMPTE 432-1

  1299. </p></dd>

  1300. <dt><span>&lsquo;<samp>jedec-p22</samp>&rsquo;</span></dt>

  1301. <dd><p>JEDEC P22

  1302. </p></dd>

  1303. </dl>

  1304. 

  1305. </dd>

  1306. <dt><span><samp>color_trc <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1307. <dd><p>Possible values:

  1308. </p><dl compact="compact">

  1309. <dt><span>&lsquo;<samp>bt709</samp>&rsquo;</span></dt>

  1310. <dd><p>BT.709

  1311. </p></dd>

  1312. <dt><span>&lsquo;<samp>gamma22</samp>&rsquo;</span></dt>

  1313. <dd><p>BT.470 M

  1314. </p></dd>

  1315. <dt><span>&lsquo;<samp>gamma28</samp>&rsquo;</span></dt>

  1316. <dd><p>BT.470 BG

  1317. </p></dd>

  1318. <dt><span>&lsquo;<samp>smpte170m</samp>&rsquo;</span></dt>

  1319. <dd><p>SMPTE 170 M

  1320. </p></dd>

  1321. <dt><span>&lsquo;<samp>smpte240m</samp>&rsquo;</span></dt>

  1322. <dd><p>SMPTE 240 M

  1323. </p></dd>

  1324. <dt><span>&lsquo;<samp>linear</samp>&rsquo;</span></dt>

  1325. <dd><p>Linear

  1326. </p></dd>

  1327. <dt><span>&lsquo;<samp>log</samp>&rsquo;</span></dt>

  1328. <dt><span>&lsquo;<samp>log100</samp>&rsquo;</span></dt>

  1329. <dd><p>Log

  1330. </p></dd>

  1331. <dt><span>&lsquo;<samp>log_sqrt</samp>&rsquo;</span></dt>

  1332. <dt><span>&lsquo;<samp>log316</samp>&rsquo;</span></dt>

  1333. <dd><p>Log square root

  1334. </p></dd>

  1335. <dt><span>&lsquo;<samp>iec61966_2_4</samp>&rsquo;</span></dt>

  1336. <dt><span>&lsquo;<samp>iec61966-2-4</samp>&rsquo;</span></dt>

  1337. <dd><p>IEC 61966-2-4

  1338. </p></dd>

  1339. <dt><span>&lsquo;<samp>bt1361</samp>&rsquo;</span></dt>

  1340. <dt><span>&lsquo;<samp>bt1361e</samp>&rsquo;</span></dt>

  1341. <dd><p>BT.1361

  1342. </p></dd>

  1343. <dt><span>&lsquo;<samp>iec61966_2_1</samp>&rsquo;</span></dt>

  1344. <dt><span>&lsquo;<samp>iec61966-2-1</samp>&rsquo;</span></dt>

  1345. <dd><p>IEC 61966-2-1

  1346. </p></dd>

  1347. <dt><span>&lsquo;<samp>bt2020_10</samp>&rsquo;</span></dt>

  1348. <dt><span>&lsquo;<samp>bt2020_10bit</samp>&rsquo;</span></dt>

  1349. <dd><p>BT.2020 - 10 bit

  1350. </p></dd>

  1351. <dt><span>&lsquo;<samp>bt2020_12</samp>&rsquo;</span></dt>

  1352. <dt><span>&lsquo;<samp>bt2020_12bit</samp>&rsquo;</span></dt>

  1353. <dd><p>BT.2020 - 12 bit

  1354. </p></dd>

  1355. <dt><span>&lsquo;<samp>smpte2084</samp>&rsquo;</span></dt>

  1356. <dd><p>SMPTE ST 2084

  1357. </p></dd>

  1358. <dt><span>&lsquo;<samp>smpte428</samp>&rsquo;</span></dt>

  1359. <dt><span>&lsquo;<samp>smpte428_1</samp>&rsquo;</span></dt>

  1360. <dd><p>SMPTE ST 428-1

  1361. </p></dd>

  1362. <dt><span>&lsquo;<samp>arib-std-b67</samp>&rsquo;</span></dt>

  1363. <dd><p>ARIB STD-B67

  1364. </p></dd>

  1365. </dl>

  1366. 

  1367. </dd>

  1368. <dt><span><samp>colorspace <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1369. <dd><p>Possible values:

  1370. </p><dl compact="compact">

  1371. <dt><span>&lsquo;<samp>rgb</samp>&rsquo;</span></dt>

  1372. <dd><p>RGB

  1373. </p></dd>

  1374. <dt><span>&lsquo;<samp>bt709</samp>&rsquo;</span></dt>

  1375. <dd><p>BT.709

  1376. </p></dd>

  1377. <dt><span>&lsquo;<samp>fcc</samp>&rsquo;</span></dt>

  1378. <dd><p>FCC

  1379. </p></dd>

  1380. <dt><span>&lsquo;<samp>bt470bg</samp>&rsquo;</span></dt>

  1381. <dd><p>BT.470 BG

  1382. </p></dd>

  1383. <dt><span>&lsquo;<samp>smpte170m</samp>&rsquo;</span></dt>

  1384. <dd><p>SMPTE 170 M

  1385. </p></dd>

  1386. <dt><span>&lsquo;<samp>smpte240m</samp>&rsquo;</span></dt>

  1387. <dd><p>SMPTE 240 M

  1388. </p></dd>

  1389. <dt><span>&lsquo;<samp>ycocg</samp>&rsquo;</span></dt>

  1390. <dd><p>YCOCG

  1391. </p></dd>

  1392. <dt><span>&lsquo;<samp>bt2020nc</samp>&rsquo;</span></dt>

  1393. <dt><span>&lsquo;<samp>bt2020_ncl</samp>&rsquo;</span></dt>

  1394. <dd><p>BT.2020 NCL

  1395. </p></dd>

  1396. <dt><span>&lsquo;<samp>bt2020c</samp>&rsquo;</span></dt>

  1397. <dt><span>&lsquo;<samp>bt2020_cl</samp>&rsquo;</span></dt>

  1398. <dd><p>BT.2020 CL

  1399. </p></dd>

  1400. <dt><span>&lsquo;<samp>smpte2085</samp>&rsquo;</span></dt>

  1401. <dd><p>SMPTE 2085

  1402. </p></dd>

  1403. <dt><span>&lsquo;<samp>chroma-derived-nc</samp>&rsquo;</span></dt>

  1404. <dd><p>Chroma-derived NCL

  1405. </p></dd>

  1406. <dt><span>&lsquo;<samp>chroma-derived-c</samp>&rsquo;</span></dt>

  1407. <dd><p>Chroma-derived CL

  1408. </p></dd>

  1409. <dt><span>&lsquo;<samp>ictcp</samp>&rsquo;</span></dt>

  1410. <dd><p>ICtCp

  1411. </p></dd>

  1412. </dl>

  1413. 

  1414. </dd>

  1415. <dt><span><samp>color_range <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1416. <dd><p>If used as input parameter, it serves as a hint to the decoder, which

  1417. color_range the input has.

  1418. Possible values:

  1419. </p><dl compact="compact">

  1420. <dt><span>&lsquo;<samp>tv</samp>&rsquo;</span></dt>

  1421. <dt><span>&lsquo;<samp>mpeg</samp>&rsquo;</span></dt>

  1422. <dd><p>MPEG (219*2^(n-8))

  1423. </p></dd>

  1424. <dt><span>&lsquo;<samp>pc</samp>&rsquo;</span></dt>

  1425. <dt><span>&lsquo;<samp>jpeg</samp>&rsquo;</span></dt>

  1426. <dd><p>JPEG (2^n-1)

  1427. </p></dd>

  1428. </dl>

  1429. 

  1430. </dd>

  1431. <dt><span><samp>chroma_sample_location <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1432. <dd><p>Possible values:

  1433. </p><dl compact="compact">

  1434. <dt><span>&lsquo;<samp>left</samp>&rsquo;</span></dt>

  1435. <dt><span>&lsquo;<samp>center</samp>&rsquo;</span></dt>

  1436. <dt><span>&lsquo;<samp>topleft</samp>&rsquo;</span></dt>

  1437. <dt><span>&lsquo;<samp>top</samp>&rsquo;</span></dt>

  1438. <dt><span>&lsquo;<samp>bottomleft</samp>&rsquo;</span></dt>

  1439. <dt><span>&lsquo;<samp>bottom</samp>&rsquo;</span></dt>

  1440. </dl>

  1441. 

  1442. </dd>

  1443. <dt><span><samp>log_level_offset <var>integer</var></samp></span></dt>

  1444. <dd><p>Set the log level offset.

  1445. </p>

  1446. </dd>

  1447. <dt><span><samp>slices <var>integer</var> (<em>encoding,video</em>)</samp></span></dt>

  1448. <dd><p>Number of slices, used in parallelized encoding.

  1449. </p>

  1450. </dd>

  1451. <dt><span><samp>thread_type <var>flags</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1452. <dd><p>Select which multithreading methods to use.

  1453. </p>

  1454. <p>Use of &lsquo;<samp>frame</samp>&rsquo; will increase decoding delay by one frame per

  1455. thread, so clients which cannot provide future frames should not use

  1456. it.

  1457. </p>

  1458. <p>Possible values:

  1459. </p><dl compact="compact">

  1460. <dt><span>&lsquo;<samp>slice</samp>&rsquo;</span></dt>

  1461. <dd><p>Decode more than one part of a single frame at once.

  1462. </p>

  1463. <p>Multithreading using slices works only when the video was encoded with

  1464. slices.

  1465. </p>

  1466. </dd>

  1467. <dt><span>&lsquo;<samp>frame</samp>&rsquo;</span></dt>

  1468. <dd><p>Decode more than one frame at once.

  1469. </p></dd>

  1470. </dl>

  1471. 

  1472. <p>Default value is &lsquo;<samp>slice+frame</samp>&rsquo;.

  1473. </p>

  1474. </dd>

  1475. <dt><span><samp>audio_service_type <var>integer</var> (<em>encoding,audio</em>)</samp></span></dt>

  1476. <dd><p>Set audio service type.

  1477. </p>

  1478. <p>Possible values:

  1479. </p><dl compact="compact">

  1480. <dt><span>&lsquo;<samp>ma</samp>&rsquo;</span></dt>

  1481. <dd><p>Main Audio Service

  1482. </p></dd>

  1483. <dt><span>&lsquo;<samp>ef</samp>&rsquo;</span></dt>

  1484. <dd><p>Effects

  1485. </p></dd>

  1486. <dt><span>&lsquo;<samp>vi</samp>&rsquo;</span></dt>

  1487. <dd><p>Visually Impaired

  1488. </p></dd>

  1489. <dt><span>&lsquo;<samp>hi</samp>&rsquo;</span></dt>

  1490. <dd><p>Hearing Impaired

  1491. </p></dd>

  1492. <dt><span>&lsquo;<samp>di</samp>&rsquo;</span></dt>

  1493. <dd><p>Dialogue

  1494. </p></dd>

  1495. <dt><span>&lsquo;<samp>co</samp>&rsquo;</span></dt>

  1496. <dd><p>Commentary

  1497. </p></dd>

  1498. <dt><span>&lsquo;<samp>em</samp>&rsquo;</span></dt>

  1499. <dd><p>Emergency

  1500. </p></dd>

  1501. <dt><span>&lsquo;<samp>vo</samp>&rsquo;</span></dt>

  1502. <dd><p>Voice Over

  1503. </p></dd>

  1504. <dt><span>&lsquo;<samp>ka</samp>&rsquo;</span></dt>

  1505. <dd><p>Karaoke

  1506. </p></dd>

  1507. </dl>

  1508. 

  1509. </dd>

  1510. <dt><span><samp>request_sample_fmt <var>sample_fmt</var> (<em>decoding,audio</em>)</samp></span></dt>

  1511. <dd><p>Set sample format audio decoders should prefer. Default value is

  1512. <code>none</code>.

  1513. </p>

  1514. </dd>

  1515. <dt><span><samp>pkt_timebase <var>rational number</var></samp></span></dt>

  1516. <dt><span><samp>sub_charenc <var>encoding</var> (<em>decoding,subtitles</em>)</samp></span></dt>

  1517. <dd><p>Set the input subtitles character encoding.

  1518. </p>

  1519. </dd>

  1520. <dt><span><samp>field_order  <var>field_order</var> (<em>video</em>)</samp></span></dt>

  1521. <dd><p>Set/override the field order of the video.

  1522. Possible values:

  1523. </p><dl compact="compact">

  1524. <dt><span>&lsquo;<samp>progressive</samp>&rsquo;</span></dt>

  1525. <dd><p>Progressive video

  1526. </p></dd>

  1527. <dt><span>&lsquo;<samp>tt</samp>&rsquo;</span></dt>

  1528. <dd><p>Interlaced video, top field coded and displayed first

  1529. </p></dd>

  1530. <dt><span>&lsquo;<samp>bb</samp>&rsquo;</span></dt>

  1531. <dd><p>Interlaced video, bottom field coded and displayed first

  1532. </p></dd>

  1533. <dt><span>&lsquo;<samp>tb</samp>&rsquo;</span></dt>

  1534. <dd><p>Interlaced video, top coded first, bottom displayed first

  1535. </p></dd>

  1536. <dt><span>&lsquo;<samp>bt</samp>&rsquo;</span></dt>

  1537. <dd><p>Interlaced video, bottom coded first, top displayed first

  1538. </p></dd>

  1539. </dl>

  1540. 

  1541. </dd>

  1542. <dt><span><samp>skip_alpha <var>bool</var> (<em>decoding,video</em>)</samp></span></dt>

  1543. <dd><p>Set to 1 to disable processing alpha (transparency). This works like the

  1544. &lsquo;<samp>gray</samp>&rsquo; flag in the <samp>flags</samp> option which skips chroma information

  1545. instead of alpha. Default is 0.

  1546. </p>

  1547. </dd>

  1548. <dt><span><samp>codec_whitelist <var>list</var> (<em>input</em>)</samp></span></dt>

  1549. <dd><p>&quot;,&quot; separated list of allowed decoders. By default all are allowed.

  1550. </p>

  1551. </dd>

  1552. <dt><span><samp>dump_separator <var>string</var> (<em>input</em>)</samp></span></dt>

  1553. <dd><p>Separator used to separate the fields printed on the command line about the

  1554. Stream parameters.

  1555. For example, to separate the fields with newlines and indentation:

  1556. </p><div class="example">

  1557. <pre class="example">ffprobe -dump_separator &quot;

  1558.                           &quot;  -i ~/videos/matrixbench_mpeg2.mpg

  1559. </pre></div>

  1560. 

  1561. </dd>

  1562. <dt><span><samp>max_pixels <var>integer</var> (<em>decoding/encoding,video</em>)</samp></span></dt>

  1563. <dd><p>Maximum number of pixels per image. This value can be used to avoid out of

  1564. memory failures due to large images.

  1565. </p>

  1566. </dd>

  1567. <dt><span><samp>apply_cropping <var>bool</var> (<em>decoding,video</em>)</samp></span></dt>

  1568. <dd><p>Enable cropping if cropping parameters are multiples of the required

  1569. alignment for the left and top parameters. If the alignment is not met the

  1570. cropping will be partially applied to maintain alignment.

  1571. Default is 1 (enabled).

  1572. Note: The required alignment depends on if <code>AV_CODEC_FLAG_UNALIGNED</code> is set and the

  1573. CPU. <code>AV_CODEC_FLAG_UNALIGNED</code> cannot be changed from the command line. Also hardware

  1574. decoders will not apply left/top Cropping.

  1575. </p>

  1576. 

  1577. </dd>

  1578. </dl>

  1579. 

  1580. 

  1581. <a name="Decoders"></a>

  1582. <h2 class="chapter">3 Decoders<span class="pull-right"><a class="anchor hidden-xs" href="#Decoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Decoders" aria-hidden="true">TOC</a></span></h2>

  1583. 

  1584. <p>Decoders are configured elements in FFmpeg which allow the decoding of

  1585. multimedia streams.

  1586. </p>

  1587. <p>When you configure your FFmpeg build, all the supported native decoders

  1588. are enabled by default. Decoders requiring an external library must be enabled

  1589. manually via the corresponding <code>--enable-lib</code> option. You can list all

  1590. available decoders using the configure option <code>--list-decoders</code>.

  1591. </p>

  1592. <p>You can disable all the decoders with the configure option

  1593. <code>--disable-decoders</code> and selectively enable / disable single decoders

  1594. with the options <code>--enable-decoder=<var>DECODER</var></code> /

  1595. <code>--disable-decoder=<var>DECODER</var></code>.

  1596. </p>

  1597. <p>The option <code>-decoders</code> of the ff* tools will display the list of

  1598. enabled decoders.

  1599. </p>

  1600. 

  1601. <a name="Video-Decoders"></a>

  1602. <h2 class="chapter">4 Video Decoders<span class="pull-right"><a class="anchor hidden-xs" href="#Video-Decoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Video-Decoders" aria-hidden="true">TOC</a></span></h2>

  1603. 

  1604. <p>A description of some of the currently available video decoders

  1605. follows.

  1606. </p>

  1607. <a name="av1"></a>

  1608. <h3 class="section">4.1 av1<span class="pull-right"><a class="anchor hidden-xs" href="#av1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-av1" aria-hidden="true">TOC</a></span></h3>

  1609. 

  1610. <p>AOMedia Video 1 (AV1) decoder.

  1611. </p>

  1612. <a name="Options"></a>

  1613. <h4 class="subsection">4.1.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options" aria-hidden="true">TOC</a></span></h4>

  1614. 

  1615. <dl compact="compact">

  1616. <dt><span><samp>operating_point</samp></span></dt>

  1617. <dd><p>Select an operating point of a scalable AV1 bitstream (0 - 31). Default is 0.

  1618. </p>

  1619. </dd>

  1620. </dl>

  1621. 

  1622. <a name="rawvideo"></a>

  1623. <h3 class="section">4.2 rawvideo<span class="pull-right"><a class="anchor hidden-xs" href="#rawvideo" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-rawvideo" aria-hidden="true">TOC</a></span></h3>

  1624. 

  1625. <p>Raw video decoder.

  1626. </p>

  1627. <p>This decoder decodes rawvideo streams.

  1628. </p>

  1629. <a name="Options-1"></a>

  1630. <h4 class="subsection">4.2.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-1" aria-hidden="true">TOC</a></span></h4>

  1631. 

  1632. <dl compact="compact">

  1633. <dt><span><samp>top <var>top_field_first</var></samp></span></dt>

  1634. <dd><p>Specify the assumed field type of the input video.

  1635. </p><dl compact="compact">

  1636. <dt><span><samp>-1</samp></span></dt>

  1637. <dd><p>the video is assumed to be progressive (default)

  1638. </p></dd>

  1639. <dt><span><samp>0</samp></span></dt>

  1640. <dd><p>bottom-field-first is assumed

  1641. </p></dd>

  1642. <dt><span><samp>1</samp></span></dt>

  1643. <dd><p>top-field-first is assumed

  1644. </p></dd>

  1645. </dl>

  1646. 

  1647. </dd>

  1648. </dl>

  1649. 

  1650. <a name="libdav1d"></a>

  1651. <h3 class="section">4.3 libdav1d<span class="pull-right"><a class="anchor hidden-xs" href="#libdav1d" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libdav1d" aria-hidden="true">TOC</a></span></h3>

  1652. 

  1653. <p>dav1d AV1 decoder.

  1654. </p>

  1655. <p>libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec.

  1656. Requires the presence of the libdav1d headers and library during configuration.

  1657. You need to explicitly configure the build with <code>--enable-libdav1d</code>.

  1658. </p>

  1659. <a name="Options-2"></a>

  1660. <h4 class="subsection">4.3.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-2" aria-hidden="true">TOC</a></span></h4>

  1661. 

  1662. <p>The following options are supported by the libdav1d wrapper.

  1663. </p>

  1664. <dl compact="compact">

  1665. <dt><span><samp>framethreads</samp></span></dt>

  1666. <dd><p>Set amount of frame threads to use during decoding. The default value is 0 (autodetect).

  1667. This option is deprecated for libdav1d &gt;= 1.0 and will be removed in the future. Use the

  1668. option <code>max_frame_delay</code> and the global option <code>threads</code> instead.

  1669. </p>

  1670. </dd>

  1671. <dt><span><samp>tilethreads</samp></span></dt>

  1672. <dd><p>Set amount of tile threads to use during decoding. The default value is 0 (autodetect).

  1673. This option is deprecated for libdav1d &gt;= 1.0 and will be removed in the future. Use the

  1674. global option <code>threads</code> instead.

  1675. </p>

  1676. </dd>

  1677. <dt><span><samp>max_frame_delay</samp></span></dt>

  1678. <dd><p>Set max amount of frames the decoder may buffer internally. The default value is 0

  1679. (autodetect).

  1680. </p>

  1681. </dd>

  1682. <dt><span><samp>filmgrain</samp></span></dt>

  1683. <dd><p>Apply film grain to the decoded video if present in the bitstream. Defaults to the

  1684. internal default of the library.

  1685. This option is deprecated and will be removed in the future. See the global option

  1686. <code>export_side_data</code> to export Film Grain parameters instead of applying it.

  1687. </p>

  1688. </dd>

  1689. <dt><span><samp>oppoint</samp></span></dt>

  1690. <dd><p>Select an operating point of a scalable AV1 bitstream (0 - 31). Defaults to the

  1691. internal default of the library.

  1692. </p>

  1693. </dd>

  1694. <dt><span><samp>alllayers</samp></span></dt>

  1695. <dd><p>Output all spatial layers of a scalable AV1 bitstream. The default value is false.

  1696. </p>

  1697. </dd>

  1698. </dl>

  1699. 

  1700. <a name="libdavs2"></a>

  1701. <h3 class="section">4.4 libdavs2<span class="pull-right"><a class="anchor hidden-xs" href="#libdavs2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libdavs2" aria-hidden="true">TOC</a></span></h3>

  1702. 

  1703. <p>AVS2-P2/IEEE1857.4 video decoder wrapper.

  1704. </p>

  1705. <p>This decoder allows libavcodec to decode AVS2 streams with davs2 library.

  1706. </p>

  1707. 

  1708. <a name="libuavs3d"></a>

  1709. <h3 class="section">4.5 libuavs3d<span class="pull-right"><a class="anchor hidden-xs" href="#libuavs3d" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libuavs3d" aria-hidden="true">TOC</a></span></h3>

  1710. 

  1711. <p>AVS3-P2/IEEE1857.10 video decoder.

  1712. </p>

  1713. <p>libuavs3d allows libavcodec to decode AVS3 streams.

  1714. Requires the presence of the libuavs3d headers and library during configuration.

  1715. You need to explicitly configure the build with <code>--enable-libuavs3d</code>.

  1716. </p>

  1717. <a name="Options-3"></a>

  1718. <h4 class="subsection">4.5.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-3" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-3" aria-hidden="true">TOC</a></span></h4>

  1719. 

  1720. <p>The following option is supported by the libuavs3d wrapper.

  1721. </p>

  1722. <dl compact="compact">

  1723. <dt><span><samp>frame_threads</samp></span></dt>

  1724. <dd><p>Set amount of frame threads to use during decoding. The default value is 0 (autodetect).

  1725. </p>

  1726. </dd>

  1727. </dl>

  1728. 

  1729. <a name="QSV-Decoders"></a>

  1730. <h3 class="section">4.6 QSV Decoders<span class="pull-right"><a class="anchor hidden-xs" href="#QSV-Decoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-QSV-Decoders" aria-hidden="true">TOC</a></span></h3>

  1731. 

  1732. <p>The family of Intel QuickSync Video decoders (VC1, MPEG-2, H.264, HEVC,

  1733. JPEG/MJPEG, VP8, VP9, AV1).

  1734. </p>

  1735. <a name="Common-Options"></a>

  1736. <h4 class="subsection">4.6.1 Common Options<span class="pull-right"><a class="anchor hidden-xs" href="#Common-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Common-Options" aria-hidden="true">TOC</a></span></h4>

  1737. 

  1738. <p>The following options are supported by all qsv decoders.

  1739. </p>

  1740. <dl compact="compact">

  1741. <dt><span><samp><var>async_depth</var></samp></span></dt>

  1742. <dd><p>Internal parallelization depth, the higher the value the higher the latency.

  1743. </p>

  1744. </dd>

  1745. <dt><span><samp><var>gpu_copy</var></samp></span></dt>

  1746. <dd><p>A GPU-accelerated copy between video and system memory

  1747. </p><dl compact="compact">

  1748. <dt><span>&lsquo;<samp>default</samp>&rsquo;</span></dt>

  1749. <dt><span>&lsquo;<samp>on</samp>&rsquo;</span></dt>

  1750. <dt><span>&lsquo;<samp>off</samp>&rsquo;</span></dt>

  1751. </dl>

  1752. 

  1753. </dd>

  1754. </dl>

  1755. 

  1756. <a name="HEVC-Options"></a>

  1757. <h4 class="subsection">4.6.2 HEVC Options<span class="pull-right"><a class="anchor hidden-xs" href="#HEVC-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-HEVC-Options" aria-hidden="true">TOC</a></span></h4>

  1758. <p>Extra options for hevc_qsv.

  1759. </p>

  1760. <dl compact="compact">

  1761. <dt><span><samp><var>load_plugin</var></samp></span></dt>

  1762. <dd><p>A user plugin to load in an internal session

  1763. </p><dl compact="compact">

  1764. <dt><span>&lsquo;<samp>none</samp>&rsquo;</span></dt>

  1765. <dt><span>&lsquo;<samp>hevc_sw</samp>&rsquo;</span></dt>

  1766. <dt><span>&lsquo;<samp>hevc_hw</samp>&rsquo;</span></dt>

  1767. </dl>

  1768. 

  1769. </dd>

  1770. <dt><span><samp><var>load_plugins</var></samp></span></dt>

  1771. <dd><p>A :-separate list of hexadecimal plugin UIDs to load in an internal session

  1772. </p>

  1773. </dd>

  1774. </dl>

  1775. 

  1776. <a name="v210"></a>

  1777. <h3 class="section">4.7 v210<span class="pull-right"><a class="anchor hidden-xs" href="#v210" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-v210" aria-hidden="true">TOC</a></span></h3>

  1778. 

  1779. <p>Uncompressed 4:2:2 10-bit decoder.

  1780. </p>

  1781. <a name="Options-4"></a>

  1782. <h4 class="subsection">4.7.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-4" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-4" aria-hidden="true">TOC</a></span></h4>

  1783. 

  1784. <dl compact="compact">

  1785. <dt><span><samp>custom_stride</samp></span></dt>

  1786. <dd><p>Set the line size of the v210 data in bytes. The default value is 0

  1787. (autodetect). You can use the special -1 value for a strideless v210 as seen in

  1788. BOXX files.

  1789. </p>

  1790. </dd>

  1791. </dl>

  1792. 

  1793. 

  1794. <a name="Audio-Decoders"></a>

  1795. <h2 class="chapter">5 Audio Decoders<span class="pull-right"><a class="anchor hidden-xs" href="#Audio-Decoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Audio-Decoders" aria-hidden="true">TOC</a></span></h2>

  1796. 

  1797. <p>A description of some of the currently available audio decoders

  1798. follows.

  1799. </p>

  1800. <a name="ac3"></a>

  1801. <h3 class="section">5.1 ac3<span class="pull-right"><a class="anchor hidden-xs" href="#ac3" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-ac3" aria-hidden="true">TOC</a></span></h3>

  1802. 

  1803. <p>AC-3 audio decoder.

  1804. </p>

  1805. <p>This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as well as

  1806. the undocumented RealAudio 3 (a.k.a. dnet).

  1807. </p>

  1808. <a name="AC_002d3-Decoder-Options"></a>

  1809. <h4 class="subsection">5.1.1 AC-3 Decoder Options<span class="pull-right"><a class="anchor hidden-xs" href="#AC_002d3-Decoder-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-AC_002d3-Decoder-Options" aria-hidden="true">TOC</a></span></h4>

  1810. 

  1811. <dl compact="compact">

  1812. <dt><span><samp>-drc_scale <var>value</var></samp></span></dt>

  1813. <dd><p>Dynamic Range Scale Factor. The factor to apply to dynamic range values

  1814. from the AC-3 stream. This factor is applied exponentially. The default value is 1.

  1815. There are 3 notable scale factor ranges:

  1816. </p><dl compact="compact">

  1817. <dt><span><samp>drc_scale == 0</samp></span></dt>

  1818. <dd><p>DRC disabled. Produces full range audio.

  1819. </p></dd>

  1820. <dt><span><samp>0 &lt; drc_scale &lt;= 1</samp></span></dt>

  1821. <dd><p>DRC enabled.  Applies a fraction of the stream DRC value.

  1822. Audio reproduction is between full range and full compression.

  1823. </p></dd>

  1824. <dt><span><samp>drc_scale &gt; 1</samp></span></dt>

  1825. <dd><p>DRC enabled. Applies drc_scale asymmetrically.

  1826. Loud sounds are fully compressed.  Soft sounds are enhanced.

  1827. </p></dd>

  1828. </dl>

  1829. 

  1830. </dd>

  1831. </dl>

  1832. 

  1833. <a name="flac-1"></a>

  1834. <h3 class="section">5.2 flac<span class="pull-right"><a class="anchor hidden-xs" href="#flac-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-flac-1" aria-hidden="true">TOC</a></span></h3>

  1835. 

  1836. <p>FLAC audio decoder.

  1837. </p>

  1838. <p>This decoder aims to implement the complete FLAC specification from Xiph.

  1839. </p>

  1840. <a name="FLAC-Decoder-options"></a>

  1841. <h4 class="subsection">5.2.1 FLAC Decoder options<span class="pull-right"><a class="anchor hidden-xs" href="#FLAC-Decoder-options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-FLAC-Decoder-options" aria-hidden="true">TOC</a></span></h4>

  1842. 

  1843. <dl compact="compact">

  1844. <dt><span><samp>-use_buggy_lpc</samp></span></dt>

  1845. <dd><p>The lavc FLAC encoder used to produce buggy streams with high lpc values

  1846. (like the default value). This option makes it possible to decode such streams

  1847. correctly by using lavc&rsquo;s old buggy lpc logic for decoding.

  1848. </p>

  1849. </dd>

  1850. </dl>

  1851. 

  1852. <a name="ffwavesynth"></a>

  1853. <h3 class="section">5.3 ffwavesynth<span class="pull-right"><a class="anchor hidden-xs" href="#ffwavesynth" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-ffwavesynth" aria-hidden="true">TOC</a></span></h3>

  1854. 

  1855. <p>Internal wave synthesizer.

  1856. </p>

  1857. <p>This decoder generates wave patterns according to predefined sequences. Its

  1858. use is purely internal and the format of the data it accepts is not publicly

  1859. documented.

  1860. </p>

  1861. <a name="libcelt"></a>

  1862. <h3 class="section">5.4 libcelt<span class="pull-right"><a class="anchor hidden-xs" href="#libcelt" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libcelt" aria-hidden="true">TOC</a></span></h3>

  1863. 

  1864. <p>libcelt decoder wrapper.

  1865. </p>

  1866. <p>libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.

  1867. Requires the presence of the libcelt headers and library during configuration.

  1868. You need to explicitly configure the build with <code>--enable-libcelt</code>.

  1869. </p>

  1870. <a name="libgsm"></a>

  1871. <h3 class="section">5.5 libgsm<span class="pull-right"><a class="anchor hidden-xs" href="#libgsm" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libgsm" aria-hidden="true">TOC</a></span></h3>

  1872. 

  1873. <p>libgsm decoder wrapper.

  1874. </p>

  1875. <p>libgsm allows libavcodec to decode the GSM full rate audio codec. Requires

  1876. the presence of the libgsm headers and library during configuration. You need

  1877. to explicitly configure the build with <code>--enable-libgsm</code>.

  1878. </p>

  1879. <p>This decoder supports both the ordinary GSM and the Microsoft variant.

  1880. </p>

  1881. <a name="libilbc"></a>

  1882. <h3 class="section">5.6 libilbc<span class="pull-right"><a class="anchor hidden-xs" href="#libilbc" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libilbc" aria-hidden="true">TOC</a></span></h3>

  1883. 

  1884. <p>libilbc decoder wrapper.

  1885. </p>

  1886. <p>libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC)

  1887. audio codec. Requires the presence of the libilbc headers and library during

  1888. configuration. You need to explicitly configure the build with

  1889. <code>--enable-libilbc</code>.

  1890. </p>

  1891. <a name="Options-5"></a>

  1892. <h4 class="subsection">5.6.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-5" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-5" aria-hidden="true">TOC</a></span></h4>

  1893. 

  1894. <p>The following option is supported by the libilbc wrapper.

  1895. </p>

  1896. <dl compact="compact">

  1897. <dt><span><samp>enhance</samp></span></dt>

  1898. <dd>

  1899. <p>Enable the enhancement of the decoded audio when set to 1. The default

  1900. value is 0 (disabled).

  1901. </p>

  1902. </dd>

  1903. </dl>

  1904. 

  1905. <a name="libopencore_002damrnb"></a>

  1906. <h3 class="section">5.7 libopencore-amrnb<span class="pull-right"><a class="anchor hidden-xs" href="#libopencore_002damrnb" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libopencore_002damrnb" aria-hidden="true">TOC</a></span></h3>

  1907. 

  1908. <p>libopencore-amrnb decoder wrapper.

  1909. </p>

  1910. <p>libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate

  1911. Narrowband audio codec. Using it requires the presence of the

  1912. libopencore-amrnb headers and library during configuration. You need to

  1913. explicitly configure the build with <code>--enable-libopencore-amrnb</code>.

  1914. </p>

  1915. <p>An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB

  1916. without this library.

  1917. </p>

  1918. <a name="libopencore_002damrwb"></a>

  1919. <h3 class="section">5.8 libopencore-amrwb<span class="pull-right"><a class="anchor hidden-xs" href="#libopencore_002damrwb" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libopencore_002damrwb" aria-hidden="true">TOC</a></span></h3>

  1920. 

  1921. <p>libopencore-amrwb decoder wrapper.

  1922. </p>

  1923. <p>libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate

  1924. Wideband audio codec. Using it requires the presence of the

  1925. libopencore-amrwb headers and library during configuration. You need to

  1926. explicitly configure the build with <code>--enable-libopencore-amrwb</code>.

  1927. </p>

  1928. <p>An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB

  1929. without this library.

  1930. </p>

  1931. <a name="libopus"></a>

  1932. <h3 class="section">5.9 libopus<span class="pull-right"><a class="anchor hidden-xs" href="#libopus" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libopus" aria-hidden="true">TOC</a></span></h3>

  1933. 

  1934. <p>libopus decoder wrapper.

  1935. </p>

  1936. <p>libopus allows libavcodec to decode the Opus Interactive Audio Codec.

  1937. Requires the presence of the libopus headers and library during

  1938. configuration. You need to explicitly configure the build with

  1939. <code>--enable-libopus</code>.

  1940. </p>

  1941. <p>An FFmpeg native decoder for Opus exists, so users can decode Opus

  1942. without this library.

  1943. </p>

  1944. 

  1945. <a name="Subtitles-Decoders"></a>

  1946. <h2 class="chapter">6 Subtitles Decoders<span class="pull-right"><a class="anchor hidden-xs" href="#Subtitles-Decoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Subtitles-Decoders" aria-hidden="true">TOC</a></span></h2>

  1947. 

  1948. <a name="libaribb24"></a>

  1949. <h3 class="section">6.1 libaribb24<span class="pull-right"><a class="anchor hidden-xs" href="#libaribb24" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libaribb24" aria-hidden="true">TOC</a></span></h3>

  1950. 

  1951. <p>ARIB STD-B24 caption decoder.

  1952. </p>

  1953. <p>Implements profiles A and C of the ARIB STD-B24 standard.

  1954. </p>

  1955. <a name="libaribb24-Decoder-Options"></a>

  1956. <h4 class="subsection">6.1.1 libaribb24 Decoder Options<span class="pull-right"><a class="anchor hidden-xs" href="#libaribb24-Decoder-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libaribb24-Decoder-Options" aria-hidden="true">TOC</a></span></h4>

  1957. 

  1958. <dl compact="compact">

  1959. <dt><span><samp>-aribb24-base-path <var>path</var></samp></span></dt>

  1960. <dd><p>Sets the base path for the libaribb24 library. This is utilized for reading of

  1961. configuration files (for custom unicode conversions), and for dumping of

  1962. non-text symbols as images under that location.

  1963. </p>

  1964. <p>Unset by default.

  1965. </p>

  1966. </dd>

  1967. <dt><span><samp>-aribb24-skip-ruby-text <var>boolean</var></samp></span></dt>

  1968. <dd><p>Tells the decoder wrapper to skip text blocks that contain half-height ruby

  1969. text.

  1970. </p>

  1971. <p>Enabled by default.

  1972. </p>

  1973. </dd>

  1974. </dl>

  1975. 

  1976. <a name="dvbsub"></a>

  1977. <h3 class="section">6.2 dvbsub<span class="pull-right"><a class="anchor hidden-xs" href="#dvbsub" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-dvbsub" aria-hidden="true">TOC</a></span></h3>

  1978. 

  1979. <a name="Options-6"></a>

  1980. <h4 class="subsection">6.2.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-6" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-6" aria-hidden="true">TOC</a></span></h4>

  1981. 

  1982. <dl compact="compact">

  1983. <dt><span><samp>compute_clut</samp></span></dt>

  1984. <dd><dl compact="compact">

  1985. <dt><span><samp>-2</samp></span></dt>

  1986. <dd><p>Compute clut once if no matching CLUT is in the stream.

  1987. </p></dd>

  1988. <dt><span><samp>-1</samp></span></dt>

  1989. <dd><p>Compute clut if no matching CLUT is in the stream.

  1990. </p></dd>

  1991. <dt><span><samp>0</samp></span></dt>

  1992. <dd><p>Never compute CLUT

  1993. </p></dd>

  1994. <dt><span><samp>1</samp></span></dt>

  1995. <dd><p>Always compute CLUT and override the one provided in the stream.

