调整264 rtp打包逻辑

This commit is contained in:
xia-chu 2021-04-15 19:39:24 +08:00
parent 9d385b36fd
commit d76c38ef72
2 changed files with 96 additions and 87 deletions

View File

@ -184,107 +184,110 @@ H264RtpEncoder::H264RtpEncoder(uint32_t ssrc, uint32_t mtu, uint32_t sample_rate
: RtpInfo(ssrc, mtu, sample_rate, pt, interleaved) {
}
void H264RtpEncoder::inputFrame(const Frame::Ptr &frame) {
auto ptr = frame->data() + frame->prefixSize();
auto len = frame->size() - frame->prefixSize();
auto pts = frame->pts();
auto nal_type = H264_TYPE(ptr[0]);
if(nal_type == H264Frame::NAL_SEI || nal_type == H264Frame::NAL_AUD){
void H264RtpEncoder::insertConfigFrame(uint32_t pts){
if (_sps.empty() || _pps.empty()) {
return;
}
//gop缓存从sps开始sps、pps后面还有时间戳相同的关键帧所以mark bit为false
packRtp(_sps.data(), _sps.size(), pts, false, true);
packRtp(_pps.data(), _pps.size(), pts, false, false);
}
if(nal_type == H264Frame::NAL_SPS){
_sps = std::string(ptr,len);
return;
void H264RtpEncoder::packRtp(const char *ptr, size_t len, uint32_t pts, bool is_mark, bool gop_pos){
if (len + 3 <= getMaxSize()) {
//STAP-A模式打包小于MTU
packRtpStapA(ptr, len, pts, is_mark, gop_pos);
} else {
//STAP-A模式打包会大于MTU,所以采用FU-A模式
packRtpFu(ptr, len, pts, is_mark, gop_pos);
}
}
if(nal_type == H264Frame::NAL_PPS){
_pps = std::string(ptr,len);
return;
}
if(!_last_frame){
_last_frame = frame;
return;
}
// 上一帧打包保证rtp 的mark是正确的
bool isMark = _last_frame->pts() != frame->pts();
ptr = _last_frame->data() + _last_frame->prefixSize();
len = _last_frame->size() - _last_frame->prefixSize();
pts = _last_frame->pts();
nal_type = H264_TYPE(ptr[0]);
if(nal_type == H264Frame::NAL_IDR && (ptr[1]&0x80))
{// 保证每一个I帧前都有SPS与PPS ,为了兼容webrtc 需要在一个rtp包中并且只能是 STAP-A
// https://blog.csdn.net/momo0853/article/details/88872873
// 多slice 一帧的情况下检查 first_mb_in_slice 是否为0 表示其为一帧的开始SPS PPS 只有在帧开始时,才插入
auto rtp = makeRtp(getTrackType(), nullptr,_sps.size()+_pps.size()+2*2+1,false,pts);
uint8_t *payload = rtp->getPayload();
payload[0] = 24;
payload[1] = _sps.size() >> 8;
payload[2] = _sps.size() & 0xff;
memcpy(payload+3,(uint8_t *) _sps.data(),_sps.size());
payload[_sps.size()+3] = _pps.size() >> 8;
payload[_sps.size()+4] = _pps.size() & 0xff;
memcpy(payload+3+_sps.size()+2,(uint8_t *) _pps.data(),_pps.size());
RtpCodec::inputRtp(rtp,true);
}
void H264RtpEncoder::packRtpFu(const char *ptr, size_t len, uint32_t pts, bool is_mark, bool gop_pos){
auto packet_size = getMaxSize() - 2;
//InfoL<<"nal type = "<<nal_type<<" pts="<<pts<<" len="<<len;
if (len <= packet_size) {
//小于FU-A打包最小字节长度要求采用STAP-A模式如果frame长度正好是mtu-2, 那么打包的rtp长度是mtu + 1
packRtpStapA(ptr, len, pts, is_mark, gop_pos);
return;
}
//末尾5bit为nalu type固定为28(FU-A)
auto fu_char_0 = (ptr[0] & (~0x1F)) | 28;
auto fu_char_1 = nal_type;
auto fu_char_1 = H264_TYPE(ptr[0]);
FuFlags *fu_flags = (FuFlags *) (&fu_char_1);
fu_flags->start_bit = 1;
//超过MTU则按照FU-A模式打包
if (len > packet_size + 1) {
size_t offset = 1;
while (!fu_flags->end_bit) {
if (!fu_flags->start_bit && len <= offset + packet_size) {
//FU-A end
packet_size = len - offset;
fu_flags->end_bit = 1;
}
//传入nullptr先不做payload的内存拷贝
auto rtp = makeRtp(getTrackType(), nullptr, packet_size + 2, fu_flags->end_bit && isMark, pts);
//rtp payload 负载部分
uint8_t *payload = rtp->getPayload();
//FU-A 第1个字节
payload[0] = fu_char_0;
//FU-A 第2个字节
payload[1] = fu_char_1;
