375 lines
14 KiB
C++
375 lines
14 KiB
C++
/*
|
||
* Copyright (c) 2016-present The ZLMediaKit project authors. All Rights Reserved.
|
||
*
|
||
* This file is part of ZLMediaKit(https://github.com/ZLMediaKit/ZLMediaKit).
|
||
*
|
||
* Use of this source code is governed by MIT-like license that can be found in the
|
||
* LICENSE file in the root of the source tree. All contributing project authors
|
||
* may be found in the AUTHORS file in the root of the source tree.
|
||
*/
|
||
|
||
#include "H264Rtp.h"
|
||
#include "Common/config.h"
|
||
|
||
namespace mediakit{
|
||
|
||
#pragma pack(push, 1)
|
||
|
||
class FuFlags {
|
||
public:
|
||
#if __BYTE_ORDER == __BIG_ENDIAN
|
||
unsigned start_bit: 1;
|
||
unsigned end_bit: 1;
|
||
unsigned reserved: 1;
|
||
unsigned nal_type: 5;
|
||
#else
|
||
unsigned nal_type: 5;
|
||
unsigned reserved: 1;
|
||
unsigned end_bit: 1;
|
||
unsigned start_bit: 1;
|
||
#endif
|
||
};
|
||
|
||
#pragma pack(pop)
|
||
|
||
H264RtpDecoder::H264RtpDecoder() {
|
||
_frame = obtainFrame();
|
||
}
|
||
|
||
H264Frame::Ptr H264RtpDecoder::obtainFrame() {
|
||
auto frame = FrameImp::create<H264Frame>();
|
||
frame->_prefix_size = 4;
|
||
return frame;
|
||
}
|
||
|
||
bool H264RtpDecoder::inputRtp(const RtpPacket::Ptr &rtp, bool key_pos) {
|
||
auto seq = rtp->getSeq();
|
||
auto last_is_gop = _is_gop;
|
||
_is_gop = decodeRtp(rtp);
|
||
if (!_gop_dropped && seq != (uint16_t)(_last_seq + 1) && _last_seq) {
|
||
_gop_dropped = true;
|
||
WarnL << "start drop h264 gop, last seq:" << _last_seq << ", rtp:\r\n" << rtp->dumpString();
|
||
}
|
||
_last_seq = seq;
|
||
// 确保有sps rtp的时候，gop从sps开始；否则从关键帧开始 [AUTO-TRANSLATED:115ae07c]
|
||
// cpp
|
||
// Ensure that when there is sps rtp, the gop starts from sps; otherwise, it starts from the key frame
|
||
return _is_gop && !last_is_gop;
|
||
}
|
||
|
||
/*
|
||
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 -
|
||
/*
|
||
RTF3984 Section 5.2 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 -
|
||
|
||
* [AUTO-TRANSLATED:57545317]
|
||
*/
|
||
|
||
bool H264RtpDecoder::singleFrame(const RtpPacket::Ptr &rtp, const uint8_t *ptr, ssize_t size, uint64_t stamp){
|
||
_frame->_buffer.assign("\x00\x00\x00\x01", 4);
|
||
_frame->_buffer.append((char *) ptr, size);
|
||
_frame->_pts = stamp;
|
||
auto key = _frame->keyFrame() || _frame->configFrame();
|
||
outputFrame(rtp, _frame);
|
||
return key;
|
||
}
|
||
|
||
bool H264RtpDecoder::unpackStapA(const RtpPacket::Ptr &rtp, const uint8_t *ptr, ssize_t size, uint64_t stamp) {
|
||
// STAP-A 单一时间的组合包 [AUTO-TRANSLATED:cfa62307]
|
||
// STAP-A single-time aggregation packet
|
||
auto have_key_frame = false;
|
||
auto end = ptr + size;
|
||
while (ptr + 2 < end) {
|
||
uint16_t len = (ptr[0] << 8) | ptr[1];
|
||
if (!len || ptr + len > end) {
|
||
WarnL << "invalid rtp data size:" << len << ",rtp:\r\n" << rtp->dumpString();
|
||
_gop_dropped = true;
|
||
break;
|
||
}
|
||
ptr += 2;
|
||