  1996. </p></dd>

  1997. </dl>

  1998. </dd>

  1999. <dt><span><samp>dvb_substream</samp></span></dt>

  2000. <dd><p>Selects the dvb substream, or all substreams if -1 which is default.

  2001. </p>

  2002. </dd>

  2003. </dl>

  2004. 

  2005. <a name="dvdsub"></a>

  2006. <h3 class="section">6.3 dvdsub<span class="pull-right"><a class="anchor hidden-xs" href="#dvdsub" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-dvdsub" aria-hidden="true">TOC</a></span></h3>

  2007. 

  2008. <p>This codec decodes the bitmap subtitles used in DVDs; the same subtitles can

  2009. also be found in VobSub file pairs and in some Matroska files.

  2010. </p>

  2011. <a name="Options-7"></a>

  2012. <h4 class="subsection">6.3.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-7" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-7" aria-hidden="true">TOC</a></span></h4>

  2013. 

  2014. <dl compact="compact">

  2015. <dt><span><samp>palette</samp></span></dt>

  2016. <dd><p>Specify the global palette used by the bitmaps. When stored in VobSub, the

  2017. palette is normally specified in the index file; in Matroska, the palette is

  2018. stored in the codec extra-data in the same format as in VobSub. In DVDs, the

  2019. palette is stored in the IFO file, and therefore not available when reading

  2020. from dumped VOB files.

  2021. </p>

  2022. <p>The format for this option is a string containing 16 24-bits hexadecimal

  2023. numbers (without 0x prefix) separated by commas, for example <code>0d00ee,

  2024. ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,

  2025. 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b</code>.

  2026. </p>

  2027. </dd>

  2028. <dt><span><samp>ifo_palette</samp></span></dt>

  2029. <dd><p>Specify the IFO file from which the global palette is obtained.

  2030. (experimental)

  2031. </p>

  2032. </dd>

  2033. <dt><span><samp>forced_subs_only</samp></span></dt>

  2034. <dd><p>Only decode subtitle entries marked as forced. Some titles have forced

  2035. and non-forced subtitles in the same track. Setting this flag to <code>1</code>

  2036. will only keep the forced subtitles. Default value is <code>0</code>.

  2037. </p></dd>

  2038. </dl>

  2039. 

  2040. <a name="libzvbi_002dteletext"></a>

  2041. <h3 class="section">6.4 libzvbi-teletext<span class="pull-right"><a class="anchor hidden-xs" href="#libzvbi_002dteletext" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libzvbi_002dteletext" aria-hidden="true">TOC</a></span></h3>

  2042. 

  2043. <p>Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext

  2044. subtitles. Requires the presence of the libzvbi headers and library during

  2045. configuration. You need to explicitly configure the build with

  2046. <code>--enable-libzvbi</code>.

  2047. </p>

  2048. <a name="Options-8"></a>

  2049. <h4 class="subsection">6.4.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-8" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-8" aria-hidden="true">TOC</a></span></h4>

  2050. 

  2051. <dl compact="compact">

  2052. <dt><span><samp>txt_page</samp></span></dt>

  2053. <dd><p>List of teletext page numbers to decode. Pages that do not match the specified

  2054. list are dropped. You may use the special <code>*</code> string to match all pages,

  2055. or <code>subtitle</code> to match all subtitle pages.

  2056. Default value is *.

  2057. </p></dd>

  2058. <dt><span><samp>txt_default_region</samp></span></dt>

  2059. <dd><p>Set default character set used for decoding, a value between 0 and 87 (see

  2060. ETS 300 706, Section 15, Table 32). Default value is -1, which does not

  2061. override the libzvbi default. This option is needed for some legacy level 1.0

  2062. transmissions which cannot signal the proper charset.

  2063. </p></dd>

  2064. <dt><span><samp>txt_chop_top</samp></span></dt>

  2065. <dd><p>Discards the top teletext line. Default value is 1.

  2066. </p></dd>

  2067. <dt><span><samp>txt_format</samp></span></dt>

  2068. <dd><p>Specifies the format of the decoded subtitles.

  2069. </p><dl compact="compact">

  2070. <dt><span><samp>bitmap</samp></span></dt>

  2071. <dd><p>The default format, you should use this for teletext pages, because certain

  2072. graphics and colors cannot be expressed in simple text or even ASS.

  2073. </p></dd>

  2074. <dt><span><samp>text</samp></span></dt>

  2075. <dd><p>Simple text based output without formatting.

  2076. </p></dd>

  2077. <dt><span><samp>ass</samp></span></dt>

  2078. <dd><p>Formatted ASS output, subtitle pages and teletext pages are returned in

  2079. different styles, subtitle pages are stripped down to text, but an effort is

  2080. made to keep the text alignment and the formatting.

  2081. </p></dd>

  2082. </dl>

  2083. </dd>

  2084. <dt><span><samp>txt_left</samp></span></dt>

  2085. <dd><p>X offset of generated bitmaps, default is 0.

  2086. </p></dd>

  2087. <dt><span><samp>txt_top</samp></span></dt>

  2088. <dd><p>Y offset of generated bitmaps, default is 0.

  2089. </p></dd>

  2090. <dt><span><samp>txt_chop_spaces</samp></span></dt>

  2091. <dd><p>Chops leading and trailing spaces and removes empty lines from the generated

  2092. text. This option is useful for teletext based subtitles where empty spaces may

  2093. be present at the start or at the end of the lines or empty lines may be

  2094. present between the subtitle lines because of double-sized teletext characters.

  2095. Default value is 1.

  2096. </p></dd>

  2097. <dt><span><samp>txt_duration</samp></span></dt>

  2098. <dd><p>Sets the display duration of the decoded teletext pages or subtitles in

  2099. milliseconds. Default value is -1 which means infinity or until the next

  2100. subtitle event comes.

  2101. </p></dd>

  2102. <dt><span><samp>txt_transparent</samp></span></dt>

  2103. <dd><p>Force transparent background of the generated teletext bitmaps. Default value

  2104. is 0 which means an opaque background.

  2105. </p></dd>

  2106. <dt><span><samp>txt_opacity</samp></span></dt>

  2107. <dd><p>Sets the opacity (0-255) of the teletext background. If

  2108. <samp>txt_transparent</samp> is not set, it only affects characters between a start

  2109. box and an end box, typically subtitles. Default value is 0 if

  2110. <samp>txt_transparent</samp> is set, 255 otherwise.

  2111. </p>

  2112. </dd>

  2113. </dl>

  2114. 

  2115. <a name="Encoders"></a>

  2116. <h2 class="chapter">7 Encoders<span class="pull-right"><a class="anchor hidden-xs" href="#Encoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Encoders" aria-hidden="true">TOC</a></span></h2>

  2117. 

  2118. <p>Encoders are configured elements in FFmpeg which allow the encoding of

  2119. multimedia streams.

  2120. </p>

  2121. <p>When you configure your FFmpeg build, all the supported native encoders

  2122. are enabled by default. Encoders requiring an external library must be enabled

  2123. manually via the corresponding <code>--enable-lib</code> option. You can list all

  2124. available encoders using the configure option <code>--list-encoders</code>.

  2125. </p>

  2126. <p>You can disable all the encoders with the configure option

  2127. <code>--disable-encoders</code> and selectively enable / disable single encoders

  2128. with the options <code>--enable-encoder=<var>ENCODER</var></code> /

  2129. <code>--disable-encoder=<var>ENCODER</var></code>.

  2130. </p>

  2131. <p>The option <code>-encoders</code> of the ff* tools will display the list of

  2132. enabled encoders.

  2133. </p>

  2134. 

  2135. <a name="Audio-Encoders"></a>

  2136. <h2 class="chapter">8 Audio Encoders<span class="pull-right"><a class="anchor hidden-xs" href="#Audio-Encoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Audio-Encoders" aria-hidden="true">TOC</a></span></h2>

  2137. 

  2138. <p>A description of some of the currently available audio encoders

  2139. follows.

  2140. </p>

  2141. <span id="aacenc"></span><a name="aac"></a>

  2142. <h3 class="section">8.1 aac<span class="pull-right"><a class="anchor hidden-xs" href="#aac" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-aac" aria-hidden="true">TOC</a></span></h3>

  2143. 

  2144. <p>Advanced Audio Coding (AAC) encoder.

  2145. </p>

  2146. <p>This encoder is the default AAC encoder, natively implemented into FFmpeg.

  2147. </p>

  2148. <a name="Options-9"></a>

  2149. <h4 class="subsection">8.1.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-9" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-9" aria-hidden="true">TOC</a></span></h4>

  2150. 

  2151. <dl compact="compact">

  2152. <dt><span><samp>b</samp></span></dt>

  2153. <dd><p>Set bit rate in bits/s. Setting this automatically activates constant bit rate

  2154. (CBR) mode. If this option is unspecified it is set to 128kbps.

  2155. </p>

  2156. </dd>

  2157. <dt><span><samp>q</samp></span></dt>

  2158. <dd><p>Set quality for variable bit rate (VBR) mode. This option is valid only using

  2159. the <code>ffmpeg</code> command-line tool. For library interface users, use

  2160. <samp>global_quality</samp>.

  2161. </p>

  2162. </dd>

  2163. <dt><span><samp>cutoff</samp></span></dt>

  2164. <dd><p>Set cutoff frequency. If unspecified will allow the encoder to dynamically

  2165. adjust the cutoff to improve clarity on low bitrates.

  2166. </p>

  2167. </dd>

  2168. <dt><span><samp>aac_coder</samp></span></dt>

  2169. <dd><p>Set AAC encoder coding method. Possible values:

  2170. </p>

  2171. <dl compact="compact">

  2172. <dt><span>&lsquo;<samp>twoloop</samp>&rsquo;</span></dt>

  2173. <dd><p>Two loop searching (TLS) method. This is the default method.

  2174. </p>

  2175. <p>This method first sets quantizers depending on band thresholds and then tries

  2176. to find an optimal combination by adding or subtracting a specific value from

  2177. all quantizers and adjusting some individual quantizer a little.  Will tune

  2178. itself based on whether <samp>aac_is</samp>, <samp>aac_ms</samp> and <samp>aac_pns</samp>

  2179. are enabled.

  2180. </p>

  2181. </dd>

  2182. <dt><span>&lsquo;<samp>anmr</samp>&rsquo;</span></dt>

  2183. <dd><p>Average noise to mask ratio (ANMR) trellis-based solution.

  2184. </p>

  2185. <p>This is an experimental coder which currently produces a lower quality, is more

  2186. unstable and is slower than the default twoloop coder but has potential.

  2187. Currently has no support for the <samp>aac_is</samp> or <samp>aac_pns</samp> options.

  2188. Not currently recommended.

  2189. </p>

  2190. </dd>

  2191. <dt><span>&lsquo;<samp>fast</samp>&rsquo;</span></dt>

  2192. <dd><p>Constant quantizer method.

  2193. </p>

  2194. <p>Uses a cheaper version of twoloop algorithm that doesn&rsquo;t try to do as many

  2195. clever adjustments. Worse with low bitrates (less than 64kbps), but is better

  2196. and much faster at higher bitrates.

  2197. </p>

  2198. </dd>

  2199. </dl>

  2200. 

  2201. </dd>

  2202. <dt><span><samp>aac_ms</samp></span></dt>

  2203. <dd><p>Sets mid/side coding mode. The default value of &quot;auto&quot; will automatically use

  2204. M/S with bands which will benefit from such coding. Can be forced for all bands

  2205. using the value &quot;enable&quot;, which is mainly useful for debugging or disabled using

  2206. &quot;disable&quot;.

  2207. </p>

  2208. </dd>

  2209. <dt><span><samp>aac_is</samp></span></dt>

  2210. <dd><p>Sets intensity stereo coding tool usage. By default, it&rsquo;s enabled and will

  2211. automatically toggle IS for similar pairs of stereo bands if it&rsquo;s beneficial.

  2212. Can be disabled for debugging by setting the value to &quot;disable&quot;.

  2213. </p>

  2214. </dd>

  2215. <dt><span><samp>aac_pns</samp></span></dt>

  2216. <dd><p>Uses perceptual noise substitution to replace low entropy high frequency bands

  2217. with imperceptible white noise during the decoding process. By default, it&rsquo;s

  2218. enabled, but can be disabled for debugging purposes by using &quot;disable&quot;.

  2219. </p>

  2220. </dd>

  2221. <dt><span><samp>aac_tns</samp></span></dt>

  2222. <dd><p>Enables the use of a multitap FIR filter which spans through the high frequency

  2223. bands to hide quantization noise during the encoding process and is reverted

  2224. by the decoder. As well as decreasing unpleasant artifacts in the high range

  2225. this also reduces the entropy in the high bands and allows for more bits to

  2226. be used by the mid-low bands. By default it&rsquo;s enabled but can be disabled for

  2227. debugging by setting the option to &quot;disable&quot;.

  2228. </p>

  2229. </dd>

  2230. <dt><span><samp>aac_ltp</samp></span></dt>

  2231. <dd><p>Enables the use of the long term prediction extension which increases coding

  2232. efficiency in very low bandwidth situations such as encoding of voice or

  2233. solo piano music by extending constant harmonic peaks in bands throughout

  2234. frames. This option is implied by profile:a aac_low and is incompatible with

  2235. aac_pred. Use in conjunction with <samp>-ar</samp> to decrease the samplerate.

  2236. </p>

  2237. </dd>

  2238. <dt><span><samp>aac_pred</samp></span></dt>

  2239. <dd><p>Enables the use of a more traditional style of prediction where the spectral

  2240. coefficients transmitted are replaced by the difference of the current

  2241. coefficients minus the previous &quot;predicted&quot; coefficients. In theory and sometimes

  2242. in practice this can improve quality for low to mid bitrate audio.

  2243. This option implies the aac_main profile and is incompatible with aac_ltp.

  2244. </p>

  2245. </dd>

  2246. <dt><span><samp>profile</samp></span></dt>

  2247. <dd><p>Sets the encoding profile, possible values:

  2248. </p>

  2249. <dl compact="compact">

  2250. <dt><span>&lsquo;<samp>aac_low</samp>&rsquo;</span></dt>

  2251. <dd><p>The default, AAC &quot;Low-complexity&quot; profile. Is the most compatible and produces

  2252. decent quality.

  2253. </p>

  2254. </dd>

  2255. <dt><span>&lsquo;<samp>mpeg2_aac_low</samp>&rsquo;</span></dt>

  2256. <dd><p>Equivalent to <code>-profile:a aac_low -aac_pns 0</code>. PNS was introduced with the

  2257. MPEG4 specifications.

  2258. </p>

  2259. </dd>

  2260. <dt><span>&lsquo;<samp>aac_ltp</samp>&rsquo;</span></dt>

  2261. <dd><p>Long term prediction profile, is enabled by and will enable the <samp>aac_ltp</samp>

  2262. option. Introduced in MPEG4.

  2263. </p>

  2264. </dd>

  2265. <dt><span>&lsquo;<samp>aac_main</samp>&rsquo;</span></dt>

  2266. <dd><p>Main-type prediction profile, is enabled by and will enable the <samp>aac_pred</samp>

  2267. option. Introduced in MPEG2.

  2268. </p>

  2269. </dd>

  2270. </dl>

  2271. <p>If this option is unspecified it is set to &lsquo;<samp>aac_low</samp>&rsquo;.

  2272. </p></dd>

  2273. </dl>

  2274. 

  2275. <a name="ac3-and-ac3_005ffixed"></a>

  2276. <h3 class="section">8.2 ac3 and ac3_fixed<span class="pull-right"><a class="anchor hidden-xs" href="#ac3-and-ac3_005ffixed" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-ac3-and-ac3_005ffixed" aria-hidden="true">TOC</a></span></h3>

  2277. 

  2278. <p>AC-3 audio encoders.

  2279. </p>

  2280. <p>These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as

  2281. the undocumented RealAudio 3 (a.k.a. dnet).

  2282. </p>

  2283. <p>The <var>ac3</var> encoder uses floating-point math, while the <var>ac3_fixed</var>

  2284. encoder only uses fixed-point integer math. This does not mean that one is

  2285. always faster, just that one or the other may be better suited to a

  2286. particular system. The <var>ac3_fixed</var> encoder is not the default codec for

  2287. any of the output formats, so it must be specified explicitly using the option

  2288. <code>-acodec ac3_fixed</code> in order to use it.

  2289. </p>

  2290. <a name="AC_002d3-Metadata"></a>

  2291. <h4 class="subsection">8.2.1 AC-3 Metadata<span class="pull-right"><a class="anchor hidden-xs" href="#AC_002d3-Metadata" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-AC_002d3-Metadata" aria-hidden="true">TOC</a></span></h4>

  2292. 

  2293. <p>The AC-3 metadata options are used to set parameters that describe the audio,

  2294. but in most cases do not affect the audio encoding itself. Some of the options

  2295. do directly affect or influence the decoding and playback of the resulting

  2296. bitstream, while others are just for informational purposes. A few of the

  2297. options will add bits to the output stream that could otherwise be used for

  2298. audio data, and will thus affect the quality of the output. Those will be

  2299. indicated accordingly with a note in the option list below.

  2300. </p>

  2301. <p>These parameters are described in detail in several publicly-available

  2302. documents.

  2303. </p><ul>

  2304. <li> <a href="http://www.atsc.org/cms/standards/a_52-2010.pdf">A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard</a>

  2305. </li><li> <a href="http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf">A/54 - Guide to the Use of the ATSC Digital Television Standard</a>

  2306. </li><li> <a href="http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf">Dolby Metadata Guide</a>

  2307. </li><li> <a href="http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf">Dolby Digital Professional Encoding Guidelines</a>

  2308. </li></ul>

  2309. 

  2310. <a name="Metadata-Control-Options"></a>

  2311. <h4 class="subsubsection">8.2.1.1 Metadata Control Options<span class="pull-right"><a class="anchor hidden-xs" href="#Metadata-Control-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Metadata-Control-Options" aria-hidden="true">TOC</a></span></h4>

  2312. 

  2313. <dl compact="compact">

  2314. <dt><span><samp>-per_frame_metadata <var>boolean</var></samp></span></dt>

  2315. <dd><p>Allow Per-Frame Metadata. Specifies if the encoder should check for changing

  2316. metadata for each frame.

  2317. </p><dl compact="compact">

  2318. <dt><span><samp>0</samp></span></dt>

  2319. <dd><p>The metadata values set at initialization will be used for every frame in the

  2320. stream. (default)

  2321. </p></dd>

  2322. <dt><span><samp>1</samp></span></dt>

  2323. <dd><p>Metadata values can be changed before encoding each frame.

  2324. </p></dd>

  2325. </dl>

  2326. 

  2327. </dd>

  2328. </dl>

  2329. 

  2330. <a name="Downmix-Levels"></a>

  2331. <h4 class="subsubsection">8.2.1.2 Downmix Levels<span class="pull-right"><a class="anchor hidden-xs" href="#Downmix-Levels" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Downmix-Levels" aria-hidden="true">TOC</a></span></h4>

  2332. 

  2333. <dl compact="compact">

  2334. <dt><span><samp>-center_mixlev <var>level</var></samp></span></dt>

  2335. <dd><p>Center Mix Level. The amount of gain the decoder should apply to the center

  2336. channel when downmixing to stereo. This field will only be written to the

  2337. bitstream if a center channel is present. The value is specified as a scale

  2338. factor. There are 3 valid values:

  2339. </p><dl compact="compact">

  2340. <dt><span><samp>0.707</samp></span></dt>

  2341. <dd><p>Apply -3dB gain

  2342. </p></dd>

  2343. <dt><span><samp>0.595</samp></span></dt>

  2344. <dd><p>Apply -4.5dB gain (default)

  2345. </p></dd>

  2346. <dt><span><samp>0.500</samp></span></dt>

  2347. <dd><p>Apply -6dB gain

  2348. </p></dd>

  2349. </dl>

  2350. 

  2351. </dd>

  2352. <dt><span><samp>-surround_mixlev <var>level</var></samp></span></dt>

  2353. <dd><p>Surround Mix Level. The amount of gain the decoder should apply to the surround

  2354. channel(s) when downmixing to stereo. This field will only be written to the

  2355. bitstream if one or more surround channels are present. The value is specified

  2356. as a scale factor.  There are 3 valid values:

  2357. </p><dl compact="compact">

  2358. <dt><span><samp>0.707</samp></span></dt>

  2359. <dd><p>Apply -3dB gain

  2360. </p></dd>

  2361. <dt><span><samp>0.500</samp></span></dt>

  2362. <dd><p>Apply -6dB gain (default)

  2363. </p></dd>

  2364. <dt><span><samp>0.000</samp></span></dt>

  2365. <dd><p>Silence Surround Channel(s)

  2366. </p></dd>

  2367. </dl>

  2368. 

  2369. </dd>

  2370. </dl>

  2371. 

  2372. <a name="Audio-Production-Information"></a>

  2373. <h4 class="subsubsection">8.2.1.3 Audio Production Information<span class="pull-right"><a class="anchor hidden-xs" href="#Audio-Production-Information" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Audio-Production-Information" aria-hidden="true">TOC</a></span></h4>

  2374. <p>Audio Production Information is optional information describing the mixing

  2375. environment.  Either none or both of the fields are written to the bitstream.

  2376. </p>

  2377. <dl compact="compact">

  2378. <dt><span><samp>-mixing_level <var>number</var></samp></span></dt>

  2379. <dd><p>Mixing Level. Specifies peak sound pressure level (SPL) in the production

  2380. environment when the mix was mastered. Valid values are 80 to 111, or -1 for

  2381. unknown or not indicated. The default value is -1, but that value cannot be

  2382. used if the Audio Production Information is written to the bitstream. Therefore,

  2383. if the <code>room_type</code> option is not the default value, the <code>mixing_level</code>

  2384. option must not be -1.

  2385. </p>

  2386. </dd>

  2387. <dt><span><samp>-room_type <var>type</var></samp></span></dt>

  2388. <dd><p>Room Type. Describes the equalization used during the final mixing session at

  2389. the studio or on the dubbing stage. A large room is a dubbing stage with the

  2390. industry standard X-curve equalization; a small room has flat equalization.

  2391. This field will not be written to the bitstream if both the <code>mixing_level</code>

  2392. option and the <code>room_type</code> option have the default values.

  2393. </p><dl compact="compact">

  2394. <dt><span><samp>0</samp></span></dt>

  2395. <dt><span><samp>notindicated</samp></span></dt>

  2396. <dd><p>Not Indicated (default)

  2397. </p></dd>

  2398. <dt><span><samp>1</samp></span></dt>

  2399. <dt><span><samp>large</samp></span></dt>

  2400. <dd><p>Large Room

  2401. </p></dd>

  2402. <dt><span><samp>2</samp></span></dt>

  2403. <dt><span><samp>small</samp></span></dt>

  2404. <dd><p>Small Room

  2405. </p></dd>

  2406. </dl>

  2407. 

  2408. </dd>

  2409. </dl>

  2410. 

  2411. <a name="Other-Metadata-Options"></a>

  2412. <h4 class="subsubsection">8.2.1.4 Other Metadata Options<span class="pull-right"><a class="anchor hidden-xs" href="#Other-Metadata-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Other-Metadata-Options" aria-hidden="true">TOC</a></span></h4>

  2413. 

  2414. <dl compact="compact">

  2415. <dt><span><samp>-copyright <var>boolean</var></samp></span></dt>

  2416. <dd><p>Copyright Indicator. Specifies whether a copyright exists for this audio.

  2417. </p><dl compact="compact">

  2418. <dt><span><samp>0</samp></span></dt>

  2419. <dt><span><samp>off</samp></span></dt>

  2420. <dd><p>No Copyright Exists (default)

  2421. </p></dd>

  2422. <dt><span><samp>1</samp></span></dt>

  2423. <dt><span><samp>on</samp></span></dt>

  2424. <dd><p>Copyright Exists

  2425. </p></dd>

  2426. </dl>

  2427. 

  2428. </dd>

  2429. <dt><span><samp>-dialnorm <var>value</var></samp></span></dt>

  2430. <dd><p>Dialogue Normalization. Indicates how far the average dialogue level of the

  2431. program is below digital 100% full scale (0 dBFS). This parameter determines a

  2432. level shift during audio reproduction that sets the average volume of the

  2433. dialogue to a preset level. The goal is to match volume level between program

  2434. sources. A value of -31dB will result in no volume level change, relative to

  2435. the source volume, during audio reproduction. Valid values are whole numbers in

  2436. the range -31 to -1, with -31 being the default.

  2437. </p>

  2438. </dd>

  2439. <dt><span><samp>-dsur_mode <var>mode</var></samp></span></dt>

  2440. <dd><p>Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround

  2441. (Pro Logic). This field will only be written to the bitstream if the audio

  2442. stream is stereo. Using this option does <b>NOT</b> mean the encoder will actually

  2443. apply Dolby Surround processing.

  2444. </p><dl compact="compact">

  2445. <dt><span><samp>0</samp></span></dt>

  2446. <dt><span><samp>notindicated</samp></span></dt>

  2447. <dd><p>Not Indicated (default)

  2448. </p></dd>

  2449. <dt><span><samp>1</samp></span></dt>

  2450. <dt><span><samp>off</samp></span></dt>

  2451. <dd><p>Not Dolby Surround Encoded

  2452. </p></dd>

  2453. <dt><span><samp>2</samp></span></dt>

  2454. <dt><span><samp>on</samp></span></dt>

  2455. <dd><p>Dolby Surround Encoded

  2456. </p></dd>

  2457. </dl>

  2458. 

  2459. </dd>

  2460. <dt><span><samp>-original <var>boolean</var></samp></span></dt>

  2461. <dd><p>Original Bit Stream Indicator. Specifies whether this audio is from the

  2462. original source and not a copy.

  2463. </p><dl compact="compact">

  2464. <dt><span><samp>0</samp></span></dt>

  2465. <dt><span><samp>off</samp></span></dt>

  2466. <dd><p>Not Original Source

  2467. </p></dd>

  2468. <dt><span><samp>1</samp></span></dt>

  2469. <dt><span><samp>on</samp></span></dt>

  2470. <dd><p>Original Source (default)

  2471. </p></dd>

  2472. </dl>

  2473. 

  2474. </dd>

  2475. </dl>

  2476. 

  2477. <a name="Extended-Bitstream-Information"></a>

  2478. <h4 class="subsection">8.2.2 Extended Bitstream Information<span class="pull-right"><a class="anchor hidden-xs" href="#Extended-Bitstream-Information" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Extended-Bitstream-Information" aria-hidden="true">TOC</a></span></h4>

  2479. <p>The extended bitstream options are part of the Alternate Bit Stream Syntax as

  2480. specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.

  2481. If any one parameter in a group is specified, all values in that group will be

  2482. written to the bitstream.  Default values are used for those that are written

  2483. but have not been specified.  If the mixing levels are written, the decoder

  2484. will use these values instead of the ones specified in the <code>center_mixlev</code>

  2485. and <code>surround_mixlev</code> options if it supports the Alternate Bit Stream

  2486. Syntax.

  2487. </p>

  2488. <a name="Extended-Bitstream-Information-_002d-Part-1"></a>

  2489. <h4 class="subsubsection">8.2.2.1 Extended Bitstream Information - Part 1<span class="pull-right"><a class="anchor hidden-xs" href="#Extended-Bitstream-Information-_002d-Part-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Extended-Bitstream-Information-_002d-Part-1" aria-hidden="true">TOC</a></span></h4>

  2490. 

  2491. <dl compact="compact">

  2492. <dt><span><samp>-dmix_mode <var>mode</var></samp></span></dt>

  2493. <dd><p>Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt

  2494. (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.

  2495. </p><dl compact="compact">

  2496. <dt><span><samp>0</samp></span></dt>

  2497. <dt><span><samp>notindicated</samp></span></dt>

  2498. <dd><p>Not Indicated (default)

  2499. </p></dd>

  2500. <dt><span><samp>1</samp></span></dt>

  2501. <dt><span><samp>ltrt</samp></span></dt>

  2502. <dd><p>Lt/Rt Downmix Preferred

  2503. </p></dd>

  2504. <dt><span><samp>2</samp></span></dt>

  2505. <dt><span><samp>loro</samp></span></dt>

  2506. <dd><p>Lo/Ro Downmix Preferred

  2507. </p></dd>

  2508. </dl>

  2509. 

  2510. </dd>

  2511. <dt><span><samp>-ltrt_cmixlev <var>level</var></samp></span></dt>

  2512. <dd><p>Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the

  2513. center channel when downmixing to stereo in Lt/Rt mode.

  2514. </p><dl compact="compact">

  2515. <dt><span><samp>1.414</samp></span></dt>

  2516. <dd><p>Apply +3dB gain

  2517. </p></dd>

  2518. <dt><span><samp>1.189</samp></span></dt>

  2519. <dd><p>Apply +1.5dB gain

  2520. </p></dd>

  2521. <dt><span><samp>1.000</samp></span></dt>

  2522. <dd><p>Apply 0dB gain

  2523. </p></dd>

  2524. <dt><span><samp>0.841</samp></span></dt>

  2525. <dd><p>Apply -1.5dB gain

  2526. </p></dd>

  2527. <dt><span><samp>0.707</samp></span></dt>

  2528. <dd><p>Apply -3.0dB gain

  2529. </p></dd>

  2530. <dt><span><samp>0.595</samp></span></dt>

  2531. <dd><p>Apply -4.5dB gain (default)

  2532. </p></dd>

  2533. <dt><span><samp>0.500</samp></span></dt>

  2534. <dd><p>Apply -6.0dB gain

  2535. </p></dd>

  2536. <dt><span><samp>0.000</samp></span></dt>

  2537. <dd><p>Silence Center Channel

  2538. </p></dd>

  2539. </dl>

  2540. 

  2541. </dd>

  2542. <dt><span><samp>-ltrt_surmixlev <var>level</var></samp></span></dt>

  2543. <dd><p>Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the

  2544. surround channel(s) when downmixing to stereo in Lt/Rt mode.

  2545. </p><dl compact="compact">

  2546. <dt><span><samp>0.841</samp></span></dt>

  2547. <dd><p>Apply -1.5dB gain

  2548. </p></dd>

  2549. <dt><span><samp>0.707</samp></span></dt>

  2550. <dd><p>Apply -3.0dB gain

  2551. </p></dd>

  2552. <dt><span><samp>0.595</samp></span></dt>

  2553. <dd><p>Apply -4.5dB gain

  2554. </p></dd>

  2555. <dt><span><samp>0.500</samp></span></dt>

  2556. <dd><p>Apply -6.0dB gain (default)

  2557. </p></dd>

  2558. <dt><span><samp>0.000</samp></span></dt>

  2559. <dd><p>Silence Surround Channel(s)

  2560. </p></dd>

  2561. </dl>

  2562. 

  2563. </dd>

  2564. <dt><span><samp>-loro_cmixlev <var>level</var></samp></span></dt>

  2565. <dd><p>Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the

  2566. center channel when downmixing to stereo in Lo/Ro mode.

  2567. </p><dl compact="compact">

  2568. <dt><span><samp>1.414</samp></span></dt>

  2569. <dd><p>Apply +3dB gain

  2570. </p></dd>

  2571. <dt><span><samp>1.189</samp></span></dt>

  2572. <dd><p>Apply +1.5dB gain

  2573. </p></dd>

  2574. <dt><span><samp>1.000</samp></span></dt>

  2575. <dd><p>Apply 0dB gain

  2576. </p></dd>

  2577. <dt><span><samp>0.841</samp></span></dt>

  2578. <dd><p>Apply -1.5dB gain

  2579. </p></dd>

  2580. <dt><span><samp>0.707</samp></span></dt>

  2581. <dd><p>Apply -3.0dB gain

  2582. </p></dd>

  2583. <dt><span><samp>0.595</samp></span></dt>

  2584. <dd><p>Apply -4.5dB gain (default)

  2585. </p></dd>

  2586. <dt><span><samp>0.500</samp></span></dt>

  2587. <dd><p>Apply -6.0dB gain

  2588. </p></dd>

  2589. <dt><span><samp>0.000</samp></span></dt>

  2590. <dd><p>Silence Center Channel

  2591. </p></dd>

  2592. </dl>

  2593. 

  2594. </dd>

  2595. <dt><span><samp>-loro_surmixlev <var>level</var></samp></span></dt>

  2596. <dd><p>Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the

  2597. surround channel(s) when downmixing to stereo in Lo/Ro mode.

  2598. </p><dl compact="compact">

  2599. <dt><span><samp>0.841</samp></span></dt>

  2600. <dd><p>Apply -1.5dB gain

  2601. </p></dd>

  2602. <dt><span><samp>0.707</samp></span></dt>

  2603. <dd><p>Apply -3.0dB gain

  2604. </p></dd>

  2605. <dt><span><samp>0.595</samp></span></dt>

  2606. <dd><p>Apply -4.5dB gain

  2607. </p></dd>

  2608. <dt><span><samp>0.500</samp></span></dt>

  2609. <dd><p>Apply -6.0dB gain (default)

  2610. </p></dd>

  2611. <dt><span><samp>0.000</samp></span></dt>

  2612. <dd><p>Silence Surround Channel(s)

  2613. </p></dd>

  2614. </dl>

  2615. 

  2616. </dd>

  2617. </dl>

  2618. 

  2619. <a name="Extended-Bitstream-Information-_002d-Part-2"></a>

  2620. <h4 class="subsubsection">8.2.2.2 Extended Bitstream Information - Part 2<span class="pull-right"><a class="anchor hidden-xs" href="#Extended-Bitstream-Information-_002d-Part-2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Extended-Bitstream-Information-_002d-Part-2" aria-hidden="true">TOC</a></span></h4>

  2621. 

  2622. <dl compact="compact">

  2623. <dt><span><samp>-dsurex_mode <var>mode</var></samp></span></dt>

  2624. <dd><p>Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX

  2625. (7.1 matrixed to 5.1). Using this option does <b>NOT</b> mean the encoder will actually

  2626. apply Dolby Surround EX processing.

  2627. </p><dl compact="compact">

  2628. <dt><span><samp>0</samp></span></dt>

  2629. <dt><span><samp>notindicated</samp></span></dt>

  2630. <dd><p>Not Indicated (default)

  2631. </p></dd>

  2632. <dt><span><samp>1</samp></span></dt>

  2633. <dt><span><samp>on</samp></span></dt>

  2634. <dd><p>Dolby Surround EX Off

  2635. </p></dd>

  2636. <dt><span><samp>2</samp></span></dt>

  2637. <dt><span><samp>off</samp></span></dt>

  2638. <dd><p>Dolby Surround EX On

  2639. </p></dd>

  2640. </dl>

  2641. 

  2642. </dd>

  2643. <dt><span><samp>-dheadphone_mode <var>mode</var></samp></span></dt>

  2644. <dd><p>Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone

  2645. encoding (multi-channel matrixed to 2.0 for use with headphones). Using this

  2646. option does <b>NOT</b> mean the encoder will actually apply Dolby Headphone

  2647. processing.

  2648. </p><dl compact="compact">

  2649. <dt><span><samp>0</samp></span></dt>

  2650. <dt><span><samp>notindicated</samp></span></dt>

  2651. <dd><p>Not Indicated (default)

  2652. </p></dd>

  2653. <dt><span><samp>1</samp></span></dt>

  2654. <dt><span><samp>on</samp></span></dt>

  2655. <dd><p>Dolby Headphone Off

  2656. </p></dd>

  2657. <dt><span><samp>2</samp></span></dt>

  2658. <dt><span><samp>off</samp></span></dt>

  2659. <dd><p>Dolby Headphone On

  2660. </p></dd>

  2661. </dl>

  2662. 

  2663. </dd>

  2664. <dt><span><samp>-ad_conv_type <var>type</var></samp></span></dt>

  2665. <dd><p>A/D Converter Type. Indicates whether the audio has passed through HDCD A/D

  2666. conversion.

  2667. </p><dl compact="compact">

  2668. <dt><span><samp>0</samp></span></dt>

  2669. <dt><span><samp>standard</samp></span></dt>

  2670. <dd><p>Standard A/D Converter (default)

  2671. </p></dd>

  2672. <dt><span><samp>1</samp></span></dt>

  2673. <dt><span><samp>hdcd</samp></span></dt>

  2674. <dd><p>HDCD A/D Converter

  2675. </p></dd>

  2676. </dl>

  2677. 

  2678. </dd>

  2679. </dl>

  2680. 

  2681. <a name="Other-AC_002d3-Encoding-Options"></a>

  2682. <h4 class="subsection">8.2.3 Other AC-3 Encoding Options<span class="pull-right"><a class="anchor hidden-xs" href="#Other-AC_002d3-Encoding-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Other-AC_002d3-Encoding-Options" aria-hidden="true">TOC</a></span></h4>

  2683. 

  2684. <dl compact="compact">

  2685. <dt><span><samp>-stereo_rematrixing <var>boolean</var></samp></span></dt>

  2686. <dd><p>Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This

  2687. is an optional AC-3 feature that increases quality by selectively encoding

  2688. the left/right channels as mid/side. This option is enabled by default, and it

  2689. is highly recommended that it be left as enabled except for testing purposes.

  2690. </p>

  2691. </dd>

  2692. <dt><span><samp>cutoff <var>frequency</var></samp></span></dt>

  2693. <dd><p>Set lowpass cutoff frequency. If unspecified, the encoder selects a default

  2694. determined by various other encoding parameters.

  2695. </p>

  2696. </dd>

  2697. </dl>

  2698. 

  2699. <a name="Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options"></a>

  2700. <h4 class="subsection">8.2.4 Floating-Point-Only AC-3 Encoding Options<span class="pull-right"><a class="anchor hidden-xs" href="#Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options" aria-hidden="true">TOC</a></span></h4>

  2701. 

  2702. <p>These options are only valid for the floating-point encoder and do not exist

  2703. for the fixed-point encoder due to the corresponding features not being

  2704. implemented in fixed-point.

  2705. </p>

  2706. <dl compact="compact">

  2707. <dt><span><samp>-channel_coupling <var>boolean</var></samp></span></dt>

  2708. <dd><p>Enables/Disables use of channel coupling, which is an optional AC-3 feature

  2709. that increases quality by combining high frequency information from multiple

  2710. channels into a single channel. The per-channel high frequency information is

  2711. sent with less accuracy in both the frequency and time domains. This allows

  2712. more bits to be used for lower frequencies while preserving enough information

  2713. to reconstruct the high frequencies. This option is enabled by default for the

  2714. floating-point encoder and should generally be left as enabled except for

  2715. testing purposes or to increase encoding speed.

