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注释，说明
This commit is contained in:
3503207480@qq.com
2019-08-30 11:17:27 +08:00
parent e3139134e8
commit 036b36f012
12 changed files with 37 additions and 12 deletions
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23
src/Extension/H264Rtp.cpp
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@@ -90,7 +90,24 @@ bool H264RtpDecoder::decodeRtp(const RtpPacket::Ptr &rtppack) {
* Type==7:SPS frame
* Type==8:PPS frame
*/
/*
RTF3984 5.2节 Common Structure of the RTP Payload Format
Table 1. Summary of NAL unit types and their payload structures
Type Packet Type name Section
---------------------------------------------------------
0 undefined -
1-23 NAL unit Single NAL unit packet per H.264 5.6
24 STAP-A Single-time aggregation packet 5.7.1
25 STAP-B Single-time aggregation packet 5.7.1
26 MTAP16 Multi-time aggregation packet 5.7.2
27 MTAP24 Multi-time aggregation packet 5.7.2
28 FU-A Fragmentation unit 5.8
29 FU-B Fragmentation unit 5.8
30-31 undefined -
*/
const uint8_t *frame = (uint8_t *) rtppack->data() + rtppack->offset;
int length = rtppack->size() - rtppack->offset;
NALU nal;
@@ -145,7 +162,7 @@ bool H264RtpDecoder::decodeRtp(const RtpPacket::Ptr &rtppack) {
FU fu;
MakeFU(frame[1], fu);
if (fu.S) {
//该帧的第一个rtp包
//该帧的第一个rtp包 FU-A start
char tmp = (nal.forbidden_zero_bit << 7 | nal.nal_ref_idc << 5 | fu.type);
_h264frame->buffer.assign("\x0\x0\x0\x1", 4);
_h264frame->buffer.push_back(tmp);
@@ -164,14 +181,14 @@ bool H264RtpDecoder::decodeRtp(const RtpPacket::Ptr &rtppack) {
}
if (!fu.E) {
//该帧的中间rtp包
//该帧的中间rtp包 FU-A mid
_h264frame->buffer.append((char *)frame + 2, length - 2);
//该函数return时，保存下当前sequence,以便下次对比seq是否连续
_lastSeq = rtppack->sequence;
return false;
}
//该帧最后一个rtp包
//该帧最后一个rtp包 FU-A end
_h264frame->buffer.append((char *)frame + 2, length - 2);
_h264frame->timeStamp = rtppack->timeStamp;
auto key = _h264frame->keyFrame();