Stop Live555 from re-using session

Question

I'm using Live555 to pull in data from a IP webcam on a remote connection. From time to time, there are brief interruptions to the stream (which might be a network QOS issues), however, live555 dies every time this happens instead of successfully restarting the connection. The debug output looks like this:

Closing session, because we stopped receiving packets.itrate=N/A speed=1.37x
Created new TCP socket 3 for connection
Connecting to 10.8.1.14, port 10111 on socket 3...
...remote connection opened
Sending request: PLAY rtsp://mycamera.test/live/ch0/ RTSP/1.0
CSeq: 6
User-Agent: /bin/openRTSP (LIVE555 Streaming Media v2017.07.18)
Session: 1487641045855494467
Range: npt=0.000-

Received 199 new bytes of response data.
Received a complete PLAY response:
RTSP/1.0 500 Internal Server Error
Server: DSS/6.0.3 (Build/526.3; Platform/Linux; Release/Darwin Streaming Server; State/Development; )
Cseq: 6
Session: 1487641045855494467
Connection: Close

Failed to start playing session: 500 Internal Server Error
Created new TCP socket 3 for connection
Connecting to 10.8.1.14, port 10111 on socket 3...
...remote connection opened
Sending request: TEARDOWN rtsp://mycamera.test/live/ch0/ RTSP/1.0
CSeq: 7
User-Agent: /bin/openRTSP (LIVE555 Streaming Media v2017.07.18)
Session: 1487641045855494467

Received 180 new bytes of response data.
Received a complete TEARDOWN response:
RTSP/1.0 200 OK
Server: DSS/6.0.3 (Build/526.3; Platform/Linux; Release/Darwin Streaming Server; State/Development; )
Cseq: 7
Session: 1487641045855494467
Connection: Close

It would seem that the reason live555 bails out is because the camera throws a 500 error when attempting to restart the stream for an existing session. Since starting a new session works, is there any way to tell live555 to discard the existing session and start again rather than just giving up? I do have a cron job which detects when live555 has stopped and restarts it, but there are knock on issues when I do this so it would be much cleaner if I could persuade live555 to compensate for the bug in the camera firmware.

I'm happy to patch the live555 code and rebuild if necessary!

Answer 1

If you look to the code of playCommon.cpp , you could see

void sessionAfterPlaying(void* /*clientData*/) {
  if (!playContinuously) {
    shutdown(0);
  } else {
    // We've been asked to play the stream(s) over again.
    // First, reset state from the current session:
    if (env != NULL) {
      env->taskScheduler().unscheduleDelayedTask(periodicFileOutputTask);
      env->taskScheduler().unscheduleDelayedTask(sessionTimerTask);
      env->taskScheduler().unscheduleDelayedTask(arrivalCheckTimerTask);
      env->taskScheduler().unscheduleDelayedTask(interPacketGapCheckTimerTask);
      env->taskScheduler().unscheduleDelayedTask(qosMeasurementTimerTask);
    }
    totNumPacketsReceived = ~0;

    startPlayingSession(session, initialSeekTime, endTime, scale, continueAfterPLAY);
  }
}

As you see in your log, it send a PLAY and doesnot reinitiate the Session. In order to change this behaviour, you need to modify the code of openRTSP.