如何使用jrtp库发送RTP视频

jrtp使用起来比较简单，这里使用分片封包模式
#ifndef RTP_RAW_SESSION_H#define RTP_RAW_SESSION_H#include "jrtplib3/rtpsession.h"#include using namespace jrtplib;class RawSession : public RTPSession{public: RawSession(); ~RawSession(); int Init(const std::string& ip, uint16_t destport); void SendData(unsigned char* pSendbuf, int buflen); void SendData(unsigned char* pSendbuf, int buflen, uint32_t timestampinc, bool mark, uint8_t pt = 96);protected: void OnAPPPacket(RTCPAPPPacket *apppacket,const RTPTime &receivetime,const RTPAddress *senderaddress); void OnBYEPacket(RTPSourceData *srcdat); void OnBYETimeout(RTPSourceData *srcdat);};#endif
#include "RawSession.h"#include #include #include "jrtplib3/rtpudpv4transmitter.h"#include "jrtplib3/rtpipv4address.h"#include "jrtplib3/rtpsessionparams.h"#include "jrtplib3/rtperrors.h"#include "jrtplib3/rtplibraryversion.h"#include "jrtplib3/rtcpapppacket.h"namespace { uint32_t SSRC = 100; uint16_t BASE_PORT = 2222; uint32_t MAX_RTP_PKT_LENGTH = 1360; uint32_t H264 = 96;} #define FUbool CheckError(int rtperr){ if (rtperr < 0) { std::cout << "ERROR: "<Create(sessparams, &transparams); this->SetDefaultPayloadType(96); this->SetDefaultTimestampIncrement(3600); this->SetDefaultMark(true); CheckError(status); RTPIPv4Address addr(destip, destport); status = this->AddDestination(addr); CheckError(status); std::cout << "RawSession::Init ip:" << destip << " status:" << status << std::endl; return status;}// 收到RTCP报文void RawSession::OnAPPPacket(RTCPAPPPacket *apppacket,const RTPTime &receivetime,const RTPAddress *senderaddress){ std::cout << "Got RTCP packet from: " << senderaddress << std::endl; std::cout << "Got RTCP subtype: " << apppacket->GetSubType() << std::endl; std::cout << "Got RTCP subtype: " << (char *)apppacket->GetAPPData() << std::endl; return ;}void RawSession::OnBYEPacket(RTPSourceData *srcdat){ std::cout << "OnBYEPacket" << std::endl;}void RawSession::OnBYETimeout(RTPSourceData *srcdat){ std::cout << "OnBYETimeout" << std::endl;}void

