/*
* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
*
* This file is part of ZLMediaKit(https://github.com/xiongziliang/ZLMediaKit).
*
* Use of this source code is governed by MIT 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"
namespace mediakit{
//41
//42 0 1
//43 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
//44 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//45 |F| Type | LayerId | TID |
//46 +-------------+-----------------+
//48 F = 0
//49 Type = 49 (fragmentation unit (FU))
//50 LayerId = 0
//51 TID = 1
//56 /*
//57 create the FU header
//58
//59 0 1 2 3 4 5 6 7
//60 +-+-+-+-+-+-+-+-+
//61 |S|E| FuType |
//62 +---------------+
//63
//64 S = variable
//65 E = variable
//66 FuType = NAL unit type
//67
typedef struct {
unsigned S :1;
unsigned E :1;
unsigned type :6;
} FU;
static void MakeFU(uint8_t in, FU &fu) {
fu.S = in >> 7;
fu.E = (in >> 6) & 0x01;
fu.type = in & 0x3f;
}
H265RtpDecoder::H265RtpDecoder() {
_h265frame = obtainFrame();
}
H265Frame::Ptr H265RtpDecoder::obtainFrame() {
//从缓存池重新申请对象，防止覆盖已经写入环形缓存的对象
auto frame = ResourcePoolHelper<H265Frame>::obtainObj();
frame->_buffer.clear();
frame->_prefix_size = 4;
return frame;
}
bool H265RtpDecoder::inputRtp(const RtpPacket::Ptr &rtp, bool key_pos) {
return decodeRtp(rtp);
}
bool H265RtpDecoder::decodeRtp(const RtpPacket::Ptr &rtppack) {
const uint8_t *frame = (uint8_t *) rtppack->data() + rtppack->offset;
int length = rtppack->size() - rtppack->offset;
int nal = H265_TYPE(frame[0]);
if (nal > 50){
WarnL << "不支持该类型的265 RTP包" << nal;
return false; // packet discard, Unsupported (HEVC) NAL type
}
switch (nal) {
case 50:
case 48: // aggregated packet (AP) - with two or more NAL units
WarnL << "不支持该类型的265 RTP包" << nal;
return false;
case 49: {
// fragmentation unit (FU)
FU fu;
MakeFU(frame[2], fu);
if (fu.S) {
//该帧的第一个rtp包
_h265frame->_buffer.assign("\x0\x0\x0\x1", 4);
_h265frame->_buffer.push_back(fu.type << 1);
_h265frame->_buffer.push_back(0x01);
_h265frame->_buffer.append((char *) frame + 3, length - 3);
_h265frame->_pts = rtppack->timeStamp;
//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 (_h265frame->keyFrame()); //i frame
}
if (rtppack->sequence != _lastSeq + 1 && rtppack->sequence != 0) {
//中间的或末尾的rtp包，其seq必须连续(如果回环了则判定为连续)，否则说明rtp丢包，那么该帧不完整，必须得丢弃
_h265frame->_buffer.clear();
WarnL << "rtp丢包: " << rtppack->sequence << " != " << _lastSeq << " + 1,该帧被废弃";
return false;
}
if (!fu.E) {
//该帧的中间rtp包
_h265frame->_buffer.append((char *) frame + 3, length - 3);
//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
_h265frame->_buffer.append((char *) frame + 3, length - 3);
_h265frame->_pts = rtppack->timeStamp;
onGetH265(_h265frame);
return false;
}
default: // 4.4.1. Single NAL Unit Packets (p24)
//a full frame
_h265frame->_buffer.assign("\x0\x0\x0\x1", 4);
_h265frame->_buffer.append((char *)frame, length);
_h265frame->_pts = rtppack->timeStamp;
auto key = _h265frame->keyFrame();
onGetH265(_h265frame);
return key;
}
}
void H265RtpDecoder::onGetH265(const H265Frame::Ptr &frame) {
//rtsp没有dts，那么根据pts排序算法生成dts
_dts_generator.getDts(frame->_pts,frame->_dts);
//写入环形缓存
RtpCodec::inputFrame(frame);
_h265frame = obtainFrame();
}
////////////////////////////////////////////////////////////////////////
H265RtpEncoder::H265RtpEncoder(uint32_t ui32Ssrc,
uint32_t ui32MtuSize,
uint32_t ui32SampleRate,
uint8_t ui8PayloadType,
uint8_t ui8Interleaved) :
RtpInfo(ui32Ssrc,
ui32MtuSize,
ui32SampleRate,
ui8PayloadType,
ui8Interleaved) {
}
void H265RtpEncoder::inputFrame(const Frame::Ptr &frame) {
GET_CONFIG(uint32_t,cycleMS,Rtp::kCycleMS);
uint8_t *pcData = (uint8_t*)frame->data() + frame->prefixSize();
auto uiStamp = frame->pts();
auto iLen = frame->size() - frame->prefixSize();
unsigned char naluType = H265_TYPE(pcData[0]); //获取NALU的5bit 帧类型
uiStamp %= cycleMS;
int maxSize = _ui32MtuSize - 3;
//超过MTU,按照FU方式打包
if (iLen > maxSize) {
//获取帧头数据，1byte
unsigned char s_e_flags;
bool bFirst = true;
bool mark = false;
int nOffset = 2;
while (!mark) {
if (iLen < nOffset + maxSize) { //是否拆分结束
maxSize = iLen - nOffset;
mark = true;
//FU end
s_e_flags = (1 << 6) | naluType;
} else if (bFirst) {
//FU start
s_e_flags = (1 << 7) | naluType;
} else {
//FU mid
s_e_flags = naluType;
}
{
//传入nullptr先不做payload的内存拷贝
auto rtp = makeRtp(getTrackType(), nullptr, maxSize + 3, mark, uiStamp);
//rtp payload 负载部分
uint8_t *payload = (uint8_t*)rtp->data() + rtp->offset;
//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] = 1;
//FU 第3个字节
payload[2] = s_e_flags;
//H265 数据
memcpy(payload + 3,pcData + nOffset, maxSize);
//输入到rtp环形缓存
RtpCodec::inputRtp(rtp,bFirst && H265Frame::isKeyFrame(naluType));
}
nOffset += maxSize;
bFirst = false;
}
} else {
makeH265Rtp(naluType,pcData, iLen, true, true, uiStamp);
}
}
void H265RtpEncoder::makeH265Rtp(int nal_type,const void* data, unsigned int len, bool mark, bool first_packet, uint32_t uiStamp) {
RtpCodec::inputRtp(makeRtp(getTrackType(),data,len,mark,uiStamp),first_packet && H265Frame::isKeyFrame(nal_type));
}
}//namespace mediakit