  2716. </p><dl compact="compact">

  2717. <dt><span><samp>-1</samp></span></dt>

  2718. <dt><span><samp>auto</samp></span></dt>

  2719. <dd><p>Selected by Encoder (default)

  2720. </p></dd>

  2721. <dt><span><samp>0</samp></span></dt>

  2722. <dt><span><samp>off</samp></span></dt>

  2723. <dd><p>Disable Channel Coupling

  2724. </p></dd>

  2725. <dt><span><samp>1</samp></span></dt>

  2726. <dt><span><samp>on</samp></span></dt>

  2727. <dd><p>Enable Channel Coupling

  2728. </p></dd>

  2729. </dl>

  2730. 

  2731. </dd>

  2732. <dt><span><samp>-cpl_start_band <var>number</var></samp></span></dt>

  2733. <dd><p>Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a

  2734. value higher than the bandwidth is used, it will be reduced to 1 less than the

  2735. coupling end band. If <var>auto</var> is used, the start band will be determined by

  2736. the encoder based on the bit rate, sample rate, and channel layout. This option

  2737. has no effect if channel coupling is disabled.

  2738. </p><dl compact="compact">

  2739. <dt><span><samp>-1</samp></span></dt>

  2740. <dt><span><samp>auto</samp></span></dt>

  2741. <dd><p>Selected by Encoder (default)

  2742. </p></dd>

  2743. </dl>

  2744. 

  2745. </dd>

  2746. </dl>

  2747. 

  2748. <span id="flac"></span><a name="flac-2"></a>

  2749. <h3 class="section">8.3 flac<span class="pull-right"><a class="anchor hidden-xs" href="#flac-2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-flac-2" aria-hidden="true">TOC</a></span></h3>

  2750. 

  2751. <p>FLAC (Free Lossless Audio Codec) Encoder

  2752. </p>

  2753. <a name="Options-10"></a>

  2754. <h4 class="subsection">8.3.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-10" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-10" aria-hidden="true">TOC</a></span></h4>

  2755. 

  2756. <p>The following options are supported by FFmpeg&rsquo;s flac encoder.

  2757. </p>

  2758. <dl compact="compact">

  2759. <dt><span><samp>compression_level</samp></span></dt>

  2760. <dd><p>Sets the compression level, which chooses defaults for many other options

  2761. if they are not set explicitly. Valid values are from 0 to 12, 5 is the

  2762. default.

  2763. </p>

  2764. </dd>

  2765. <dt><span><samp>frame_size</samp></span></dt>

  2766. <dd><p>Sets the size of the frames in samples per channel.

  2767. </p>

  2768. </dd>

  2769. <dt><span><samp>lpc_coeff_precision</samp></span></dt>

  2770. <dd><p>Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the

  2771. default.

  2772. </p>

  2773. </dd>

  2774. <dt><span><samp>lpc_type</samp></span></dt>

  2775. <dd><p>Sets the first stage LPC algorithm

  2776. </p><dl compact="compact">

  2777. <dt><span>&lsquo;<samp>none</samp>&rsquo;</span></dt>

  2778. <dd><p>LPC is not used

  2779. </p>

  2780. </dd>

  2781. <dt><span>&lsquo;<samp>fixed</samp>&rsquo;</span></dt>

  2782. <dd><p>fixed LPC coefficients

  2783. </p>

  2784. </dd>

  2785. <dt><span>&lsquo;<samp>levinson</samp>&rsquo;</span></dt>

  2786. <dt><span>&lsquo;<samp>cholesky</samp>&rsquo;</span></dt>

  2787. </dl>

  2788. 

  2789. </dd>

  2790. <dt><span><samp>lpc_passes</samp></span></dt>

  2791. <dd><p>Number of passes to use for Cholesky factorization during LPC analysis

  2792. </p>

  2793. </dd>

  2794. <dt><span><samp>min_partition_order</samp></span></dt>

  2795. <dd><p>The minimum partition order

  2796. </p>

  2797. </dd>

  2798. <dt><span><samp>max_partition_order</samp></span></dt>

  2799. <dd><p>The maximum partition order

  2800. </p>

  2801. </dd>

  2802. <dt><span><samp>prediction_order_method</samp></span></dt>

  2803. <dd><dl compact="compact">

  2804. <dt><span>&lsquo;<samp>estimation</samp>&rsquo;</span></dt>

  2805. <dt><span>&lsquo;<samp>2level</samp>&rsquo;</span></dt>

  2806. <dt><span>&lsquo;<samp>4level</samp>&rsquo;</span></dt>

  2807. <dt><span>&lsquo;<samp>8level</samp>&rsquo;</span></dt>

  2808. <dt><span>&lsquo;<samp>search</samp>&rsquo;</span></dt>

  2809. <dd><p>Bruteforce search

  2810. </p></dd>

  2811. <dt><span>&lsquo;<samp>log</samp>&rsquo;</span></dt>

  2812. </dl>

  2813. 

  2814. </dd>

  2815. <dt><span><samp>ch_mode</samp></span></dt>

  2816. <dd><p>Channel mode

  2817. </p><dl compact="compact">

  2818. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  2819. <dd><p>The mode is chosen automatically for each frame

  2820. </p></dd>

  2821. <dt><span>&lsquo;<samp>indep</samp>&rsquo;</span></dt>

  2822. <dd><p>Channels are independently coded

  2823. </p></dd>

  2824. <dt><span>&lsquo;<samp>left_side</samp>&rsquo;</span></dt>

  2825. <dt><span>&lsquo;<samp>right_side</samp>&rsquo;</span></dt>

  2826. <dt><span>&lsquo;<samp>mid_side</samp>&rsquo;</span></dt>

  2827. </dl>

  2828. 

  2829. </dd>

  2830. <dt><span><samp>exact_rice_parameters</samp></span></dt>

  2831. <dd><p>Chooses if rice parameters are calculated exactly or approximately.

  2832. if set to 1 then they are chosen exactly, which slows the code down slightly and

  2833. improves compression slightly.

  2834. </p>

  2835. </dd>

  2836. <dt><span><samp>multi_dim_quant</samp></span></dt>

  2837. <dd><p>Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is

  2838. applied after the first stage to finetune the coefficients. This is quite slow

  2839. and slightly improves compression.

  2840. </p>

  2841. </dd>

  2842. </dl>

  2843. 

  2844. <span id="opusenc"></span><a name="opus"></a>

  2845. <h3 class="section">8.4 opus<span class="pull-right"><a class="anchor hidden-xs" href="#opus" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-opus" aria-hidden="true">TOC</a></span></h3>

  2846. 

  2847. <p>Opus encoder.

  2848. </p>

  2849. <p>This is a native FFmpeg encoder for the Opus format. Currently its in development and

  2850. only implements the CELT part of the codec. Its quality is usually worse and at best

  2851. is equal to the libopus encoder.

  2852. </p>

  2853. <a name="Options-11"></a>

  2854. <h4 class="subsection">8.4.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-11" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-11" aria-hidden="true">TOC</a></span></h4>

  2855. 

  2856. <dl compact="compact">

  2857. <dt><span><samp>b</samp></span></dt>

  2858. <dd><p>Set bit rate in bits/s. If unspecified it uses the number of channels and the layout

  2859. to make a good guess.

  2860. </p>

  2861. </dd>

  2862. <dt><span><samp>opus_delay</samp></span></dt>

  2863. <dd><p>Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly

  2864. decrease quality.

  2865. </p></dd>

  2866. </dl>

  2867. 

  2868. <span id="libfdk_002daac_002denc"></span><a name="libfdk_005faac"></a>

  2869. <h3 class="section">8.5 libfdk_aac<span class="pull-right"><a class="anchor hidden-xs" href="#libfdk_005faac" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libfdk_005faac" aria-hidden="true">TOC</a></span></h3>

  2870. 

  2871. <p>libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.

  2872. </p>

  2873. <p>The libfdk-aac library is based on the Fraunhofer FDK AAC code from

  2874. the Android project.

  2875. </p>

  2876. <p>Requires the presence of the libfdk-aac headers and library during

  2877. configuration. You need to explicitly configure the build with

  2878. <code>--enable-libfdk-aac</code>. The library is also incompatible with GPL,

  2879. so if you allow the use of GPL, you should configure with

  2880. <code>--enable-gpl --enable-nonfree --enable-libfdk-aac</code>.

  2881. </p>

  2882. <p>This encoder has support for the AAC-HE profiles.

  2883. </p>

  2884. <p>VBR encoding, enabled through the <samp>vbr</samp> or <samp>flags

  2885. +qscale</samp> options, is experimental and only works with some

  2886. combinations of parameters.

  2887. </p>

  2888. <p>Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or

  2889. higher.

  2890. </p>

  2891. <p>For more information see the fdk-aac project at

  2892. <a href="http://sourceforge.net/p/opencore-amr/fdk-aac/">http://sourceforge.net/p/opencore-amr/fdk-aac/</a>.

  2893. </p>

  2894. <a name="Options-12"></a>

  2895. <h4 class="subsection">8.5.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-12" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-12" aria-hidden="true">TOC</a></span></h4>

  2896. 

  2897. <p>The following options are mapped on the shared FFmpeg codec options.

  2898. </p>

  2899. <dl compact="compact">

  2900. <dt><span><samp>b</samp></span></dt>

  2901. <dd><p>Set bit rate in bits/s. If the bitrate is not explicitly specified, it

  2902. is automatically set to a suitable value depending on the selected

  2903. profile.

  2904. </p>

  2905. <p>In case VBR mode is enabled the option is ignored.

  2906. </p>

  2907. </dd>

  2908. <dt><span><samp>ar</samp></span></dt>

  2909. <dd><p>Set audio sampling rate (in Hz).

  2910. </p>

  2911. </dd>

  2912. <dt><span><samp>channels</samp></span></dt>

  2913. <dd><p>Set the number of audio channels.

  2914. </p>

  2915. </dd>

  2916. <dt><span><samp>flags +qscale</samp></span></dt>

  2917. <dd><p>Enable fixed quality, VBR (Variable Bit Rate) mode.

  2918. Note that VBR is implicitly enabled when the <samp>vbr</samp> value is

  2919. positive.

  2920. </p>

  2921. </dd>

  2922. <dt><span><samp>cutoff</samp></span></dt>

  2923. <dd><p>Set cutoff frequency. If not specified (or explicitly set to 0) it

  2924. will use a value automatically computed by the library. Default value

  2925. is 0.

  2926. </p>

  2927. </dd>

  2928. <dt><span><samp>profile</samp></span></dt>

  2929. <dd><p>Set audio profile.

  2930. </p>

  2931. <p>The following profiles are recognized:

  2932. </p><dl compact="compact">

  2933. <dt><span>&lsquo;<samp>aac_low</samp>&rsquo;</span></dt>

  2934. <dd><p>Low Complexity AAC (LC)

  2935. </p>

  2936. </dd>

  2937. <dt><span>&lsquo;<samp>aac_he</samp>&rsquo;</span></dt>

  2938. <dd><p>High Efficiency AAC (HE-AAC)

  2939. </p>

  2940. </dd>

  2941. <dt><span>&lsquo;<samp>aac_he_v2</samp>&rsquo;</span></dt>

  2942. <dd><p>High Efficiency AAC version 2 (HE-AACv2)

  2943. </p>

  2944. </dd>

  2945. <dt><span>&lsquo;<samp>aac_ld</samp>&rsquo;</span></dt>

  2946. <dd><p>Low Delay AAC (LD)

  2947. </p>

  2948. </dd>

  2949. <dt><span>&lsquo;<samp>aac_eld</samp>&rsquo;</span></dt>

  2950. <dd><p>Enhanced Low Delay AAC (ELD)

  2951. </p></dd>

  2952. </dl>

  2953. 

  2954. <p>If not specified it is set to &lsquo;<samp>aac_low</samp>&rsquo;.

  2955. </p></dd>

  2956. </dl>

  2957. 

  2958. <p>The following are private options of the libfdk_aac encoder.

  2959. </p>

  2960. <dl compact="compact">

  2961. <dt><span><samp>afterburner</samp></span></dt>

  2962. <dd><p>Enable afterburner feature if set to 1, disabled if set to 0. This

  2963. improves the quality but also the required processing power.

  2964. </p>

  2965. <p>Default value is 1.

  2966. </p>

  2967. </dd>

  2968. <dt><span><samp>eld_sbr</samp></span></dt>

  2969. <dd><p>Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled

  2970. if set to 0.

  2971. </p>

  2972. <p>Default value is 0.

  2973. </p>

  2974. </dd>

  2975. <dt><span><samp>eld_v2</samp></span></dt>

  2976. <dd><p>Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if set to 1,

  2977. disabled if set to 0.

  2978. </p>

  2979. <p>Note that option is available when fdk-aac version (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) &gt; (4.0.0).

  2980. </p>

  2981. <p>Default value is 0.

  2982. </p>

  2983. </dd>

  2984. <dt><span><samp>signaling</samp></span></dt>

  2985. <dd><p>Set SBR/PS signaling style.

  2986. </p>

  2987. <p>It can assume one of the following values:

  2988. </p><dl compact="compact">

  2989. <dt><span>&lsquo;<samp>default</samp>&rsquo;</span></dt>

  2990. <dd><p>choose signaling implicitly (explicit hierarchical by default,

  2991. implicit if global header is disabled)

  2992. </p>

  2993. </dd>

  2994. <dt><span>&lsquo;<samp>implicit</samp>&rsquo;</span></dt>

  2995. <dd><p>implicit backwards compatible signaling

  2996. </p>

  2997. </dd>

  2998. <dt><span>&lsquo;<samp>explicit_sbr</samp>&rsquo;</span></dt>

  2999. <dd><p>explicit SBR, implicit PS signaling

  3000. </p>

  3001. </dd>

  3002. <dt><span>&lsquo;<samp>explicit_hierarchical</samp>&rsquo;</span></dt>

  3003. <dd><p>explicit hierarchical signaling

  3004. </p></dd>

  3005. </dl>

  3006. 

  3007. <p>Default value is &lsquo;<samp>default</samp>&rsquo;.

  3008. </p>

  3009. </dd>

  3010. <dt><span><samp>latm</samp></span></dt>

  3011. <dd><p>Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.

  3012. </p>

  3013. <p>Default value is 0.

  3014. </p>

  3015. </dd>

  3016. <dt><span><samp>header_period</samp></span></dt>

  3017. <dd><p>Set StreamMuxConfig and PCE repetition period (in frames) for sending

  3018. in-band configuration buffers within LATM/LOAS transport layer.

  3019. </p>

  3020. <p>Must be a 16-bits non-negative integer.

  3021. </p>

  3022. <p>Default value is 0.

  3023. </p>

  3024. </dd>

  3025. <dt><span><samp>vbr</samp></span></dt>

  3026. <dd><p>Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty

  3027. good) and 5 is highest quality. A value of 0 will disable VBR, and CBR

  3028. (Constant Bit Rate) is enabled.

  3029. </p>

  3030. <p>Currently only the &lsquo;<samp>aac_low</samp>&rsquo; profile supports VBR encoding.

  3031. </p>

  3032. <p>VBR modes 1-5 correspond to roughly the following average bit rates:

  3033. </p>

  3034. <dl compact="compact">

  3035. <dt><span>&lsquo;<samp>1</samp>&rsquo;</span></dt>

  3036. <dd><p>32 kbps/channel

  3037. </p></dd>

  3038. <dt><span>&lsquo;<samp>2</samp>&rsquo;</span></dt>

  3039. <dd><p>40 kbps/channel

  3040. </p></dd>

  3041. <dt><span>&lsquo;<samp>3</samp>&rsquo;</span></dt>

  3042. <dd><p>48-56 kbps/channel

  3043. </p></dd>

  3044. <dt><span>&lsquo;<samp>4</samp>&rsquo;</span></dt>

  3045. <dd><p>64 kbps/channel

  3046. </p></dd>

  3047. <dt><span>&lsquo;<samp>5</samp>&rsquo;</span></dt>

  3048. <dd><p>about 80-96 kbps/channel

  3049. </p></dd>

  3050. </dl>

  3051. 

  3052. <p>Default value is 0.

  3053. </p></dd>

  3054. </dl>

  3055. 

  3056. <a name="Examples"></a>

  3057. <h4 class="subsection">8.5.2 Examples<span class="pull-right"><a class="anchor hidden-xs" href="#Examples" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Examples" aria-hidden="true">TOC</a></span></h4>

  3058. 

  3059. <ul>

  3060. <li> Use <code>ffmpeg</code> to convert an audio file to VBR AAC in an M4A (MP4)

  3061. container:

  3062. <div class="example">

  3063. <pre class="example">ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a

  3064. </pre></div>

  3065. 

  3066. </li><li> Use <code>ffmpeg</code> to convert an audio file to CBR 64k kbps AAC, using the

  3067. High-Efficiency AAC profile:

  3068. <div class="example">

  3069. <pre class="example">ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a

  3070. </pre></div>

  3071. </li></ul>

  3072. 

  3073. <span id="libmp3lame"></span><a name="libmp3lame-1"></a>

  3074. <h3 class="section">8.6 libmp3lame<span class="pull-right"><a class="anchor hidden-xs" href="#libmp3lame-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libmp3lame-1" aria-hidden="true">TOC</a></span></h3>

  3075. 

  3076. <p>LAME (Lame Ain&rsquo;t an MP3 Encoder) MP3 encoder wrapper.

  3077. </p>

  3078. <p>Requires the presence of the libmp3lame headers and library during

  3079. configuration. You need to explicitly configure the build with

  3080. <code>--enable-libmp3lame</code>.

  3081. </p>

  3082. <p>See <a href="#libshine">libshine</a> for a fixed-point MP3 encoder, although with a

  3083. lower quality.

  3084. </p>

  3085. <a name="Options-13"></a>

  3086. <h4 class="subsection">8.6.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-13" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-13" aria-hidden="true">TOC</a></span></h4>

  3087. 

  3088. <p>The following options are supported by the libmp3lame wrapper. The

  3089. <code>lame</code>-equivalent of the options are listed in parentheses.

  3090. </p>

  3091. <dl compact="compact">

  3092. <dt><span><samp>b (<em>-b</em>)</samp></span></dt>

  3093. <dd><p>Set bitrate expressed in bits/s for CBR or ABR. LAME <code>bitrate</code> is

  3094. expressed in kilobits/s.

  3095. </p>

  3096. </dd>

  3097. <dt><span><samp>q (<em>-V</em>)</samp></span></dt>

  3098. <dd><p>Set constant quality setting for VBR. This option is valid only

  3099. using the <code>ffmpeg</code> command-line tool. For library interface

  3100. users, use <samp>global_quality</samp>.

  3101. </p>

  3102. </dd>

  3103. <dt><span><samp>compression_level (<em>-q</em>)</samp></span></dt>

  3104. <dd><p>Set algorithm quality. Valid arguments are integers in the 0-9 range,

  3105. with 0 meaning highest quality but slowest, and 9 meaning fastest

  3106. while producing the worst quality.

  3107. </p>

  3108. </dd>

  3109. <dt><span><samp>cutoff (<em>--lowpass</em>)</samp></span></dt>

  3110. <dd><p>Set lowpass cutoff frequency. If unspecified, the encoder dynamically

  3111. adjusts the cutoff.

  3112. </p>

  3113. </dd>

  3114. <dt><span><samp>reservoir</samp></span></dt>

  3115. <dd><p>Enable use of bit reservoir when set to 1. Default value is 1. LAME

  3116. has this enabled by default, but can be overridden by use

  3117. <samp>--nores</samp> option.

  3118. </p>

  3119. </dd>

  3120. <dt><span><samp>joint_stereo (<em>-m j</em>)</samp></span></dt>

  3121. <dd><p>Enable the encoder to use (on a frame by frame basis) either L/R

  3122. stereo or mid/side stereo. Default value is 1.

  3123. </p>

  3124. </dd>

  3125. <dt><span><samp>abr (<em>--abr</em>)</samp></span></dt>

  3126. <dd><p>Enable the encoder to use ABR when set to 1. The <code>lame</code>

  3127. <samp>--abr</samp> sets the target bitrate, while this options only

  3128. tells FFmpeg to use ABR still relies on <samp>b</samp> to set bitrate.

  3129. </p>

  3130. </dd>

  3131. </dl>

  3132. 

  3133. <a name="libopencore_002damrnb-1"></a>

  3134. <h3 class="section">8.7 libopencore-amrnb<span class="pull-right"><a class="anchor hidden-xs" href="#libopencore_002damrnb-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libopencore_002damrnb-1" aria-hidden="true">TOC</a></span></h3>

  3135. 

  3136. <p>OpenCORE Adaptive Multi-Rate Narrowband encoder.

  3137. </p>

  3138. <p>Requires the presence of the libopencore-amrnb headers and library during

  3139. configuration. You need to explicitly configure the build with

  3140. <code>--enable-libopencore-amrnb --enable-version3</code>.

  3141. </p>

  3142. <p>This is a mono-only encoder. Officially it only supports 8000Hz sample rate,

  3143. but you can override it by setting <samp>strict</samp> to &lsquo;<samp>unofficial</samp>&rsquo; or

  3144. lower.

  3145. </p>

  3146. <a name="Options-14"></a>

  3147. <h4 class="subsection">8.7.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-14" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-14" aria-hidden="true">TOC</a></span></h4>

  3148. 

  3149. <dl compact="compact">

  3150. <dt><span><samp>b</samp></span></dt>

  3151. <dd><p>Set bitrate in bits per second. Only the following bitrates are supported,

  3152. otherwise libavcodec will round to the nearest valid bitrate.

  3153. </p>

  3154. <dl compact="compact">

  3155. <dt><span><samp>4750</samp></span></dt>

  3156. <dt><span><samp>5150</samp></span></dt>

  3157. <dt><span><samp>5900</samp></span></dt>

  3158. <dt><span><samp>6700</samp></span></dt>

  3159. <dt><span><samp>7400</samp></span></dt>

  3160. <dt><span><samp>7950</samp></span></dt>

  3161. <dt><span><samp>10200</samp></span></dt>

  3162. <dt><span><samp>12200</samp></span></dt>

  3163. </dl>

  3164. 

  3165. </dd>

  3166. <dt><span><samp>dtx</samp></span></dt>

  3167. <dd><p>Allow discontinuous transmission (generate comfort noise) when set to 1. The

  3168. default value is 0 (disabled).

  3169. </p>

  3170. </dd>

  3171. </dl>

  3172. 

  3173. <a name="libopus-1"></a>

  3174. <h3 class="section">8.8 libopus<span class="pull-right"><a class="anchor hidden-xs" href="#libopus-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libopus-1" aria-hidden="true">TOC</a></span></h3>

  3175. 

  3176. <p>libopus Opus Interactive Audio Codec encoder wrapper.

  3177. </p>

  3178. <p>Requires the presence of the libopus headers and library during

  3179. configuration. You need to explicitly configure the build with

  3180. <code>--enable-libopus</code>.

  3181. </p>

  3182. <a name="Option-Mapping"></a>

  3183. <h4 class="subsection">8.8.1 Option Mapping<span class="pull-right"><a class="anchor hidden-xs" href="#Option-Mapping" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Option-Mapping" aria-hidden="true">TOC</a></span></h4>

  3184. 

  3185. <p>Most libopus options are modelled after the <code>opusenc</code> utility from

  3186. opus-tools. The following is an option mapping chart describing options

  3187. supported by the libopus wrapper, and their <code>opusenc</code>-equivalent

  3188. in parentheses.

  3189. </p>

  3190. <dl compact="compact">

  3191. <dt><span><samp>b (<em>bitrate</em>)</samp></span></dt>

  3192. <dd><p>Set the bit rate in bits/s.  FFmpeg&rsquo;s <samp>b</samp> option is

  3193. expressed in bits/s, while <code>opusenc</code>&rsquo;s <samp>bitrate</samp> in

  3194. kilobits/s.

  3195. </p>

  3196. </dd>

  3197. <dt><span><samp>vbr (<em>vbr</em>, <em>hard-cbr</em>, and <em>cvbr</em>)</samp></span></dt>

  3198. <dd><p>Set VBR mode. The FFmpeg <samp>vbr</samp> option has the following

  3199. valid arguments, with the <code>opusenc</code> equivalent options

  3200. in parentheses:

  3201. </p>

  3202. <dl compact="compact">

  3203. <dt><span>&lsquo;<samp>off (<em>hard-cbr</em>)</samp>&rsquo;</span></dt>

  3204. <dd><p>Use constant bit rate encoding.

  3205. </p>

  3206. </dd>

  3207. <dt><span>&lsquo;<samp>on (<em>vbr</em>)</samp>&rsquo;</span></dt>

  3208. <dd><p>Use variable bit rate encoding (the default).

  3209. </p>

  3210. </dd>

  3211. <dt><span>&lsquo;<samp>constrained (<em>cvbr</em>)</samp>&rsquo;</span></dt>

  3212. <dd><p>Use constrained variable bit rate encoding.

  3213. </p></dd>

  3214. </dl>

  3215. 

  3216. </dd>

  3217. <dt><span><samp>compression_level (<em>comp</em>)</samp></span></dt>

  3218. <dd><p>Set encoding algorithm complexity. Valid options are integers in

  3219. the 0-10 range. 0 gives the fastest encodes but lower quality, while 10

  3220. gives the highest quality but slowest encoding. The default is 10.

  3221. </p>

  3222. </dd>

  3223. <dt><span><samp>frame_duration (<em>framesize</em>)</samp></span></dt>

  3224. <dd><p>Set maximum frame size, or duration of a frame in milliseconds. The

  3225. argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller

  3226. frame sizes achieve lower latency but less quality at a given bitrate.

  3227. Sizes greater than 20ms are only interesting at fairly low bitrates.

  3228. The default is 20ms.

  3229. </p>

  3230. </dd>

  3231. <dt><span><samp>packet_loss (<em>expect-loss</em>)</samp></span></dt>

  3232. <dd><p>Set expected packet loss percentage. The default is 0.

  3233. </p>

  3234. </dd>

  3235. <dt><span><samp>fec (<em>n/a</em>)</samp></span></dt>

  3236. <dd><p>Enable inband forward error correction. <samp>packet_loss</samp> must be non-zero

  3237. to take advantage - frequency of FEC &rsquo;side-data&rsquo; is proportional to expected packet loss.

  3238. Default is disabled.

  3239. </p>

  3240. </dd>

  3241. <dt><span><samp>application (N.A.)</samp></span></dt>

  3242. <dd><p>Set intended application type. Valid options are listed below:

  3243. </p>

  3244. <dl compact="compact">

  3245. <dt><span>&lsquo;<samp>voip</samp>&rsquo;</span></dt>

  3246. <dd><p>Favor improved speech intelligibility.

  3247. </p></dd>

  3248. <dt><span>&lsquo;<samp>audio</samp>&rsquo;</span></dt>

  3249. <dd><p>Favor faithfulness to the input (the default).

  3250. </p></dd>

  3251. <dt><span>&lsquo;<samp>lowdelay</samp>&rsquo;</span></dt>

  3252. <dd><p>Restrict to only the lowest delay modes.

  3253. </p></dd>

  3254. </dl>

  3255. 

  3256. </dd>

  3257. <dt><span><samp>cutoff (N.A.)</samp></span></dt>

  3258. <dd><p>Set cutoff bandwidth in Hz. The argument must be exactly one of the

  3259. following: 4000, 6000, 8000, 12000, or 20000, corresponding to

  3260. narrowband, mediumband, wideband, super wideband, and fullband

  3261. respectively. The default is 0 (cutoff disabled).

  3262. </p>

  3263. </dd>

  3264. <dt><span><samp>mapping_family (<em>mapping_family</em>)</samp></span></dt>

  3265. <dd><p>Set channel mapping family to be used by the encoder. The default value of -1

  3266. uses mapping family 0 for mono and stereo inputs, and mapping family 1

  3267. otherwise. The default also disables the surround masking and LFE bandwidth

  3268. optimzations in libopus, and requires that the input contains 8 channels or

  3269. fewer.

  3270. </p>

  3271. <p>Other values include 0 for mono and stereo, 1 for surround sound with masking

  3272. and LFE bandwidth optimizations, and 255 for independent streams with an

  3273. unspecified channel layout.

  3274. </p>

  3275. </dd>

  3276. <dt><span><samp>apply_phase_inv (N.A.) (requires libopus &gt;= 1.2)</samp></span></dt>

  3277. <dd><p>If set to 0, disables the use of phase inversion for intensity stereo,

  3278. improving the quality of mono downmixes, but slightly reducing normal stereo

  3279. quality. The default is 1 (phase inversion enabled).

  3280. </p>

  3281. </dd>

  3282. </dl>

  3283. 

  3284. <span id="libshine"></span><a name="libshine-1"></a>

  3285. <h3 class="section">8.9 libshine<span class="pull-right"><a class="anchor hidden-xs" href="#libshine-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libshine-1" aria-hidden="true">TOC</a></span></h3>

  3286. 

  3287. <p>Shine Fixed-Point MP3 encoder wrapper.

  3288. </p>

  3289. <p>Shine is a fixed-point MP3 encoder. It has a far better performance on

  3290. platforms without an FPU, e.g. armel CPUs, and some phones and tablets.

  3291. However, as it is more targeted on performance than quality, it is not on par

  3292. with LAME and other production-grade encoders quality-wise. Also, according to

  3293. the project&rsquo;s homepage, this encoder may not be free of bugs as the code was

  3294. written a long time ago and the project was dead for at least 5 years.

  3295. </p>

  3296. <p>This encoder only supports stereo and mono input. This is also CBR-only.

  3297. </p>

  3298. <p>The original project (last updated in early 2007) is at

  3299. <a href="http://sourceforge.net/projects/libshine-fxp/">http://sourceforge.net/projects/libshine-fxp/</a>. We only support the

  3300. updated fork by the Savonet/Liquidsoap project at <a href="https://github.com/savonet/shine">https://github.com/savonet/shine</a>.

  3301. </p>

  3302. <p>Requires the presence of the libshine headers and library during

  3303. configuration. You need to explicitly configure the build with

  3304. <code>--enable-libshine</code>.

  3305. </p>

  3306. <p>See also <a href="#libmp3lame">libmp3lame</a>.

  3307. </p>

  3308. <a name="Options-15"></a>

  3309. <h4 class="subsection">8.9.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-15" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-15" aria-hidden="true">TOC</a></span></h4>

  3310. 

  3311. <p>The following options are supported by the libshine wrapper. The

  3312. <code>shineenc</code>-equivalent of the options are listed in parentheses.

  3313. </p>

  3314. <dl compact="compact">

  3315. <dt><span><samp>b (<em>-b</em>)</samp></span></dt>

  3316. <dd><p>Set bitrate expressed in bits/s for CBR. <code>shineenc</code> <samp>-b</samp> option

  3317. is expressed in kilobits/s.

  3318. </p>

  3319. </dd>

  3320. </dl>

  3321. 

  3322. <a name="libtwolame"></a>

  3323. <h3 class="section">8.10 libtwolame<span class="pull-right"><a class="anchor hidden-xs" href="#libtwolame" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libtwolame" aria-hidden="true">TOC</a></span></h3>

  3324. 

  3325. <p>TwoLAME MP2 encoder wrapper.

  3326. </p>

  3327. <p>Requires the presence of the libtwolame headers and library during

  3328. configuration. You need to explicitly configure the build with

  3329. <code>--enable-libtwolame</code>.

  3330. </p>

  3331. <a name="Options-16"></a>

  3332. <h4 class="subsection">8.10.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-16" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-16" aria-hidden="true">TOC</a></span></h4>

  3333. 

  3334. <p>The following options are supported by the libtwolame wrapper. The

  3335. <code>twolame</code>-equivalent options follow the FFmpeg ones and are in

  3336. parentheses.

  3337. </p>

  3338. <dl compact="compact">

  3339. <dt><span><samp>b (<em>-b</em>)</samp></span></dt>

  3340. <dd><p>Set bitrate expressed in bits/s for CBR. <code>twolame</code> <samp>b</samp>

  3341. option is expressed in kilobits/s. Default value is 128k.

  3342. </p>

  3343. </dd>

  3344. <dt><span><samp>q (<em>-V</em>)</samp></span></dt>

  3345. <dd><p>Set quality for experimental VBR support. Maximum value range is

  3346. from -50 to 50, useful range is from -10 to 10. The higher the

  3347. value, the better the quality. This option is valid only using the

  3348. <code>ffmpeg</code> command-line tool. For library interface users,

  3349. use <samp>global_quality</samp>.

  3350. </p>

  3351. </dd>

  3352. <dt><span><samp>mode (<em>--mode</em>)</samp></span></dt>

  3353. <dd><p>Set the mode of the resulting audio. Possible values:

  3354. </p>

  3355. <dl compact="compact">

  3356. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  3357. <dd><p>Choose mode automatically based on the input. This is the default.

  3358. </p></dd>

  3359. <dt><span>&lsquo;<samp>stereo</samp>&rsquo;</span></dt>

  3360. <dd><p>Stereo

  3361. </p></dd>

  3362. <dt><span>&lsquo;<samp>joint_stereo</samp>&rsquo;</span></dt>

  3363. <dd><p>Joint stereo

  3364. </p></dd>

  3365. <dt><span>&lsquo;<samp>dual_channel</samp>&rsquo;</span></dt>

  3366. <dd><p>Dual channel

  3367. </p></dd>

  3368. <dt><span>&lsquo;<samp>mono</samp>&rsquo;</span></dt>

  3369. <dd><p>Mono

  3370. </p></dd>

  3371. </dl>

  3372. 

  3373. </dd>

  3374. <dt><span><samp>psymodel (<em>--psyc-mode</em>)</samp></span></dt>

  3375. <dd><p>Set psychoacoustic model to use in encoding. The argument must be

  3376. an integer between -1 and 4, inclusive. The higher the value, the

  3377. better the quality. The default value is 3.

  3378. </p>

  3379. </dd>

  3380. <dt><span><samp>energy_levels (<em>--energy</em>)</samp></span></dt>

  3381. <dd><p>Enable energy levels extensions when set to 1. The default value is

  3382. 0 (disabled).

  3383. </p>

  3384. </dd>

  3385. <dt><span><samp>error_protection (<em>--protect</em>)</samp></span></dt>

  3386. <dd><p>Enable CRC error protection when set to 1. The default value is 0

  3387. (disabled).

  3388. </p>

  3389. </dd>

  3390. <dt><span><samp>copyright (<em>--copyright</em>)</samp></span></dt>

  3391. <dd><p>Set MPEG audio copyright flag when set to 1. The default value is 0

  3392. (disabled).

  3393. </p>

  3394. </dd>

  3395. <dt><span><samp>original (<em>--original</em>)</samp></span></dt>

  3396. <dd><p>Set MPEG audio original flag when set to 1. The default value is 0

  3397. (disabled).

  3398. </p>

  3399. </dd>

  3400. </dl>

  3401. 

  3402. <a name="libvo_002damrwbenc"></a>

  3403. <h3 class="section">8.11 libvo-amrwbenc<span class="pull-right"><a class="anchor hidden-xs" href="#libvo_002damrwbenc" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libvo_002damrwbenc" aria-hidden="true">TOC</a></span></h3>

  3404. 

  3405. <p>VisualOn Adaptive Multi-Rate Wideband encoder.

  3406. </p>

  3407. <p>Requires the presence of the libvo-amrwbenc headers and library during

  3408. configuration. You need to explicitly configure the build with

  3409. <code>--enable-libvo-amrwbenc --enable-version3</code>.

  3410. </p>

  3411. <p>This is a mono-only encoder. Officially it only supports 16000Hz sample

  3412. rate, but you can override it by setting <samp>strict</samp> to

  3413. &lsquo;<samp>unofficial</samp>&rsquo; or lower.

  3414. </p>

  3415. <a name="Options-17"></a>

  3416. <h4 class="subsection">8.11.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-17" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-17" aria-hidden="true">TOC</a></span></h4>

  3417. 

  3418. <dl compact="compact">

  3419. <dt><span><samp>b</samp></span></dt>

  3420. <dd><p>Set bitrate in bits/s. Only the following bitrates are supported, otherwise

  3421. libavcodec will round to the nearest valid bitrate.

  3422. </p>

  3423. <dl compact="compact">

  3424. <dt><span>&lsquo;<samp>6600</samp>&rsquo;</span></dt>

  3425. <dt><span>&lsquo;<samp>8850</samp>&rsquo;</span></dt>

  3426. <dt><span>&lsquo;<samp>12650</samp>&rsquo;</span></dt>

  3427. <dt><span>&lsquo;<samp>14250</samp>&rsquo;</span></dt>

  3428. <dt><span>&lsquo;<samp>15850</samp>&rsquo;</span></dt>

  3429. <dt><span>&lsquo;<samp>18250</samp>&rsquo;</span></dt>

  3430. <dt><span>&lsquo;<samp>19850</samp>&rsquo;</span></dt>

  3431. <dt><span>&lsquo;<samp>23050</samp>&rsquo;</span></dt>

  3432. <dt><span>&lsquo;<samp>23850</samp>&rsquo;</span></dt>

  3433. </dl>

  3434. 

  3435. </dd>

  3436. <dt><span><samp>dtx</samp></span></dt>

  3437. <dd><p>Allow discontinuous transmission (generate comfort noise) when set to 1. The

  3438. default value is 0 (disabled).

  3439. </p>

  3440. </dd>

  3441. </dl>

  3442. 

  3443. <a name="libvorbis"></a>

  3444. <h3 class="section">8.12 libvorbis<span class="pull-right"><a class="anchor hidden-xs" href="#libvorbis" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libvorbis" aria-hidden="true">TOC</a></span></h3>

  3445. 

  3446. <p>libvorbis encoder wrapper.

  3447. </p>

  3448. <p>Requires the presence of the libvorbisenc headers and library during

  3449. configuration. You need to explicitly configure the build with

  3450. <code>--enable-libvorbis</code>.

