Synchronizing h264 stream from appsink to appsrc for RTSP

Oliver ogtifs at
Sun May 21 11:39:32 UTC 2017

Hi all,

I am trying to use gstreamer to simultaneously stream a video source via
RTSP and record it (and in the future, more parallel processes).

My main problem with the gst-rtsp-server examples is that the RTSP
component wants to control the whole pipeline, and I don't want it to
impact one of the other branches. My approach to this problem (I would be
happy to hear a simpler way) is to use a primary, always-running pipeline
which branches to an appsink, and allow the RTSP server to create its own
pipeline using an appsrc, which I connect to the appsink in the
GstRtspMediaFactory's "media-configured" signal handler.

For the purposes of example, my "main" pipeline can be "videotestsrc !
appsink" (later with tee to filesink), and the rtsp factory bin can be
"appsrc ! x264enc ! rtph264pay". In this case, it works, that is to say I
can connect a media player to the RTSP stream and see the test image,
although the memory usage explodes uncontrollably quite quickly.

If I move the x264enc element to the "main" pipeline, which I want to do so
it can be shared between the parallel functions, I never see any picture,
and gst-play reports "Could not receive any udp packets". In neither case
do I see errors on the server side with GST_DEBUG=*:3, and in both cases I
set the appsrc caps to the caps from the last element in the "main"
pipeline before the appsink.

I checked that the RTSP pipeline's clock is slaved to the main pipeline
clock (this seemed to happen automatically), but I guess I have some
synchronization issues. Perhaps that can explain the memory explosion when
passing raw packets too? Since assumedly the appsink is receiving frames
much more quickly than the appsrc can send them onwards. In any case I am
more interested in first getting the h264 appsink->appsrc link to work.

I pasted a short code listing at (not sure of the
preferred etiquette for this ML)

Thanks for all advice!
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