使用jrtplib传输H.264视频文件（3）

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介绍如何发送h264，下面我们介绍下如何接收h264文件。

其中主要关注的就是被拆分的数据包的重组，下面的代码中有详尽的注释。

class CRTPReceiver : public RTPSession
{
protected:
void OnPollThreadStep();
void ProcessRTPPacket(const RTPSourceData &srcdat,const RTPPacket &rtppack);
void OnRTCPCompoundPacket(RTCPCompoundPacket *pack,const RTPTime &receivetime,const RTPAddress *senderaddress);

public:
CThreadSafeArray m_ReceiveArray;
void InitBufferSize();

private:
CVideoData* m_pVideoData;
unsigned char m_buffer[BUFFER_SIZE];
int m_current_size;
};

void CRTPReceiver::InitBufferSize()
{
m_ReceiveArray.SetMemberSize(BUFFER_SIZE);
m_pVideoData = new CVideoData();
memset(m_buffer,0,BUFFER_SIZE);
m_current_size = 0;
}

void CRTPReceiver::OnRTCPCompoundPacket(RTCPCompoundPacket *pack,const RTPTime &receivetime,const RTPAddress *senderaddress)
{
//std::cout<<"Got RTCP packet from: "<<senderaddress<<std::endl;
}

void CRTPReceiver::OnPollThreadStep()
{
BeginDataAccess();

// check incoming packets
if (GotoFirstSourceWithData())
{
do
{
RTPPacket *pack;
RTPSourceData *srcdat;

srcdat = GetCurrentSourceInfo();

while ((pack = GetNextPacket()) != NULL)
{
ProcessRTPPacket(*srcdat,*pack);
DeletePacket(pack);
}
} while (GotoNextSourceWithData());
}

EndDataAccess();
}

void CRTPReceiver::ProcessRTPPacket(const RTPSourceData &srcdat,const RTPPacket &rtppack)
{
// You can inspect the packet and the source's info here
//std::cout<<"Packet type: "<<rtppack.GetPayloadType()<<std::endl;
//std::cout<<"Packet says: "<<(char *)rtppack.GetPayloadData()<<std::endl;
//test RTCP packet
/*int status = this->SendRTCPAPPPacket(0,(uint8_t*)&("123"),(void*)&("hel"),4);
checkerror(status);*/

if(rtppack.GetPayloadType() == H264)
{
//std::cout<<"Got H264 packet：êo " << rtppack.GetExtendedSequenceNumber() << " from SSRC " << srcdat.GetSSRC() <<std::endl;
if(rtppack.HasMarker())//如果是最后一包则进行组包
{
m_pVideoData->m_lLength = m_current_size + rtppack.GetPayloadLength();//得到数据包总的长度
memcpy(m_pVideoData->m_pBuffer,m_buffer,m_current_size);
memcpy(m_pVideoData->m_pBuffer + m_current_size ,rtppack.GetPayloadData(),rtppack.GetPayloadLength());

m_ReceiveArray.Add(m_pVideoData);//添加到接收队列

memset(m_buffer,0,m_current_size);//清空缓存，为下次做准备
m_current_size = 0;
}
else//放入缓冲区，在此必须确保有序
{
unsigned char* p = rtppack.GetPayloadData();

memcpy(m_buffer + m_current_size,rtppack.GetPayloadData(),rtppack.GetPayloadLength());
m_current_size += rtppack.GetPayloadLength();
}
}

}

void StartReceive()
{
/*CRTPReceiver sess;*/
sess.InitBufferSize();
std::string ipstr;
int status;

// Now, we'll create a RTP session, set the destination
// and poll for incoming data.
RTPUDPv4TransmissionParams transparams;
RTPSessionParams sessparams;

// IMPORTANT: The local timestamp unit MUST be set, otherwise
//            RTCP Sender Report info will be calculated wrong
// In this case, we'll be just use 9000 samples per second.
sessparams.SetOwnTimestampUnit(1.0/9000.0);

transparams.SetPortbase(PORT_BASE);
status = sess.Create(sessparams,&transparams);
checkerror(status);

uint32_t dst_ip = inet_addr(DST_IP);
dst_ip = ntohl(dst_ip);
RTPIPv4Address addr(dst_ip,DST_PORT);
status = sess.AddDestination(addr);

checkerror(status);
}

int main(int argc, char* argv[])
{
WSADATA dat;
WSAStartup(MAKEWORD(2,2),&dat);
StartReceive();
RTPTime::Wait(RTPTime(3,0));
return 0;
}

至此，使用jrtplib传输h264全部完成。