  3451. </p>

  3452. <a name="Options-18"></a>

  3453. <h4 class="subsection">8.12.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-18" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-18" aria-hidden="true">TOC</a></span></h4>

  3454. 

  3455. <p>The following options are supported by the libvorbis wrapper. The

  3456. <code>oggenc</code>-equivalent of the options are listed in parentheses.

  3457. </p>

  3458. <p>To get a more accurate and extensive documentation of the libvorbis

  3459. options, consult the libvorbisenc&rsquo;s and <code>oggenc</code>&rsquo;s documentations.

  3460. See <a href="http://xiph.org/vorbis/">http://xiph.org/vorbis/</a>,

  3461. <a href="http://wiki.xiph.org/Vorbis-tools">http://wiki.xiph.org/Vorbis-tools</a>, and oggenc(1).

  3462. </p>

  3463. <dl compact="compact">

  3464. <dt><span><samp>b (<em>-b</em>)</samp></span></dt>

  3465. <dd><p>Set bitrate expressed in bits/s for ABR. <code>oggenc</code> <samp>-b</samp> is

  3466. expressed in kilobits/s.

  3467. </p>

  3468. </dd>

  3469. <dt><span><samp>q (<em>-q</em>)</samp></span></dt>

  3470. <dd><p>Set constant quality setting for VBR. The value should be a float

  3471. number in the range of -1.0 to 10.0. The higher the value, the better

  3472. the quality. The default value is &lsquo;<samp>3.0</samp>&rsquo;.

  3473. </p>

  3474. <p>This option is valid only using the <code>ffmpeg</code> command-line tool.

  3475. For library interface users, use <samp>global_quality</samp>.

  3476. </p>

  3477. </dd>

  3478. <dt><span><samp>cutoff (<em>--advanced-encode-option lowpass_frequency=N</em>)</samp></span></dt>

  3479. <dd><p>Set cutoff bandwidth in Hz, a value of 0 disables cutoff. <code>oggenc</code>&rsquo;s

  3480. related option is expressed in kHz. The default value is &lsquo;<samp>0</samp>&rsquo; (cutoff

  3481. disabled).

  3482. </p>

  3483. </dd>

  3484. <dt><span><samp>minrate (<em>-m</em>)</samp></span></dt>

  3485. <dd><p>Set minimum bitrate expressed in bits/s. <code>oggenc</code> <samp>-m</samp> is

  3486. expressed in kilobits/s.

  3487. </p>

  3488. </dd>

  3489. <dt><span><samp>maxrate (<em>-M</em>)</samp></span></dt>

  3490. <dd><p>Set maximum bitrate expressed in bits/s. <code>oggenc</code> <samp>-M</samp> is

  3491. expressed in kilobits/s. This only has effect on ABR mode.

  3492. </p>

  3493. </dd>

  3494. <dt><span><samp>iblock (<em>--advanced-encode-option impulse_noisetune=N</em>)</samp></span></dt>

  3495. <dd><p>Set noise floor bias for impulse blocks. The value is a float number from

  3496. -15.0 to 0.0. A negative bias instructs the encoder to pay special attention

  3497. to the crispness of transients in the encoded audio. The tradeoff for better

  3498. transient response is a higher bitrate.

  3499. </p>

  3500. </dd>

  3501. </dl>

  3502. 

  3503. <span id="mjpegenc"></span><a name="mjpeg"></a>

  3504. <h3 class="section">8.13 mjpeg<span class="pull-right"><a class="anchor hidden-xs" href="#mjpeg" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-mjpeg" aria-hidden="true">TOC</a></span></h3>

  3505. 

  3506. <p>Motion JPEG encoder.

  3507. </p>

  3508. <a name="Options-19"></a>

  3509. <h4 class="subsection">8.13.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-19" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-19" aria-hidden="true">TOC</a></span></h4>

  3510. 

  3511. <dl compact="compact">

  3512. <dt><span><samp>huffman</samp></span></dt>

  3513. <dd><p>Set the huffman encoding strategy. Possible values:

  3514. </p>

  3515. <dl compact="compact">

  3516. <dt><span>&lsquo;<samp>default</samp>&rsquo;</span></dt>

  3517. <dd><p>Use the default huffman tables. This is the default strategy.

  3518. </p>

  3519. </dd>

  3520. <dt><span>&lsquo;<samp>optimal</samp>&rsquo;</span></dt>

  3521. <dd><p>Compute and use optimal huffman tables.

  3522. </p>

  3523. </dd>

  3524. </dl>

  3525. </dd>

  3526. </dl>

  3527. 

  3528. <span id="wavpackenc"></span><a name="wavpack"></a>

  3529. <h3 class="section">8.14 wavpack<span class="pull-right"><a class="anchor hidden-xs" href="#wavpack" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-wavpack" aria-hidden="true">TOC</a></span></h3>

  3530. 

  3531. <p>WavPack lossless audio encoder.

  3532. </p>

  3533. <a name="Options-20"></a>

  3534. <h4 class="subsection">8.14.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-20" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-20" aria-hidden="true">TOC</a></span></h4>

  3535. 

  3536. <p>The equivalent options for <code>wavpack</code> command line utility are listed in

  3537. parentheses.

  3538. </p>

  3539. <a name="Shared-options"></a>

  3540. <h4 class="subsubsection">8.14.1.1 Shared options<span class="pull-right"><a class="anchor hidden-xs" href="#Shared-options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Shared-options" aria-hidden="true">TOC</a></span></h4>

  3541. 

  3542. <p>The following shared options are effective for this encoder. Only special notes

  3543. about this particular encoder will be documented here. For the general meaning

  3544. of the options, see <a href="#codec_002doptions">the Codec Options chapter</a>.

  3545. </p>

  3546. <dl compact="compact">

  3547. <dt><span><samp>frame_size (<em>--blocksize</em>)</samp></span></dt>

  3548. <dd><p>For this encoder, the range for this option is between 128 and 131072. Default

  3549. is automatically decided based on sample rate and number of channel.

  3550. </p>

  3551. <p>For the complete formula of calculating default, see

  3552. <samp>libavcodec/wavpackenc.c</samp>.

  3553. </p>

  3554. </dd>

  3555. <dt><span><samp>compression_level (<em>-f</em>, <em>-h</em>, <em>-hh</em>, and <em>-x</em>)</samp></span></dt>

  3556. </dl>

  3557. 

  3558. <a name="Private-options"></a>

  3559. <h4 class="subsubsection">8.14.1.2 Private options<span class="pull-right"><a class="anchor hidden-xs" href="#Private-options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Private-options" aria-hidden="true">TOC</a></span></h4>

  3560. 

  3561. <dl compact="compact">

  3562. <dt><span><samp>joint_stereo (<em>-j</em>)</samp></span></dt>

  3563. <dd><p>Set whether to enable joint stereo. Valid values are:

  3564. </p>

  3565. <dl compact="compact">

  3566. <dt><span>&lsquo;<samp>on (<em>1</em>)</samp>&rsquo;</span></dt>

  3567. <dd><p>Force mid/side audio encoding.

  3568. </p></dd>

  3569. <dt><span>&lsquo;<samp>off (<em>0</em>)</samp>&rsquo;</span></dt>

  3570. <dd><p>Force left/right audio encoding.

  3571. </p></dd>

  3572. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  3573. <dd><p>Let the encoder decide automatically.

  3574. </p></dd>

  3575. </dl>

  3576. 

  3577. </dd>

  3578. <dt><span><samp>optimize_mono</samp></span></dt>

  3579. <dd><p>Set whether to enable optimization for mono. This option is only effective for

  3580. non-mono streams. Available values:

  3581. </p>

  3582. <dl compact="compact">

  3583. <dt><span>&lsquo;<samp>on</samp>&rsquo;</span></dt>

  3584. <dd><p>enabled

  3585. </p></dd>

  3586. <dt><span>&lsquo;<samp>off</samp>&rsquo;</span></dt>

  3587. <dd><p>disabled

  3588. </p></dd>

  3589. </dl>

  3590. 

  3591. </dd>

  3592. </dl>

  3593. 

  3594. 

  3595. <a name="Video-Encoders"></a>

  3596. <h2 class="chapter">9 Video Encoders<span class="pull-right"><a class="anchor hidden-xs" href="#Video-Encoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Video-Encoders" aria-hidden="true">TOC</a></span></h2>

  3597. 

  3598. <p>A description of some of the currently available video encoders

  3599. follows.

  3600. </p>

  3601. <a name="a64_005fmulti_002c-a64_005fmulti5"></a>

  3602. <h3 class="section">9.1 a64_multi, a64_multi5<span class="pull-right"><a class="anchor hidden-xs" href="#a64_005fmulti_002c-a64_005fmulti5" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-a64_005fmulti_002c-a64_005fmulti5" aria-hidden="true">TOC</a></span></h3>

  3603. 

  3604. <p>A64 / Commodore 64 multicolor charset encoder. <code>a64_multi5</code> is extended with 5th color (colram).

  3605. </p>

  3606. <a name="Cinepak"></a>

  3607. <h3 class="section">9.2 Cinepak<span class="pull-right"><a class="anchor hidden-xs" href="#Cinepak" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Cinepak" aria-hidden="true">TOC</a></span></h3>

  3608. 

  3609. <p>Cinepak aka CVID encoder.

  3610. Compatible with Windows 3.1 and vintage MacOS.

  3611. </p>

  3612. <a name="Options-21"></a>

  3613. <h4 class="subsection">9.2.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-21" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-21" aria-hidden="true">TOC</a></span></h4>

  3614. 

  3615. <dl compact="compact">

  3616. <dt><span><samp>g <var>integer</var></samp></span></dt>

  3617. <dd><p>Keyframe interval.

  3618. A keyframe is inserted at least every <code>-g</code> frames, sometimes sooner.

  3619. </p>

  3620. </dd>

  3621. <dt><span><samp>q:v <var>integer</var></samp></span></dt>

  3622. <dd><p>Quality factor. Lower is better. Higher gives lower bitrate.

  3623. The following table lists bitrates when encoding akiyo_cif.y4m for various values of <code>-q:v</code> with <code>-g 100</code>:

  3624. </p>

  3625. <dl compact="compact">

  3626. <dt><span><samp><code>-q:v 1</code> 1918 kb/s</samp></span></dt>

  3627. <dt><span><samp><code>-q:v 2</code> 1735 kb/s</samp></span></dt>

  3628. <dt><span><samp><code>-q:v 4</code> 1500 kb/s</samp></span></dt>

  3629. <dt><span><samp><code>-q:v 10</code> 1041 kb/s</samp></span></dt>

  3630. <dt><span><samp><code>-q:v 20</code> 826 kb/s</samp></span></dt>

  3631. <dt><span><samp><code>-q:v 40</code> 553 kb/s</samp></span></dt>

  3632. <dt><span><samp><code>-q:v 100</code> 394 kb/s</samp></span></dt>

  3633. <dt><span><samp><code>-q:v 200</code> 312 kb/s</samp></span></dt>

  3634. <dt><span><samp><code>-q:v 400</code> 266 kb/s</samp></span></dt>

  3635. <dt><span><samp><code>-q:v 1000</code> 237 kb/s</samp></span></dt>

  3636. </dl>

  3637. 

  3638. </dd>

  3639. <dt><span><samp>max_extra_cb_iterations <var>integer</var></samp></span></dt>

  3640. <dd><p>Max extra codebook recalculation passes, more is better and slower.

  3641. </p>

  3642. </dd>

  3643. <dt><span><samp>skip_empty_cb <var>boolean</var></samp></span></dt>

  3644. <dd><p>Avoid wasting bytes, ignore vintage MacOS decoder.

  3645. </p>

  3646. </dd>

  3647. <dt><span><samp>max_strips <var>integer</var></samp></span></dt>

  3648. <dt><span><samp>min_strips <var>integer</var></samp></span></dt>

  3649. <dd><p>The minimum and maximum number of strips to use.

  3650. Wider range sometimes improves quality.

  3651. More strips is generally better quality but costs more bits.

  3652. Fewer strips tend to yield more keyframes.

  3653. Vintage compatible is 1..3.

  3654. </p>

  3655. </dd>

  3656. <dt><span><samp>strip_number_adaptivity <var>integer</var></samp></span></dt>

  3657. <dd><p>How much number of strips is allowed to change between frames.

  3658. Higher is better but slower.

  3659. </p>

  3660. </dd>

  3661. </dl>

  3662. 

  3663. <a name="GIF"></a>

  3664. <h3 class="section">9.3 GIF<span class="pull-right"><a class="anchor hidden-xs" href="#GIF" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-GIF" aria-hidden="true">TOC</a></span></h3>

  3665. 

  3666. <p>GIF image/animation encoder.

  3667. </p>

  3668. <a name="Options-22"></a>

  3669. <h4 class="subsection">9.3.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-22" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-22" aria-hidden="true">TOC</a></span></h4>

  3670. 

  3671. <dl compact="compact">

  3672. <dt><span><samp>gifflags <var>integer</var></samp></span></dt>

  3673. <dd><p>Sets the flags used for GIF encoding.

  3674. </p>

  3675. <dl compact="compact">

  3676. <dt><span><samp>offsetting</samp></span></dt>

  3677. <dd><p>Enables picture offsetting.

  3678. </p>

  3679. <p>Default is enabled.

  3680. </p>

  3681. </dd>

  3682. <dt><span><samp>transdiff</samp></span></dt>

  3683. <dd><p>Enables transparency detection between frames.

  3684. </p>

  3685. <p>Default is enabled.

  3686. </p>

  3687. </dd>

  3688. </dl>

  3689. 

  3690. </dd>

  3691. <dt><span><samp>gifimage <var>integer</var></samp></span></dt>

  3692. <dd><p>Enables encoding one full GIF image per frame, rather than an animated GIF.

  3693. </p>

  3694. <p>Default value is <samp>0</samp>.

  3695. </p>

  3696. </dd>

  3697. <dt><span><samp>global_palette <var>integer</var></samp></span></dt>

  3698. <dd><p>Writes a palette to the global GIF header where feasible.

  3699. </p>

  3700. <p>If disabled, every frame will always have a palette written, even if there

  3701. is a global palette supplied.

  3702. </p>

  3703. <p>Default value is <samp>1</samp>.

  3704. </p>

  3705. </dd>

  3706. </dl>

  3707. 

  3708. <a name="Hap"></a>

  3709. <h3 class="section">9.4 Hap<span class="pull-right"><a class="anchor hidden-xs" href="#Hap" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Hap" aria-hidden="true">TOC</a></span></h3>

  3710. 

  3711. <p>Vidvox Hap video encoder.

  3712. </p>

  3713. <a name="Options-23"></a>

  3714. <h4 class="subsection">9.4.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-23" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-23" aria-hidden="true">TOC</a></span></h4>

  3715. 

  3716. <dl compact="compact">

  3717. <dt><span><samp>format <var>integer</var></samp></span></dt>

  3718. <dd><p>Specifies the Hap format to encode.

  3719. </p>

  3720. <dl compact="compact">

  3721. <dt><span><samp>hap</samp></span></dt>

  3722. <dt><span><samp>hap_alpha</samp></span></dt>

  3723. <dt><span><samp>hap_q</samp></span></dt>

  3724. </dl>

  3725. 

  3726. <p>Default value is <samp>hap</samp>.

  3727. </p>

  3728. </dd>

  3729. <dt><span><samp>chunks <var>integer</var></samp></span></dt>

  3730. <dd><p>Specifies the number of chunks to split frames into, between 1 and 64. This

  3731. permits multithreaded decoding of large frames, potentially at the cost of

  3732. data-rate. The encoder may modify this value to divide frames evenly.

  3733. </p>

  3734. <p>Default value is <var>1</var>.

  3735. </p>

  3736. </dd>

  3737. <dt><span><samp>compressor <var>integer</var></samp></span></dt>

  3738. <dd><p>Specifies the second-stage compressor to use. If set to <samp>none</samp>,

  3739. <samp>chunks</samp> will be limited to 1, as chunked uncompressed frames offer no

  3740. benefit.

  3741. </p>

  3742. <dl compact="compact">

  3743. <dt><span><samp>none</samp></span></dt>

  3744. <dt><span><samp>snappy</samp></span></dt>

  3745. </dl>

  3746. 

  3747. <p>Default value is <samp>snappy</samp>.

  3748. </p>

  3749. </dd>

  3750. </dl>

  3751. 

  3752. <a name="jpeg2000"></a>

  3753. <h3 class="section">9.5 jpeg2000<span class="pull-right"><a class="anchor hidden-xs" href="#jpeg2000" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-jpeg2000" aria-hidden="true">TOC</a></span></h3>

  3754. 

  3755. <p>The native jpeg 2000 encoder is lossy by default, the <code>-q:v</code>

  3756. option can be used to set the encoding quality. Lossless encoding

  3757. can be selected with <code>-pred 1</code>.

  3758. </p>

  3759. <a name="Options-24"></a>

  3760. <h4 class="subsection">9.5.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-24" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-24" aria-hidden="true">TOC</a></span></h4>

  3761. 

  3762. <dl compact="compact">

  3763. <dt><span><samp>format <var>integer</var></samp></span></dt>

  3764. <dd><p>Can be set to either <code>j2k</code> or <code>jp2</code> (the default) that

  3765. makes it possible to store non-rgb pix_fmts.

  3766. </p>

  3767. </dd>

  3768. <dt><span><samp>tile_width <var>integer</var></samp></span></dt>

  3769. <dd><p>Sets tile width. Range is 1 to 1073741824. Default is 256.

  3770. </p>

  3771. </dd>

  3772. <dt><span><samp>tile_height <var>integer</var></samp></span></dt>

  3773. <dd><p>Sets tile height. Range is 1 to 1073741824. Default is 256.

  3774. </p>

  3775. </dd>

  3776. <dt><span><samp>pred <var>integer</var></samp></span></dt>

  3777. <dd><p>Allows setting the discrete wavelet transform (DWT) type

  3778. </p><dl compact="compact">

  3779. <dt><span><samp>dwt97int (Lossy)</samp></span></dt>

  3780. <dt><span><samp>dwt53 (Lossless)</samp></span></dt>

  3781. </dl>

  3782. <p>Default is <code>dwt97int</code>

  3783. </p>

  3784. </dd>

  3785. <dt><span><samp>sop <var>boolean</var></samp></span></dt>

  3786. <dd><p>Enable this to add SOP marker at the start of each packet. Disabled by default.

  3787. </p>

  3788. </dd>

  3789. <dt><span><samp>eph <var>boolean</var></samp></span></dt>

  3790. <dd><p>Enable this to add EPH marker at the end of each packet header. Disabled by default.

  3791. </p>

  3792. </dd>

  3793. <dt><span><samp>prog <var>integer</var></samp></span></dt>

  3794. <dd><p>Sets the progression order to be used by the encoder.

  3795. Possible values are:

  3796. </p><dl compact="compact">

  3797. <dt><span><samp>lrcp</samp></span></dt>

  3798. <dt><span><samp>rlcp</samp></span></dt>

  3799. <dt><span><samp>rpcl</samp></span></dt>

  3800. <dt><span><samp>pcrl</samp></span></dt>

  3801. <dt><span><samp>cprl</samp></span></dt>

  3802. </dl>

  3803. <p>Set to <code>lrcp</code> by default.

  3804. </p>

  3805. </dd>

  3806. <dt><span><samp>layer_rates <var>string</var></samp></span></dt>

  3807. <dd><p>By default, when this option is not used, compression is done using the quality metric.

  3808. This option allows for compression using compression ratio. The compression ratio for each

  3809. level could be specified. The compression ratio of a layer <code>l</code> species the what ratio of

  3810. total file size is contained in the first <code>l</code> layers.

  3811. </p>

  3812. <p>Example usage:

  3813. </p>

  3814. <div class="example">

  3815. <pre class="example">ffmpeg -i input.bmp -c:v jpeg2000 -layer_rates &quot;100,10,1&quot; output.j2k

  3816. </pre></div>

  3817. 

  3818. <p>This would compress the image to contain 3 layers, where the data contained in the

  3819. first layer would be compressed by 1000 times, compressed by 100 in the first two layers,

  3820. and shall contain all data while using all 3 layers.

  3821. </p>

  3822. </dd>

  3823. </dl>

  3824. 

  3825. <a name="librav1e"></a>

  3826. <h3 class="section">9.6 librav1e<span class="pull-right"><a class="anchor hidden-xs" href="#librav1e" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-librav1e" aria-hidden="true">TOC</a></span></h3>

  3827. 

  3828. <p>rav1e AV1 encoder wrapper.

  3829. </p>

  3830. <p>Requires the presence of the rav1e headers and library during configuration.

  3831. You need to explicitly configure the build with <code>--enable-librav1e</code>.

  3832. </p>

  3833. <a name="Options-25"></a>

  3834. <h4 class="subsection">9.6.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-25" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-25" aria-hidden="true">TOC</a></span></h4>

  3835. 

  3836. <dl compact="compact">

  3837. <dt><span><samp>qmax</samp></span></dt>

  3838. <dd><p>Sets the maximum quantizer to use when using bitrate mode.

  3839. </p>

  3840. </dd>

  3841. <dt><span><samp>qmin</samp></span></dt>

  3842. <dd><p>Sets the minimum quantizer to use when using bitrate mode.

  3843. </p>

  3844. </dd>

  3845. <dt><span><samp>qp</samp></span></dt>

  3846. <dd><p>Uses quantizer mode to encode at the given quantizer (0-255).

  3847. </p>

  3848. </dd>

  3849. <dt><span><samp>speed</samp></span></dt>

  3850. <dd><p>Selects the speed preset (0-10) to encode with.

  3851. </p>

  3852. </dd>

  3853. <dt><span><samp>tiles</samp></span></dt>

  3854. <dd><p>Selects how many tiles to encode with.

  3855. </p>

  3856. </dd>

  3857. <dt><span><samp>tile-rows</samp></span></dt>

  3858. <dd><p>Selects how many rows of tiles to encode with.

  3859. </p>

  3860. </dd>

  3861. <dt><span><samp>tile-columns</samp></span></dt>

  3862. <dd><p>Selects how many columns of tiles to encode with.

  3863. </p>

  3864. </dd>

  3865. <dt><span><samp>rav1e-params</samp></span></dt>

  3866. <dd><p>Set rav1e options using a list of <var>key</var>=<var>value</var> pairs separated

  3867. by &quot;:&quot;. See <code>rav1e --help</code> for a list of options.

  3868. </p>

  3869. <p>For example to specify librav1e encoding options with <samp>-rav1e-params</samp>:

  3870. </p>

  3871. <div class="example">

  3872. <pre class="example">ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4

  3873. </pre></div>

  3874. 

  3875. </dd>

  3876. </dl>

  3877. 

  3878. <a name="libaom_002dav1"></a>

  3879. <h3 class="section">9.7 libaom-av1<span class="pull-right"><a class="anchor hidden-xs" href="#libaom_002dav1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libaom_002dav1" aria-hidden="true">TOC</a></span></h3>

  3880. 

  3881. <p>libaom AV1 encoder wrapper.

  3882. </p>

  3883. <p>Requires the presence of the libaom headers and library during

  3884. configuration.  You need to explicitly configure the build with

  3885. <code>--enable-libaom</code>.

  3886. </p>

  3887. <a name="Options-26"></a>

  3888. <h4 class="subsection">9.7.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-26" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-26" aria-hidden="true">TOC</a></span></h4>

  3889. 

  3890. <p>The wrapper supports the following standard libavcodec options:

  3891. </p>

  3892. <dl compact="compact">

  3893. <dt><span><samp>b</samp></span></dt>

  3894. <dd><p>Set bitrate target in bits/second.  By default this will use

  3895. variable-bitrate mode.  If <samp>maxrate</samp> and <samp>minrate</samp> are

  3896. also set to the same value then it will use constant-bitrate mode,

  3897. otherwise if <samp>crf</samp> is set as well then it will use

  3898. constrained-quality mode.

  3899. </p>

  3900. </dd>

  3901. <dt><span><samp>g keyint_min</samp></span></dt>

  3902. <dd><p>Set key frame placement.  The GOP size sets the maximum distance between

  3903. key frames; if zero the output stream will be intra-only.  The minimum

  3904. distance is ignored unless it is the same as the GOP size, in which case

  3905. key frames will always appear at a fixed interval.  Not set by default,

  3906. so without this option the library has completely free choice about

  3907. where to place key frames.

  3908. </p>

  3909. </dd>

  3910. <dt><span><samp>qmin qmax</samp></span></dt>

  3911. <dd><p>Set minimum/maximum quantisation values.  Valid range is from 0 to 63

  3912. (warning: this does not match the quantiser values actually used by AV1

  3913. - divide by four to map real quantiser values to this range).  Defaults

  3914. to min/max (no constraint).

  3915. </p>

  3916. </dd>

  3917. <dt><span><samp>minrate maxrate bufsize rc_init_occupancy</samp></span></dt>

  3918. <dd><p>Set rate control buffering parameters.  Not used if not set - defaults

  3919. to unconstrained variable bitrate.

  3920. </p>

  3921. </dd>

  3922. <dt><span><samp>threads</samp></span></dt>

  3923. <dd><p>Set the number of threads to use while encoding.  This may require the

  3924. <samp>tiles</samp> or <samp>row-mt</samp> options to also be set to actually

  3925. use the specified number of threads fully. Defaults to the number of

  3926. hardware threads supported by the host machine.

  3927. </p>

  3928. </dd>

  3929. <dt><span><samp>profile</samp></span></dt>

  3930. <dd><p>Set the encoding profile.  Defaults to using the profile which matches

  3931. the bit depth and chroma subsampling of the input.

  3932. </p>

  3933. </dd>

  3934. </dl>

  3935. 

  3936. <p>The wrapper also has some specific options:

  3937. </p>

  3938. <dl compact="compact">

  3939. <dt><span><samp>cpu-used</samp></span></dt>

  3940. <dd><p>Set the quality/encoding speed tradeoff.  Valid range is from 0 to 8,

  3941. higher numbers indicating greater speed and lower quality.  The default

  3942. value is 1, which will be slow and high quality.

  3943. </p>

  3944. </dd>

  3945. <dt><span><samp>auto-alt-ref</samp></span></dt>

  3946. <dd><p>Enable use of alternate reference frames.  Defaults to the internal

  3947. default of the library.

  3948. </p>

  3949. </dd>

  3950. <dt><span><samp>arnr-max-frames (<em>frames</em>)</samp></span></dt>

  3951. <dd><p>Set altref noise reduction max frame count. Default is -1.

  3952. </p>

  3953. </dd>

  3954. <dt><span><samp>arnr-strength (<em>strength</em>)</samp></span></dt>

  3955. <dd><p>Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.

  3956. </p>

  3957. </dd>

  3958. <dt><span><samp>aq-mode (<em>aq-mode</em>)</samp></span></dt>

  3959. <dd><p>Set adaptive quantization mode. Possible values:

  3960. </p>

  3961. <dl compact="compact">

  3962. <dt><span>&lsquo;<samp>none (<em>0</em>)</samp>&rsquo;</span></dt>

  3963. <dd><p>Disabled.

  3964. </p>

  3965. </dd>

  3966. <dt><span>&lsquo;<samp>variance (<em>1</em>)</samp>&rsquo;</span></dt>

  3967. <dd><p>Variance-based.

  3968. </p>

  3969. </dd>

  3970. <dt><span>&lsquo;<samp>complexity (<em>2</em>)</samp>&rsquo;</span></dt>

  3971. <dd><p>Complexity-based.

  3972. </p>

  3973. </dd>

  3974. <dt><span>&lsquo;<samp>cyclic (<em>3</em>)</samp>&rsquo;</span></dt>

  3975. <dd><p>Cyclic refresh.

  3976. </p></dd>

  3977. </dl>

  3978. 

  3979. </dd>

  3980. <dt><span><samp>tune (<em>tune</em>)</samp></span></dt>

  3981. <dd><p>Set the distortion metric the encoder is tuned with. Default is <code>psnr</code>.

  3982. </p>

  3983. <dl compact="compact">

  3984. <dt><span>&lsquo;<samp>psnr (<em>0</em>)</samp>&rsquo;</span></dt>

  3985. <dt><span>&lsquo;<samp>ssim (<em>1</em>)</samp>&rsquo;</span></dt>

  3986. </dl>

  3987. 

  3988. </dd>

  3989. <dt><span><samp>lag-in-frames</samp></span></dt>

  3990. <dd><p>Set the maximum number of frames which the encoder may keep in flight

  3991. at any one time for lookahead purposes.  Defaults to the internal

  3992. default of the library.

  3993. </p>

  3994. </dd>

  3995. <dt><span><samp>error-resilience</samp></span></dt>

  3996. <dd><p>Enable error resilience features:

  3997. </p><dl compact="compact">

  3998. <dt><span><samp>default</samp></span></dt>

  3999. <dd><p>Improve resilience against losses of whole frames.

  4000. </p></dd>

  4001. </dl>

  4002. <p>Not enabled by default.

  4003. </p>

  4004. </dd>

  4005. <dt><span><samp>crf</samp></span></dt>

  4006. <dd><p>Set the quality/size tradeoff for constant-quality (no bitrate target)

  4007. and constrained-quality (with maximum bitrate target) modes. Valid

  4008. range is 0 to 63, higher numbers indicating lower quality and smaller

  4009. output size.  Only used if set; by default only the bitrate target is

  4010. used.

  4011. </p>

  4012. </dd>

  4013. <dt><span><samp>static-thresh</samp></span></dt>

  4014. <dd><p>Set a change threshold on blocks below which they will be skipped by

  4015. the encoder.  Defined in arbitrary units as a nonnegative integer,

  4016. defaulting to zero (no blocks are skipped).

  4017. </p>

  4018. </dd>

  4019. <dt><span><samp>drop-threshold</samp></span></dt>

  4020. <dd><p>Set a threshold for dropping frames when close to rate control bounds.

  4021. Defined as a percentage of the target buffer - when the rate control

  4022. buffer falls below this percentage, frames will be dropped until it

  4023. has refilled above the threshold.  Defaults to zero (no frames are

  4024. dropped).

  4025. </p>

  4026. </dd>

  4027. <dt><span><samp>denoise-noise-level (<em>level</em>)</samp></span></dt>

  4028. <dd><p>Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if

  4029. this option is not set or set to 0.

  4030. </p>

  4031. </dd>

  4032. <dt><span><samp>denoise-block-size (<em>pixels</em>)</samp></span></dt>

  4033. <dd><p>Block size used for denoising for grain synthesis. If not set, AV1 codec

  4034. uses the default value of 32.

  4035. </p>

  4036. </dd>

  4037. <dt><span><samp>undershoot-pct (<em>pct</em>)</samp></span></dt>

  4038. <dd><p>Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100.

  4039. Default is -1.

  4040. </p>

  4041. </dd>

  4042. <dt><span><samp>overshoot-pct (<em>pct</em>)</samp></span></dt>

  4043. <dd><p>Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000.

  4044. Default is -1.

  4045. </p>

  4046. </dd>

  4047. <dt><span><samp>minsection-pct (<em>pct</em>)</samp></span></dt>

  4048. <dd><p>Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct

  4049. is not set, the libaomenc wrapper computes it as follows: <code>(minrate * 100 / bitrate)</code>.

  4050. Range is -1 to 100. Default is -1 (unset).

  4051. </p>

  4052. </dd>

  4053. <dt><span><samp>maxsection-pct (<em>pct</em>)</samp></span></dt>

  4054. <dd><p>Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct

  4055. is not set, the libaomenc wrapper computes it as follows: <code>(maxrate * 100 / bitrate)</code>.

  4056. Range is -1 to 5000. Default is -1 (unset).

  4057. </p>

  4058. </dd>

  4059. <dt><span><samp>frame-parallel (<em>boolean</em>)</samp></span></dt>

  4060. <dd><p>Enable frame parallel decodability features. Default is true.

  4061. </p>

  4062. </dd>

  4063. <dt><span><samp>tiles</samp></span></dt>

  4064. <dd><p>Set the number of tiles to encode the input video with, as columns x

  4065. rows.  Larger numbers allow greater parallelism in both encoding and

  4066. decoding, but may decrease coding efficiency.  Defaults to the minimum

  4067. number of tiles required by the size of the input video (this is 1x1

  4068. (that is, a single tile) for sizes up to and including 4K).

  4069. </p>

  4070. </dd>

  4071. <dt><span><samp>tile-columns tile-rows</samp></span></dt>

  4072. <dd><p>Set the number of tiles as log2 of the number of tile rows and columns.

  4073. Provided for compatibility with libvpx/VP9.

  4074. </p>

  4075. </dd>

  4076. <dt><span><samp>row-mt (Requires libaom &gt;= 1.0.0-759-g90a15f4f2)</samp></span></dt>

  4077. <dd><p>Enable row based multi-threading. Disabled by default.

  4078. </p>

  4079. </dd>

  4080. <dt><span><samp>enable-cdef (<em>boolean</em>)</samp></span></dt>

  4081. <dd><p>Enable Constrained Directional Enhancement Filter. The libaom-av1

  4082. encoder enables CDEF by default.

  4083. </p>

  4084. </dd>

  4085. <dt><span><samp>enable-restoration (<em>boolean</em>)</samp></span></dt>

  4086. <dd><p>Enable Loop Restoration Filter. Default is true for libaom-av1.

  4087. </p>

  4088. </dd>

  4089. <dt><span><samp>enable-global-motion (<em>boolean</em>)</samp></span></dt>

  4090. <dd><p>Enable the use of global motion for block prediction. Default is true.

  4091. </p>

  4092. </dd>

  4093. <dt><span><samp>enable-intrabc (<em>boolean</em>)</samp></span></dt>

  4094. <dd><p>Enable block copy mode for intra block prediction. This mode is

  4095. useful for screen content. Default is true.

  4096. </p>

  4097. </dd>

  4098. <dt><span><samp>enable-rect-partitions (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4099. <dd><p>Enable rectangular partitions. Default is true.

  4100. </p>

  4101. </dd>

  4102. <dt><span><samp>enable-1to4-partitions (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4103. <dd><p>Enable 1:4/4:1 partitions. Default is true.

  4104. </p>

  4105. </dd>

  4106. <dt><span><samp>enable-ab-partitions (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4107. <dd><p>Enable AB shape partitions. Default is true.

  4108. </p>

  4109. </dd>

  4110. <dt><span><samp>enable-angle-delta (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4111. <dd><p>Enable angle delta intra prediction. Default is true.

  4112. </p>

  4113. </dd>

  4114. <dt><span><samp>enable-cfl-intra (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4115. <dd><p>Enable chroma predicted from luma intra prediction. Default is true.

  4116. </p>

  4117. </dd>

  4118. <dt><span><samp>enable-filter-intra (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4119. <dd><p>Enable filter intra predictor. Default is true.

  4120. </p>

  4121. </dd>

  4122. <dt><span><samp>enable-intra-edge-filter (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4123. <dd><p>Enable intra edge filter. Default is true.

  4124. </p>

  4125. </dd>

  4126. <dt><span><samp>enable-smooth-intra (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4127. <dd><p>Enable smooth intra prediction mode. Default is true.

  4128. </p>

  4129. </dd>

  4130. <dt><span><samp>enable-paeth-intra (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4131. <dd><p>Enable paeth predictor in intra prediction. Default is true.

  4132. </p>

  4133. </dd>

  4134. <dt><span><samp>enable-palette (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4135. <dd><p>Enable palette prediction mode. Default is true.

  4136. </p>

  4137. </dd>

  4138. <dt><span><samp>enable-flip-idtx (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4139. <dd><p>Enable extended transform type, including FLIPADST_DCT, DCT_FLIPADST,

  4140. FLIPADST_FLIPADST, ADST_FLIPADST, FLIPADST_ADST, IDTX, V_DCT, H_DCT,

  4141. V_ADST, H_ADST, V_FLIPADST, H_FLIPADST. Default is true.

  4142. </p>

  4143. </dd>

  4144. <dt><span><samp>enable-tx64 (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4145. <dd><p>Enable 64-pt transform. Default is true.

  4146. </p>

  4147. </dd>

  4148. <dt><span><samp>reduced-tx-type-set (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4149. <dd><p>Use reduced set of transform types. Default is false.

  4150. </p>

  4151. </dd>

  4152. <dt><span><samp>use-intra-dct-only (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4153. <dd><p>Use DCT only for INTRA modes. Default is false.

  4154. </p>

  4155. </dd>

  4156. <dt><span><samp>use-inter-dct-only (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4157. <dd><p>Use DCT only for INTER modes. Default is false.

  4158. </p>

  4159. </dd>

  4160. <dt><span><samp>use-intra-default-tx-only (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4161. <dd><p>Use Default-transform only for INTRA modes. Default is false.

  4162. </p>

  4163. </dd>

  4164. <dt><span><samp>enable-ref-frame-mvs (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4165. <dd><p>Enable temporal mv prediction. Default is true.

  4166. </p>

  4167. </dd>

  4168. <dt><span><samp>enable-reduced-reference-set (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4169. <dd><p>Use reduced set of single and compound references. Default is false.

  4170. </p>

  4171. </dd>

  4172. <dt><span><samp>enable-obmc (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4173. <dd><p>Enable obmc. Default is true.

  4174. </p>

  4175. </dd>

  4176. <dt><span><samp>enable-dual-filter (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4177. <dd><p>Enable dual filter. Default is true.

  4178. </p>

  4179. </dd>

  4180. <dt><span><samp>enable-diff-wtd-comp (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4181. <dd><p>Enable difference-weighted compound. Default is true.

  4182. </p>

  4183. </dd>

  4184. <dt><span><samp>enable-dist-wtd-comp (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4185. <dd><p>Enable distance-weighted compound. Default is true.

  4186. </p>

  4187. </dd>

  4188. <dt><span><samp>enable-onesided-comp (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4189. <dd><p>Enable one sided compound. Default is true.

  4190. </p>

  4191. </dd>

  4192. <dt><span><samp>enable-interinter-wedge (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4193. <dd><p>Enable interinter wedge compound. Default is true.

  4194. </p>

  4195. </dd>

  4196. <dt><span><samp>enable-interintra-wedge (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4197. <dd><p>Enable interintra wedge compound. Default is true.

