/*
* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
*
* This file is part of ZLMediaKit(https://github.com/xia-chu/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{
//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 << "数据不够:" << total << " " << size; 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 uint8_t *ptr, ssize_t size, uint32_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(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 uint8_t *ptr, ssize_t size, uint16_t seq, uint32_t stamp){
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);
//恢复nalu头两个字节
_frame->_buffer.push_back((type << 1) | (ptr[0] & 0x81));
_frame->_buffer.push_back(ptr[1]);
}
if (!s_bit && seq != (uint16_t) (_last_seq + 1) && seq != 0) {
//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
_frame->_buffer.clear();
WarnL << "rtp丢包: " << seq << " != " << _last_seq << " + 1,该帧被废弃";
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);
if (!e_bit) {
//非末尾包
_last_seq = seq;
_frame->_buffer.append((char *) ptr, size);
return s_bit ? _frame->keyFrame() : false;
}
//该帧最后一个rtp包
_frame->_pts = stamp;
_frame->_buffer.append((char *) ptr, size);
outputFrame(_frame);
return false;
}
bool H265RtpDecoder::inputRtp(const RtpPacket::Ptr &rtp, bool ) {
auto frame = rtp->getPayload();
auto length = rtp->getPayloadSize();
auto stamp = rtp->getStampMS();
auto seq = rtp->getSeq();
int nal = H265_TYPE(frame[0]);
if (nal > 50){
// packet discard, Unsupported (HEVC) NAL type
WarnL << "不支持该类型的265 RTP包" << nal;
return false;
}
switch (nal) {
case 50:
//4.4.4. PACI Packets (p32)
WarnL << "不支持该类型的265 RTP包" << nal;
return false;
case 48:
// aggregated packet (AP) - with two or more NAL units
return unpackAp(frame, length, stamp);
case 49:
// fragmentation unit (FU)
return mergeFu(frame, length, seq, stamp);
default:
// 4.4.1. Single NAL Unit Packets (p24)
return singleFrame(frame, length, stamp);
}
}
bool H265RtpDecoder::singleFrame(const uint8_t *ptr, ssize_t size, uint32_t stamp){
//a full frame
_frame->_buffer.assign("\x00\x00\x00\x01", 4);
_frame->_buffer.append((char *) ptr, size);
_frame->_pts = stamp;
auto key = _frame->keyFrame();
outputFrame(_frame);
return key;
}
void H265RtpDecoder::outputFrame(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);
//输出frame
RtpCodec::inputFrame(frame);
_frame = 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) {
auto ptr = (uint8_t *) frame->data() + frame->prefixSize();
auto len = frame->size() - frame->prefixSize();
auto pts = frame->pts();
auto nal_type = H265_TYPE(ptr[0]); //获取NALU的5bit 帧类型
auto max_size = getMaxSize() - 3;
//超过MTU,按照FU方式打包
if (len > max_size + 2) {
//获取帧头数据，1byte
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 = makeRtp(getTrackType(), 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] = 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 && H265Frame::isKeyFrame(nal_type));
}
offset += max_size;
fu_start = false;
}
} else {
makeH265Rtp(nal_type, ptr, len, false, true, pts);
}
}
void H265RtpEncoder::makeH265Rtp(int nal_type,const void* data, size_t 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