//H264 数据
memcpy(payload + 2, (uint8_t *) ptr + offset, packet_size);
//输入到rtp环形缓存
RtpCodec::inputRtp(rtp, false);
offset += packet_size;
fu_flags->start_bit = 0;
size_t offset = 1;
while (!fu_flags->end_bit) {
if (!fu_flags->start_bit && len <= offset + packet_size) {
//FU-A end
packet_size = len - offset;
fu_flags->end_bit = 1;
}
} else {
//如果帧长度不超过mtu, 则按照Single NAL unit packet per H.264 方式打包
//为了兼容性 webrtc使用 STAP-A 打包
auto rtp = makeRtp(getTrackType(), nullptr,len+3,isMark,pts);
uint8_t *payload = rtp->getPayload();
payload[0] = (ptr[0] & (~0x1F)) | 24;
payload[1] = len >> 8;
payload[2] = len & 0xff;
memcpy(payload+3,(uint8_t *) ptr,len);
RtpCodec::inputRtp(rtp,false);
//makeH264Rtp(ptr, len, false, false, pts);
}
_last_frame = frame;
//传入nullptr先不做payload的内存拷贝
auto rtp = makeRtp(getTrackType(), nullptr, packet_size + 2, fu_flags->end_bit && is_mark, pts);
//rtp payload 负载部分
uint8_t *payload = rtp->getPayload();
//FU-A 第1个字节
payload[0] = fu_char_0;
//FU-A 第2个字节
payload[1] = fu_char_1;
//H264 数据
memcpy(payload + 2, (uint8_t *) ptr + offset, packet_size);
//输入到rtp环形缓存
RtpCodec::inputRtp(rtp, gop_pos);
offset += packet_size;
fu_flags->start_bit = 0;
}
}
void H264RtpEncoder::makeH264Rtp(const void* data, size_t len, bool mark, bool gop_pos, uint32_t uiStamp) {
RtpCodec::inputRtp(makeRtp(getTrackType(), data, len, mark, uiStamp), gop_pos);
void H264RtpEncoder::packRtpStapA(const char *ptr, size_t len, uint32_t pts, bool is_mark, bool gop_pos){
//如果帧长度不超过mtu,为了兼容性 webrtc采用STAP-A模式打包
auto rtp = makeRtp(getTrackType(), nullptr, len + 3, is_mark, pts);
uint8_t *payload = rtp->getPayload();
//STAP-A
payload[0] = (ptr[0] & (~0x1F)) | 24;
payload[1] = (len >> 8) & 0xFF;
payload[2] = len & 0xff;
memcpy(payload + 3, (uint8_t *) ptr, len);
RtpCodec::inputRtp(rtp, gop_pos);
}
void H264RtpEncoder::inputFrame(const Frame::Ptr &frame) {
auto ptr = frame->data() + frame->prefixSize();
auto len = frame->size() - frame->prefixSize();
switch (H264_TYPE(ptr[0])) {
case H264Frame::NAL_AUD:
case H264Frame::NAL_SEI : {
return;
}
case H264Frame::NAL_SPS: {
_sps = std::string(ptr, len);
return;
}
case H264Frame::NAL_PPS: {
_pps = std::string(ptr, len);
return;
}
default: break;
}
if (_last_frame) {
//如果时间戳发生了变化那么markbit才置true
inputFrame_l(_last_frame, _last_frame->pts() != frame->pts());
}
_last_frame = Frame::getCacheAbleFrame(frame);
}
void H264RtpEncoder::inputFrame_l(const Frame::Ptr &frame, bool is_mark){
if (frame->keyFrame()) {
//保证每一个关键帧前都有SPS与PPS
insertConfigFrame(frame->pts());
}
packRtp(frame->data() + frame->prefixSize(), frame->size() - frame->prefixSize(), frame->pts(), is_mark, false);
}
}//namespace mediakit

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@ -82,7 +82,13 @@ public:
void inputFrame(const Frame::Ptr &frame) override;
private:
void makeH264Rtp(const void *pData, size_t uiLen, bool bMark, bool gop_pos, uint32_t uiStamp);
void insertConfigFrame(uint32_t pts);
void inputFrame_l(const Frame::Ptr &frame, bool is_mark);
void packRtp(const char *data, size_t len, uint32_t pts, bool is_mark, bool gop_pos);
void packRtpFu(const char *data, size_t len, uint32_t pts, bool is_mark, bool gop_pos);
void packRtpStapA(const char *data, size_t len, uint32_t pts, bool is_mark, bool gop_pos);
private:
string _sps;
string _pps;
Frame::Ptr _last_frame;