Hello all!
I'm developing RTSP server based on liveMedia library.
I have started separate thread for liveMedia in my class RMXFRTSPThread and
call doEventLoop().
Then I start VLC and connect to RTSP stream. This stream must take media
data from my live H264 video source
(I have written child class of FramedSource and child class of
OnDemandServerMediaSubsession to do it).
The live video source take about 10 sec to initialize (in separate thread).
My child of FramedSource triggers
event in task scheduler to signal live stream ready.
Then H264VideoRTPSink must get SPS and PPS from this live stream to compose
SDP lines.
To wait for live source and SDP lines my class
H264VideoDeviceServerMediaSubsession (child of
OnDemandServerMediaSubsession)
calls doEventLoop() exactly as H264VideoFileServerMediaSubsession library
class.
But RTSP client (VLC) closes TCP connection to server before all
initializations are complete.
This stream initialization process causes exception - library code accesses
RTSPClientSession object which has already been deleted.
This is a stack when the RTSPClientSession object is deleted:
1. RTSPServer::RTSPClientSession::handleRequestBytes
2. RTSPServer::RTSPClientSession::incomingRequestHandler1
3. RTSPServer::RTSPClientSession::incomingRequestHandler
4. BasicTaskScheduler::SingleStep
5. RMXFRTSPTaskScheduler::SingleStep
6. BasicTaskScheduler0::doEventLoop
7. H264VideoDeviceServerMediaSubsession::getAuxSDPLine
8. OnDemandServerMediaSubsession::setSDPLinesFromRTPSink
9. OnDemandServerMediaSubsession::sdpLines
10. ServerMediaSession::generateSDPDescription
11. RTSPServer::RTSPClientSession::handleCmd_DESCRIBE
12. RTSPServer::RTSPClientSession::handleRequestBytes
13. RTSPServer::RTSPClientSession::incomingRequestHandler1
14. RTSPServer::RTSPClientSession::incomingRequestHandler
15. BasicTaskScheduler::SingleStep
16. RMXFRTSPTaskScheduler::SingleStep
17. BasicTaskScheduler0::doEventLoop
18. RMXFRTSPThread::ThreadProc
Some explanations of names in stack:
RMXFRTSPThread::ThreadProc - my class with single thread for liveMedia lib
RMXFRTSPTaskScheduler - my child class of BasicTaskScheduler
H264VideoDeviceServerMediaSubsession - my child class of
OnDemandServerMediaSubsession
What causes this exception? There are explanation:
RTSPServer::RTSPClientSession::handleRequestBytes on top of stack deletes
current RTSPClientSession object because incoming client TCP connection is
closed (newBytesRead argument is 0 - see first 'if' on top of
handleRequestBytes method). But the same RTSPClientSession object is
handling DESCRIBE client command below in stack (lines 11-14; it waits for
SDP) and when the live video device SDP lines is ready, library code
accesses already deleted RTSPClientSession object.
I think there are error in choosing RTSPClientSession deleting point
(because of possible nested doEventLoop calls).
Best regards,
Vadim Kosarev
_______________________________________________
live-devel mailing list
live-devel@lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