  4198. </p>

  4199. </dd>

  4200. <dt><span><samp>enable-masked-comp (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4201. <dd><p>Enable masked compound. Default is true.

  4202. </p>

  4203. </dd>

  4204. <dt><span><samp>enable-interintra-comp (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4205. <dd><p>Enable interintra compound. Default is true.

  4206. </p>

  4207. </dd>

  4208. <dt><span><samp>enable-smooth-interintra (<em>boolean</em>) (Requires libaom &gt;= v2.0.0)</samp></span></dt>

  4209. <dd><p>Enable smooth interintra mode. Default is true.

  4210. </p>

  4211. </dd>

  4212. <dt><span><samp>aom-params</samp></span></dt>

  4213. <dd><p>Set libaom options using a list of <var>key</var>=<var>value</var> pairs separated

  4214. by &quot;:&quot;. For a list of supported options, see <code>aomenc --help</code> under the

  4215. section &quot;AV1 Specific Options&quot;.

  4216. </p>

  4217. <p>For example to specify libaom encoding options with <samp>-aom-params</samp>:

  4218. </p>

  4219. <div class="example">

  4220. <pre class="example">ffmpeg -i input -c:v libaom-av1 -b:v 500K -aom-params tune=psnr:enable-tpl-model=1 output.mp4

  4221. </pre></div>

  4222. 

  4223. </dd>

  4224. </dl>

  4225. 

  4226. <a name="libsvtav1"></a>

  4227. <h3 class="section">9.8 libsvtav1<span class="pull-right"><a class="anchor hidden-xs" href="#libsvtav1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libsvtav1" aria-hidden="true">TOC</a></span></h3>

  4228. 

  4229. <p>SVT-AV1 encoder wrapper.

  4230. </p>

  4231. <p>Requires the presence of the SVT-AV1 headers and library during configuration.

  4232. You need to explicitly configure the build with <code>--enable-libsvtav1</code>.

  4233. </p>

  4234. <a name="Options-27"></a>

  4235. <h4 class="subsection">9.8.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-27" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-27" aria-hidden="true">TOC</a></span></h4>

  4236. 

  4237. <dl compact="compact">

  4238. <dt><span><samp>profile</samp></span></dt>

  4239. <dd><p>Set the encoding profile.

  4240. </p><dl compact="compact">

  4241. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  4242. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  4243. <dt><span>&lsquo;<samp>professional</samp>&rsquo;</span></dt>

  4244. </dl>

  4245. 

  4246. </dd>

  4247. <dt><span><samp>level</samp></span></dt>

  4248. <dd><p>Set the operating point level. For example: &rsquo;4.0&rsquo;

  4249. </p>

  4250. </dd>

  4251. <dt><span><samp>hielevel</samp></span></dt>

  4252. <dd><p>Set the Hierarchical prediction levels.

  4253. </p><dl compact="compact">

  4254. <dt><span>&lsquo;<samp>3level</samp>&rsquo;</span></dt>

  4255. <dt><span>&lsquo;<samp>4level</samp>&rsquo;</span></dt>

  4256. <dd><p>This is the default.

  4257. </p></dd>

  4258. </dl>

  4259. 

  4260. </dd>

  4261. <dt><span><samp>tier</samp></span></dt>

  4262. <dd><p>Set the operating point tier.

  4263. </p><dl compact="compact">

  4264. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  4265. <dd><p>This is the default.

  4266. </p></dd>

  4267. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  4268. </dl>

  4269. 

  4270. </dd>

  4271. <dt><span><samp>qmax</samp></span></dt>

  4272. <dd><p>Set the maximum quantizer to use when using a bitrate mode.

  4273. </p>

  4274. </dd>

  4275. <dt><span><samp>qmin</samp></span></dt>

  4276. <dd><p>Set the minimum quantizer to use when using a bitrate mode.

  4277. </p>

  4278. </dd>

  4279. <dt><span><samp>crf</samp></span></dt>

  4280. <dd><p>Constant rate factor value used in crf rate control mode (0-63).

  4281. </p>

  4282. </dd>

  4283. <dt><span><samp>qp</samp></span></dt>

  4284. <dd><p>Set the quantizer used in cqp rate control mode (0-63).

  4285. </p>

  4286. </dd>

  4287. <dt><span><samp>sc_detection</samp></span></dt>

  4288. <dd><p>Enable scene change detection.

  4289. </p>

  4290. </dd>

  4291. <dt><span><samp>la_depth</samp></span></dt>

  4292. <dd><p>Set number of frames to look ahead (0-120).

  4293. </p>

  4294. </dd>

  4295. <dt><span><samp>preset</samp></span></dt>

  4296. <dd><p>Set the quality-speed tradeoff, in the range 0 to 13.  Higher values are

  4297. faster but lower quality.

  4298. </p>

  4299. </dd>

  4300. <dt><span><samp>tile_rows</samp></span></dt>

  4301. <dd><p>Set log2 of the number of rows of tiles to use (0-6).

  4302. </p>

  4303. </dd>

  4304. <dt><span><samp>tile_columns</samp></span></dt>

  4305. <dd><p>Set log2 of the number of columns of tiles to use (0-4).

  4306. </p>

  4307. </dd>

  4308. <dt><span><samp>svtav1-params</samp></span></dt>

  4309. <dd><p>Set SVT-AV1 options using a list of <var>key</var>=<var>value</var> pairs separated

  4310. by &quot;:&quot;. See the SVT-AV1 encoder user guide for a list of accepted parameters.

  4311. </p>

  4312. </dd>

  4313. </dl>

  4314. 

  4315. <a name="libjxl"></a>

  4316. <h3 class="section">9.9 libjxl<span class="pull-right"><a class="anchor hidden-xs" href="#libjxl" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libjxl" aria-hidden="true">TOC</a></span></h3>

  4317. 

  4318. <p>libjxl JPEG XL encoder wrapper.

  4319. </p>

  4320. <p>Requires the presence of the libjxl headers and library during

  4321. configuration. You need to explicitly configure the build with

  4322. <code>--enable-libjxl</code>.

  4323. </p>

  4324. <a name="Options-28"></a>

  4325. <h4 class="subsection">9.9.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-28" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-28" aria-hidden="true">TOC</a></span></h4>

  4326. 

  4327. <p>The libjxl wrapper supports the following options:

  4328. </p>

  4329. <dl compact="compact">

  4330. <dt><span><samp>distance</samp></span></dt>

  4331. <dd><p>Set the target Butteraugli distance. This is a quality setting: lower

  4332. distance yields higher quality, with distance=1.0 roughly comparable to

  4333. libjpeg Quality 90 for photographic content. Setting distance=0.0 yields

  4334. true lossless encoding. Valid values range between 0.0 and 15.0, and sane

  4335. values rarely exceed 5.0. Setting distance=0.1 usually attains

  4336. transparency for most input. The default is 1.0.

  4337. </p>

  4338. </dd>

  4339. <dt><span><samp>effort</samp></span></dt>

  4340. <dd><p>Set the encoding effort used. Higher effort values produce more consistent

  4341. quality and usually produces a better quality/bpp curve, at the cost of

  4342. more CPU time required. Valid values range from 1 to 9, and the default is 7.

  4343. </p>

  4344. </dd>

  4345. <dt><span><samp>modular</samp></span></dt>

  4346. <dd><p>Force the encoder to use Modular mode instead of choosing automatically. The

  4347. default is to use VarDCT for lossy encoding and Modular for lossless. VarDCT

  4348. is generally superior to Modular for lossy encoding but does not support

  4349. lossless encoding.

  4350. </p>

  4351. </dd>

  4352. </dl>

  4353. 

  4354. <a name="libkvazaar"></a>

  4355. <h3 class="section">9.10 libkvazaar<span class="pull-right"><a class="anchor hidden-xs" href="#libkvazaar" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libkvazaar" aria-hidden="true">TOC</a></span></h3>

  4356. 

  4357. <p>Kvazaar H.265/HEVC encoder.

  4358. </p>

  4359. <p>Requires the presence of the libkvazaar headers and library during

  4360. configuration. You need to explicitly configure the build with

  4361. <samp>--enable-libkvazaar</samp>.

  4362. </p>

  4363. <a name="Options-29"></a>

  4364. <h4 class="subsection">9.10.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-29" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-29" aria-hidden="true">TOC</a></span></h4>

  4365. 

  4366. <dl compact="compact">

  4367. <dt><span><samp>b</samp></span></dt>

  4368. <dd><p>Set target video bitrate in bit/s and enable rate control.

  4369. </p>

  4370. </dd>

  4371. <dt><span><samp>kvazaar-params</samp></span></dt>

  4372. <dd><p>Set kvazaar parameters as a list of <var>name</var>=<var>value</var> pairs separated

  4373. by commas (,). See kvazaar documentation for a list of options.

  4374. </p>

  4375. </dd>

  4376. </dl>

  4377. 

  4378. <a name="libopenh264"></a>

  4379. <h3 class="section">9.11 libopenh264<span class="pull-right"><a class="anchor hidden-xs" href="#libopenh264" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libopenh264" aria-hidden="true">TOC</a></span></h3>

  4380. 

  4381. <p>Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.

  4382. </p>

  4383. <p>This encoder requires the presence of the libopenh264 headers and

  4384. library during configuration. You need to explicitly configure the

  4385. build with <code>--enable-libopenh264</code>. The library is detected using

  4386. <code>pkg-config</code>.

  4387. </p>

  4388. <p>For more information about the library see

  4389. <a href="http://www.openh264.org">http://www.openh264.org</a>.

  4390. </p>

  4391. <a name="Options-30"></a>

  4392. <h4 class="subsection">9.11.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-30" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-30" aria-hidden="true">TOC</a></span></h4>

  4393. 

  4394. <p>The following FFmpeg global options affect the configurations of the

  4395. libopenh264 encoder.

  4396. </p>

  4397. <dl compact="compact">

  4398. <dt><span><samp>b</samp></span></dt>

  4399. <dd><p>Set the bitrate (as a number of bits per second).

  4400. </p>

  4401. </dd>

  4402. <dt><span><samp>g</samp></span></dt>

  4403. <dd><p>Set the GOP size.

  4404. </p>

  4405. </dd>

  4406. <dt><span><samp>maxrate</samp></span></dt>

  4407. <dd><p>Set the max bitrate (as a number of bits per second).

  4408. </p>

  4409. </dd>

  4410. <dt><span><samp>flags +global_header</samp></span></dt>

  4411. <dd><p>Set global header in the bitstream.

  4412. </p>

  4413. </dd>

  4414. <dt><span><samp>slices</samp></span></dt>

  4415. <dd><p>Set the number of slices, used in parallelized encoding. Default value

  4416. is 0. This is only used when <samp>slice_mode</samp> is set to

  4417. &lsquo;<samp>fixed</samp>&rsquo;.

  4418. </p>

  4419. </dd>

  4420. <dt><span><samp>loopfilter</samp></span></dt>

  4421. <dd><p>Enable loop filter, if set to 1 (automatically enabled). To disable

  4422. set a value of 0.

  4423. </p>

  4424. </dd>

  4425. <dt><span><samp>profile</samp></span></dt>

  4426. <dd><p>Set profile restrictions. If set to the value of &lsquo;<samp>main</samp>&rsquo; enable

  4427. CABAC (set the <code>SEncParamExt.iEntropyCodingModeFlag</code> flag to 1).

  4428. </p>

  4429. </dd>

  4430. <dt><span><samp>max_nal_size</samp></span></dt>

  4431. <dd><p>Set maximum NAL size in bytes.

  4432. </p>

  4433. </dd>

  4434. <dt><span><samp>allow_skip_frames</samp></span></dt>

  4435. <dd><p>Allow skipping frames to hit the target bitrate if set to 1.

  4436. </p></dd>

  4437. </dl>

  4438. 

  4439. <a name="libtheora"></a>

  4440. <h3 class="section">9.12 libtheora<span class="pull-right"><a class="anchor hidden-xs" href="#libtheora" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libtheora" aria-hidden="true">TOC</a></span></h3>

  4441. 

  4442. <p>libtheora Theora encoder wrapper.

  4443. </p>

  4444. <p>Requires the presence of the libtheora headers and library during

  4445. configuration. You need to explicitly configure the build with

  4446. <code>--enable-libtheora</code>.

  4447. </p>

  4448. <p>For more information about the libtheora project see

  4449. <a href="http://www.theora.org/">http://www.theora.org/</a>.

  4450. </p>

  4451. <a name="Options-31"></a>

  4452. <h4 class="subsection">9.12.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-31" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-31" aria-hidden="true">TOC</a></span></h4>

  4453. 

  4454. <p>The following global options are mapped to internal libtheora options

  4455. which affect the quality and the bitrate of the encoded stream.

  4456. </p>

  4457. <dl compact="compact">

  4458. <dt><span><samp>b</samp></span></dt>

  4459. <dd><p>Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode.  In

  4460. case VBR (Variable Bit Rate) mode is enabled this option is ignored.

  4461. </p>

  4462. </dd>

  4463. <dt><span><samp>flags</samp></span></dt>

  4464. <dd><p>Used to enable constant quality mode (VBR) encoding through the

  4465. <samp>qscale</samp> flag, and to enable the <code>pass1</code> and <code>pass2</code>

  4466. modes.

  4467. </p>

  4468. </dd>

  4469. <dt><span><samp>g</samp></span></dt>

  4470. <dd><p>Set the GOP size.

  4471. </p>

  4472. </dd>

  4473. <dt><span><samp>global_quality</samp></span></dt>

  4474. <dd><p>Set the global quality as an integer in lambda units.

  4475. </p>

  4476. <p>Only relevant when VBR mode is enabled with <code>flags +qscale</code>. The

  4477. value is converted to QP units by dividing it by <code>FF_QP2LAMBDA</code>,

  4478. clipped in the [0 - 10] range, and then multiplied by 6.3 to get a

  4479. value in the native libtheora range [0-63]. A higher value corresponds

  4480. to a higher quality.

  4481. </p>

  4482. </dd>

  4483. <dt><span><samp>q</samp></span></dt>

  4484. <dd><p>Enable VBR mode when set to a non-negative value, and set constant

  4485. quality value as a double floating point value in QP units.

  4486. </p>

  4487. <p>The value is clipped in the [0-10] range, and then multiplied by 6.3

  4488. to get a value in the native libtheora range [0-63].

  4489. </p>

  4490. <p>This option is valid only using the <code>ffmpeg</code> command-line

  4491. tool. For library interface users, use <samp>global_quality</samp>.

  4492. </p></dd>

  4493. </dl>

  4494. 

  4495. <a name="Examples-1"></a>

  4496. <h4 class="subsection">9.12.2 Examples<span class="pull-right"><a class="anchor hidden-xs" href="#Examples-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Examples-1" aria-hidden="true">TOC</a></span></h4>

  4497. 

  4498. <ul>

  4499. <li> Set maximum constant quality (VBR) encoding with <code>ffmpeg</code>:

  4500. <div class="example">

  4501. <pre class="example">ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg

  4502. </pre></div>

  4503. 

  4504. </li><li> Use <code>ffmpeg</code> to convert a CBR 1000 kbps Theora video stream:

  4505. <div class="example">

  4506. <pre class="example">ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg

  4507. </pre></div>

  4508. </li></ul>

  4509. 

  4510. <a name="libvpx"></a>

  4511. <h3 class="section">9.13 libvpx<span class="pull-right"><a class="anchor hidden-xs" href="#libvpx" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libvpx" aria-hidden="true">TOC</a></span></h3>

  4512. 

  4513. <p>VP8/VP9 format supported through libvpx.

  4514. </p>

  4515. <p>Requires the presence of the libvpx headers and library during configuration.

  4516. You need to explicitly configure the build with <code>--enable-libvpx</code>.

  4517. </p>

  4518. <a name="Options-32"></a>

  4519. <h4 class="subsection">9.13.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-32" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-32" aria-hidden="true">TOC</a></span></h4>

  4520. 

  4521. <p>The following options are supported by the libvpx wrapper. The

  4522. <code>vpxenc</code>-equivalent options or values are listed in parentheses

  4523. for easy migration.

  4524. </p>

  4525. <p>To reduce the duplication of documentation, only the private options

  4526. and some others requiring special attention are documented here. For

  4527. the documentation of the undocumented generic options, see

  4528. <a href="#codec_002doptions">the Codec Options chapter</a>.

  4529. </p>

  4530. <p>To get more documentation of the libvpx options, invoke the command

  4531. <code>ffmpeg -h encoder=libvpx</code>, <code>ffmpeg -h encoder=libvpx-vp9</code> or

  4532. <code>vpxenc --help</code>. Further information is available in the libvpx API

  4533. documentation.

  4534. </p>

  4535. <dl compact="compact">

  4536. <dt><span><samp>b (<em>target-bitrate</em>)</samp></span></dt>

  4537. <dd><p>Set bitrate in bits/s. Note that FFmpeg&rsquo;s <samp>b</samp> option is

  4538. expressed in bits/s, while <code>vpxenc</code>&rsquo;s <samp>target-bitrate</samp> is in

  4539. kilobits/s.

  4540. </p>

  4541. </dd>

  4542. <dt><span><samp>g (<em>kf-max-dist</em>)</samp></span></dt>

  4543. <dt><span><samp>keyint_min (<em>kf-min-dist</em>)</samp></span></dt>

  4544. <dt><span><samp>qmin (<em>min-q</em>)</samp></span></dt>

  4545. <dd><p>Minimum (Best Quality) Quantizer.

  4546. </p>

  4547. </dd>

  4548. <dt><span><samp>qmax (<em>max-q</em>)</samp></span></dt>

  4549. <dd><p>Maximum (Worst Quality) Quantizer.

  4550. Can be changed per-frame.

  4551. </p>

  4552. </dd>

  4553. <dt><span><samp>bufsize (<em>buf-sz</em>, <em>buf-optimal-sz</em>)</samp></span></dt>

  4554. <dd><p>Set ratecontrol buffer size (in bits). Note <code>vpxenc</code>&rsquo;s options are

  4555. specified in milliseconds, the libvpx wrapper converts this value as follows:

  4556. <code>buf-sz = bufsize * 1000 / bitrate</code>,

  4557. <code>buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6</code>.

  4558. </p>

  4559. </dd>

  4560. <dt><span><samp>rc_init_occupancy (<em>buf-initial-sz</em>)</samp></span></dt>

  4561. <dd><p>Set number of bits which should be loaded into the rc buffer before decoding

  4562. starts. Note <code>vpxenc</code>&rsquo;s option is specified in milliseconds, the libvpx

  4563. wrapper converts this value as follows:

  4564. <code>rc_init_occupancy * 1000 / bitrate</code>.

  4565. </p>

  4566. </dd>

  4567. <dt><span><samp>undershoot-pct</samp></span></dt>

  4568. <dd><p>Set datarate undershoot (min) percentage of the target bitrate.

  4569. </p>

  4570. </dd>

  4571. <dt><span><samp>overshoot-pct</samp></span></dt>

  4572. <dd><p>Set datarate overshoot (max) percentage of the target bitrate.

  4573. </p>

  4574. </dd>

  4575. <dt><span><samp>skip_threshold (<em>drop-frame</em>)</samp></span></dt>

  4576. <dt><span><samp>qcomp (<em>bias-pct</em>)</samp></span></dt>

  4577. <dt><span><samp>maxrate (<em>maxsection-pct</em>)</samp></span></dt>

  4578. <dd><p>Set GOP max bitrate in bits/s. Note <code>vpxenc</code>&rsquo;s option is specified as a

  4579. percentage of the target bitrate, the libvpx wrapper converts this value as

  4580. follows: <code>(maxrate * 100 / bitrate)</code>.

  4581. </p>

  4582. </dd>

  4583. <dt><span><samp>minrate (<em>minsection-pct</em>)</samp></span></dt>

  4584. <dd><p>Set GOP min bitrate in bits/s. Note <code>vpxenc</code>&rsquo;s option is specified as a

  4585. percentage of the target bitrate, the libvpx wrapper converts this value as

  4586. follows: <code>(minrate * 100 / bitrate)</code>.

  4587. </p>

  4588. </dd>

  4589. <dt><span><samp>minrate, maxrate, b <em>end-usage=cbr</em></samp></span></dt>

  4590. <dd><p><code>(minrate == maxrate == bitrate)</code>.

  4591. </p>

  4592. </dd>

  4593. <dt><span><samp>crf (<em>end-usage=cq</em>, <em>cq-level</em>)</samp></span></dt>

  4594. <dt><span><samp>tune (<em>tune</em>)</samp></span></dt>

  4595. <dd><dl compact="compact">

  4596. <dt><span>&lsquo;<samp>psnr (<em>psnr</em>)</samp>&rsquo;</span></dt>

  4597. <dt><span>&lsquo;<samp>ssim (<em>ssim</em>)</samp>&rsquo;</span></dt>

  4598. </dl>

  4599. 

  4600. </dd>

  4601. <dt><span><samp>quality, deadline (<em>deadline</em>)</samp></span></dt>

  4602. <dd><dl compact="compact">

  4603. <dt><span>&lsquo;<samp>best</samp>&rsquo;</span></dt>

  4604. <dd><p>Use best quality deadline. Poorly named and quite slow, this option should be

  4605. avoided as it may give worse quality output than good.

  4606. </p></dd>

  4607. <dt><span>&lsquo;<samp>good</samp>&rsquo;</span></dt>

  4608. <dd><p>Use good quality deadline. This is a good trade-off between speed and quality

  4609. when used with the <samp>cpu-used</samp> option.

  4610. </p></dd>

  4611. <dt><span>&lsquo;<samp>realtime</samp>&rsquo;</span></dt>

  4612. <dd><p>Use realtime quality deadline.

  4613. </p></dd>

  4614. </dl>

  4615. 

  4616. </dd>

  4617. <dt><span><samp>speed, cpu-used (<em>cpu-used</em>)</samp></span></dt>

  4618. <dd><p>Set quality/speed ratio modifier. Higher values speed up the encode at the cost

  4619. of quality.

  4620. </p>

  4621. </dd>

  4622. <dt><span><samp>nr (<em>noise-sensitivity</em>)</samp></span></dt>

  4623. <dt><span><samp>static-thresh</samp></span></dt>

  4624. <dd><p>Set a change threshold on blocks below which they will be skipped by the

  4625. encoder.

  4626. </p>

  4627. </dd>

  4628. <dt><span><samp>slices (<em>token-parts</em>)</samp></span></dt>

  4629. <dd><p>Note that FFmpeg&rsquo;s <samp>slices</samp> option gives the total number of partitions,

  4630. while <code>vpxenc</code>&rsquo;s <samp>token-parts</samp> is given as

  4631. <code>log2(partitions)</code>.

  4632. </p>

  4633. </dd>

  4634. <dt><span><samp>max-intra-rate</samp></span></dt>

  4635. <dd><p>Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0

  4636. means unlimited.

  4637. </p>

  4638. </dd>

  4639. <dt><span><samp>force_key_frames</samp></span></dt>

  4640. <dd><p><code>VPX_EFLAG_FORCE_KF</code>

  4641. </p>

  4642. </dd>

  4643. <dt><span><samp>Alternate reference frame related</samp></span></dt>

  4644. <dd><dl compact="compact">

  4645. <dt><span><samp>auto-alt-ref</samp></span></dt>

  4646. <dd><p>Enable use of alternate reference frames (2-pass only).

  4647. Values greater than 1 enable multi-layer alternate reference frames (VP9 only).

  4648. </p></dd>

  4649. <dt><span><samp>arnr-maxframes</samp></span></dt>

  4650. <dd><p>Set altref noise reduction max frame count.

  4651. </p></dd>

  4652. <dt><span><samp>arnr-type</samp></span></dt>

  4653. <dd><p>Set altref noise reduction filter type: backward, forward, centered.

  4654. </p></dd>

  4655. <dt><span><samp>arnr-strength</samp></span></dt>

  4656. <dd><p>Set altref noise reduction filter strength.

  4657. </p></dd>

  4658. <dt><span><samp>rc-lookahead, lag-in-frames (<em>lag-in-frames</em>)</samp></span></dt>

  4659. <dd><p>Set number of frames to look ahead for frametype and ratecontrol.

  4660. </p></dd>

  4661. <dt><span><samp>min-gf-interval</samp></span></dt>

  4662. <dd><p>Set minimum golden/alternate reference frame interval (VP9 only).

  4663. </p></dd>

  4664. </dl>

  4665. 

  4666. </dd>

  4667. <dt><span><samp>error-resilient</samp></span></dt>

  4668. <dd><p>Enable error resiliency features.

  4669. </p>

  4670. </dd>

  4671. <dt><span><samp>sharpness <var>integer</var></samp></span></dt>

  4672. <dd><p>Increase sharpness at the expense of lower PSNR.

  4673. The valid range is [0, 7].

  4674. </p>

  4675. </dd>

  4676. <dt><span><samp>ts-parameters</samp></span></dt>

  4677. <dd><p>Sets the temporal scalability configuration using a :-separated list of

  4678. key=value pairs. For example, to specify temporal scalability parameters

  4679. with <code>ffmpeg</code>:

  4680. </p><div class="example">

  4681. <pre class="example">ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\

  4682. ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\

  4683. ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT

  4684. </pre></div>

  4685. <p>Below is a brief explanation of each of the parameters, please

  4686. refer to <code>struct vpx_codec_enc_cfg</code> in <code>vpx/vpx_encoder.h</code> for more

  4687. details.

  4688. </p><dl compact="compact">

  4689. <dt><span><samp>ts_number_layers</samp></span></dt>

  4690. <dd><p>Number of temporal coding layers.

  4691. </p></dd>

  4692. <dt><span><samp>ts_target_bitrate</samp></span></dt>

  4693. <dd><p>Target bitrate for each temporal layer (in kbps).

  4694. (bitrate should be inclusive of the lower temporal layer).

  4695. </p></dd>

  4696. <dt><span><samp>ts_rate_decimator</samp></span></dt>

  4697. <dd><p>Frame rate decimation factor for each temporal layer.

  4698. </p></dd>

  4699. <dt><span><samp>ts_periodicity</samp></span></dt>

  4700. <dd><p>Length of the sequence defining frame temporal layer membership.

  4701. </p></dd>

  4702. <dt><span><samp>ts_layer_id</samp></span></dt>

  4703. <dd><p>Template defining the membership of frames to temporal layers.

  4704. </p></dd>

  4705. <dt><span><samp>ts_layering_mode</samp></span></dt>

  4706. <dd><p>(optional) Selecting the temporal structure from a set of pre-defined temporal layering modes.

  4707. Currently supports the following options.

  4708. </p><dl compact="compact">

  4709. <dt><span><samp>0</samp></span></dt>

  4710. <dd><p>No temporal layering flags are provided internally,

  4711. relies on flags being passed in using <code>metadata</code> field in <code>AVFrame</code>

  4712. with following keys.

  4713. </p><dl compact="compact">

  4714. <dt><span><samp>vp8-flags</samp></span></dt>

  4715. <dd><p>Sets the flags passed into the encoder to indicate the referencing scheme for

  4716. the current frame.

  4717. Refer to function <code>vpx_codec_encode</code> in <code>vpx/vpx_encoder.h</code> for more

  4718. details.

  4719. </p></dd>

  4720. <dt><span><samp>temporal_id</samp></span></dt>

  4721. <dd><p>Explicitly sets the temporal id of the current frame to encode.

  4722. </p></dd>

  4723. </dl>

  4724. </dd>

  4725. <dt><span><samp>2</samp></span></dt>

  4726. <dd><p>Two temporal layers. 0-1...

  4727. </p></dd>

  4728. <dt><span><samp>3</samp></span></dt>

  4729. <dd><p>Three temporal layers. 0-2-1-2...; with single reference frame.

  4730. </p></dd>

  4731. <dt><span><samp>4</samp></span></dt>

  4732. <dd><p>Same as option &quot;3&quot;, except there is a dependency between

  4733. the two temporal layer 2 frames within the temporal period.

  4734. </p></dd>

  4735. </dl>

  4736. </dd>

  4737. </dl>

  4738. 

  4739. </dd>

  4740. <dt><span><samp>VP9-specific options</samp></span></dt>

  4741. <dd><dl compact="compact">

  4742. <dt><span><samp>lossless</samp></span></dt>

  4743. <dd><p>Enable lossless mode.

  4744. </p></dd>

  4745. <dt><span><samp>tile-columns</samp></span></dt>

  4746. <dd><p>Set number of tile columns to use. Note this is given as

  4747. <code>log2(tile_columns)</code>. For example, 8 tile columns would be requested by

  4748. setting the <samp>tile-columns</samp> option to 3.

  4749. </p></dd>

  4750. <dt><span><samp>tile-rows</samp></span></dt>

  4751. <dd><p>Set number of tile rows to use. Note this is given as <code>log2(tile_rows)</code>.

  4752. For example, 4 tile rows would be requested by setting the <samp>tile-rows</samp>

  4753. option to 2.

  4754. </p></dd>

  4755. <dt><span><samp>frame-parallel</samp></span></dt>

  4756. <dd><p>Enable frame parallel decodability features.

  4757. </p></dd>

  4758. <dt><span><samp>aq-mode</samp></span></dt>

  4759. <dd><p>Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:

  4760. cyclic refresh, 4: equator360).

  4761. </p></dd>

  4762. <dt><span><samp>colorspace <em>color-space</em></samp></span></dt>

  4763. <dd><p>Set input color space. The VP9 bitstream supports signaling the following

  4764. colorspaces:

  4765. </p><dl compact="compact">

  4766. <dt><span><samp>&lsquo;<samp>rgb</samp>&rsquo; <em>sRGB</em></samp></span></dt>

  4767. <dt><span><samp>&lsquo;<samp>bt709</samp>&rsquo; <em>bt709</em></samp></span></dt>

  4768. <dt><span><samp>&lsquo;<samp>unspecified</samp>&rsquo; <em>unknown</em></samp></span></dt>

  4769. <dt><span><samp>&lsquo;<samp>bt470bg</samp>&rsquo; <em>bt601</em></samp></span></dt>

  4770. <dt><span><samp>&lsquo;<samp>smpte170m</samp>&rsquo; <em>smpte170</em></samp></span></dt>

  4771. <dt><span><samp>&lsquo;<samp>smpte240m</samp>&rsquo; <em>smpte240</em></samp></span></dt>

  4772. <dt><span><samp>&lsquo;<samp>bt2020_ncl</samp>&rsquo; <em>bt2020</em></samp></span></dt>

  4773. </dl>

  4774. </dd>

  4775. <dt><span><samp>row-mt <var>boolean</var></samp></span></dt>

  4776. <dd><p>Enable row based multi-threading.

  4777. </p></dd>

  4778. <dt><span><samp>tune-content</samp></span></dt>

  4779. <dd><p>Set content type: default (0), screen (1), film (2).

  4780. </p></dd>

  4781. <dt><span><samp>corpus-complexity</samp></span></dt>

  4782. <dd><p>Corpus VBR mode is a variant of standard VBR where the complexity distribution

  4783. midpoint is passed in rather than calculated for a specific clip or chunk.

  4784. </p>

  4785. <p>The valid range is [0, 10000]. 0 (default) uses standard VBR.

  4786. </p></dd>

  4787. <dt><span><samp>enable-tpl <var>boolean</var></samp></span></dt>

  4788. <dd><p>Enable temporal dependency model.

  4789. </p></dd>

  4790. <dt><span><samp>ref-frame-config</samp></span></dt>

  4791. <dd><p>Using per-frame metadata, set members of the structure <code>vpx_svc_ref_frame_config_t</code> in <code>vpx/vp8cx.h</code> to fine-control referencing schemes and frame buffer management.

  4792. <br>Use a :-separated list of key=value pairs.

  4793. For example,

  4794. </p><div class="example">

  4795. <pre class="example">av_dict_set(&amp;av_frame-&gt;metadata, &quot;ref-frame-config&quot;, \

  4796. &quot;rfc_update_buffer_slot=7:rfc_lst_fb_idx=0:rfc_gld_fb_idx=1:rfc_alt_fb_idx=2:rfc_reference_last=0:rfc_reference_golden=0:rfc_reference_alt_ref=0&quot;);

  4797. </pre></div>

  4798. <dl compact="compact">

  4799. <dt><span><samp>rfc_update_buffer_slot</samp></span></dt>

  4800. <dd><p>Indicates the buffer slot number to update

  4801. </p></dd>

  4802. <dt><span><samp>rfc_update_last</samp></span></dt>

  4803. <dd><p>Indicates whether to update the LAST frame

  4804. </p></dd>

  4805. <dt><span><samp>rfc_update_golden</samp></span></dt>

  4806. <dd><p>Indicates whether to update GOLDEN frame

  4807. </p></dd>

  4808. <dt><span><samp>rfc_update_alt_ref</samp></span></dt>

  4809. <dd><p>Indicates whether to update ALT_REF frame

  4810. </p></dd>

  4811. <dt><span><samp>rfc_lst_fb_idx</samp></span></dt>

  4812. <dd><p>LAST frame buffer index

  4813. </p></dd>

  4814. <dt><span><samp>rfc_gld_fb_idx</samp></span></dt>

  4815. <dd><p>GOLDEN frame buffer index

  4816. </p></dd>

  4817. <dt><span><samp>rfc_alt_fb_idx</samp></span></dt>

  4818. <dd><p>ALT_REF frame buffer index

  4819. </p></dd>

  4820. <dt><span><samp>rfc_reference_last</samp></span></dt>

  4821. <dd><p>Indicates whether to reference LAST frame

  4822. </p></dd>

  4823. <dt><span><samp>rfc_reference_golden</samp></span></dt>

  4824. <dd><p>Indicates whether to reference GOLDEN frame

  4825. </p></dd>

  4826. <dt><span><samp>rfc_reference_alt_ref</samp></span></dt>

  4827. <dd><p>Indicates whether to reference ALT_REF frame

  4828. </p></dd>

  4829. <dt><span><samp>rfc_reference_duration</samp></span></dt>

  4830. <dd><p>Indicates frame duration

  4831. </p></dd>

  4832. </dl>

  4833. </dd>

  4834. </dl>

  4835. 

  4836. </dd>

  4837. </dl>

  4838. 

  4839. <p>For more information about libvpx see:

  4840. <a href="http://www.webmproject.org/">http://www.webmproject.org/</a>

  4841. </p>

  4842. <a name="libwebp"></a>

  4843. <h3 class="section">9.14 libwebp<span class="pull-right"><a class="anchor hidden-xs" href="#libwebp" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libwebp" aria-hidden="true">TOC</a></span></h3>

  4844. 

  4845. <p>libwebp WebP Image encoder wrapper

  4846. </p>

  4847. <p>libwebp is Google&rsquo;s official encoder for WebP images. It can encode in either

  4848. lossy or lossless mode. Lossy images are essentially a wrapper around a VP8

  4849. frame. Lossless images are a separate codec developed by Google.

  4850. </p>

  4851. <a name="Pixel-Format"></a>

  4852. <h4 class="subsection">9.14.1 Pixel Format<span class="pull-right"><a class="anchor hidden-xs" href="#Pixel-Format" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Pixel-Format" aria-hidden="true">TOC</a></span></h4>

  4853. 

  4854. <p>Currently, libwebp only supports YUV420 for lossy and RGB for lossless due

  4855. to limitations of the format and libwebp. Alpha is supported for either mode.

  4856. Because of API limitations, if RGB is passed in when encoding lossy or YUV is

  4857. passed in for encoding lossless, the pixel format will automatically be

  4858. converted using functions from libwebp. This is not ideal and is done only for

  4859. convenience.

  4860. </p>

  4861. <a name="Options-33"></a>

  4862. <h4 class="subsection">9.14.2 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-33" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-33" aria-hidden="true">TOC</a></span></h4>

  4863. 

  4864. <dl compact="compact">

  4865. <dt><span><samp>-lossless <var>boolean</var></samp></span></dt>

  4866. <dd><p>Enables/Disables use of lossless mode. Default is 0.

  4867. </p>

  4868. </dd>

  4869. <dt><span><samp>-compression_level <var>integer</var></samp></span></dt>

  4870. <dd><p>For lossy, this is a quality/speed tradeoff. Higher values give better quality

  4871. for a given size at the cost of increased encoding time. For lossless, this is

  4872. a size/speed tradeoff. Higher values give smaller size at the cost of increased

  4873. encoding time. More specifically, it controls the number of extra algorithms

  4874. and compression tools used, and varies the combination of these tools. This

  4875. maps to the <var>method</var> option in libwebp. The valid range is 0 to 6.

  4876. Default is 4.

  4877. </p>

  4878. </dd>

  4879. <dt><span><samp>-quality <var>float</var></samp></span></dt>

  4880. <dd><p>For lossy encoding, this controls image quality. For lossless encoding, this

  4881. controls the effort and time spent in compression.

  4882. Range is 0 to 100. Default is 75.

  4883. </p>

  4884. </dd>

  4885. <dt><span><samp>-preset <var>type</var></samp></span></dt>

  4886. <dd><p>Configuration preset. This does some automatic settings based on the general

  4887. type of the image.

  4888. </p><dl compact="compact">

  4889. <dt><span><samp>none</samp></span></dt>

  4890. <dd><p>Do not use a preset.

  4891. </p></dd>

  4892. <dt><span><samp>default</samp></span></dt>

  4893. <dd><p>Use the encoder default.

  4894. </p></dd>

  4895. <dt><span><samp>picture</samp></span></dt>

  4896. <dd><p>Digital picture, like portrait, inner shot

  4897. </p></dd>

  4898. <dt><span><samp>photo</samp></span></dt>

  4899. <dd><p>Outdoor photograph, with natural lighting

  4900. </p></dd>

  4901. <dt><span><samp>drawing</samp></span></dt>

  4902. <dd><p>Hand or line drawing, with high-contrast details

  4903. </p></dd>

  4904. <dt><span><samp>icon</samp></span></dt>

  4905. <dd><p>Small-sized colorful images

  4906. </p></dd>

  4907. <dt><span><samp>text</samp></span></dt>

  4908. <dd><p>Text-like

  4909. </p></dd>

  4910. </dl>

  4911. 

  4912. </dd>

  4913. </dl>

  4914. 

