xref: /aosp_15_r20/external/webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.cc (revision d9f758449e529ab9291ac668be2861e7a55c2422)
1 /*
2  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "modules/rtp_rtcp/source/rtcp_packet/psfb.h"
12 
13 #include "modules/rtp_rtcp/source/byte_io.h"
14 
15 namespace webrtc {
16 namespace rtcp {
17 constexpr uint8_t Psfb::kPacketType;
18 constexpr uint8_t Psfb::kAfbMessageType;
19 constexpr size_t Psfb::kCommonFeedbackLength;
20 // RFC 4585: Feedback format.
21 //
22 // Common packet format:
23 //
24 //    0                   1                   2                   3
25 //    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
26 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
27 //   |V=2|P|   FMT   |       PT      |          length               |
28 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
29 // 0 |                  SSRC of packet sender                        |
30 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
31 // 4 |                  SSRC of media source                         |
32 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
33 //   :            Feedback Control Information (FCI)                 :
34 //   :                                                               :
35 
ParseCommonFeedback(const uint8_t * payload)36 void Psfb::ParseCommonFeedback(const uint8_t* payload) {
37   SetSenderSsrc(ByteReader<uint32_t>::ReadBigEndian(&payload[0]));
38   SetMediaSsrc(ByteReader<uint32_t>::ReadBigEndian(&payload[4]));
39 }
40 
CreateCommonFeedback(uint8_t * payload) const41 void Psfb::CreateCommonFeedback(uint8_t* payload) const {
42   ByteWriter<uint32_t>::WriteBigEndian(&payload[0], sender_ssrc());
43   ByteWriter<uint32_t>::WriteBigEndian(&payload[4], media_ssrc());
44 }
45 
46 }  // namespace rtcp
47 }  // namespace webrtc
48