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  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 Scaler 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 Scaler 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-Scaler-Options" href="#Scaler-Options">2 Scaler Options</a></li>

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

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

  34. </ul>

  35. </div>

  36. </div>

  37. 

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

  39. <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>

  40. 

  41. <p>The FFmpeg rescaler provides a high-level interface to the libswscale

  42. library image conversion utilities. In particular it allows one to perform

  43. image rescaling and pixel format conversion.

  44. </p>

  45. 

  46. <span id="scaler_005foptions"></span><a name="Scaler-Options"></a>

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

  48. 

  49. <p>The video scaler supports the following named options.

  50. </p>

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

  52. FFmpeg tools, with a few API-only exceptions noted below.

  53. For programmatic use, they can be set explicitly in the

  54. <code>SwsContext</code> options or through the <samp>libavutil/opt.h</samp> API.

  55. </p>

  56. <dl compact="compact">

  57. <dd>

  58. <span id="sws_005fflags"></span></dd>

  59. <dt><span><samp>sws_flags</samp></span></dt>

  60. <dd><p>Set the scaler flags. This is also used to set the scaling

  61. algorithm. Only a single algorithm should be selected. Default

  62. value is &lsquo;<samp>bicubic</samp>&rsquo;.

  63. </p>

  64. <p>It accepts the following values:

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

  66. <dt><span>&lsquo;<samp>fast_bilinear</samp>&rsquo;</span></dt>

  67. <dd><p>Select fast bilinear scaling algorithm.

  68. </p>

  69. </dd>

  70. <dt><span>&lsquo;<samp>bilinear</samp>&rsquo;</span></dt>

  71. <dd><p>Select bilinear scaling algorithm.

  72. </p>

  73. </dd>

  74. <dt><span>&lsquo;<samp>bicubic</samp>&rsquo;</span></dt>

  75. <dd><p>Select bicubic scaling algorithm.

  76. </p>

  77. </dd>

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

  79. <dd><p>Select experimental scaling algorithm.

  80. </p>

  81. </dd>

  82. <dt><span>&lsquo;<samp>neighbor</samp>&rsquo;</span></dt>

  83. <dd><p>Select nearest neighbor rescaling algorithm.

  84. </p>

  85. </dd>

  86. <dt><span>&lsquo;<samp>area</samp>&rsquo;</span></dt>

  87. <dd><p>Select averaging area rescaling algorithm.

  88. </p>

  89. </dd>

  90. <dt><span>&lsquo;<samp>bicublin</samp>&rsquo;</span></dt>

  91. <dd><p>Select bicubic scaling algorithm for the luma component, bilinear for

  92. chroma components.

  93. </p>

  94. </dd>

  95. <dt><span>&lsquo;<samp>gauss</samp>&rsquo;</span></dt>

  96. <dd><p>Select Gaussian rescaling algorithm.

  97. </p>

  98. </dd>

  99. <dt><span>&lsquo;<samp>sinc</samp>&rsquo;</span></dt>

  100. <dd><p>Select sinc rescaling algorithm.

  101. </p>

  102. </dd>

  103. <dt><span>&lsquo;<samp>lanczos</samp>&rsquo;</span></dt>

  104. <dd><p>Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be

  105. changed by setting <code>param0</code>.

  106. </p>

  107. </dd>

  108. <dt><span>&lsquo;<samp>spline</samp>&rsquo;</span></dt>

  109. <dd><p>Select natural bicubic spline rescaling algorithm.

  110. </p>

  111. </dd>

  112. <dt><span>&lsquo;<samp>print_info</samp>&rsquo;</span></dt>

  113. <dd><p>Enable printing/debug logging.

  114. </p>

  115. </dd>

  116. <dt><span>&lsquo;<samp>accurate_rnd</samp>&rsquo;</span></dt>

  117. <dd><p>Enable accurate rounding.

  118. </p>

  119. </dd>

  120. <dt><span>&lsquo;<samp>full_chroma_int</samp>&rsquo;</span></dt>

  121. <dd><p>Enable full chroma interpolation.

  122. </p>

  123. </dd>

  124. <dt><span>&lsquo;<samp>full_chroma_inp</samp>&rsquo;</span></dt>

  125. <dd><p>Select full chroma input.

  126. </p>

  127. </dd>

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

  129. <dd><p>Enable bitexact output.

  130. </p></dd>

  131. </dl>

  132. 

  133. </dd>

  134. <dt><span><samp>srcw <var>(API only)</var></samp></span></dt>

  135. <dd><p>Set source width.

  136. </p>

  137. </dd>

  138. <dt><span><samp>srch <var>(API only)</var></samp></span></dt>

  139. <dd><p>Set source height.