  4915. <a name="libx264_002c-libx264rgb"></a>

  4916. <h3 class="section">9.15 libx264, libx264rgb<span class="pull-right"><a class="anchor hidden-xs" href="#libx264_002c-libx264rgb" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libx264_002c-libx264rgb" aria-hidden="true">TOC</a></span></h3>

  4917. 

  4918. <p>x264 H.264/MPEG-4 AVC encoder wrapper.

  4919. </p>

  4920. <p>This encoder requires the presence of the libx264 headers and library

  4921. during configuration. You need to explicitly configure the build with

  4922. <code>--enable-libx264</code>.

  4923. </p>

  4924. <p>libx264 supports an impressive number of features, including 8x8 and

  4925. 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC

  4926. entropy coding, interlacing (MBAFF), lossless mode, psy optimizations

  4927. for detail retention (adaptive quantization, psy-RD, psy-trellis).

  4928. </p>

  4929. <p>Many libx264 encoder options are mapped to FFmpeg global codec

  4930. options, while unique encoder options are provided through private

  4931. options. Additionally the <samp>x264opts</samp> and <samp>x264-params</samp>

  4932. private options allows one to pass a list of key=value tuples as accepted

  4933. by the libx264 <code>x264_param_parse</code> function.

  4934. </p>

  4935. <p>The x264 project website is at

  4936. <a href="http://www.videolan.org/developers/x264.html">http://www.videolan.org/developers/x264.html</a>.

  4937. </p>

  4938. <p>The libx264rgb encoder is the same as libx264, except it accepts packed RGB

  4939. pixel formats as input instead of YUV.

  4940. </p>

  4941. <a name="Supported-Pixel-Formats"></a>

  4942. <h4 class="subsection">9.15.1 Supported Pixel Formats<span class="pull-right"><a class="anchor hidden-xs" href="#Supported-Pixel-Formats" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Supported-Pixel-Formats" aria-hidden="true">TOC</a></span></h4>

  4943. 

  4944. <p>x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at

  4945. x264&rsquo;s configure time.

  4946. </p>

  4947. <a name="Options-34"></a>

  4948. <h4 class="subsection">9.15.2 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-34" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-34" aria-hidden="true">TOC</a></span></h4>

  4949. 

  4950. <p>The following options are supported by the libx264 wrapper. The

  4951. <code>x264</code>-equivalent options or values are listed in parentheses

  4952. for easy migration.

  4953. </p>

  4954. <p>To reduce the duplication of documentation, only the private options

  4955. and some others requiring special attention are documented here. For

  4956. the documentation of the undocumented generic options, see

  4957. <a href="#codec_002doptions">the Codec Options chapter</a>.

  4958. </p>

  4959. <p>To get a more accurate and extensive documentation of the libx264

  4960. options, invoke the command <code>x264 --fullhelp</code> or consult

  4961. the libx264 documentation.

  4962. </p>

  4963. <dl compact="compact">

  4964. <dt><span><samp>b (<em>bitrate</em>)</samp></span></dt>

  4965. <dd><p>Set bitrate in bits/s. Note that FFmpeg&rsquo;s <samp>b</samp> option is

  4966. expressed in bits/s, while <code>x264</code>&rsquo;s <samp>bitrate</samp> is in

  4967. kilobits/s.

  4968. </p>

  4969. </dd>

  4970. <dt><span><samp>bf (<em>bframes</em>)</samp></span></dt>

  4971. <dt><span><samp>g (<em>keyint</em>)</samp></span></dt>

  4972. <dt><span><samp>qmin (<em>qpmin</em>)</samp></span></dt>

  4973. <dd><p>Minimum quantizer scale.

  4974. </p>

  4975. </dd>

  4976. <dt><span><samp>qmax (<em>qpmax</em>)</samp></span></dt>

  4977. <dd><p>Maximum quantizer scale.

  4978. </p>

  4979. </dd>

  4980. <dt><span><samp>qdiff (<em>qpstep</em>)</samp></span></dt>

  4981. <dd><p>Maximum difference between quantizer scales.

  4982. </p>

  4983. </dd>

  4984. <dt><span><samp>qblur (<em>qblur</em>)</samp></span></dt>

  4985. <dd><p>Quantizer curve blur

  4986. </p>

  4987. </dd>

  4988. <dt><span><samp>qcomp (<em>qcomp</em>)</samp></span></dt>

  4989. <dd><p>Quantizer curve compression factor

  4990. </p>

  4991. </dd>

  4992. <dt><span><samp>refs (<em>ref</em>)</samp></span></dt>

  4993. <dd><p>Number of reference frames each P-frame can use. The range is from <var>0-16</var>.

  4994. </p>

  4995. </dd>

  4996. <dt><span><samp>sc_threshold (<em>scenecut</em>)</samp></span></dt>

  4997. <dd><p>Sets the threshold for the scene change detection.

  4998. </p>

  4999. </dd>

  5000. <dt><span><samp>trellis (<em>trellis</em>)</samp></span></dt>

  5001. <dd><p>Performs Trellis quantization to increase efficiency. Enabled by default.

  5002. </p>

  5003. </dd>

  5004. <dt><span><samp>nr  (<em>nr</em>)</samp></span></dt>

  5005. <dt><span><samp>me_range (<em>merange</em>)</samp></span></dt>

  5006. <dd><p>Maximum range of the motion search in pixels.

  5007. </p>

  5008. </dd>

  5009. <dt><span><samp>me_method (<em>me</em>)</samp></span></dt>

  5010. <dd><p>Set motion estimation method. Possible values in the decreasing order

  5011. of speed:

  5012. </p>

  5013. <dl compact="compact">

  5014. <dt><span>&lsquo;<samp>dia (<em>dia</em>)</samp>&rsquo;</span></dt>

  5015. <dt><span>&lsquo;<samp>epzs (<em>dia</em>)</samp>&rsquo;</span></dt>

  5016. <dd><p>Diamond search with radius 1 (fastest). &lsquo;<samp>epzs</samp>&rsquo; is an alias for

  5017. &lsquo;<samp>dia</samp>&rsquo;.

  5018. </p></dd>

  5019. <dt><span>&lsquo;<samp>hex (<em>hex</em>)</samp>&rsquo;</span></dt>

  5020. <dd><p>Hexagonal search with radius 2.

  5021. </p></dd>

  5022. <dt><span>&lsquo;<samp>umh (<em>umh</em>)</samp>&rsquo;</span></dt>

  5023. <dd><p>Uneven multi-hexagon search.

  5024. </p></dd>

  5025. <dt><span>&lsquo;<samp>esa (<em>esa</em>)</samp>&rsquo;</span></dt>

  5026. <dd><p>Exhaustive search.

  5027. </p></dd>

  5028. <dt><span>&lsquo;<samp>tesa (<em>tesa</em>)</samp>&rsquo;</span></dt>

  5029. <dd><p>Hadamard exhaustive search (slowest).

  5030. </p></dd>

  5031. </dl>

  5032. 

  5033. </dd>

  5034. <dt><span><samp>forced-idr</samp></span></dt>

  5035. <dd><p>Normally, when forcing a I-frame type, the encoder can select any type

  5036. of I-frame. This option forces it to choose an IDR-frame.

  5037. </p>

  5038. </dd>

  5039. <dt><span><samp>subq (<em>subme</em>)</samp></span></dt>

  5040. <dd><p>Sub-pixel motion estimation method.

  5041. </p>

  5042. </dd>

  5043. <dt><span><samp>b_strategy (<em>b-adapt</em>)</samp></span></dt>

  5044. <dd><p>Adaptive B-frame placement decision algorithm. Use only on first-pass.

  5045. </p>

  5046. </dd>

  5047. <dt><span><samp>keyint_min (<em>min-keyint</em>)</samp></span></dt>

  5048. <dd><p>Minimum GOP size.

  5049. </p>

  5050. </dd>

  5051. <dt><span><samp>coder</samp></span></dt>

  5052. <dd><p>Set entropy encoder. Possible values:

  5053. </p>

  5054. <dl compact="compact">

  5055. <dt><span>&lsquo;<samp>ac</samp>&rsquo;</span></dt>

  5056. <dd><p>Enable CABAC.

  5057. </p>

  5058. </dd>

  5059. <dt><span>&lsquo;<samp>vlc</samp>&rsquo;</span></dt>

  5060. <dd><p>Enable CAVLC and disable CABAC. It generates the same effect as

  5061. <code>x264</code>&rsquo;s <samp>--no-cabac</samp> option.

  5062. </p></dd>

  5063. </dl>

  5064. 

  5065. </dd>

  5066. <dt><span><samp>cmp</samp></span></dt>

  5067. <dd><p>Set full pixel motion estimation comparison algorithm. Possible values:

  5068. </p>

  5069. <dl compact="compact">

  5070. <dt><span>&lsquo;<samp>chroma</samp>&rsquo;</span></dt>

  5071. <dd><p>Enable chroma in motion estimation.

  5072. </p>

  5073. </dd>

  5074. <dt><span>&lsquo;<samp>sad</samp>&rsquo;</span></dt>

  5075. <dd><p>Ignore chroma in motion estimation. It generates the same effect as

  5076. <code>x264</code>&rsquo;s <samp>--no-chroma-me</samp> option.

  5077. </p></dd>

  5078. </dl>

  5079. 

  5080. </dd>

  5081. <dt><span><samp>threads (<em>threads</em>)</samp></span></dt>

  5082. <dd><p>Number of encoding threads.

  5083. </p>

  5084. </dd>

  5085. <dt><span><samp>thread_type</samp></span></dt>

  5086. <dd><p>Set multithreading technique. Possible values:

  5087. </p>

  5088. <dl compact="compact">

  5089. <dt><span>&lsquo;<samp>slice</samp>&rsquo;</span></dt>

  5090. <dd><p>Slice-based multithreading. It generates the same effect as

  5091. <code>x264</code>&rsquo;s <samp>--sliced-threads</samp> option.

  5092. </p></dd>

  5093. <dt><span>&lsquo;<samp>frame</samp>&rsquo;</span></dt>

  5094. <dd><p>Frame-based multithreading.

  5095. </p></dd>

  5096. </dl>

  5097. 

  5098. </dd>

  5099. <dt><span><samp>flags</samp></span></dt>

  5100. <dd><p>Set encoding flags. It can be used to disable closed GOP and enable

  5101. open GOP by setting it to <code>-cgop</code>. The result is similar to

  5102. the behavior of <code>x264</code>&rsquo;s <samp>--open-gop</samp> option.

  5103. </p>

  5104. </dd>

  5105. <dt><span><samp>rc_init_occupancy (<em>vbv-init</em>)</samp></span></dt>

  5106. <dt><span><samp>preset (<em>preset</em>)</samp></span></dt>

  5107. <dd><p>Set the encoding preset.

  5108. </p>

  5109. </dd>

  5110. <dt><span><samp>tune (<em>tune</em>)</samp></span></dt>

  5111. <dd><p>Set tuning of the encoding params.

  5112. </p>

  5113. </dd>

  5114. <dt><span><samp>profile (<em>profile</em>)</samp></span></dt>

  5115. <dd><p>Set profile restrictions.

  5116. </p>

  5117. </dd>

  5118. <dt><span><samp>fastfirstpass</samp></span></dt>

  5119. <dd><p>Enable fast settings when encoding first pass, when set to 1. When set

  5120. to 0, it has the same effect of <code>x264</code>&rsquo;s

  5121. <samp>--slow-firstpass</samp> option.

  5122. </p>

  5123. </dd>

  5124. <dt><span><samp>crf (<em>crf</em>)</samp></span></dt>

  5125. <dd><p>Set the quality for constant quality mode.

  5126. </p>

  5127. </dd>

  5128. <dt><span><samp>crf_max (<em>crf-max</em>)</samp></span></dt>

  5129. <dd><p>In CRF mode, prevents VBV from lowering quality beyond this point.

  5130. </p>

  5131. </dd>

  5132. <dt><span><samp>qp (<em>qp</em>)</samp></span></dt>

  5133. <dd><p>Set constant quantization rate control method parameter.

  5134. </p>

  5135. </dd>

  5136. <dt><span><samp>aq-mode (<em>aq-mode</em>)</samp></span></dt>

  5137. <dd><p>Set AQ method. Possible values:

  5138. </p>

  5139. <dl compact="compact">

  5140. <dt><span>&lsquo;<samp>none (<em>0</em>)</samp>&rsquo;</span></dt>

  5141. <dd><p>Disabled.

  5142. </p>

  5143. </dd>

  5144. <dt><span>&lsquo;<samp>variance (<em>1</em>)</samp>&rsquo;</span></dt>

  5145. <dd><p>Variance AQ (complexity mask).

  5146. </p>

  5147. </dd>

  5148. <dt><span>&lsquo;<samp>autovariance (<em>2</em>)</samp>&rsquo;</span></dt>

  5149. <dd><p>Auto-variance AQ (experimental).

  5150. </p></dd>

  5151. </dl>

  5152. 

  5153. </dd>

  5154. <dt><span><samp>aq-strength (<em>aq-strength</em>)</samp></span></dt>

  5155. <dd><p>Set AQ strength, reduce blocking and blurring in flat and textured areas.

  5156. </p>

  5157. </dd>

  5158. <dt><span><samp>psy</samp></span></dt>

  5159. <dd><p>Use psychovisual optimizations when set to 1. When set to 0, it has the

  5160. same effect as <code>x264</code>&rsquo;s <samp>--no-psy</samp> option.

  5161. </p>

  5162. </dd>

  5163. <dt><span><samp>psy-rd  (<em>psy-rd</em>)</samp></span></dt>

  5164. <dd><p>Set strength of psychovisual optimization, in

  5165. <var>psy-rd</var>:<var>psy-trellis</var> format.

  5166. </p>

  5167. </dd>

  5168. <dt><span><samp>rc-lookahead (<em>rc-lookahead</em>)</samp></span></dt>

  5169. <dd><p>Set number of frames to look ahead for frametype and ratecontrol.

  5170. </p>

  5171. </dd>

  5172. <dt><span><samp>weightb</samp></span></dt>

  5173. <dd><p>Enable weighted prediction for B-frames when set to 1. When set to 0,

  5174. it has the same effect as <code>x264</code>&rsquo;s <samp>--no-weightb</samp> option.

  5175. </p>

  5176. </dd>

  5177. <dt><span><samp>weightp (<em>weightp</em>)</samp></span></dt>

  5178. <dd><p>Set weighted prediction method for P-frames. Possible values:

  5179. </p>

  5180. <dl compact="compact">

  5181. <dt><span>&lsquo;<samp>none (<em>0</em>)</samp>&rsquo;</span></dt>

  5182. <dd><p>Disabled

  5183. </p></dd>

  5184. <dt><span>&lsquo;<samp>simple (<em>1</em>)</samp>&rsquo;</span></dt>

  5185. <dd><p>Enable only weighted refs

  5186. </p></dd>

  5187. <dt><span>&lsquo;<samp>smart (<em>2</em>)</samp>&rsquo;</span></dt>

  5188. <dd><p>Enable both weighted refs and duplicates

  5189. </p></dd>

  5190. </dl>

  5191. 

  5192. </dd>

  5193. <dt><span><samp>ssim (<em>ssim</em>)</samp></span></dt>

  5194. <dd><p>Enable calculation and printing SSIM stats after the encoding.

  5195. </p>

  5196. </dd>

  5197. <dt><span><samp>intra-refresh (<em>intra-refresh</em>)</samp></span></dt>

  5198. <dd><p>Enable the use of Periodic Intra Refresh instead of IDR frames when set

  5199. to 1.

  5200. </p>

  5201. </dd>

  5202. <dt><span><samp>avcintra-class (<em>class</em>)</samp></span></dt>

  5203. <dd><p>Configure the encoder to generate AVC-Intra.

  5204. Valid values are 50,100 and 200

  5205. </p>

  5206. </dd>

  5207. <dt><span><samp>bluray-compat (<em>bluray-compat</em>)</samp></span></dt>

  5208. <dd><p>Configure the encoder to be compatible with the bluray standard.

  5209. It is a shorthand for setting &quot;bluray-compat=1 force-cfr=1&quot;.

  5210. </p>

  5211. </dd>

  5212. <dt><span><samp>b-bias (<em>b-bias</em>)</samp></span></dt>

  5213. <dd><p>Set the influence on how often B-frames are used.

  5214. </p>

  5215. </dd>

  5216. <dt><span><samp>b-pyramid (<em>b-pyramid</em>)</samp></span></dt>

  5217. <dd><p>Set method for keeping of some B-frames as references. Possible values:

  5218. </p>

  5219. <dl compact="compact">

  5220. <dt><span>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</span></dt>

  5221. <dd><p>Disabled.

  5222. </p></dd>

  5223. <dt><span>&lsquo;<samp>strict (<em>strict</em>)</samp>&rsquo;</span></dt>

  5224. <dd><p>Strictly hierarchical pyramid.

  5225. </p></dd>

  5226. <dt><span>&lsquo;<samp>normal (<em>normal</em>)</samp>&rsquo;</span></dt>

  5227. <dd><p>Non-strict (not Blu-ray compatible).

  5228. </p></dd>

  5229. </dl>

  5230. 

  5231. </dd>

  5232. <dt><span><samp>mixed-refs</samp></span></dt>

  5233. <dd><p>Enable the use of one reference per partition, as opposed to one

  5234. reference per macroblock when set to 1. When set to 0, it has the

  5235. same effect as <code>x264</code>&rsquo;s <samp>--no-mixed-refs</samp> option.

  5236. </p>

  5237. </dd>

  5238. <dt><span><samp>8x8dct</samp></span></dt>

  5239. <dd><p>Enable adaptive spatial transform (high profile 8x8 transform)

  5240. when set to 1. When set to 0, it has the same effect as

  5241. <code>x264</code>&rsquo;s <samp>--no-8x8dct</samp> option.

  5242. </p>

  5243. </dd>

  5244. <dt><span><samp>fast-pskip</samp></span></dt>

  5245. <dd><p>Enable early SKIP detection on P-frames when set to 1. When set

  5246. to 0, it has the same effect as <code>x264</code>&rsquo;s

  5247. <samp>--no-fast-pskip</samp> option.

  5248. </p>

  5249. </dd>

  5250. <dt><span><samp>aud (<em>aud</em>)</samp></span></dt>

  5251. <dd><p>Enable use of access unit delimiters when set to 1.

  5252. </p>

  5253. </dd>

  5254. <dt><span><samp>mbtree</samp></span></dt>

  5255. <dd><p>Enable use macroblock tree ratecontrol when set to 1. When set

  5256. to 0, it has the same effect as <code>x264</code>&rsquo;s

  5257. <samp>--no-mbtree</samp> option.

  5258. </p>

  5259. </dd>

  5260. <dt><span><samp>deblock (<em>deblock</em>)</samp></span></dt>

  5261. <dd><p>Set loop filter parameters, in <var>alpha</var>:<var>beta</var> form.

  5262. </p>

  5263. </dd>

  5264. <dt><span><samp>cplxblur (<em>cplxblur</em>)</samp></span></dt>

  5265. <dd><p>Set fluctuations reduction in QP (before curve compression).

  5266. </p>

  5267. </dd>

  5268. <dt><span><samp>partitions (<em>partitions</em>)</samp></span></dt>

  5269. <dd><p>Set partitions to consider as a comma-separated list of. Possible

  5270. values in the list:

  5271. </p>

  5272. <dl compact="compact">

  5273. <dt><span>&lsquo;<samp>p8x8</samp>&rsquo;</span></dt>

  5274. <dd><p>8x8 P-frame partition.

  5275. </p></dd>

  5276. <dt><span>&lsquo;<samp>p4x4</samp>&rsquo;</span></dt>

  5277. <dd><p>4x4 P-frame partition.

  5278. </p></dd>

  5279. <dt><span>&lsquo;<samp>b8x8</samp>&rsquo;</span></dt>

  5280. <dd><p>4x4 B-frame partition.

  5281. </p></dd>

  5282. <dt><span>&lsquo;<samp>i8x8</samp>&rsquo;</span></dt>

  5283. <dd><p>8x8 I-frame partition.

  5284. </p></dd>

  5285. <dt><span>&lsquo;<samp>i4x4</samp>&rsquo;</span></dt>

  5286. <dd><p>4x4 I-frame partition.

  5287. (Enabling &lsquo;<samp>p4x4</samp>&rsquo; requires &lsquo;<samp>p8x8</samp>&rsquo; to be enabled. Enabling

  5288. &lsquo;<samp>i8x8</samp>&rsquo; requires adaptive spatial transform (<samp>8x8dct</samp>

  5289. option) to be enabled.)

  5290. </p></dd>

  5291. <dt><span>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</span></dt>

  5292. <dd><p>Do not consider any partitions.

  5293. </p></dd>

  5294. <dt><span>&lsquo;<samp>all (<em>all</em>)</samp>&rsquo;</span></dt>

  5295. <dd><p>Consider every partition.

  5296. </p></dd>

  5297. </dl>

  5298. 

  5299. </dd>

  5300. <dt><span><samp>direct-pred (<em>direct</em>)</samp></span></dt>

  5301. <dd><p>Set direct MV prediction mode. Possible values:

  5302. </p>

  5303. <dl compact="compact">

  5304. <dt><span>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</span></dt>

  5305. <dd><p>Disable MV prediction.

  5306. </p></dd>

  5307. <dt><span>&lsquo;<samp>spatial (<em>spatial</em>)</samp>&rsquo;</span></dt>

  5308. <dd><p>Enable spatial predicting.

  5309. </p></dd>

  5310. <dt><span>&lsquo;<samp>temporal (<em>temporal</em>)</samp>&rsquo;</span></dt>

  5311. <dd><p>Enable temporal predicting.

  5312. </p></dd>

  5313. <dt><span>&lsquo;<samp>auto (<em>auto</em>)</samp>&rsquo;</span></dt>

  5314. <dd><p>Automatically decided.

  5315. </p></dd>

  5316. </dl>

  5317. 

  5318. </dd>

  5319. <dt><span><samp>slice-max-size (<em>slice-max-size</em>)</samp></span></dt>

  5320. <dd><p>Set the limit of the size of each slice in bytes. If not specified

  5321. but RTP payload size (<samp>ps</samp>) is specified, that is used.

  5322. </p>

  5323. </dd>

  5324. <dt><span><samp>stats (<em>stats</em>)</samp></span></dt>

  5325. <dd><p>Set the file name for multi-pass stats.

  5326. </p>

  5327. </dd>

  5328. <dt><span><samp>nal-hrd (<em>nal-hrd</em>)</samp></span></dt>

  5329. <dd><p>Set signal HRD information (requires <samp>vbv-bufsize</samp> to be set).

  5330. Possible values:

  5331. </p>

  5332. <dl compact="compact">

  5333. <dt><span>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</span></dt>

  5334. <dd><p>Disable HRD information signaling.

  5335. </p></dd>

  5336. <dt><span>&lsquo;<samp>vbr (<em>vbr</em>)</samp>&rsquo;</span></dt>

  5337. <dd><p>Variable bit rate.

  5338. </p></dd>

  5339. <dt><span>&lsquo;<samp>cbr (<em>cbr</em>)</samp>&rsquo;</span></dt>

  5340. <dd><p>Constant bit rate (not allowed in MP4 container).

  5341. </p></dd>

  5342. </dl>

  5343. 

  5344. </dd>

  5345. <dt><span><samp>x264opts (N.A.)</samp></span></dt>

  5346. <dd><p>Set any x264 option, see <code>x264 --fullhelp</code> for a list.

  5347. </p>

  5348. <p>Argument is a list of <var>key</var>=<var>value</var> couples separated by

  5349. &quot;:&quot;. In <var>filter</var> and <var>psy-rd</var> options that use &quot;:&quot; as a separator

  5350. themselves, use &quot;,&quot; instead. They accept it as well since long ago but this

  5351. is kept undocumented for some reason.

  5352. </p>

  5353. <p>For example to specify libx264 encoding options with <code>ffmpeg</code>:

  5354. </p><div class="example">

  5355. <pre class="example">ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv

  5356. </pre></div>

  5357. 

  5358. </dd>

  5359. <dt><span><samp>a53cc <var>boolean</var></samp></span></dt>

  5360. <dd><p>Import closed captions (which must be ATSC compatible format) into output.

  5361. Only the mpeg2 and h264 decoders provide these. Default is 1 (on).

  5362. </p>

  5363. </dd>

  5364. <dt><span><samp>udu_sei <var>boolean</var></samp></span></dt>

  5365. <dd><p>Import user data unregistered SEI if available into output. Default is 0 (off).

  5366. </p>

  5367. </dd>

  5368. <dt><span><samp>x264-params (N.A.)</samp></span></dt>

  5369. <dd><p>Override the x264 configuration using a :-separated list of key=value

  5370. parameters.

  5371. </p>

  5372. <p>This option is functionally the same as the <samp>x264opts</samp>, but is

  5373. duplicated for compatibility with the Libav fork.

  5374. </p>

  5375. <p>For example to specify libx264 encoding options with <code>ffmpeg</code>:

  5376. </p><div class="example">

  5377. <pre class="example">ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\

  5378. cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\

  5379. no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT

  5380. </pre></div>

  5381. </dd>

  5382. </dl>

  5383. 

  5384. <p>Encoding ffpresets for common usages are provided so they can be used with the

  5385. general presets system (e.g. passing the <samp>pre</samp> option).

  5386. </p>

  5387. <a name="libx265"></a>

  5388. <h3 class="section">9.16 libx265<span class="pull-right"><a class="anchor hidden-xs" href="#libx265" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libx265" aria-hidden="true">TOC</a></span></h3>

  5389. 

  5390. <p>x265 H.265/HEVC encoder wrapper.

  5391. </p>

  5392. <p>This encoder requires the presence of the libx265 headers and library

  5393. during configuration. You need to explicitly configure the build with

  5394. <samp>--enable-libx265</samp>.

  5395. </p>

  5396. <a name="Options-35"></a>

  5397. <h4 class="subsection">9.16.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-35" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-35" aria-hidden="true">TOC</a></span></h4>

  5398. 

  5399. <dl compact="compact">

  5400. <dt><span><samp>b</samp></span></dt>

  5401. <dd><p>Sets target video bitrate.

  5402. </p>

  5403. </dd>

  5404. <dt><span><samp>bf</samp></span></dt>

  5405. <dt><span><samp>g</samp></span></dt>

  5406. <dd><p>Set the GOP size.

  5407. </p>

  5408. </dd>

  5409. <dt><span><samp>keyint_min</samp></span></dt>

  5410. <dd><p>Minimum GOP size.

  5411. </p>

  5412. </dd>

  5413. <dt><span><samp>refs</samp></span></dt>

  5414. <dd><p>Number of reference frames each P-frame can use. The range is from <var>1-16</var>.

  5415. </p>

  5416. </dd>

  5417. <dt><span><samp>preset</samp></span></dt>

  5418. <dd><p>Set the x265 preset.

  5419. </p>

  5420. </dd>

  5421. <dt><span><samp>tune</samp></span></dt>

  5422. <dd><p>Set the x265 tune parameter.

  5423. </p>

  5424. </dd>

  5425. <dt><span><samp>profile</samp></span></dt>

  5426. <dd><p>Set profile restrictions.

  5427. </p>

  5428. </dd>

  5429. <dt><span><samp>crf</samp></span></dt>

  5430. <dd><p>Set the quality for constant quality mode.

  5431. </p>

  5432. </dd>

  5433. <dt><span><samp>qp</samp></span></dt>

  5434. <dd><p>Set constant quantization rate control method parameter.

  5435. </p>

  5436. </dd>

  5437. <dt><span><samp>qmin</samp></span></dt>

  5438. <dd><p>Minimum quantizer scale.

  5439. </p>

  5440. </dd>

  5441. <dt><span><samp>qmax</samp></span></dt>

  5442. <dd><p>Maximum quantizer scale.

  5443. </p>

  5444. </dd>

  5445. <dt><span><samp>qdiff</samp></span></dt>

  5446. <dd><p>Maximum difference between quantizer scales.

  5447. </p>

  5448. </dd>

  5449. <dt><span><samp>qblur</samp></span></dt>

  5450. <dd><p>Quantizer curve blur

  5451. </p>

  5452. </dd>

  5453. <dt><span><samp>qcomp</samp></span></dt>

  5454. <dd><p>Quantizer curve compression factor

  5455. </p>

  5456. </dd>

  5457. <dt><span><samp>i_qfactor</samp></span></dt>

  5458. <dt><span><samp>b_qfactor</samp></span></dt>

  5459. <dt><span><samp>forced-idr</samp></span></dt>

  5460. <dd><p>Normally, when forcing a I-frame type, the encoder can select any type

  5461. of I-frame. This option forces it to choose an IDR-frame.

  5462. </p>

  5463. </dd>

  5464. <dt><span><samp>udu_sei <var>boolean</var></samp></span></dt>

  5465. <dd><p>Import user data unregistered SEI if available into output. Default is 0 (off).

  5466. </p>

  5467. </dd>

  5468. <dt><span><samp>x265-params</samp></span></dt>

  5469. <dd><p>Set x265 options using a list of <var>key</var>=<var>value</var> couples separated

  5470. by &quot;:&quot;. See <code>x265 --help</code> for a list of options.

  5471. </p>

  5472. <p>For example to specify libx265 encoding options with <samp>-x265-params</samp>:

  5473. </p>

  5474. <div class="example">

  5475. <pre class="example">ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4

  5476. </pre></div>

  5477. </dd>

  5478. </dl>

  5479. 

  5480. <a name="libxavs2"></a>

  5481. <h3 class="section">9.17 libxavs2<span class="pull-right"><a class="anchor hidden-xs" href="#libxavs2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libxavs2" aria-hidden="true">TOC</a></span></h3>

  5482. 

  5483. <p>xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.

  5484. </p>

  5485. <p>This encoder requires the presence of the libxavs2 headers and library

  5486. during configuration. You need to explicitly configure the build with

  5487. <samp>--enable-libxavs2</samp>.

  5488. </p>

  5489. <p>The following standard libavcodec options are used:

  5490. </p><ul>

  5491. <li> <samp>b</samp> / <samp>bit_rate</samp>

  5492. </li><li> <samp>g</samp> / <samp>gop_size</samp>

  5493. </li><li> <samp>bf</samp> / <samp>max_b_frames</samp>

  5494. </li></ul>

  5495. 

  5496. <p>The encoder also has its own specific options:

  5497. </p><a name="Options-36"></a>

  5498. <h4 class="subsection">9.17.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-36" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-36" aria-hidden="true">TOC</a></span></h4>

  5499. 

  5500. <dl compact="compact">

  5501. <dt><span><samp>lcu_row_threads</samp></span></dt>

  5502. <dd><p>Set the number of parallel threads for rows from 1 to 8 (default 5).

  5503. </p>

  5504. </dd>

  5505. <dt><span><samp>initial_qp</samp></span></dt>

  5506. <dd><p>Set the xavs2 quantization parameter from 1 to 63 (default 34). This is

  5507. used to set the initial qp for the first frame.

  5508. </p>

  5509. </dd>

  5510. <dt><span><samp>qp</samp></span></dt>

  5511. <dd><p>Set the xavs2 quantization parameter from 1 to 63 (default 34). This is

  5512. used to set the qp value under constant-QP mode.

  5513. </p>

  5514. </dd>

  5515. <dt><span><samp>max_qp</samp></span></dt>

  5516. <dd><p>Set the max qp for rate control from 1 to 63 (default 55).

  5517. </p>

  5518. </dd>

  5519. <dt><span><samp>min_qp</samp></span></dt>

  5520. <dd><p>Set the min qp for rate control from 1 to 63 (default 20).

  5521. </p>

  5522. </dd>

  5523. <dt><span><samp>speed_level</samp></span></dt>

  5524. <dd><p>Set the Speed level from 0 to 9 (default 0). Higher is better but slower.

  5525. </p>

  5526. </dd>

  5527. <dt><span><samp>log_level</samp></span></dt>

  5528. <dd><p>Set the log level from -1 to 3 (default 0). -1: none, 0: error,

  5529. 1: warning, 2: info, 3: debug.

  5530. </p>

  5531. </dd>

  5532. <dt><span><samp>xavs2-params</samp></span></dt>

  5533. <dd><p>Set xavs2 options using a list of <var>key</var>=<var>value</var> couples separated

  5534. by &quot;:&quot;.

  5535. </p>

  5536. <p>For example to specify libxavs2 encoding options with <samp>-xavs2-params</samp>:

  5537. </p>

  5538. <div class="example">

  5539. <pre class="example">ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2

  5540. </pre></div>

  5541. </dd>

  5542. </dl>

  5543. 

  5544. <a name="libxvid"></a>

  5545. <h3 class="section">9.18 libxvid<span class="pull-right"><a class="anchor hidden-xs" href="#libxvid" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-libxvid" aria-hidden="true">TOC</a></span></h3>

  5546. 

  5547. <p>Xvid MPEG-4 Part 2 encoder wrapper.

  5548. </p>

  5549. <p>This encoder requires the presence of the libxvidcore headers and library

  5550. during configuration. You need to explicitly configure the build with

  5551. <code>--enable-libxvid --enable-gpl</code>.

  5552. </p>

  5553. <p>The native <code>mpeg4</code> encoder supports the MPEG-4 Part 2 format, so

  5554. users can encode to this format without this library.

  5555. </p>

  5556. <a name="Options-37"></a>

  5557. <h4 class="subsection">9.18.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-37" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-37" aria-hidden="true">TOC</a></span></h4>

  5558. 

  5559. <p>The following options are supported by the libxvid wrapper. Some of

  5560. the following options are listed but are not documented, and

  5561. correspond to shared codec options. See <a href="#codec_002doptions">the Codec

  5562. Options chapter</a> for their documentation. The other shared options

  5563. which are not listed have no effect for the libxvid encoder.

  5564. </p>

  5565. <dl compact="compact">

  5566. <dt><span><samp>b</samp></span></dt>

  5567. <dt><span><samp>g</samp></span></dt>

  5568. <dt><span><samp>qmin</samp></span></dt>

  5569. <dt><span><samp>qmax</samp></span></dt>

  5570. <dt><span><samp>mpeg_quant</samp></span></dt>

  5571. <dt><span><samp>threads</samp></span></dt>

  5572. <dt><span><samp>bf</samp></span></dt>

  5573. <dt><span><samp>b_qfactor</samp></span></dt>

  5574. <dt><span><samp>b_qoffset</samp></span></dt>

  5575. <dt><span><samp>flags</samp></span></dt>

  5576. <dd><p>Set specific encoding flags. Possible values:

  5577. </p>

  5578. <dl compact="compact">

  5579. <dt><span>&lsquo;<samp>mv4</samp>&rsquo;</span></dt>

  5580. <dd><p>Use four motion vector by macroblock.

  5581. </p>

  5582. </dd>

  5583. <dt><span>&lsquo;<samp>aic</samp>&rsquo;</span></dt>

  5584. <dd><p>Enable high quality AC prediction.

  5585. </p>

  5586. </dd>

  5587. <dt><span>&lsquo;<samp>gray</samp>&rsquo;</span></dt>

  5588. <dd><p>Only encode grayscale.

  5589. </p>

  5590. </dd>

  5591. <dt><span>&lsquo;<samp>gmc</samp>&rsquo;</span></dt>

  5592. <dd><p>Enable the use of global motion compensation (GMC).

  5593. </p>

  5594. </dd>

  5595. <dt><span>&lsquo;<samp>qpel</samp>&rsquo;</span></dt>

  5596. <dd><p>Enable quarter-pixel motion compensation.

  5597. </p>

  5598. </dd>

  5599. <dt><span>&lsquo;<samp>cgop</samp>&rsquo;</span></dt>

  5600. <dd><p>Enable closed GOP.

  5601. </p>

  5602. </dd>

  5603. <dt><span>&lsquo;<samp>global_header</samp>&rsquo;</span></dt>

  5604. <dd><p>Place global headers in extradata instead of every keyframe.

  5605. </p>

  5606. </dd>

  5607. </dl>

  5608. 

  5609. </dd>

  5610. <dt><span><samp>trellis</samp></span></dt>

  5611. <dt><span><samp>me_method</samp></span></dt>

  5612. <dd><p>Set motion estimation method. Possible values in decreasing order of

  5613. speed and increasing order of quality:

  5614. </p>

  5615. <dl compact="compact">

  5616. <dt><span>&lsquo;<samp>zero</samp>&rsquo;</span></dt>

  5617. <dd><p>Use no motion estimation (default).

  5618. </p>

  5619. </dd>

  5620. <dt><span>&lsquo;<samp>phods</samp>&rsquo;</span></dt>

  5621. <dt><span>&lsquo;<samp>x1</samp>&rsquo;</span></dt>

  5622. <dt><span>&lsquo;<samp>log</samp>&rsquo;</span></dt>

  5623. <dd><p>Enable advanced diamond zonal search for 16x16 blocks and half-pixel

  5624. refinement for 16x16 blocks. &lsquo;<samp>x1</samp>&rsquo; and &lsquo;<samp>log</samp>&rsquo; are aliases for

  5625. &lsquo;<samp>phods</samp>&rsquo;.

  5626. </p>

  5627. </dd>

  5628. <dt><span>&lsquo;<samp>epzs</samp>&rsquo;</span></dt>

  5629. <dd><p>Enable all of the things described above, plus advanced diamond zonal

  5630. search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion

  5631. estimation on chroma planes.

  5632. </p>

  5633. </dd>

  5634. <dt><span>&lsquo;<samp>full</samp>&rsquo;</span></dt>

  5635. <dd><p>Enable all of the things described above, plus extended 16x16 and 8x8

  5636. blocks search.

  5637. </p></dd>

  5638. </dl>

  5639. 

  5640. </dd>

  5641. <dt><span><samp>mbd</samp></span></dt>

  5642. <dd><p>Set macroblock decision algorithm. Possible values in the increasing

  5643. order of quality:

  5644. </p>

  5645. <dl compact="compact">

  5646. <dt><span>&lsquo;<samp>simple</samp>&rsquo;</span></dt>

  5647. <dd><p>Use macroblock comparing function algorithm (default).

  5648. </p>

  5649. </dd>

  5650. <dt><span>&lsquo;<samp>bits</samp>&rsquo;</span></dt>

  5651. <dd><p>Enable rate distortion-based half pixel and quarter pixel refinement for

  5652. 16x16 blocks.