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刘超

2020-11-4 11:30:05

RawSession::SendData(unsigned char* pSendbuf, int buflen){ //std::cout << "send packet length : " << buflen << std::endl;       char sendbuf[1430]; //发送的数据缓冲 memset(sendbuf, 0, 1430);    int status;       if ( buflen <= MAX_RTP_PKT_LENGTH )    {       memcpy(sendbuf, pSendbuf, buflen);       status = this->SendPacket((void *)sendbuf, buflen);       CheckError(status); }    else if(buflen > MAX_RTP_PKT_LENGTH)    {       //设置标志位Mark为0       this->SetDefaultMark(false);       //printf("buflen = %d/n",buflen);       //得到该需要用多少长度为MAX_RTP_PKT_LENGTH字节的RTP包来发送       int k = 0, l = 0;       #ifdef FU          buflen = buflen -1;       #endif       k = buflen / MAX_RTP_PKT_LENGTH;       l = buflen % MAX_RTP_PKT_LENGTH;       int t = 0;//用指示当前发送的是第几个分片RTP包       char nalHeader = pSendbuf[0]; // NALU 头ª¡¤       while( t < k || ( t==k && l>0 ) )       {             if ( ( t < (k-1) ) || ( t== (k-1) && l!=0 ) )//第一包到最后包的前一包          {#ifdef FU             sendbuf[0] = (nalHeader & 0x60)|28;                sendbuf[1] = (nalHeader & 0x1f);             if ( 0 == t )             {                   sendbuf[1] |= 0x80;             }             memcpy(sendbuf+2, &pSendbuf[t*MAX_RTP_PKT_LENGTH + 1], MAX_RTP_PKT_LENGTH);             status = this->SendPacket((void *)sendbuf, MAX_RTP_PKT_LENGTH+2);#else                   memcpy(sendbuf, &pSendbuf[t*MAX_RTP_PKT_LENGTH], MAX_RTP_PKT_LENGTH);             status = this->SendPacket((void *)sendbuf, MAX_RTP_PKT_LENGTH);#endif             CheckError(status);             t++;          }          //最后一包          else if( ( k==t && l>0 ) || ( t== (k-1) && l==0 ))          {             //设置标志位Mark为1             this->SetDefaultMark(true);                int iSendLen;             if ( l > 0) {                   iSendLen = buflen - t * MAX_RTP_PKT_LENGTH;             } else {                   iSendLen = MAX_RTP_PKT_LENGTH;             } #ifdef FU             sendbuf[0] = (nalHeader & 0x60)|28;                sendbuf[1] = (nalHeader & 0x1f);             sendbuf[1] |= 0x40;                memcpy(sendbuf+2, &pSendbuf[t*MAX_RTP_PKT_LENGTH + 1], iSendLen);             status = this->SendPacket((void *)sendbuf, iSendLen+2);#else             memcpy(sendbuf, &pSendbuf[t*MAX_RTP_PKT_LENGTH], iSendLen);             status = this->SendPacket((void *)sendbuf, iSendLen);#endif             CheckError(status);             t++;          }       } }}void RawSession::SendData(unsigned char* pSendbuf, int buflen, uint32_t timestampinc,  bool mark, uint8_t pt){ char sendbuf[1430]; //发送的数据缓冲 memset(sendbuf, 0, 1430); timestampinc = timestampinc * 90; int status;       if ( buflen <= MAX_RTP_PKT_LENGTH )    {       memcpy(sendbuf, pSendbuf, buflen);       status = this->SendPacket((void *)sendbuf, buflen, pt, mark, timestampinc);       CheckError(status); }    else if(buflen > MAX_RTP_PKT_LENGTH)    {       //设置标志位Mark为0       this->SetDefaultMark(false);       //printf("buflen = %d/n",buflen);       //得到该需要用多少长度为MAX_RTP_PKT_LENGTH字节的RTP包来发送       int k = 0, l = 0;       #ifdef FU          buflen = buflen -1;       #endif       k = buflen / MAX_RTP_PKT_LENGTH;       l = buflen % MAX_RTP_PKT_LENGTH;       int t = 0;//用指示当前发送的是第几个分片RTP包       char nalHeader = pSendbuf[0]; // NALU 头ª¡¤       while( t < k || ( t==k && l>0 ) )       {             if ( ( t < (k-1) ) || ( t== (k-1) && l!=0 ) )//第一包到最后包的前一包          {#ifdef FU             sendbuf[0] = (nalHeader & 0x60)|28;                sendbuf[1] = (nalHeader & 0x1f);             if ( 0 == t )             {                   sendbuf[1] |= 0x80;             }             memcpy(sendbuf+2, &pSendbuf[t*MAX_RTP_PKT_LENGTH + 1], MAX_RTP_PKT_LENGTH);             status = this->SendPacket((void *)sendbuf, MAX_RTP_PKT_LENGTH + 2, pt, false, 0);#else                   memcpy(sendbuf, &pSendbuf[t*MAX_RTP_PKT_LENGTH], MAX_RTP_PKT_LENGTH);             status = this->SendPacket((void *)sendbuf, MAX_RTP_PKT_LENGTH, pt, false, 0);#endif             CheckError(status);             t++;          }          //最后一包          else if( ( k==t && l>0 ) || ( t== (k-1) && l==0 ))          {             //设置标志位Mark为1             this->SetDefaultMark(true);                int iSendLen;             if ( l > 0) {                   iSendLen = buflen - t * MAX_RTP_PKT_LENGTH;             } else {                   iSendLen = MAX_RTP_PKT_LENGTH;             } #ifdef FU             sendbuf[0] = (nalHeader & 0x60)|28;                sendbuf[1] = (nalHeader & 0x1f);             sendbuf[1] |= 0x40;                memcpy(sendbuf+2, &pSendbuf[t*MAX_RTP_PKT_LENGTH + 1], iSendLen);             status = this->SendPacket((void *)sendbuf, iSendLen+2, pt, true, timestampinc);#else             memcpy(sendbuf, &pSendbuf[t*MAX_RTP_PKT_LENGTH], iSendLen);             status = this->SendPacket((void *)sendbuf, iSendLen, pt, true, timestampinc);#endif             CheckError(status);             t++;          }       } }       }
int Init(const std::string& ip, uint16_t destport);
初始化部分有几点需要注意的：
1.H264固定的采样率是90000HZ，对于时间戳单位应为
sessparams.SetOwnTimestampUnit(1.0/90000.0); //时间戳单位
2.如果视频帧率是25fps，那么时间戳间隔就是3600
this->SetDefaultTimestampIncrement(3600);
void SendData(unsigned char* pSendbuf, int buflen);
使用分片封包模式，这里大概介绍一下
当NALU的长度超过MTU时,就必须对NALU单元进行分片封包.也称为Fragmentation Units(FUs).

   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | FU indicator  | FU header |                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                            |
   |                                                             |
   |                      FU payload                         |
   |                                                             |
   |                            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            :...OPTIONAL RTP padding       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   Figure 14.  RTP payload format for FU-A
The FU indicator octet has the following format:
   +---------------+
   |0|1|2|3|4|5|6|7|
   +-+-+-+-+-+-+-+-+
   |F|NRI|  Type |
   +---------------+
别被名字吓到这个格式就是上面提到的RTP h264负载类型，Type为FU-A
The FU header has the following format:
   +---------------+
   |0|1|2|3|4|5|6|7|
   +-+-+-+-+-+-+-+-+
   |S|E|R|  Type |
   +---------------+
   S bit为1表示分片的NAL开始，当它为1时，E不能为1
E bit为1表示结束，当它为1，S不能为1
R bit保留位
Type就是NALU头中的Type,取1-23的那个值
这里有几个问题需要强调一下：
1.就是长度小于MTU时候，一个RTP发送一个nalu
2.每个I帧前面发送一个sps pps，这两个RTP包和接下来的I帧RTP包的时间戳相同
3.当nalu大于MTU，添加FU头，同时注意，要去掉nalu的header，就是第一个字节。FU indicator  + FU header + nalu[1]

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王颖

如何使用jrtp库发送RTP视频

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刘超

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