ZLMediaKit/ext-codec/H265Rtp.cpp
2023-12-10 11:09:04 +08:00

367 lines
12 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*
* 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 "H265Rtp.h"
#include "Common/config.h"
namespace mediakit{
//https://datatracker.ietf.org/doc/rfc7798/
//H265 nalu 头两个字节的定义
/*
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|F| Type | LayerId | TID |
+-------------+-----------------+
Forbidden zero(F) : 1 bit
NAL unit type(Type) : 6 bits
NUH layer ID(LayerId) : 6 bits
NUH temporal ID plus 1 (TID) : 3 bits
*/
H265RtpDecoder::H265RtpDecoder() {
_frame = obtainFrame();
}
H265Frame::Ptr H265RtpDecoder::obtainFrame() {
auto frame = FrameImp::create<H265Frame>();
frame->_prefix_size = 4;
return frame;
}
#define AV_RB16(x) \
((((const uint8_t*)(x))[0] << 8) | \
((const uint8_t*)(x))[1])
#define CHECK_SIZE(total, size, ret) \
if (total < size) { \
WarnL << "invalid rtp data size:" << total << " < " << size << ",rtp:\r\n" << rtp->dumpString(); _gop_dropped = true; return ret; \
}
// 4.4.2. Aggregation Packets (APs) (p25)
/*
0 1 2 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RTP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PayloadHdr (Type=48) | NALU 1 DONL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NALU 1 Size | NALU 1 HDR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| NALU 1 Data . . . |
| |
+ . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | NALU 2 DOND | NALU 2 Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NALU 2 HDR | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ NALU 2 Data |
| |
| . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : ...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
bool H265RtpDecoder::unpackAp(const RtpPacket::Ptr &rtp, const uint8_t *ptr, ssize_t size, uint64_t stamp){
bool have_key_frame = false;
//忽略PayloadHdr
CHECK_SIZE(size, 2, have_key_frame);
ptr += 2;
size -= 2;
while (size) {
if (_using_donl_field) {
CHECK_SIZE(size, 2, have_key_frame);
uint16_t donl = AV_RB16(ptr);
size -= 2;
ptr += 2;
}
CHECK_SIZE(size, 2, have_key_frame);
uint16_t nalu_size = AV_RB16(ptr);
size -= 2;
ptr += 2;
CHECK_SIZE(size, nalu_size, have_key_frame)
if (singleFrame(rtp, ptr, nalu_size, stamp)) {
have_key_frame = true;
}
size -= nalu_size;
ptr += nalu_size;
}
return have_key_frame;
}
// 4.4.3. Fragmentation Units (p29)
/*
0 1 2 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PayloadHdr (Type=49) | FU header | DONL (cond) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
| DONL (cond) | |
|-+-+-+-+-+-+-+-+ |
| FU payload |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : ...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+---------------+
|0|1|2|3|4|5|6|7|
+-+-+-+-+-+-+-+-+
|S|E| FuType |
+---------------+
*/
bool H265RtpDecoder::mergeFu(const RtpPacket::Ptr &rtp, const uint8_t *ptr, ssize_t size, uint64_t stamp, uint16_t seq){
CHECK_SIZE(size, 4, false);
auto s_bit = ptr[2] >> 7;
auto e_bit = (ptr[2] >> 6) & 0x01;
auto type = ptr[2] & 0x3f;
if (s_bit) {
//该帧的第一个rtp包
_frame->_buffer.assign("\x00\x00\x00\x01", 4);
_frame->_buffer.push_back((type << 1) | (ptr[0] & 0x81));
_frame->_buffer.push_back(ptr[1]);
_frame->_pts = stamp;
_fu_dropped = false;
}
if (_fu_dropped) {
//该帧不完整
return false;
}
if (!s_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
_fu_dropped = true;
_frame->_buffer.clear();
return false;
}
//跳过PayloadHdr + FU header
ptr += 3;
size -= 3;
if (_using_donl_field) {
//DONL确保不少于2个字节
CHECK_SIZE(size, 2, false);
uint16_t donl = AV_RB16(ptr);
size -= 2;
ptr += 2;
}
CHECK_SIZE(size, 1, false);
//后面追加数据
_frame->_buffer.append((char *) ptr, size);
if (!e_bit) {
//非末尾包
return s_bit ? (_frame->keyFrame() || _frame->configFrame()) : false;
}
//确保下一次fu必须收到第一个包
_fu_dropped = true;
//该帧最后一个rtp包
outputFrame(rtp, _frame);
return false;
}
bool H265RtpDecoder::inputRtp(const RtpPacket::Ptr &rtp, bool) {
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 h265 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