  5653. </p>

  5654. </dd>

  5655. <dt><span>&lsquo;<samp>rd</samp>&rsquo;</span></dt>

  5656. <dd><p>Enable all of the things described above, plus rate distortion-based

  5657. half pixel and quarter pixel refinement for 8x8 blocks, and rate

  5658. distortion-based search using square pattern.

  5659. </p></dd>

  5660. </dl>

  5661. 

  5662. </dd>

  5663. <dt><span><samp>lumi_aq</samp></span></dt>

  5664. <dd><p>Enable lumi masking adaptive quantization when set to 1. Default is 0

  5665. (disabled).

  5666. </p>

  5667. </dd>

  5668. <dt><span><samp>variance_aq</samp></span></dt>

  5669. <dd><p>Enable variance adaptive quantization when set to 1. Default is 0

  5670. (disabled).

  5671. </p>

  5672. <p>When combined with <samp>lumi_aq</samp>, the resulting quality will not

  5673. be better than any of the two specified individually. In other

  5674. words, the resulting quality will be the worse one of the two

  5675. effects.

  5676. </p>

  5677. </dd>

  5678. <dt><span><samp>ssim</samp></span></dt>

  5679. <dd><p>Set structural similarity (SSIM) displaying method. Possible values:

  5680. </p>

  5681. <dl compact="compact">

  5682. <dt><span>&lsquo;<samp>off</samp>&rsquo;</span></dt>

  5683. <dd><p>Disable displaying of SSIM information.

  5684. </p>

  5685. </dd>

  5686. <dt><span>&lsquo;<samp>avg</samp>&rsquo;</span></dt>

  5687. <dd><p>Output average SSIM at the end of encoding to stdout. The format of

  5688. showing the average SSIM is:

  5689. </p>

  5690. <div class="example">

  5691. <pre class="example">Average SSIM: %f

  5692. </pre></div>

  5693. 

  5694. <p>For users who are not familiar with C, %f means a float number, or

  5695. a decimal (e.g. 0.939232).

  5696. </p>

  5697. </dd>

  5698. <dt><span>&lsquo;<samp>frame</samp>&rsquo;</span></dt>

  5699. <dd><p>Output both per-frame SSIM data during encoding and average SSIM at

  5700. the end of encoding to stdout. The format of per-frame information

  5701. is:

  5702. </p>

  5703. <div class="example">

  5704. <pre class="example">       SSIM: avg: %1.3f min: %1.3f max: %1.3f

  5705. </pre></div>

  5706. 

  5707. <p>For users who are not familiar with C, %1.3f means a float number

  5708. rounded to 3 digits after the dot (e.g. 0.932).

  5709. </p>

  5710. </dd>

  5711. </dl>

  5712. 

  5713. </dd>

  5714. <dt><span><samp>ssim_acc</samp></span></dt>

  5715. <dd><p>Set SSIM accuracy. Valid options are integers within the range of

  5716. 0-4, while 0 gives the most accurate result and 4 computes the

  5717. fastest.

  5718. </p>

  5719. </dd>

  5720. </dl>

  5721. 

  5722. <a name="MediaFoundation"></a>

  5723. <h3 class="section">9.19 MediaFoundation<span class="pull-right"><a class="anchor hidden-xs" href="#MediaFoundation" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-MediaFoundation" aria-hidden="true">TOC</a></span></h3>

  5724. 

  5725. <p>This provides wrappers to encoders (both audio and video) in the

  5726. MediaFoundation framework. It can access both SW and HW encoders.

  5727. Video encoders can take input in either of nv12 or yuv420p form

  5728. (some encoders support both, some support only either - in practice,

  5729. nv12 is the safer choice, especially among HW encoders).

  5730. </p>

  5731. <a name="mpeg2"></a>

  5732. <h3 class="section">9.20 mpeg2<span class="pull-right"><a class="anchor hidden-xs" href="#mpeg2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-mpeg2" aria-hidden="true">TOC</a></span></h3>

  5733. 

  5734. <p>MPEG-2 video encoder.

  5735. </p>

  5736. <a name="Options-38"></a>

  5737. <h4 class="subsection">9.20.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-38" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-38" aria-hidden="true">TOC</a></span></h4>

  5738. 

  5739. <dl compact="compact">

  5740. <dt><span><samp>profile</samp></span></dt>

  5741. <dd><p>Select the mpeg2 profile to encode:

  5742. </p>

  5743. <dl compact="compact">

  5744. <dt><span>&lsquo;<samp>422</samp>&rsquo;</span></dt>

  5745. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  5746. <dt><span>&lsquo;<samp>ss</samp>&rsquo;</span></dt>

  5747. <dd><p>Spatially Scalable

  5748. </p></dd>

  5749. <dt><span>&lsquo;<samp>snr</samp>&rsquo;</span></dt>

  5750. <dd><p>SNR Scalable

  5751. </p></dd>

  5752. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  5753. <dt><span>&lsquo;<samp>simple</samp>&rsquo;</span></dt>

  5754. </dl>

  5755. 

  5756. </dd>

  5757. <dt><span><samp>level</samp></span></dt>

  5758. <dd><p>Select the mpeg2 level to encode:

  5759. </p>

  5760. <dl compact="compact">

  5761. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  5762. <dt><span>&lsquo;<samp>high1440</samp>&rsquo;</span></dt>

  5763. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  5764. <dt><span>&lsquo;<samp>low</samp>&rsquo;</span></dt>

  5765. </dl>

  5766. 

  5767. </dd>

  5768. <dt><span><samp>seq_disp_ext <var>integer</var></samp></span></dt>

  5769. <dd><p>Specifies if the encoder should write a sequence_display_extension to the

  5770. output.

  5771. </p><dl compact="compact">

  5772. <dt><span><samp>-1</samp></span></dt>

  5773. <dt><span><samp>auto</samp></span></dt>

  5774. <dd><p>Decide automatically to write it or not (this is the default) by checking if

  5775. the data to be written is different from the default or unspecified values.

  5776. </p></dd>

  5777. <dt><span><samp>0</samp></span></dt>

  5778. <dt><span><samp>never</samp></span></dt>

  5779. <dd><p>Never write it.

  5780. </p></dd>

  5781. <dt><span><samp>1</samp></span></dt>

  5782. <dt><span><samp>always</samp></span></dt>

  5783. <dd><p>Always write it.

  5784. </p></dd>

  5785. </dl>

  5786. </dd>

  5787. <dt><span><samp>video_format <var>integer</var></samp></span></dt>

  5788. <dd><p>Specifies the video_format written into the sequence display extension

  5789. indicating the source of the video pictures. The default is &lsquo;<samp>unspecified</samp>&rsquo;,

  5790. can be &lsquo;<samp>component</samp>&rsquo;, &lsquo;<samp>pal</samp>&rsquo;, &lsquo;<samp>ntsc</samp>&rsquo;, &lsquo;<samp>secam</samp>&rsquo; or &lsquo;<samp>mac</samp>&rsquo;.

  5791. For maximum compatibility, use &lsquo;<samp>component</samp>&rsquo;.

  5792. </p></dd>

  5793. <dt><span><samp>a53cc <var>boolean</var></samp></span></dt>

  5794. <dd><p>Import closed captions (which must be ATSC compatible format) into output.

  5795. Default is 1 (on).

  5796. </p></dd>

  5797. </dl>

  5798. 

  5799. <a name="png"></a>

  5800. <h3 class="section">9.21 png<span class="pull-right"><a class="anchor hidden-xs" href="#png" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-png" aria-hidden="true">TOC</a></span></h3>

  5801. 

  5802. <p>PNG image encoder.

  5803. </p>

  5804. <a name="Private-options-1"></a>

  5805. <h4 class="subsection">9.21.1 Private options<span class="pull-right"><a class="anchor hidden-xs" href="#Private-options-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Private-options-1" aria-hidden="true">TOC</a></span></h4>

  5806. 

  5807. <dl compact="compact">

  5808. <dt><span><samp>dpi <var>integer</var></samp></span></dt>

  5809. <dd><p>Set physical density of pixels, in dots per inch, unset by default

  5810. </p></dd>

  5811. <dt><span><samp>dpm <var>integer</var></samp></span></dt>

  5812. <dd><p>Set physical density of pixels, in dots per meter, unset by default

  5813. </p></dd>

  5814. </dl>

  5815. 

  5816. <a name="ProRes"></a>

  5817. <h3 class="section">9.22 ProRes<span class="pull-right"><a class="anchor hidden-xs" href="#ProRes" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-ProRes" aria-hidden="true">TOC</a></span></h3>

  5818. 

  5819. <p>Apple ProRes encoder.

  5820. </p>

  5821. <p>FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.

  5822. The used encoder can be chosen with the <code>-vcodec</code> option.

  5823. </p>

  5824. <a name="Private-Options-for-prores_002dks"></a>

  5825. <h4 class="subsection">9.22.1 Private Options for prores-ks<span class="pull-right"><a class="anchor hidden-xs" href="#Private-Options-for-prores_002dks" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Private-Options-for-prores_002dks" aria-hidden="true">TOC</a></span></h4>

  5826. 

  5827. <dl compact="compact">

  5828. <dt><span><samp>profile <var>integer</var></samp></span></dt>

  5829. <dd><p>Select the ProRes profile to encode

  5830. </p><dl compact="compact">

  5831. <dt><span>&lsquo;<samp>proxy</samp>&rsquo;</span></dt>

  5832. <dt><span>&lsquo;<samp>lt</samp>&rsquo;</span></dt>

  5833. <dt><span>&lsquo;<samp>standard</samp>&rsquo;</span></dt>

  5834. <dt><span>&lsquo;<samp>hq</samp>&rsquo;</span></dt>

  5835. <dt><span>&lsquo;<samp>4444</samp>&rsquo;</span></dt>

  5836. <dt><span>&lsquo;<samp>4444xq</samp>&rsquo;</span></dt>

  5837. </dl>

  5838. 

  5839. </dd>

  5840. <dt><span><samp>quant_mat <var>integer</var></samp></span></dt>

  5841. <dd><p>Select quantization matrix.

  5842. </p><dl compact="compact">

  5843. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  5844. <dt><span>&lsquo;<samp>default</samp>&rsquo;</span></dt>

  5845. <dt><span>&lsquo;<samp>proxy</samp>&rsquo;</span></dt>

  5846. <dt><span>&lsquo;<samp>lt</samp>&rsquo;</span></dt>

  5847. <dt><span>&lsquo;<samp>standard</samp>&rsquo;</span></dt>

  5848. <dt><span>&lsquo;<samp>hq</samp>&rsquo;</span></dt>

  5849. </dl>

  5850. <p>If set to <var>auto</var>, the matrix matching the profile will be picked.

  5851. If not set, the matrix providing the highest quality, <var>default</var>, will be

  5852. picked.

  5853. </p>

  5854. </dd>

  5855. <dt><span><samp>bits_per_mb <var>integer</var></samp></span></dt>

  5856. <dd><p>How many bits to allot for coding one macroblock. Different profiles use

  5857. between 200 and 2400 bits per macroblock, the maximum is 8000.

  5858. </p>

  5859. </dd>

  5860. <dt><span><samp>mbs_per_slice <var>integer</var></samp></span></dt>

  5861. <dd><p>Number of macroblocks in each slice (1-8); the default value (8)

  5862. should be good in almost all situations.

  5863. </p>

  5864. </dd>

  5865. <dt><span><samp>vendor <var>string</var></samp></span></dt>

  5866. <dd><p>Override the 4-byte vendor ID.

  5867. A custom vendor ID like <var>apl0</var> would claim the stream was produced by

  5868. the Apple encoder.

  5869. </p>

  5870. </dd>

  5871. <dt><span><samp>alpha_bits <var>integer</var></samp></span></dt>

  5872. <dd><p>Specify number of bits for alpha component.

  5873. Possible values are <var>0</var>, <var>8</var> and <var>16</var>.

  5874. Use <var>0</var> to disable alpha plane coding.

  5875. </p>

  5876. </dd>

  5877. </dl>

  5878. 

  5879. <a name="Speed-considerations"></a>

  5880. <h4 class="subsection">9.22.2 Speed considerations<span class="pull-right"><a class="anchor hidden-xs" href="#Speed-considerations" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Speed-considerations" aria-hidden="true">TOC</a></span></h4>

  5881. 

  5882. <p>In the default mode of operation the encoder has to honor frame constraints

  5883. (i.e. not produce frames with size bigger than requested) while still making

  5884. output picture as good as possible.

  5885. A frame containing a lot of small details is harder to compress and the encoder

  5886. would spend more time searching for appropriate quantizers for each slice.

  5887. </p>

  5888. <p>Setting a higher <samp>bits_per_mb</samp> limit will improve the speed.

  5889. </p>

  5890. <p>For the fastest encoding speed set the <samp>qscale</samp> parameter (4 is the

  5891. recommended value) and do not set a size constraint.

  5892. </p>

  5893. <a name="QSV-Encoders"></a>

  5894. <h3 class="section">9.23 QSV Encoders<span class="pull-right"><a class="anchor hidden-xs" href="#QSV-Encoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-QSV-Encoders" aria-hidden="true">TOC</a></span></h3>

  5895. 

  5896. <p>The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC, JPEG/MJPEG

  5897. and VP9)

  5898. </p>

  5899. <a name="Ratecontrol-Method"></a>

  5900. <h4 class="subsection">9.23.1 Ratecontrol Method<span class="pull-right"><a class="anchor hidden-xs" href="#Ratecontrol-Method" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Ratecontrol-Method" aria-hidden="true">TOC</a></span></h4>

  5901. <p>The ratecontrol method is selected as follows:

  5902. </p><ul>

  5903. <li> When <samp>global_quality</samp> is specified, a quality-based mode is used.

  5904. Specifically this means either

  5905. <ul class="no-bullet">

  5906. <li>- <var>CQP</var> - constant quantizer scale, when the <samp>qscale</samp> codec flag is

  5907. also set (the <samp>-qscale</samp> ffmpeg option).

  5908. 

  5909. </li><li>- <var>LA_ICQ</var> - intelligent constant quality with lookahead, when the

  5910. <samp>look_ahead</samp> option is also set.

  5911. 

  5912. </li><li>- <var>ICQ</var> &ndash; intelligent constant quality otherwise. For the ICQ modes, global

  5913. quality range is 1 to 51, with 1 being the best quality.

  5914. </li></ul>

  5915. 

  5916. </li><li> Otherwise, a bitrate-based mode is used. For all of those, you should specify at

  5917. least the desired average bitrate with the <samp>b</samp> option.

  5918. <ul class="no-bullet">

  5919. <li>- <var>LA</var> - VBR with lookahead, when the <samp>look_ahead</samp> option is specified.

  5920. 

  5921. </li><li>- <var>VCM</var> - video conferencing mode, when the <samp>vcm</samp> option is set.

  5922. 

  5923. </li><li>- <var>CBR</var> - constant bitrate, when <samp>maxrate</samp> is specified and equal to

  5924. the average bitrate.

  5925. 

  5926. </li><li>- <var>VBR</var> - variable bitrate, when <samp>maxrate</samp> is specified, but is higher

  5927. than the average bitrate.

  5928. 

  5929. </li><li>- <var>AVBR</var> - average VBR mode, when <samp>maxrate</samp> is not specified, both

  5930. <samp>avbr_accuracy</samp> and <samp>avbr_convergence</samp> are set to non-zero. This

  5931. mode is available for H264 and HEVC on Windows.

  5932. </li></ul>

  5933. </li></ul>

  5934. 

  5935. <p>Note that depending on your system, a different mode than the one you specified

  5936. may be selected by the encoder. Set the verbosity level to <var>verbose</var> or

  5937. higher to see the actual settings used by the QSV runtime.

  5938. </p>

  5939. <a name="Global-Options-_002d_003e-MSDK-Options"></a>

  5940. <h4 class="subsection">9.23.2 Global Options -&gt; MSDK Options<span class="pull-right"><a class="anchor hidden-xs" href="#Global-Options-_002d_003e-MSDK-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Global-Options-_002d_003e-MSDK-Options" aria-hidden="true">TOC</a></span></h4>

  5941. <p>Additional libavcodec global options are mapped to MSDK options as follows:

  5942. </p>

  5943. <ul>

  5944. <li> <samp>g/gop_size</samp> -&gt; <samp>GopPicSize</samp>

  5945. 

  5946. </li><li> <samp>bf/max_b_frames</samp>+1 -&gt; <samp>GopRefDist</samp>

  5947. 

  5948. </li><li> <samp>rc_init_occupancy/rc_initial_buffer_occupancy</samp> -&gt;

  5949. <samp>InitialDelayInKB</samp>

  5950. 

  5951. </li><li> <samp>slices</samp> -&gt; <samp>NumSlice</samp>

  5952. 

  5953. </li><li> <samp>refs</samp> -&gt; <samp>NumRefFrame</samp>

  5954. 

  5955. </li><li> <samp>b_strategy/b_frame_strategy</samp> -&gt; <samp>BRefType</samp>

  5956. 

  5957. </li><li> <samp>cgop/CLOSED_GOP</samp> codec flag -&gt; <samp>GopOptFlag</samp>

  5958. 

  5959. </li><li> For the <var>CQP</var> mode, the <samp>i_qfactor/i_qoffset</samp> and

  5960. <samp>b_qfactor/b_qoffset</samp> set the difference between <var>QPP</var> and <var>QPI</var>,

  5961. and <var>QPP</var> and <var>QPB</var> respectively.

  5962. 

  5963. </li><li> Setting the <samp>coder</samp> option to the value <var>vlc</var> will make the H.264

  5964. encoder use CAVLC instead of CABAC.

  5965. 

  5966. </li></ul>

  5967. 

  5968. <a name="Common-Options-1"></a>

  5969. <h4 class="subsection">9.23.3 Common Options<span class="pull-right"><a class="anchor hidden-xs" href="#Common-Options-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Common-Options-1" aria-hidden="true">TOC</a></span></h4>

  5970. <p>Following options are used by all qsv encoders.

  5971. </p>

  5972. <dl compact="compact">

  5973. <dt><span><samp><var>async_depth</var></samp></span></dt>

  5974. <dd><p>Specifies how many asynchronous operations an application performs

  5975. before the application explicitly synchronizes the result. If zero,

  5976. the value is not specified.

  5977. </p>

  5978. </dd>

  5979. <dt><span><samp><var>preset</var></samp></span></dt>

  5980. <dd><p>This option itemizes a range of choices from veryfast (best speed) to veryslow

  5981. (best quality).

  5982. </p><dl compact="compact">

  5983. <dt><span>&lsquo;<samp>veryfast</samp>&rsquo;</span></dt>

  5984. <dt><span>&lsquo;<samp>faster</samp>&rsquo;</span></dt>

  5985. <dt><span>&lsquo;<samp>fast</samp>&rsquo;</span></dt>

  5986. <dt><span>&lsquo;<samp>medium</samp>&rsquo;</span></dt>

  5987. <dt><span>&lsquo;<samp>slow</samp>&rsquo;</span></dt>

  5988. <dt><span>&lsquo;<samp>slower</samp>&rsquo;</span></dt>

  5989. <dt><span>&lsquo;<samp>veryslow</samp>&rsquo;</span></dt>

  5990. </dl>

  5991. 

  5992. </dd>

  5993. <dt><span><samp><var>forced_idr</var></samp></span></dt>

  5994. <dd><p>Forcing I frames as IDR frames.

  5995. </p>

  5996. </dd>

  5997. <dt><span><samp><var>low_power</var></samp></span></dt>

  5998. <dd><p>For encoders set this flag to ON to reduce power consumption and GPU usage.

  5999. </p></dd>

  6000. </dl>

  6001. 

  6002. <a name="Runtime-Options"></a>

  6003. <h4 class="subsection">9.23.4 Runtime Options<span class="pull-right"><a class="anchor hidden-xs" href="#Runtime-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Runtime-Options" aria-hidden="true">TOC</a></span></h4>

  6004. <p>Following options can be used durning qsv encoding.

  6005. </p>

  6006. <dl compact="compact">

  6007. <dt><span><samp><var>global_quality</var></samp></span></dt>

  6008. <dt><span><samp><var>i_quant_factor</var></samp></span></dt>

  6009. <dt><span><samp><var>i_quant_offset</var></samp></span></dt>

  6010. <dt><span><samp><var>b_quant_factor</var></samp></span></dt>

  6011. <dt><span><samp><var>b_quant_offset</var></samp></span></dt>

  6012. <dd><p>Supported in h264_qsv and hevc_qsv.

  6013. Change these value to reset qsv codec&rsquo;s qp configuration.

  6014. </p>

  6015. </dd>

  6016. <dt><span><samp><var>max_frame_size</var></samp></span></dt>

  6017. <dd><p>Supported in h264_qsv and hevc_qsv.

  6018. Change this value to reset qsv codec&rsquo;s MaxFrameSize configuration.

  6019. </p>

  6020. </dd>

  6021. <dt><span><samp><var>gop_size</var></samp></span></dt>

  6022. <dd><p>Change this value to reset qsv codec&rsquo;s gop configuration.

  6023. </p>

  6024. </dd>

  6025. <dt><span><samp><var>int_ref_type</var></samp></span></dt>

  6026. <dt><span><samp><var>int_ref_cycle_size</var></samp></span></dt>

  6027. <dt><span><samp><var>int_ref_qp_delta</var></samp></span></dt>

  6028. <dt><span><samp><var>int_ref_cycle_dist</var></samp></span></dt>

  6029. <dd><p>Supported in h264_qsv and hevc_qsv.

  6030. Change these value to reset qsv codec&rsquo;s Intra Refresh configuration.

  6031. </p>

  6032. </dd>

  6033. <dt><span><samp><var>qmax</var></samp></span></dt>

  6034. <dt><span><samp><var>qmin</var></samp></span></dt>

  6035. <dt><span><samp><var>max_qp_i</var></samp></span></dt>

  6036. <dt><span><samp><var>min_qp_i</var></samp></span></dt>

  6037. <dt><span><samp><var>max_qp_p</var></samp></span></dt>

  6038. <dt><span><samp><var>min_qp_p</var></samp></span></dt>

  6039. <dt><span><samp><var>max_qp_b</var></samp></span></dt>

  6040. <dt><span><samp><var>min_qp_b</var></samp></span></dt>

  6041. <dd><p>Supported in h264_qsv.

  6042. Change these value to reset qsv codec&rsquo;s max/min qp configuration.

  6043. </p>

  6044. </dd>

  6045. <dt><span><samp><var>low_delay_brc</var></samp></span></dt>

  6046. <dd><p>Supported in h264_qsv and hevc_qsv.

  6047. Change this value to reset qsv codec&rsquo;s low_delay_brc configuration.

  6048. </p>

  6049. </dd>

  6050. <dt><span><samp><var>framerate</var></samp></span></dt>

  6051. <dd><p>Change this value to reset qsv codec&rsquo;s framerate configuration.

  6052. </p>

  6053. </dd>

  6054. <dt><span><samp><var>bit_rate</var></samp></span></dt>

  6055. <dt><span><samp><var>rc_buffer_size</var></samp></span></dt>

  6056. <dt><span><samp><var>rc_initial_buffer_occupancy</var></samp></span></dt>

  6057. <dt><span><samp><var>rc_max_rate</var></samp></span></dt>

  6058. <dd><p>Change these value to reset qsv codec&rsquo;s bitrate control configuration.

  6059. </p>

  6060. </dd>

  6061. <dt><span><samp><var>pic_timing_sei</var></samp></span></dt>

  6062. <dd><p>Supported in h264_qsv and hevc_qsv.

  6063. Change this value to reset qsv codec&rsquo;s pic_timing_sei configuration.

  6064. </p></dd>

  6065. </dl>

  6066. 

  6067. <a name="H264-options"></a>

  6068. <h4 class="subsection">9.23.5 H264 options<span class="pull-right"><a class="anchor hidden-xs" href="#H264-options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-H264-options" aria-hidden="true">TOC</a></span></h4>

  6069. <p>These options are used by h264_qsv

  6070. </p>

  6071. <dl compact="compact">

  6072. <dt><span><samp><var>extbrc</var></samp></span></dt>

  6073. <dd><p>Extended bitrate control.

  6074. </p>

  6075. </dd>

  6076. <dt><span><samp><var>recovery_point_sei</var></samp></span></dt>

  6077. <dd><p>Set this flag to insert the recovery point SEI message at the beginning of every

  6078. intra refresh cycle.

  6079. </p>

  6080. </dd>

  6081. <dt><span><samp><var>rdo</var></samp></span></dt>

  6082. <dd><p>Enable rate distortion optimization.

  6083. </p>

  6084. </dd>

  6085. <dt><span><samp><var>max_frame_size</var></samp></span></dt>

  6086. <dd><p>Maximum encoded frame size in bytes.

  6087. </p>

  6088. </dd>

  6089. <dt><span><samp><var>max_frame_size_i</var></samp></span></dt>

  6090. <dd><p>Maximum encoded frame size for I frames in bytes. If this value is set as larger

  6091. than zero, then for I frames the value set by max_frame_size is ignored.

  6092. </p>

  6093. </dd>

  6094. <dt><span><samp><var>max_frame_size_p</var></samp></span></dt>

  6095. <dd><p>Maximum encoded frame size for P frames in bytes. If this value is set as larger

  6096. than zero, then for P frames the value set by max_frame_size is ignored.

  6097. </p>

  6098. </dd>

  6099. <dt><span><samp><var>max_slice_size</var></samp></span></dt>

  6100. <dd><p>Maximum encoded slice size in bytes.

  6101. </p>

  6102. </dd>

  6103. <dt><span><samp><var>bitrate_limit</var></samp></span></dt>

  6104. <dd><p>Toggle bitrate limitations.

  6105. Modifies bitrate to be in the range imposed by the QSV encoder. Setting this

  6106. flag off may lead to violation of HRD conformance. Mind that specifying bitrate

  6107. below the QSV encoder range might significantly affect quality. If on this

  6108. option takes effect in non CQP modes: if bitrate is not in the range imposed

  6109. by the QSV encoder, it will be changed to be in the range.

  6110. </p>

  6111. </dd>

  6112. <dt><span><samp><var>mbbrc</var></samp></span></dt>

  6113. <dd><p>Setting this flag enables macroblock level bitrate control that generally

  6114. improves subjective visual quality. Enabling this flag may have negative impact

  6115. on performance and objective visual quality metric.

  6116. </p>

  6117. </dd>

  6118. <dt><span><samp><var>low_delay_brc</var></samp></span></dt>

  6119. <dd><p>Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which provides

  6120. more accurate bitrate control to minimize the variance of bitstream size frame

  6121. by frame. Value: -1-default 0-off 1-on

  6122. </p>

  6123. </dd>

  6124. <dt><span><samp><var>adaptive_i</var></samp></span></dt>

  6125. <dd><p>This flag controls insertion of I frames by the QSV encoder. Turn ON this flag

  6126. to allow changing of frame type from P and B to I.

  6127. </p>

  6128. </dd>

  6129. <dt><span><samp><var>adaptive_b</var></samp></span></dt>

  6130. <dd><p>This flag controls changing of frame type from B to P.

  6131. </p>

  6132. </dd>

  6133. <dt><span><samp><var>p_strategy</var></samp></span></dt>

  6134. <dd><p>Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to 0).

  6135. </p>

  6136. </dd>

  6137. <dt><span><samp><var>b_strategy</var></samp></span></dt>

  6138. <dd><p>This option controls usage of B frames as reference.

  6139. </p>

  6140. </dd>

  6141. <dt><span><samp><var>dblk_idc</var></samp></span></dt>

  6142. <dd><p>This option disable deblocking. It has value in range 0~2.

  6143. </p>

  6144. </dd>

  6145. <dt><span><samp><var>cavlc</var></samp></span></dt>

  6146. <dd><p>If set, CAVLC is used; if unset, CABAC is used for encoding.

  6147. </p>

  6148. </dd>

  6149. <dt><span><samp><var>vcm</var></samp></span></dt>

  6150. <dd><p>Video conferencing mode, please see ratecontrol method.

  6151. </p>

  6152. </dd>

  6153. <dt><span><samp><var>idr_interval</var></samp></span></dt>

  6154. <dd><p>Distance (in I-frames) between IDR frames.

  6155. </p>

  6156. </dd>

  6157. <dt><span><samp><var>pic_timing_sei</var></samp></span></dt>

  6158. <dd><p>Insert picture timing SEI with pic_struct_syntax element.

  6159. </p>

  6160. </dd>

  6161. <dt><span><samp><var>single_sei_nal_unit</var></samp></span></dt>

  6162. <dd><p>Put all the SEI messages into one NALU.

  6163. </p>

  6164. </dd>

  6165. <dt><span><samp><var>max_dec_frame_buffering</var></samp></span></dt>

  6166. <dd><p>Maximum number of frames buffered in the DPB.

  6167. </p>

  6168. </dd>

  6169. <dt><span><samp><var>look_ahead</var></samp></span></dt>

  6170. <dd><p>Use VBR algorithm with look ahead.

  6171. </p>

  6172. </dd>

  6173. <dt><span><samp><var>look_ahead_depth</var></samp></span></dt>

  6174. <dd><p>Depth of look ahead in number frames.

  6175. </p>

  6176. </dd>

  6177. <dt><span><samp><var>look_ahead_downsampling</var></samp></span></dt>

  6178. <dd><p>Downscaling factor for the frames saved for the lookahead analysis.

  6179. </p><dl compact="compact">

  6180. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6181. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  6182. <dt><span>&lsquo;<samp>off</samp>&rsquo;</span></dt>

  6183. <dt><span>&lsquo;<samp>2x</samp>&rsquo;</span></dt>

  6184. <dt><span>&lsquo;<samp>4x</samp>&rsquo;</span></dt>

  6185. </dl>

  6186. 

  6187. </dd>

  6188. <dt><span><samp><var>int_ref_type</var></samp></span></dt>

  6189. <dd><p>Specifies intra refresh type. The major goal of intra refresh is improvement of

  6190. error resilience without significant impact on encoded bitstream size caused by

  6191. I frames. The SDK encoder achieves this by encoding part of each frame in

  6192. refresh cycle using intra MBs. <var>none</var> means no refresh. <var>vertical</var> means

  6193. vertical refresh, by column of MBs. <var>horizontal</var> means horizontal refresh,

  6194. by rows of MBs. <var>slice</var> means horizontal refresh by slices without

  6195. overlapping. In case of <var>slice</var>, in_ref_cycle_size is ignored. To enable

  6196. intra refresh, B frame should be set to 0.

  6197. </p>

  6198. </dd>

  6199. <dt><span><samp><var>int_ref_cycle_size</var></samp></span></dt>

  6200. <dd><p>Specifies number of pictures within refresh cycle starting from 2. 0 and 1 are

  6201. invalid values.

  6202. </p>

  6203. </dd>

  6204. <dt><span><samp><var>int_ref_qp_delta</var></samp></span></dt>

  6205. <dd><p>Specifies QP difference for inserted intra MBs. This is signed value in

  6206. [-51, 51] range if target encoding bit-depth for luma samples is 8 and this

  6207. range is [-63, 63] for 10 bit-depth or [-75, 75] for 12 bit-depth respectively.

  6208. </p>

  6209. </dd>

  6210. <dt><span><samp><var>int_ref_cycle_dist</var></samp></span></dt>

  6211. <dd><p>Distance between the beginnings of the intra-refresh cycles in frames.

  6212. </p>

  6213. </dd>

  6214. <dt><span><samp><var>profile</var></samp></span></dt>

  6215. <dd><dl compact="compact">

  6216. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6217. <dt><span>&lsquo;<samp>baseline</samp>&rsquo;</span></dt>

  6218. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  6219. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  6220. </dl>

  6221. 

  6222. </dd>

  6223. <dt><span><samp><var>a53cc</var></samp></span></dt>

  6224. <dd><p>Use A53 Closed Captions (if available).

  6225. </p>

  6226. </dd>

  6227. <dt><span><samp><var>aud</var></samp></span></dt>

  6228. <dd><p>Insert the Access Unit Delimiter NAL.

  6229. </p>

  6230. </dd>

  6231. <dt><span><samp><var>mfmode</var></samp></span></dt>

  6232. <dd><p>Multi-Frame Mode.

  6233. </p><dl compact="compact">

  6234. <dt><span>&lsquo;<samp>off</samp>&rsquo;</span></dt>

  6235. <dt><span>&lsquo;<samp>auto</samp>&rsquo;</span></dt>

  6236. </dl>

  6237. 

  6238. </dd>

  6239. <dt><span><samp><var>repeat_pps</var></samp></span></dt>

  6240. <dd><p>Repeat pps for every frame.

  6241. </p>

  6242. </dd>

  6243. <dt><span><samp><var>max_qp_i</var></samp></span></dt>

  6244. <dd><p>Maximum video quantizer scale for I frame.

  6245. </p>

  6246. </dd>

  6247. <dt><span><samp><var>min_qp_i</var></samp></span></dt>

  6248. <dd><p>Minimum video quantizer scale for I frame.

  6249. </p>

  6250. </dd>

  6251. <dt><span><samp><var>max_qp_p</var></samp></span></dt>

  6252. <dd><p>Maximum video quantizer scale for P frame.

  6253. </p>

  6254. </dd>

  6255. <dt><span><samp><var>min_qp_p</var></samp></span></dt>

  6256. <dd><p>Minimum video quantizer scale for P frame.

  6257. </p>

  6258. </dd>

  6259. <dt><span><samp><var>max_qp_b</var></samp></span></dt>

  6260. <dd><p>Maximum video quantizer scale for B frame.

  6261. </p>

  6262. </dd>

  6263. <dt><span><samp><var>min_qp_b</var></samp></span></dt>

  6264. <dd><p>Minimum video quantizer scale for B frame.

  6265. </p>

  6266. </dd>

  6267. <dt><span><samp><var>scenario</var></samp></span></dt>

  6268. <dd><p>Provides a hint to encoder about the scenario for the encoding session.

  6269. </p><dl compact="compact">

  6270. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6271. <dt><span>&lsquo;<samp>displayremoting</samp>&rsquo;</span></dt>

  6272. <dt><span>&lsquo;<samp>videoconference</samp>&rsquo;</span></dt>

  6273. <dt><span>&lsquo;<samp>archive</samp>&rsquo;</span></dt>

  6274. <dt><span>&lsquo;<samp>livestreaming</samp>&rsquo;</span></dt>

  6275. <dt><span>&lsquo;<samp>cameracapture</samp>&rsquo;</span></dt>

  6276. <dt><span>&lsquo;<samp>videosurveillance</samp>&rsquo;</span></dt>

  6277. <dt><span>&lsquo;<samp>gamestreaming</samp>&rsquo;</span></dt>

  6278. <dt><span>&lsquo;<samp>remotegaming</samp>&rsquo;</span></dt>

  6279. </dl>

  6280. 

  6281. </dd>

  6282. <dt><span><samp><var>avbr_accuracy</var></samp></span></dt>

  6283. <dd><p>Accuracy of the AVBR ratecontrol (unit of tenth of percent).

  6284. </p>

  6285. </dd>

  6286. <dt><span><samp><var>avbr_convergence</var></samp></span></dt>

  6287. <dd><p>Convergence of the AVBR ratecontrol (unit of 100 frames)

  6288. </p>

  6289. <p>The parameters <var>avbr_accuracy</var> and <var>avbr_convergence</var> are for the

  6290. average variable bitrate control (AVBR) algorithm.

  6291. The algorithm focuses on overall encoding quality while meeting the specified

  6292. bitrate, <var>target_bitrate</var>, within the accuracy range <var>avbr_accuracy</var>,

  6293. after a <var>avbr_Convergence</var> period. This method does not follow HRD and the

  6294. instant bitrate is not capped or padded.

  6295. </p>

  6296. </dd>

  6297. <dt><span><samp><var>skip_frame</var></samp></span></dt>

  6298. <dd><p>Use per-frame metadata &quot;qsv_skip_frame&quot; to skip frame when encoding. This option

  6299. defines the usage of this metadata.

  6300. </p><dl compact="compact">

  6301. <dt><span>&lsquo;<samp>no_skip</samp>&rsquo;</span></dt>

  6302. <dd><p>Frame skipping is disabled.

  6303. </p></dd>

  6304. <dt><span>&lsquo;<samp>insert_dummy</samp>&rsquo;</span></dt>

  6305. <dd><p>Encoder inserts into bitstream frame where all macroblocks are encoded as

  6306. skipped.

  6307. </p></dd>

  6308. <dt><span>&lsquo;<samp>insert_nothing</samp>&rsquo;</span></dt>

  6309. <dd><p>Similar to insert_dummy, but encoder inserts nothing into bitstream. The skipped

  6310. frames are still used in brc. For example, gop still include skipped frames, and

  6311. the frames after skipped frames will be larger in size.

  6312. </p></dd>

  6313. <dt><span>&lsquo;<samp>brc_only</samp>&rsquo;</span></dt>

  6314. <dd><p>skip_frame metadata indicates the number of missed frames before the current

  6315. frame.

  6316. </p></dd>

  6317. </dl>

  6318. 

  6319. </dd>

  6320. </dl>

  6321. 

  6322. <a name="HEVC-Options-1"></a>

  6323. <h4 class="subsection">9.23.6 HEVC Options<span class="pull-right"><a class="anchor hidden-xs" href="#HEVC-Options-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-HEVC-Options-1" aria-hidden="true">TOC</a></span></h4>

  6324. <p>These options are used by hevc_qsv

  6325. </p>

  6326. <dl compact="compact">

  6327. <dt><span><samp><var>extbrc</var></samp></span></dt>

  6328. <dd><p>Extended bitrate control.

  6329. </p>

  6330. </dd>

  6331. <dt><span><samp><var>recovery_point_sei</var></samp></span></dt>

  6332. <dd><p>Set this flag to insert the recovery point SEI message at the beginning of every

  6333. intra refresh cycle.

  6334. </p>

  6335. </dd>

  6336. <dt><span><samp><var>rdo</var></samp></span></dt>

  6337. <dd><p>Enable rate distortion optimization.