if (singleFrame(rtp, ptr, len, stamp)) {
|
||
have_key_frame = true;
|
||
}
|
||
ptr += len;
|
||
}
|
||
return have_key_frame;
|
||
}
|
||
|
||
bool H264RtpDecoder::mergeFu(const RtpPacket::Ptr &rtp, const uint8_t *ptr, ssize_t size, uint64_t stamp, uint16_t seq){
|
||
auto nal_suffix = *ptr & (~0x1F);
|
||
FuFlags *fu = (FuFlags *) (ptr + 1);
|
||
if (fu->start_bit) {
|
||
// 该帧的第一个rtp包 [AUTO-TRANSLATED:a9581a23]
|
||
// The first rtp packet of this frame
|
||
_frame->_buffer.assign("\x00\x00\x00\x01", 4);
|
||
_frame->_buffer.push_back(nal_suffix | fu->nal_type);
|
||
_frame->_pts = stamp;
|
||
_fu_dropped = false;
|
||
}
|
||
|
||
if (_fu_dropped) {
|
||
// 该帧不完整 [AUTO-TRANSLATED:6bd7eca7]
|
||
// This frame is incomplete
|
||
return false;
|
||
}
|
||
|
||
if (!fu->start_bit && seq != (uint16_t) (_last_seq + 1)) {
|
||
// 中间的或末尾的rtp包，其seq必须连续，否则说明rtp丢包，那么该帧不完整，必须得丢弃 [AUTO-TRANSLATED:6953b332]
|
||
// The middle or end rtp packet, its seq must be continuous, otherwise it indicates that the rtp packet is lost, then the frame is incomplete and must be discarded
|
||
_fu_dropped = true;
|
||
_frame->_buffer.clear();
|
||
return false;
|
||
}
|
||
|
||
// 后面追加数据 [AUTO-TRANSLATED:248516e9]
|
||
// Append data
|
||
_frame->_buffer.append((char *) ptr + 2, size - 2);
|
||
|
||
if (!fu->end_bit) {
|
||
// 非末尾包 [AUTO-TRANSLATED:2e43ac3c]
|
||
// Not the end packet
|
||
return fu->start_bit ? (_frame->keyFrame() || _frame->configFrame()) : false;
|
||
}
|
||
|
||
// 确保下一次fu必须收到第一个包 [AUTO-TRANSLATED:491d81ec]
|
||
// Ensure that the next fu must receive the first packet
|
||
_fu_dropped = true;
|
||
// 该帧最后一个rtp包,输出frame [AUTO-TRANSLATED:a648aaa5]
|
||
// The last rtp packet of this frame, output frame
|
||
outputFrame(rtp, _frame);
|
||
return false;
|
||
}
|
||
|
||
bool H264RtpDecoder::decodeRtp(const RtpPacket::Ptr &rtp) {
|
||
auto payload_size = rtp->getPayloadSize();
|
||
if (payload_size <= 0) {
|
||
// 无实际负载 [AUTO-TRANSLATED:305af48f]
|
||
// No actual payload
|
||
return false;
|
||
}
|
||
auto frame = rtp->getPayload();
|
||
auto stamp = rtp->getStampMS();
|
||
auto seq = rtp->getSeq();
|
||
int nal = H264_TYPE(frame[0]);
|
||
|
||
switch (nal) {
|
||
case 24:
|
||
// 24 STAP-A Single-time aggregation packet 5.7.1
|
||
return unpackStapA(rtp, frame + 1, payload_size - 1, stamp);
|
||
|
||
case 28:
|
||
// 28 FU-A Fragmentation unit
|
||
return mergeFu(rtp, frame, payload_size, stamp, seq);
|
||
|
||
default: {
|
||
if (nal < 24) {
|
||
//Single NAL Unit Packets
|
||
return singleFrame(rtp, frame, payload_size, stamp);
|
||
}
|
||
_gop_dropped = true;
|
||
WarnL << "不支持该类型的264 RTP包, nal type:" << nal << ", rtp:\r\n" << rtp->dumpString();
|
||
return false;
|
||
}
|
||
}
|
||
}
|
||
|
||
void H264RtpDecoder::outputFrame(const RtpPacket::Ptr &rtp, const H264Frame::Ptr &frame) {
|
||
if (frame->dropAble()) {
|
||
// 不参与dts生成 [AUTO-TRANSLATED:dff3b747]
|
||
// Not involved in dts generation
|
||
