[gst-devel] Problem with rtp live streaming and 'computer too slow' message

[Mark Sauer]

I've been trying to set up a gstreamer graph (using gst-launch, as well 
as a C application) to receive a multicasted rtp video sequence encoded 
with a mpeg 2 transport stream, using h.264 video and aac audio, and 
rendering it to a window.

I have a graph that works pretty well, and it is described by this call 
to gst-launch:

gst-launch-0.10.exe udpsrc uri=udp://224.0.22.1:40000 
caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, 
encoding-name=(string)MP2T-ES, payload=(int)33" ! gstrtpbin latency=4000 
! rtpmp2tdepay ! mpegtsdemux name=a a. ! queue ! ffdec_h264 ! 
ffmpegcolorspace ! b. b. ! autovideosink a. ! queue ! faad ! 
audioconvert ! b. b. ! autoaudiosink multiqueue max-size-bytes=0 
max-size-buffers=40000 max-size-time=0 name=b

I have a live encoder streaming to the address 224.0.22.1 on port 
40000.  The window pops up with this graph, and the video/audio play 
fine for a few minutes, sometimes even up to 20-30 minutes.  But more 
often after about 1-2 minutes I start seeing lots of messages like this 
in the console:

..\..\libs\gst\base\gstbasesink.c(2572): gst_base_sink_is_too_late (): 
/GstPipeline:pipeline0/GstDshowVideoSink:dshowvideosink0:
There may be a timestamping problem, or this computer is too slow.

This is repeated over and over, and the video becomes very choppy, as 
many frames are dropped.  My computer is not too slow, gstreamer uses 
only about 10% of one cpu to decode this stream (it is 720x480 at 1 mbps).

I have tried this under both Windows (using the dshowvideosink), and 
under linux (using the xvimagesink and ximagesink).  The problem seems 
to always occur, although it is worse on Windows.

I am wondering if I am doing something wrong here, and/or if it is a 
gstreamer bug?

Thanks,
Mark Sauer