  6338. </p>

  6339. </dd>

  6340. <dt><span><samp><var>max_frame_size</var></samp></span></dt>

  6341. <dd><p>Maximum encoded frame size in bytes.

  6342. </p>

  6343. </dd>

  6344. <dt><span><samp><var>max_frame_size_i</var></samp></span></dt>

  6345. <dd><p>Maximum encoded frame size for I frames in bytes. If this value is set as larger

  6346. than zero, then for I frames the value set by max_frame_size is ignored.

  6347. </p>

  6348. </dd>

  6349. <dt><span><samp><var>max_frame_size_p</var></samp></span></dt>

  6350. <dd><p>Maximum encoded frame size for P frames in bytes. If this value is set as larger

  6351. than zero, then for P frames the value set by max_frame_size is ignored.

  6352. </p>

  6353. </dd>

  6354. <dt><span><samp><var>max_slice_size</var></samp></span></dt>

  6355. <dd><p>Maximum encoded slice size in bytes.

  6356. </p>

  6357. </dd>

  6358. <dt><span><samp><var>mbbrc</var></samp></span></dt>

  6359. <dd><p>Setting this flag enables macroblock level bitrate control that generally

  6360. improves subjective visual quality. Enabling this flag may have negative impact

  6361. on performance and objective visual quality metric.

  6362. </p>

  6363. </dd>

  6364. <dt><span><samp><var>low_delay_brc</var></samp></span></dt>

  6365. <dd><p>Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which provides

  6366. more accurate bitrate control to minimize the variance of bitstream size frame

  6367. by frame. Value: -1-default 0-off 1-on

  6368. </p>

  6369. </dd>

  6370. <dt><span><samp><var>adaptive_i</var></samp></span></dt>

  6371. <dd><p>This flag controls insertion of I frames by the QSV encoder. Turn ON this flag

  6372. to allow changing of frame type from P and B to I.

  6373. </p>

  6374. </dd>

  6375. <dt><span><samp><var>adaptive_b</var></samp></span></dt>

  6376. <dd><p>This flag controls changing of frame type from B to P.

  6377. </p>

  6378. </dd>

  6379. <dt><span><samp><var>p_strategy</var></samp></span></dt>

  6380. <dd><p>Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to 0).

  6381. </p>

  6382. </dd>

  6383. <dt><span><samp><var>b_strategy</var></samp></span></dt>

  6384. <dd><p>This option controls usage of B frames as reference.

  6385. </p>

  6386. </dd>

  6387. <dt><span><samp><var>dblk_idc</var></samp></span></dt>

  6388. <dd><p>This option disable deblocking. It has value in range 0~2.

  6389. </p>

  6390. </dd>

  6391. <dt><span><samp><var>idr_interval</var></samp></span></dt>

  6392. <dd><p>Distance (in I-frames) between IDR frames.

  6393. </p><dl compact="compact">

  6394. <dt><span>&lsquo;<samp>begin_only</samp>&rsquo;</span></dt>

  6395. <dd><p>Output an IDR-frame only at the beginning of the stream.

  6396. </p></dd>

  6397. </dl>

  6398. 

  6399. </dd>

  6400. <dt><span><samp><var>load_plugin</var></samp></span></dt>

  6401. <dd><p>A user plugin to load in an internal session.

  6402. </p><dl compact="compact">

  6403. <dt><span>&lsquo;<samp>none</samp>&rsquo;</span></dt>

  6404. <dt><span>&lsquo;<samp>hevc_sw</samp>&rsquo;</span></dt>

  6405. <dt><span>&lsquo;<samp>hevc_hw</samp>&rsquo;</span></dt>

  6406. </dl>

  6407. 

  6408. </dd>

  6409. <dt><span><samp><var>load_plugins</var></samp></span></dt>

  6410. <dd><p>A :-separate list of hexadecimal plugin UIDs to load in

  6411. an internal session.

  6412. </p>

  6413. </dd>

  6414. <dt><span><samp><var>look_ahead_depth</var></samp></span></dt>

  6415. <dd><p>Depth of look ahead in number frames, available when extbrc option is enabled.

  6416. </p>

  6417. </dd>

  6418. <dt><span><samp><var>profile</var></samp></span></dt>

  6419. <dd><p>Set the encoding profile (scc requires libmfx &gt;= 1.32).

  6420. </p>

  6421. <dl compact="compact">

  6422. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6423. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  6424. <dt><span>&lsquo;<samp>main10</samp>&rsquo;</span></dt>

  6425. <dt><span>&lsquo;<samp>mainsp</samp>&rsquo;</span></dt>

  6426. <dt><span>&lsquo;<samp>rext</samp>&rsquo;</span></dt>

  6427. <dt><span>&lsquo;<samp>scc</samp>&rsquo;</span></dt>

  6428. </dl>

  6429. 

  6430. </dd>

  6431. <dt><span><samp><var>tier</var></samp></span></dt>

  6432. <dd><p>Set the encoding tier (only level &gt;= 4 can support high tier).

  6433. This option only takes effect when the level option is specified.

  6434. </p>

  6435. <dl compact="compact">

  6436. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  6437. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  6438. </dl>

  6439. 

  6440. </dd>

  6441. <dt><span><samp><var>gpb</var></samp></span></dt>

  6442. <dd><p>1: GPB (generalized P/B frame)

  6443. </p>

  6444. <p>0: regular P frame.

  6445. </p>

  6446. </dd>

  6447. <dt><span><samp><var>tile_cols</var></samp></span></dt>

  6448. <dd><p>Number of columns for tiled encoding.

  6449. </p>

  6450. </dd>

  6451. <dt><span><samp><var>tile_rows</var></samp></span></dt>

  6452. <dd><p>Number of rows for tiled encoding.

  6453. </p>

  6454. </dd>

  6455. <dt><span><samp><var>aud</var></samp></span></dt>

  6456. <dd><p>Insert the Access Unit Delimiter NAL.

  6457. </p>

  6458. </dd>

  6459. <dt><span><samp><var>pic_timing_sei</var></samp></span></dt>

  6460. <dd><p>Insert picture timing SEI with pic_struct_syntax element.

  6461. </p>

  6462. </dd>

  6463. <dt><span><samp><var>transform_skip</var></samp></span></dt>

  6464. <dd><p>Turn this option ON to enable transformskip. It is supported on platform equal

  6465. or newer than ICL.

  6466. </p>

  6467. </dd>

  6468. <dt><span><samp><var>int_ref_type</var></samp></span></dt>

  6469. <dd><p>Specifies intra refresh type. The major goal of intra refresh is improvement of

  6470. error resilience without significant impact on encoded bitstream size caused by

  6471. I frames. The SDK encoder achieves this by encoding part of each frame in

  6472. refresh cycle using intra MBs. <var>none</var> means no refresh. <var>vertical</var> means

  6473. vertical refresh, by column of MBs. <var>horizontal</var> means horizontal refresh,

  6474. by rows of MBs. <var>slice</var> means horizontal refresh by slices without

  6475. overlapping. In case of <var>slice</var>, in_ref_cycle_size is ignored. To enable

  6476. intra refresh, B frame should be set to 0.

  6477. </p>

  6478. </dd>

  6479. <dt><span><samp><var>int_ref_cycle_size</var></samp></span></dt>

  6480. <dd><p>Specifies number of pictures within refresh cycle starting from 2. 0 and 1 are

  6481. invalid values.

  6482. </p>

  6483. </dd>

  6484. <dt><span><samp><var>int_ref_qp_delta</var></samp></span></dt>

  6485. <dd><p>Specifies QP difference for inserted intra MBs. This is signed value in

  6486. [-51, 51] range if target encoding bit-depth for luma samples is 8 and this

  6487. range is [-63, 63] for 10 bit-depth or [-75, 75] for 12 bit-depth respectively.

  6488. </p>

  6489. </dd>

  6490. <dt><span><samp><var>int_ref_cycle_dist</var></samp></span></dt>

  6491. <dd><p>Distance between the beginnings of the intra-refresh cycles in frames.

  6492. </p>

  6493. </dd>

  6494. <dt><span><samp><var>max_qp_i</var></samp></span></dt>

  6495. <dd><p>Maximum video quantizer scale for I frame.

  6496. </p>

  6497. </dd>

  6498. <dt><span><samp><var>min_qp_i</var></samp></span></dt>

  6499. <dd><p>Minimum video quantizer scale for I frame.

  6500. </p>

  6501. </dd>

  6502. <dt><span><samp><var>max_qp_p</var></samp></span></dt>

  6503. <dd><p>Maximum video quantizer scale for P frame.

  6504. </p>

  6505. </dd>

  6506. <dt><span><samp><var>min_qp_p</var></samp></span></dt>

  6507. <dd><p>Minimum video quantizer scale for P frame.

  6508. </p>

  6509. </dd>

  6510. <dt><span><samp><var>max_qp_b</var></samp></span></dt>

  6511. <dd><p>Maximum video quantizer scale for B frame.

  6512. </p>

  6513. </dd>

  6514. <dt><span><samp><var>min_qp_b</var></samp></span></dt>

  6515. <dd><p>Minimum video quantizer scale for B frame.

  6516. </p>

  6517. </dd>

  6518. <dt><span><samp><var>scenario</var></samp></span></dt>

  6519. <dd><p>Provides a hint to encoder about the scenario for the encoding session.

  6520. </p><dl compact="compact">

  6521. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6522. <dt><span>&lsquo;<samp>displayremoting</samp>&rsquo;</span></dt>

  6523. <dt><span>&lsquo;<samp>videoconference</samp>&rsquo;</span></dt>

  6524. <dt><span>&lsquo;<samp>archive</samp>&rsquo;</span></dt>

  6525. <dt><span>&lsquo;<samp>livestreaming</samp>&rsquo;</span></dt>

  6526. <dt><span>&lsquo;<samp>cameracapture</samp>&rsquo;</span></dt>

  6527. <dt><span>&lsquo;<samp>videosurveillance</samp>&rsquo;</span></dt>

  6528. <dt><span>&lsquo;<samp>gamestreaming</samp>&rsquo;</span></dt>

  6529. <dt><span>&lsquo;<samp>remotegaming</samp>&rsquo;</span></dt>

  6530. </dl>

  6531. 

  6532. </dd>

  6533. <dt><span><samp><var>avbr_accuracy</var></samp></span></dt>

  6534. <dd><p>Accuracy of the AVBR ratecontrol (unit of tenth of percent).

  6535. </p>

  6536. </dd>

  6537. <dt><span><samp><var>avbr_convergence</var></samp></span></dt>

  6538. <dd><p>Convergence of the AVBR ratecontrol (unit of 100 frames)

  6539. </p>

  6540. <p>The parameters <var>avbr_accuracy</var> and <var>avbr_convergence</var> are for the

  6541. average variable bitrate control (AVBR) algorithm.

  6542. The algorithm focuses on overall encoding quality while meeting the specified

  6543. bitrate, <var>target_bitrate</var>, within the accuracy range <var>avbr_accuracy</var>,

  6544. after a <var>avbr_Convergence</var> period. This method does not follow HRD and the

  6545. instant bitrate is not capped or padded.

  6546. </p>

  6547. </dd>

  6548. <dt><span><samp><var>skip_frame</var></samp></span></dt>

  6549. <dd><p>Use per-frame metadata &quot;qsv_skip_frame&quot; to skip frame when encoding. This option

  6550. defines the usage of this metadata.

  6551. </p><dl compact="compact">

  6552. <dt><span>&lsquo;<samp>no_skip</samp>&rsquo;</span></dt>

  6553. <dd><p>Frame skipping is disabled.

  6554. </p></dd>

  6555. <dt><span>&lsquo;<samp>insert_dummy</samp>&rsquo;</span></dt>

  6556. <dd><p>Encoder inserts into bitstream frame where all macroblocks are encoded as

  6557. skipped.

  6558. </p></dd>

  6559. <dt><span>&lsquo;<samp>insert_nothing</samp>&rsquo;</span></dt>

  6560. <dd><p>Similar to insert_dummy, but encoder inserts nothing into bitstream. The skipped

  6561. frames are still used in brc. For example, gop still include skipped frames, and

  6562. the frames after skipped frames will be larger in size.

  6563. </p></dd>

  6564. <dt><span>&lsquo;<samp>brc_only</samp>&rsquo;</span></dt>

  6565. <dd><p>skip_frame metadata indicates the number of missed frames before the current

  6566. frame.

  6567. </p></dd>

  6568. </dl>

  6569. 

  6570. </dd>

  6571. </dl>

  6572. 

  6573. <a name="MPEG2-Options"></a>

  6574. <h4 class="subsection">9.23.7 MPEG2 Options<span class="pull-right"><a class="anchor hidden-xs" href="#MPEG2-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-MPEG2-Options" aria-hidden="true">TOC</a></span></h4>

  6575. <p>These options are used by mpeg2_qsv

  6576. </p><dl compact="compact">

  6577. <dt><span><samp><var>profile</var></samp></span></dt>

  6578. <dd><dl compact="compact">

  6579. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6580. <dt><span>&lsquo;<samp>simple</samp>&rsquo;</span></dt>

  6581. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  6582. <dt><span>&lsquo;<samp>high</samp>&rsquo;</span></dt>

  6583. </dl>

  6584. </dd>

  6585. </dl>

  6586. 

  6587. <a name="VP9-Options"></a>

  6588. <h4 class="subsection">9.23.8 VP9 Options<span class="pull-right"><a class="anchor hidden-xs" href="#VP9-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-VP9-Options" aria-hidden="true">TOC</a></span></h4>

  6589. <p>These options are used by vp9_qsv

  6590. </p><dl compact="compact">

  6591. <dt><span><samp><var>profile</var></samp></span></dt>

  6592. <dd><dl compact="compact">

  6593. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6594. <dt><span>&lsquo;<samp>profile0</samp>&rsquo;</span></dt>

  6595. <dt><span>&lsquo;<samp>profile1</samp>&rsquo;</span></dt>

  6596. <dt><span>&lsquo;<samp>profile2</samp>&rsquo;</span></dt>

  6597. <dt><span>&lsquo;<samp>profile3</samp>&rsquo;</span></dt>

  6598. </dl>

  6599. 

  6600. </dd>

  6601. <dt><span><samp><var>tile_cols</var></samp></span></dt>

  6602. <dd><p>Number of columns for tiled encoding (requires libmfx &gt;= 1.29).

  6603. </p>

  6604. </dd>

  6605. <dt><span><samp><var>tile_rows</var></samp></span></dt>

  6606. <dd><p>Number of rows for tiled encoding (requires libmfx  &gt;= 1.29).

  6607. </p></dd>

  6608. </dl>

  6609. 

  6610. <a name="AV1-Options"></a>

  6611. <h4 class="subsection">9.23.9 AV1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#AV1-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-AV1-Options" aria-hidden="true">TOC</a></span></h4>

  6612. <p>These options are used by av1_qsv (requires libvpl).

  6613. </p><dl compact="compact">

  6614. <dt><span><samp><var>profile</var></samp></span></dt>

  6615. <dd><dl compact="compact">

  6616. <dt><span>&lsquo;<samp>unknown</samp>&rsquo;</span></dt>

  6617. <dt><span>&lsquo;<samp>main</samp>&rsquo;</span></dt>

  6618. </dl>

  6619. 

  6620. </dd>

  6621. <dt><span><samp><var>tile_cols</var></samp></span></dt>

  6622. <dd><p>Number of columns for tiled encoding.

  6623. </p>

  6624. </dd>

  6625. <dt><span><samp><var>tile_rows</var></samp></span></dt>

  6626. <dd><p>Number of rows for tiled encoding.

  6627. </p>

  6628. </dd>

  6629. <dt><span><samp><var>adaptive_i</var></samp></span></dt>

  6630. <dd><p>This flag controls insertion of I frames by the QSV encoder. Turn ON this flag

  6631. to allow changing of frame type from P and B to I.

  6632. </p>

  6633. </dd>

  6634. <dt><span><samp><var>adaptive_b</var></samp></span></dt>

  6635. <dd><p>This flag controls changing of frame type from B to P.

  6636. </p>

  6637. </dd>

  6638. <dt><span><samp><var>b_strategy</var></samp></span></dt>

  6639. <dd><p>This option controls usage of B frames as reference.

  6640. </p>

  6641. </dd>

  6642. <dt><span><samp><var>extbrc</var></samp></span></dt>

  6643. <dd><p>Extended bitrate control.

  6644. </p>

  6645. </dd>

  6646. <dt><span><samp><var>look_ahead_depth</var></samp></span></dt>

  6647. <dd><p>Depth of look ahead in number frames, available when extbrc option is enabled.

  6648. </p>

  6649. </dd>

  6650. <dt><span><samp><var>low_delay_brc</var></samp></span></dt>

  6651. <dd><p>Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which provides

  6652. more accurate bitrate control to minimize the variance of bitstream size frame

  6653. by frame. Value: -1-default 0-off 1-on

  6654. </p>

  6655. </dd>

  6656. <dt><span><samp>max_frame_size</samp></span></dt>

  6657. <dd><p>Set the allowed max size in bytes for each frame. If the frame size exceeds

  6658. the limitation, encoder will adjust the QP value to control the frame size.

  6659. Invalid in CQP rate control mode.

  6660. </p></dd>

  6661. </dl>

  6662. 

  6663. <a name="snow"></a>

  6664. <h3 class="section">9.24 snow<span class="pull-right"><a class="anchor hidden-xs" href="#snow" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-snow" aria-hidden="true">TOC</a></span></h3>

  6665. 

  6666. <a name="Options-39"></a>

  6667. <h4 class="subsection">9.24.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-39" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-39" aria-hidden="true">TOC</a></span></h4>

  6668. 

  6669. <dl compact="compact">

  6670. <dt><span><samp>iterative_dia_size</samp></span></dt>

  6671. <dd><p>dia size for the iterative motion estimation

  6672. </p></dd>

  6673. </dl>

  6674. 

  6675. <a name="VAAPI-encoders"></a>

  6676. <h3 class="section">9.25 VAAPI encoders<span class="pull-right"><a class="anchor hidden-xs" href="#VAAPI-encoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-VAAPI-encoders" aria-hidden="true">TOC</a></span></h3>

  6677. 

  6678. <p>Wrappers for hardware encoders accessible via VAAPI.

  6679. </p>

  6680. <p>These encoders only accept input in VAAPI hardware surfaces.  If you have input

  6681. in software frames, use the <samp>hwupload</samp> filter to upload them to the GPU.

  6682. </p>

  6683. <p>The following standard libavcodec options are used:

  6684. </p><ul>

  6685. <li> <samp>g</samp> / <samp>gop_size</samp>

  6686. </li><li> <samp>bf</samp> / <samp>max_b_frames</samp>

  6687. </li><li> <samp>profile</samp>

  6688. 

  6689. <p>If not set, this will be determined automatically from the format of the input

  6690. frames and the profiles supported by the driver.

  6691. </p></li><li> <samp>level</samp>

  6692. </li><li> <samp>b</samp> / <samp>bit_rate</samp>

  6693. </li><li> <samp>maxrate</samp> / <samp>rc_max_rate</samp>

  6694. </li><li> <samp>bufsize</samp> / <samp>rc_buffer_size</samp>

  6695. </li><li> <samp>rc_init_occupancy</samp> / <samp>rc_initial_buffer_occupancy</samp>

  6696. </li><li> <samp>compression_level</samp>

  6697. 

  6698. <p>Speed / quality tradeoff: higher values are faster / worse quality.

  6699. </p></li><li> <samp>q</samp> / <samp>global_quality</samp>

  6700. 

  6701. <p>Size / quality tradeoff: higher values are smaller / worse quality.

  6702. </p></li><li> <samp>qmin</samp>

  6703. </li><li> <samp>qmax</samp>

  6704. </li><li> <samp>i_qfactor</samp> / <samp>i_quant_factor</samp>

  6705. </li><li> <samp>i_qoffset</samp> / <samp>i_quant_offset</samp>

  6706. </li><li> <samp>b_qfactor</samp> / <samp>b_quant_factor</samp>

  6707. </li><li> <samp>b_qoffset</samp> / <samp>b_quant_offset</samp>

  6708. </li><li> <samp>slices</samp>

  6709. </li></ul>

  6710. 

  6711. <p>All encoders support the following options:

  6712. </p><dl compact="compact">

  6713. <dt><span><samp>low_power</samp></span></dt>

  6714. <dd><p>Some drivers/platforms offer a second encoder for some codecs intended to use

  6715. less power than the default encoder; setting this option will attempt to use

  6716. that encoder.  Note that it may support a reduced feature set, so some other

  6717. options may not be available in this mode.

  6718. </p>

  6719. </dd>

  6720. <dt><span><samp>idr_interval</samp></span></dt>

  6721. <dd><p>Set the number of normal intra frames between full-refresh (IDR) frames in

  6722. open-GOP mode.  The intra frames are still IRAPs, but will not include global

  6723. headers and may have non-decodable leading pictures.

  6724. </p>

  6725. </dd>

  6726. <dt><span><samp>b_depth</samp></span></dt>

  6727. <dd><p>Set the B-frame reference depth.  When set to one (the default), all B-frames

  6728. will refer only to P- or I-frames.  When set to greater values multiple layers

  6729. of B-frames will be present, frames in each layer only referring to frames in

  6730. higher layers.

  6731. </p>

  6732. </dd>

  6733. <dt><span><samp>async_depth</samp></span></dt>

  6734. <dd><p>Maximum processing parallelism. Increase this to improve single channel

  6735. performance. This option doesn&rsquo;t work if driver doesn&rsquo;t implement vaSyncBuffer

  6736. function. Please make sure there are enough hw_frames allocated if a large

  6737. number of async_depth is used.

  6738. </p>

  6739. </dd>

  6740. <dt><span><samp>max_frame_size</samp></span></dt>

  6741. <dd><p>Set the allowed max size in bytes for each frame. If the frame size exceeds

  6742. the limitation, encoder will adjust the QP value to control the frame size.

  6743. Invalid in CQP rate control mode.

  6744. </p>

  6745. </dd>

  6746. <dt><span><samp>rc_mode</samp></span></dt>

  6747. <dd><p>Set the rate control mode to use.  A given driver may only support a subset of

  6748. modes.

  6749. </p>

  6750. <p>Possible modes:

  6751. </p><dl compact="compact">

  6752. <dt><span><samp>auto</samp></span></dt>

  6753. <dd><p>Choose the mode automatically based on driver support and the other options.

  6754. This is the default.

  6755. </p></dd>

  6756. <dt><span><samp>CQP</samp></span></dt>

  6757. <dd><p>Constant-quality.

  6758. </p></dd>

  6759. <dt><span><samp>CBR</samp></span></dt>

  6760. <dd><p>Constant-bitrate.

  6761. </p></dd>

  6762. <dt><span><samp>VBR</samp></span></dt>

  6763. <dd><p>Variable-bitrate.

  6764. </p></dd>

  6765. <dt><span><samp>ICQ</samp></span></dt>

  6766. <dd><p>Intelligent constant-quality.

  6767. </p></dd>

  6768. <dt><span><samp>QVBR</samp></span></dt>

  6769. <dd><p>Quality-defined variable-bitrate.

  6770. </p></dd>

  6771. <dt><span><samp>AVBR</samp></span></dt>

  6772. <dd><p>Average variable bitrate.

  6773. </p></dd>

  6774. </dl>

  6775. 

  6776. </dd>

  6777. </dl>

  6778. 

  6779. <p>Each encoder also has its own specific options:

  6780. </p><dl compact="compact">

  6781. <dt><span><samp>h264_vaapi</samp></span></dt>

  6782. <dd><p><samp>profile</samp> sets the value of <em>profile_idc</em> and the <em>constraint_set*_flag</em>s.

  6783. <samp>level</samp> sets the value of <em>level_idc</em>.

  6784. </p>

  6785. <dl compact="compact">

  6786. <dt><span><samp>coder</samp></span></dt>

  6787. <dd><p>Set entropy encoder (default is <em>cabac</em>).  Possible values:

  6788. </p>

  6789. <dl compact="compact">

  6790. <dt><span>&lsquo;<samp>ac</samp>&rsquo;</span></dt>

  6791. <dt><span>&lsquo;<samp>cabac</samp>&rsquo;</span></dt>

  6792. <dd><p>Use CABAC.

  6793. </p>

  6794. </dd>

  6795. <dt><span>&lsquo;<samp>vlc</samp>&rsquo;</span></dt>

  6796. <dt><span>&lsquo;<samp>cavlc</samp>&rsquo;</span></dt>

  6797. <dd><p>Use CAVLC.

  6798. </p></dd>

  6799. </dl>

  6800. 

  6801. </dd>

  6802. <dt><span><samp>aud</samp></span></dt>

  6803. <dd><p>Include access unit delimiters in the stream (not included by default).

  6804. </p>

  6805. </dd>

  6806. <dt><span><samp>sei</samp></span></dt>

  6807. <dd><p>Set SEI message types to include.

  6808. Some combination of the following values:

  6809. </p><dl compact="compact">

  6810. <dt><span>&lsquo;<samp>identifier</samp>&rsquo;</span></dt>

  6811. <dd><p>Include a <em>user_data_unregistered</em> message containing information about

  6812. the encoder.

  6813. </p></dd>

  6814. <dt><span>&lsquo;<samp>timing</samp>&rsquo;</span></dt>

  6815. <dd><p>Include picture timing parameters (<em>buffering_period</em> and

  6816. <em>pic_timing</em> messages).

  6817. </p></dd>

  6818. <dt><span>&lsquo;<samp>recovery_point</samp>&rsquo;</span></dt>

  6819. <dd><p>Include recovery points where appropriate (<em>recovery_point</em> messages).

  6820. </p></dd>

  6821. </dl>

  6822. 

  6823. </dd>

  6824. </dl>

  6825. 

  6826. </dd>

  6827. <dt><span><samp>hevc_vaapi</samp></span></dt>

  6828. <dd><p><samp>profile</samp> and <samp>level</samp> set the values of

  6829. <em>general_profile_idc</em> and <em>general_level_idc</em> respectively.

  6830. </p>

  6831. <dl compact="compact">

  6832. <dt><span><samp>aud</samp></span></dt>

  6833. <dd><p>Include access unit delimiters in the stream (not included by default).

  6834. </p>

  6835. </dd>

  6836. <dt><span><samp>tier</samp></span></dt>

  6837. <dd><p>Set <em>general_tier_flag</em>.  This may affect the level chosen for the stream

  6838. if it is not explicitly specified.

  6839. </p>

  6840. </dd>

  6841. <dt><span><samp>sei</samp></span></dt>

  6842. <dd><p>Set SEI message types to include.

  6843. Some combination of the following values:

  6844. </p><dl compact="compact">

  6845. <dt><span>&lsquo;<samp>hdr</samp>&rsquo;</span></dt>

  6846. <dd><p>Include HDR metadata if the input frames have it

  6847. (<em>mastering_display_colour_volume</em> and <em>content_light_level</em>

  6848. messages).

  6849. </p></dd>

  6850. </dl>

  6851. 

  6852. </dd>

  6853. <dt><span><samp>tiles</samp></span></dt>

  6854. <dd><p>Set the number of tiles to encode the input video with, as columns x rows.

  6855. Larger numbers allow greater parallelism in both encoding and decoding, but

  6856. may decrease coding efficiency.

  6857. </p>

  6858. </dd>

  6859. </dl>

  6860. 

  6861. </dd>

  6862. <dt><span><samp>mjpeg_vaapi</samp></span></dt>

  6863. <dd><p>Only baseline DCT encoding is supported.  The encoder always uses the standard

  6864. quantisation and huffman tables - <samp>global_quality</samp> scales the standard

  6865. quantisation table (range 1-100).

  6866. </p>

  6867. <p>For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported.  RGB is also

  6868. supported, and will create an RGB JPEG.

  6869. </p>

  6870. <dl compact="compact">

  6871. <dt><span><samp>jfif</samp></span></dt>

  6872. <dd><p>Include JFIF header in each frame (not included by default).

  6873. </p></dd>

  6874. <dt><span><samp>huffman</samp></span></dt>

  6875. <dd><p>Include standard huffman tables (on by default).  Turning this off will save

  6876. a few hundred bytes in each output frame, but may lose compatibility with some

  6877. JPEG decoders which don&rsquo;t fully handle MJPEG.

  6878. </p></dd>

  6879. </dl>

  6880. 

  6881. </dd>

  6882. <dt><span><samp>mpeg2_vaapi</samp></span></dt>

  6883. <dd><p><samp>profile</samp> and <samp>level</samp> set the value of <em>profile_and_level_indication</em>.

  6884. </p>

  6885. </dd>

  6886. <dt><span><samp>vp8_vaapi</samp></span></dt>

  6887. <dd><p>B-frames are not supported.

  6888. </p>

  6889. <p><samp>global_quality</samp> sets the <em>q_idx</em> used for non-key frames (range 0-127).

  6890. </p>

  6891. <dl compact="compact">

  6892. <dt><span><samp>loop_filter_level</samp></span></dt>

  6893. <dt><span><samp>loop_filter_sharpness</samp></span></dt>

  6894. <dd><p>Manually set the loop filter parameters.

  6895. </p></dd>

  6896. </dl>

  6897. 

  6898. </dd>

  6899. <dt><span><samp>vp9_vaapi</samp></span></dt>

  6900. <dd><p><samp>global_quality</samp> sets the <em>q_idx</em> used for P-frames (range 0-255).

  6901. </p>

  6902. <dl compact="compact">

  6903. <dt><span><samp>loop_filter_level</samp></span></dt>

  6904. <dt><span><samp>loop_filter_sharpness</samp></span></dt>

  6905. <dd><p>Manually set the loop filter parameters.

  6906. </p></dd>

  6907. </dl>

  6908. 

  6909. <p>B-frames are supported, but the output stream is always in encode order rather than display

  6910. order.  If B-frames are enabled, it may be necessary to use the <samp>vp9_raw_reorder</samp>

  6911. bitstream filter to modify the output stream to display frames in the correct order.

  6912. </p>

  6913. <p>Only normal frames are produced - the <samp>vp9_superframe</samp> bitstream filter may be

  6914. required to produce a stream usable with all decoders.

  6915. </p>

  6916. </dd>

  6917. </dl>

  6918. 

  6919. <a name="vbn"></a>

  6920. <h3 class="section">9.26 vbn<span class="pull-right"><a class="anchor hidden-xs" href="#vbn" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-vbn" aria-hidden="true">TOC</a></span></h3>

  6921. 

  6922. <p>Vizrt Binary Image encoder.

  6923. </p>

  6924. <p>This format is used by the broadcast vendor Vizrt for quick texture streaming.

  6925. Advanced features of the format such as LZW compression of texture data or

  6926. generation of mipmaps are not supported.

  6927. </p>

  6928. <a name="Options-40"></a>

  6929. <h4 class="subsection">9.26.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-40" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-40" aria-hidden="true">TOC</a></span></h4>

  6930. 

  6931. <dl compact="compact">

  6932. <dt><span><samp>format <var>string</var></samp></span></dt>

  6933. <dd><p>Sets the texture compression used by the VBN file. Can be <var>dxt1</var>,

  6934. <var>dxt5</var> or <var>raw</var>. Default is <var>dxt5</var>.

  6935. </p></dd>

  6936. </dl>

  6937. 

  6938. <a name="vc2"></a>

  6939. <h3 class="section">9.27 vc2<span class="pull-right"><a class="anchor hidden-xs" href="#vc2" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-vc2" aria-hidden="true">TOC</a></span></h3>

  6940. 

  6941. <p>SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at

  6942. professional broadcasting but since it supports yuv420, yuv422 and yuv444 at

  6943. 8 (limited range or full range), 10 or 12 bits, this makes it suitable for

  6944. other tasks which require low overhead and low compression (like screen

  6945. recording).

  6946. </p>

  6947. <a name="Options-41"></a>

  6948. <h4 class="subsection">9.27.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-41" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-41" aria-hidden="true">TOC</a></span></h4>

  6949. 

  6950. <dl compact="compact">

  6951. <dt><span><samp>b</samp></span></dt>

  6952. <dd><p>Sets target video bitrate. Usually that&rsquo;s around 1:6 of the uncompressed

  6953. video bitrate (e.g. for 1920x1080 50fps yuv422p10 that&rsquo;s around 400Mbps). Higher

  6954. values (close to the uncompressed bitrate) turn on lossless compression mode.

  6955. </p>

  6956. </dd>

  6957. <dt><span><samp>field_order</samp></span></dt>

  6958. <dd><p>Enables field coding when set (e.g. to tt - top field first) for interlaced

  6959. inputs. Should increase compression with interlaced content as it splits the

  6960. fields and encodes each separately.

  6961. </p>

  6962. </dd>

  6963. <dt><span><samp>wavelet_depth</samp></span></dt>

  6964. <dd><p>Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).

  6965. Lower values reduce compression and quality. Less capable decoders may not be

  6966. able to handle values of <samp>wavelet_depth</samp> over 3.

  6967. </p>

  6968. </dd>

  6969. <dt><span><samp>wavelet_type</samp></span></dt>

  6970. <dd><p>Sets the transform type. Currently only <var>5_3</var> (LeGall) and <var>9_7</var>

  6971. (Deslauriers-Dubuc)

  6972. are implemented, with 9_7 being the one with better compression and thus

  6973. is the default.

  6974. </p>

  6975. </dd>

  6976. <dt><span><samp>slice_width</samp></span></dt>

  6977. <dt><span><samp>slice_height</samp></span></dt>

  6978. <dd><p>Sets the slice size for each slice. Larger values result in better compression.

  6979. For compatibility with other more limited decoders use <samp>slice_width</samp> of

  6980. 32 and <samp>slice_height</samp> of 8.

  6981. </p>

  6982. </dd>

  6983. <dt><span><samp>tolerance</samp></span></dt>

  6984. <dd><p>Sets the undershoot tolerance of the rate control system in percent. This is

  6985. to prevent an expensive search from being run.

  6986. </p>

  6987. </dd>

  6988. <dt><span><samp>qm</samp></span></dt>

  6989. <dd><p>Sets the quantization matrix preset to use by default or when <samp>wavelet_depth</samp>

  6990. is set to 5

  6991. </p><ul class="no-bullet">

  6992. <li>- <var>default</var>

  6993. Uses the default quantization matrix from the specifications, extended with

  6994. values for the fifth level. This provides a good balance between keeping detail

  6995. and omitting artifacts.

  6996. 

  6997. </li><li>- <var>flat</var>

  6998. Use a completely zeroed out quantization matrix. This increases PSNR but might

  6999. reduce perception. Use in bogus benchmarks.

  7000. 

  7001. </li><li>- <var>color</var>

  7002. Reduces detail but attempts to preserve color at extremely low bitrates.

  7003. </li></ul>

  7004. 

  7005. </dd>

  7006. </dl>

  7007. 

  7008. 

  7009. <a name="Subtitles-Encoders"></a>

  7010. <h2 class="chapter">10 Subtitles Encoders<span class="pull-right"><a class="anchor hidden-xs" href="#Subtitles-Encoders" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Subtitles-Encoders" aria-hidden="true">TOC</a></span></h2>

  7011. 

  7012. <a name="dvdsub-1"></a>

  7013. <h3 class="section">10.1 dvdsub<span class="pull-right"><a class="anchor hidden-xs" href="#dvdsub-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-dvdsub-1" aria-hidden="true">TOC</a></span></h3>

  7014. 

  7015. <p>This codec encodes the bitmap subtitle format that is used in DVDs.

  7016. Typically they are stored in VOBSUB file pairs (*.idx + *.sub),

  7017. and they can also be used in Matroska files.

  7018. </p>

  7019. <a name="Options-42"></a>

  7020. <h4 class="subsection">10.1.1 Options<span class="pull-right"><a class="anchor hidden-xs" href="#Options-42" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Options-42" aria-hidden="true">TOC</a></span></h4>

  7021. 

  7022. <dl compact="compact">

  7023. <dt><span><samp>palette</samp></span></dt>

  7024. <dd><p>Specify the global palette used by the bitmaps.

  7025. </p>

  7026. <p>The format for this option is a string containing 16 24-bits hexadecimal

  7027. numbers (without 0x prefix) separated by commas, for example <code>0d00ee,

  7028. ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,

  7029. 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b</code>.

  7030. </p>

  7031. </dd>

  7032. <dt><span><samp>even_rows_fix</samp></span></dt>

  7033. <dd><p>When set to 1, enable a work-around that makes the number of pixel rows

  7034. even in all subtitles.  This fixes a problem with some players that

  7035. cut off the bottom row if the number is odd.  The work-around just adds

  7036. a fully transparent row if needed.  The overhead is low, typically

  7037. one byte per subtitle on average.

  7038. </p>

  7039. <p>By default, this work-around is disabled.

  7040. </p></dd>

  7041. </dl>

  7042. 

  7043. 

  7044. <a name="See-Also"></a>

  7045. <h2 class="chapter">11 See Also<span class="pull-right"><a class="anchor hidden-xs" href="#See-Also" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-See-Also" aria-hidden="true">TOC</a></span></h2>

  7046. 

  7047. <p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>,

  7048. <a href="libavcodec.html">libavcodec</a>

  7049. </p>

  7050. 

  7051. <a name="Authors"></a>

  7052. <h2 class="chapter">12 Authors<span class="pull-right"><a class="anchor hidden-xs" href="#Authors" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Authors" aria-hidden="true">TOC</a></span></h2>

  7053. 

  7054. <p>The FFmpeg developers.

  7055. </p>

  7056. <p>For details about the authorship, see the Git history of the project

  7057. (https://git.ffmpeg.org/ffmpeg), e.g. by typing the command

  7058. <code>git log</code> in the FFmpeg source directory, or browsing the

  7059. online repository at <a href="https://git.ffmpeg.org/ffmpeg">https://git.ffmpeg.org/ffmpeg</a>.

  7060. </p>

  7061. <p>Maintainers for the specific components are listed in the file

  7062. <samp>MAINTAINERS</samp> in the source code tree.

  7063. </p>

  7064. 

  7065.       <p style="font-size: small;">

  7066.         This document was generated using <a href="https://www.gnu.org/software/texinfo/"><em>makeinfo</em></a>.

  7067.       </p>

  7068.     </div>

  7069.   </body>

  7070. </html>