  140. </p>

  141. </dd>

  142. <dt><span><samp>dstw <var>(API only)</var></samp></span></dt>

  143. <dd><p>Set destination width.

  144. </p>

  145. </dd>

  146. <dt><span><samp>dsth <var>(API only)</var></samp></span></dt>

  147. <dd><p>Set destination height.

  148. </p>

  149. </dd>

  150. <dt><span><samp>src_format <var>(API only)</var></samp></span></dt>

  151. <dd><p>Set source pixel format (must be expressed as an integer).

  152. </p>

  153. </dd>

  154. <dt><span><samp>dst_format <var>(API only)</var></samp></span></dt>

  155. <dd><p>Set destination pixel format (must be expressed as an integer).

  156. </p>

  157. </dd>

  158. <dt><span><samp>src_range <var>(boolean)</var></samp></span></dt>

  159. <dd><p>If value is set to <code>1</code>, indicates source is full range. Default value is

  160. <code>0</code>, which indicates source is limited range.

  161. </p>

  162. </dd>

  163. <dt><span><samp>dst_range <var>(boolean)</var></samp></span></dt>

  164. <dd><p>If value is set to <code>1</code>, enable full range for destination. Default value

  165. is <code>0</code>, which enables limited range.

  166. </p>

  167. <span id="sws_005fparams"></span></dd>

  168. <dt><span><samp>param0, param1</samp></span></dt>

  169. <dd><p>Set scaling algorithm parameters. The specified values are specific of

  170. some scaling algorithms and ignored by others. The specified values

  171. are floating point number values.

  172. </p>

  173. </dd>

  174. <dt><span><samp>sws_dither</samp></span></dt>

  175. <dd><p>Set the dithering algorithm. Accepts one of the following

  176. values. Default value is &lsquo;<samp>auto</samp>&rsquo;.

  177. </p>

  178. <dl compact="compact">

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

  180. <dd><p>automatic choice

  181. </p>

  182. </dd>

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

  184. <dd><p>no dithering

  185. </p>

  186. </dd>

  187. <dt><span>&lsquo;<samp>bayer</samp>&rsquo;</span></dt>

  188. <dd><p>bayer dither

  189. </p>

  190. </dd>

  191. <dt><span>&lsquo;<samp>ed</samp>&rsquo;</span></dt>

  192. <dd><p>error diffusion dither

  193. </p>

  194. </dd>

  195. <dt><span>&lsquo;<samp>a_dither</samp>&rsquo;</span></dt>

  196. <dd><p>arithmetic dither, based using addition

  197. </p>

  198. </dd>

  199. <dt><span>&lsquo;<samp>x_dither</samp>&rsquo;</span></dt>

  200. <dd><p>arithmetic dither, based using xor (more random/less apparent patterning that

  201. a_dither).

  202. </p>

  203. </dd>

  204. </dl>

  205. 

  206. </dd>

  207. <dt><span><samp>alphablend</samp></span></dt>

  208. <dd><p>Set the alpha blending to use when the input has alpha but the output does not.

  209. Default value is &lsquo;<samp>none</samp>&rsquo;.

  210. </p>

  211. <dl compact="compact">

  212. <dt><span>&lsquo;<samp>uniform_color</samp>&rsquo;</span></dt>

  213. <dd><p>Blend onto a uniform background color

  214. </p>

  215. </dd>

  216. <dt><span>&lsquo;<samp>checkerboard</samp>&rsquo;</span></dt>

  217. <dd><p>Blend onto a checkerboard

  218. </p>

  219. </dd>

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

  221. <dd><p>No blending

  222. </p>

  223. </dd>

  224. </dl>

  225. 

  226. </dd>

  227. </dl>

  228. 

  229. 

  230. <a name="See-Also"></a>

  231. <h2 class="chapter">3 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>

  232. 

  233. <p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>,

  234. <a href="libswscale.html">libswscale</a>

  235. </p>

  236. 

  237. <a name="Authors"></a>

  238. <h2 class="chapter">4 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>

  239. 

  240. <p>The FFmpeg developers.

  241. </p>

  242. <p>For details about the authorship, see the Git history of the project

  243. (https://git.ffmpeg.org/ffmpeg), e.g. by typing the command

  244. <code>git log</code> in the FFmpeg source directory, or browsing the

  245. online repository at <a href="https://git.ffmpeg.org/ffmpeg">https://git.ffmpeg.org/ffmpeg</a>.

  246. </p>

  247. <p>Maintainers for the specific components are listed in the file

  248. <samp>MAINTAINERS</samp> in the source code tree.

  249. </p>

  250. 

  251.       <p style="font-size: small;">

  252.         This document was generated using <a href="https://www.gnu.org/software/texinfo/"><em>makeinfo</em></a>.

  253.       </p>

  254.     </div>

  255.   </body>

  256. </html>