53 lines
1.8 KiB
C++
53 lines
1.8 KiB
C++
#include "rtp-ext.h"
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// https://datatracker.ietf.org/doc/html/rfc6464
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/*
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The audio level header extension carries the level of the audio in
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the RTP [RFC3550] payload of the packet with which it is associated.
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This information is carried in an RTP header extension element as
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defined by "A General Mechanism for RTP Header Extensions" [RFC5285].
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The payload of the audio level header extension element can be
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encoded using either the one-byte or two-byte header defined in
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[RFC5285]. Figures 1 and 2 show sample audio level encodings with
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each of these header formats.
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0 1
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| ID | len=0 |V| level |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 1: Sample Audio Level Encoding Using the
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One-Byte Header Format
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| ID | len=1 |V| level | 0 (pad) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 2: Sample Audio Level Encoding Using the
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Two-Byte Header Format
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*/
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int rtp_ext_ssrc_audio_level_parse(const uint8_t* data, int bytes, uint8_t *activity, uint8_t *level)
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{
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if (bytes < 1)
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return -1;
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*activity = (data[0] & 0x80) ? 1 : 0;
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*level = data[0] & 0x7f;
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return 0;
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}
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int rtp_ext_ssrc_audio_level_write(uint8_t* data, int bytes, uint8_t activity, uint8_t level)
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{
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if (bytes < 1)
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return -1;
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data[0] = (activity ? 0x80 : 0) | level;
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return 1;
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}
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