//建立RTP的数据接收
sessParams.SetOwnTimestampUnit(1.0 / 8000.0); //30 video frames per second
sessParams.SetUsePollThread(1); //background thread to call virtual callbacks - set by default, but just to be sure
sessParams.SetMaximumPacketSize(MAX_PACKET_SIZE);
transParams.SetPortbase(port);
RTPTime time(0.02);
m_sessData.rtp->SetPreTransmissionDelay(time);
m_sessData.rtp->SetDefaultTimestampIncrement(160UL);
int recresult=m_sessData.rtp->Create(sessParams, &transParams);