frame->_dts = frame->_pts;
|
||
} else {
|
||
// rtsp没有dts，那么根据pts排序算法生成dts [AUTO-TRANSLATED:f37c17f3]
|
||
// Rtsp does not have dts, so dts is generated according to the pts sorting algorithm
|
||
_dts_generator.getDts(frame->_pts, frame->_dts);
|
||
}
|
||
|
||
if (frame->keyFrame() && _gop_dropped) {
|
||
_gop_dropped = false;
|
||
InfoL << "new gop received, rtp:\r\n" << rtp->dumpString();
|
||
}
|
||
if (!_gop_dropped || frame->configFrame()) {
|
||
RtpCodec::inputFrame(frame);
|
||
}
|
||
_frame = obtainFrame();
|
||
}
|
||
|
||
////////////////////////////////////////////////////////////////////////
|
||
|
||
void H264RtpEncoder::insertConfigFrame(uint64_t pts){
|
||
if (!_sps || !_pps) {
|
||
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 [AUTO-TRANSLATED:e8dcff77]
|
||
// The gop cache starts from sps, sps, pps and then there are key frames with the same timestamp, so the mark bit is false
|
||
packRtp(_sps->data() + _sps->prefixSize(), _sps->size() - _sps->prefixSize(), pts, false, true);
|
||
packRtp(_pps->data() + _pps->prefixSize(), _pps->size() - _pps->prefixSize(), pts, false, false);
|
||
}
|
||
|
||
void H264RtpEncoder::packRtp(const char *ptr, size_t len, uint64_t pts, bool is_mark, bool gop_pos){
|
||
if (len + 3 <= getRtpInfo().getMaxSize()) {
|
||
// 采用STAP-A/Single NAL unit packet per H.264 模式 [AUTO-TRANSLATED:1a719984]
|
||
// Use STAP-A/Single NAL unit packet per H.264 mode
|
||
packRtpSmallFrame(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 [AUTO-TRANSLATED:f3923abc]
|
||
// STAP-A mode packaging will be larger than MTU, so FU-A mode is used
|
||
packRtpFu(ptr, len, pts, is_mark, gop_pos);
|
||
}
|
||
}
|
||
|
||
void H264RtpEncoder::packRtpFu(const char *ptr, size_t len, uint64_t pts, bool is_mark, bool gop_pos){
|
||
auto packet_size = getRtpInfo().getMaxSize() - 2;
|
||
if (len <= packet_size + 1) {
|
||
// 小于FU-A打包最小字节长度要求，采用STAP-A/Single NAL unit packet per H.264 模式 [AUTO-TRANSLATED:b83bb4d1]
|
||
// Less than the minimum byte length requirement for FU-A packaging, use STAP-A/Single NAL unit packet per H.264 mode
|
||
packRtpSmallFrame(ptr, len, pts, is_mark, gop_pos);
|
||
return;
|
||
}
|
||
|
||
// 末尾5bit为nalu type，固定为28(FU-A) [AUTO-TRANSLATED:6293f1a9]
|
||
// The last 5 bits are the nalu type, fixed to 28 (FU-A)
|
||
auto fu_char_0 = (ptr[0] & (~0x1F)) | 28;
|
||
auto fu_char_1 = H264_TYPE(ptr[0]);
|
||
FuFlags *fu_flags = (FuFlags *) (&fu_char_1);
|
||
fu_flags->start_bit = 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-TRANSLATED:1858cf77]
|
||
// Pass in nullptr first, do not copy the payload memory
|
||
auto rtp = getRtpInfo().makeRtp(TrackVideo, nullptr, packet_size + 2, fu_flags->end_bit && is_mark, pts);
|
||
// rtp payload 负载部分 [AUTO-TRANSLATED:aecf73cc]
|
||
// rtp payload load part
|
||
uint8_t *payload = rtp->getPayload();
|
||
// FU-A 第1个字节 [AUTO-TRANSLATED:b5558495]
|
||
// FU-A first byte
|
||
payload[0] = fu_char_0;
|
||
