rtsp客戶端傳送播放請求後,rtsp伺服器呼叫流程如下 h264 video rtsp 1.ServerMediaSubsession::startStream -> OnDemandServerMediaSubsession::startStream 2.startStream -> StreamState::startPlaying 3.MediaSink::startPlaying 4.MediaSink::continuePlaying->MultiFramedRTPSink::continuePlaying 5.MultiFramedRTPSink::buildAndSendPacket 6.MultiFramedRTPSink::packFrame()  fSource->getNextFrame fSource type is H264FUAFragmenter 7.FramedSource::getNextFrame 8.FramedSource::doGetNextFrame ->H264FUAFragmenter::doGetNextFrame  ->  fInputSource->getNextFrame fInputSource type is H264VideoStreamFramer 9.H264VideoStreamFramer::getNextFrame -> MPEGVideoStreamFramer::doGetNextFrame 10.MPEGVideoStreamFramer::continueReadProcessing -> fParser->parse()   fParser type is H264VideoStreamParser 11.H264VideoStreamParser::parse()   -> ByteStreamFileSource::doGetNextFrame -> ByteStreamFileSource::doReadFromFile 時間戳生成流程 1.MultiFramedRTPSink::buildAndSendPacket 中組建rtp包頭時，獲取時間戳的位置fTimestampPosition，然後等待獲取資料與時間戳後寫入 2.MultiFramedRTPSink::afterGettingFrame1 ->H264VideoRTPSink::doSpecialFrameHandling->MultiFramedRTPSink::setTimestamp 將時間戳寫入到rtp包中 3.H264VideoStreamParser::parse 中呼叫H264VideoStreamFramer::setPresentationTime { fPresentationTime = fNextPresentationTime; } 此fPresentationTime最終將傳到步驟2中 4.fNextPresentationTime 初始化由建構函式獲取當前時間戳 ，後續在H264VideoStreamParser::parse 當thisNALUnitEndsAccessUnit=TRUE後，根據幀率計算幀duration，然後計算下一幀的時間戳