Hi, I have two separated live sources of video (H264) and audio (ACC) content. I created the FrameSource the OnDemandServerMediaSubsession classes where the corresponding RTPSink objects are created (H264VideoRTPSink and MPEG4GenericRTPSink). The fPresentationTime parameter is set as the current time by gettimeofday() routine in both FrameSource objects.
If I stream each of subsession as the separated stream everything works correctly and the receiver (VLC) handles them properly. The problem begins when I add video and audio subsessions into one ServerMediaSession. It looks like that those subsessions are not synchronized. Video's RTP frames have totally different timestamps than audio's frames. I dug a little bit and saw that the frame timestamp is calculated in RTPSink class in convertToRTPTimestamp() method basing on fTimestampBase and fTimestampFrequency parameters. The fTimestampBase is set as the random value, so there is no possibility to have similar timestamps in both subessions. As far as I understand, there is also a need to have the same fTimestampFrequency values, but the audio has 44100 sampling frequency and video has this value hardcoded to 90000. I performed an experiment and set the fTimestampBase parameters to the same hardcoded value and fTimestampFrequency members to 90000. In this case, everything works correctly and frames have similar timestamps. How can I achieve above result without this dirty modification? Is there any possibility to have similar timestamps (use the same fTimestampBase) in both subsessions? Thank you in advance for your engagement. -- Piotr Piwko http://www.embedded-engineering.pl/ _______________________________________________ live-devel mailing list live-devel@lists.live555.com http://lists.live555.com/mailman/listinfo/live-devel