return _is_gop && !last_is_gop;
}
bool H265RtpDecoder::decodeRtp(const RtpPacket::Ptr &rtp) {
auto payload_size = rtp->getPayloadSize();
if (payload_size <= 0) {
//无实际负载
return false;
}
auto frame = rtp->getPayload();
auto stamp = rtp->getStampMS();
auto seq = rtp->getSeq();
int nal = H265_TYPE(frame[0]);
switch (nal) {
case 48:
// aggregated packet (AP) - with two or more NAL units
return unpackAp(rtp, frame, payload_size, stamp);
case 49:
// fragmentation unit (FU)
return mergeFu(rtp, frame, payload_size, stamp, seq);
default: {
if (nal < 48) {
// Single NAL Unit Packets (p24)
return singleFrame(rtp, frame, payload_size, stamp);
}
_gop_dropped = true;
WarnL << "不支持该类型的265 RTP包, nal type" << nal << ", rtp:\r\n" << rtp->dumpString();
return false;
}
}
}
bool H265RtpDecoder::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;
}
void H265RtpDecoder::outputFrame(const RtpPacket::Ptr &rtp, const H265Frame::Ptr &frame) {
if (frame->dropAble()) {
//不参与dts生成
frame->_dts = frame->_pts;
} else {
//rtsp没有dts那么根据pts排序算法生成dts
_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) {
RtpCodec::inputFrame(frame);
}
_frame = obtainFrame();
}
////////////////////////////////////////////////////////////////////////
void H265RtpEncoder::packRtpFu(const char *ptr, size_t len, uint64_t pts, bool is_mark, bool gop_pos){
auto max_size = getRtpInfo().getMaxSize() - 3;
auto nal_type = H265_TYPE(ptr[0]); //获取NALU的5bit 帧类型
unsigned char s_e_flags;
bool fu_start = true;
bool mark_bit = false;
size_t offset = 2;
while (!mark_bit) {
if (len <= offset + max_size) {
// FU end
mark_bit = true;
max_size = len - offset;
s_e_flags = (1 << 6) | nal_type;
} else if (fu_start) {
// FU start
s_e_flags = (1 << 7) | nal_type;
} else {
// FU mid
s_e_flags = nal_type;
}
{
// 传入nullptr先不做payload的内存拷贝
auto rtp = getRtpInfo().makeRtp(TrackVideo, nullptr, max_size + 3, mark_bit, pts);
// rtp payload 负载部分
uint8_t *payload = rtp->getPayload();
// FU 第1个字节表明为FU
payload[0] = 49 << 1;
// FU 第2个字节貌似固定为1
payload[1] = ptr[1]; // 1;
// FU 第3个字节
payload[2] = s_e_flags;
// H265 数据
memcpy(payload + 3, ptr + offset, max_size);
// 输入到rtp环形缓存
RtpCodec::inputRtp(rtp, fu_start && gop_pos);
}
offset += max_size;
fu_start = false;
}
}
void H265RtpEncoder::packRtp(const char *ptr, size_t len, uint64_t pts, bool is_mark, bool gop_pos){
if (len <= getRtpInfo().getMaxSize()) {
//signal-nalu
RtpCodec::inputRtp(getRtpInfo().makeRtp(TrackVideo, ptr, len, is_mark, pts), gop_pos);
} else {
//FU-A模式
packRtpFu(ptr, len, pts, is_mark, gop_pos);
}
}
void H265RtpEncoder::insertConfigFrame(uint64_t pts){
if (!_sps || !_pps || !_vps) {
WarnL<<" not ok";
return;
}
//gop缓存从vps 开始vps ,sps、pps后面还有时间戳相同的关键帧所以mark bit为false
packRtp(_vps->data() + _vps->prefixSize(), _vps->size() - _vps->prefixSize(), pts, false, true);
packRtp(_sps->data() + _sps->prefixSize(), _sps->size() - _sps->prefixSize(), pts, false, false);
packRtp(_pps->data() + _pps->prefixSize(), _pps->size() - _pps->prefixSize(), pts, false, false);
}
bool H265RtpEncoder::inputFrame_l(const Frame::Ptr &frame, bool is_mark){
if (frame->keyFrame()) {
//保证每一个关键帧前都有SPS PPS VPS
insertConfigFrame(frame->pts());
}
packRtp(frame->data() + frame->prefixSize(), frame->size() - frame->prefixSize(), frame->pts(), is_mark, false);
return true;
}
bool H265RtpEncoder::inputFrame(const Frame::Ptr &frame) {
auto ptr = (uint8_t *) frame->data() + frame->prefixSize();
auto nal_type = H265_TYPE(ptr[0]); //获取NALU的5bit 帧类型
switch (nal_type) {
case H265Frame::NAL_SPS: {
_sps = Frame::getCacheAbleFrame(frame);
return true;
}
case H265Frame::NAL_PPS: {
_pps = Frame::getCacheAbleFrame(frame);
return true;
}
case H265Frame::NAL_VPS:{
_vps = 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
inputFrame_l(_last_frame, _last_frame->pts() != frame->pts());
}
_last_frame = Frame::getCacheAbleFrame(frame);
}
return true;
}
void H265RtpEncoder::flush() {
if (_last_frame) {
// 如果时间戳发生了变化那么markbit才置true
inputFrame_l(_last_frame, true);
_last_frame = nullptr;
}
}
}//namespace mediakit