// FU-A 第2个字节 [AUTO-TRANSLATED:6b4540bb]
|
||
// FU-A second byte
|
||
payload[1] = fu_char_1;
|
||
// H264 数据 [AUTO-TRANSLATED:79204239]
|
||
// H264 data
|
||
memcpy(payload + 2, (uint8_t *) ptr + offset, packet_size);
|
||
// 输入到rtp环形缓存 [AUTO-TRANSLATED:5208ef90]
|
||
// Input to the rtp ring buffer
|
||
RtpCodec::inputRtp(rtp, gop_pos);
|
||
|
||
offset += packet_size;
|
||
fu_flags->start_bit = 0;
|
||
}
|
||
}
|
||
|
||
void H264RtpEncoder::packRtpSmallFrame(const char *data, size_t len, uint64_t pts, bool is_mark, bool gop_pos) {
|
||
GET_CONFIG(bool, h264_stap_a, Rtp::kH264StapA);
|
||
if (h264_stap_a) {
|
||
packRtpStapA(data, len, pts, is_mark, gop_pos);
|
||
} else {
|
||
packRtpSingleNalu(data, len, pts, is_mark, gop_pos);
|
||
}
|
||
}
|
||
|
||
void H264RtpEncoder::packRtpStapA(const char *ptr, size_t len, uint64_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-TRANSLATED:a091199c]
|
||
// If the frame length does not exceed mtu, for compatibility with webrtc, use STAP-A mode packaging
|
||
auto rtp = getRtpInfo().makeRtp(TrackVideo, 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::packRtpSingleNalu(const char *data, size_t len, uint64_t pts, bool is_mark, bool gop_pos) {
|
||
// Single NAL unit packet per H.264 模式 [AUTO-TRANSLATED:9332a8e4]
|
||
// Single NAL unit packet per H.264 mode
|
||
RtpCodec::inputRtp(getRtpInfo().makeRtp(TrackVideo, data, len, is_mark, pts), gop_pos);
|
||
}
|
||
|
||
bool H264RtpEncoder::inputFrame(const Frame::Ptr &frame) {
|
||
auto ptr = frame->data() + frame->prefixSize();
|
||
switch (H264_TYPE(ptr[0])) {
|
||
case H264Frame::NAL_SPS: {
|
||
_sps = Frame::getCacheAbleFrame(frame);
|
||
return true;
|
||
}
|
||
case H264Frame::NAL_PPS: {
|
||
_pps = Frame::getCacheAbleFrame(frame);
|
||
return true;
|
||
}
|
||
default: break;
|
||
}
|
||
|
||
GET_CONFIG(int,lowLatency,Rtp::kLowLatency);
|
||
if (lowLatency) { // 低延迟模式
|
||
if (_last_frame) {
|
||
flush();
|
||
}
|
||
inputFrame_l(frame, true);
|
||
} else {
|
||
if (_last_frame) {
|
||
// 如果时间戳发生了变化，那么markbit才置true [AUTO-TRANSLATED:19b68429]
|
||
// If the timestamp changes, then the markbit is set to true
|
||
inputFrame_l(_last_frame, _last_frame->pts() != frame->pts());
|
||
}
|
||
_last_frame = Frame::getCacheAbleFrame(frame);
|
||
}
|
||
return true;
|
||
}
|
||
|
||
void H264RtpEncoder::flush() {
|
||
if (_last_frame) {
|
||
// 如果时间戳发生了变化，那么markbit才置true [AUTO-TRANSLATED:6b1d0fe0]
|
||
// If the timestamp changes, then the markbit is set to true
|
||
inputFrame_l(_last_frame, true);
|
||
_last_frame = nullptr;
|
||
}
|
||
}
|
||
|
||
bool 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 [AUTO-TRANSLATED:9d1a9d5e]
|
||
// Ensure that there are SPS and PPS before each key frame
|
||
insertConfigFrame(frame->pts());
|
||
}
|
||
packRtp(frame->data() + frame->prefixSize(), frame->size() - frame->prefixSize(), frame->pts(), is_mark, false);
|
||
return true;
|
||
}
|
||
|
||
}//namespace mediakit
|