campus streaming with gstreamer fails

DI Mag Gergely Rakoczi rakoczi at
Tue Jul 12 07:40:53 PDT 2011


we at Vienna University want to enable live campus streaming from one
lecturehall to another. So to begin, we try to stream a simple testvideo via
gstreamer to our media server (wowza) by using this simple command: 

gst-launch-0.10 -v videotestsrc ! "video/x-raw-yuv, format=(fourcc)I420,
width=(int)640, height=(int)480, framerate=(fraction)15/1" ! queue ! x264enc
bitrate=500 cabac=false pass=qual quantizer=27 subme=4 threads=0 bframes=0
dct8x8=false ! queue ! rtph264pay ! queue ! udpsink host=

For your information, we have this cap for our videostream: 

caps = application/x-rtp, media=(string)video, clock-rate=(int)90000,
aM4XIA\\=\\=\", payload=(int)96, ssrc=(guint)2438042987,
clock-base=(guint)2413324687, seqnum-base=(guint)449100 

our SDP-file looks like this: 

o=- 1208520720 2590316916 IN IP4 
c=IN IP4 
t=0 0 
m=video 10004 RTP/AVP 96 
a=rtpmap:96 H264/90000 
a=fmtp:96 media=video; clock-rate=90000; encoding-name=H264;
ssrc=2438042987; clock-base=2413324687; seqnum-base=449100 

The rtp packets are recieved just fine, so firewall settings are not the
reason for our problem. We try to view the stream by JW Player (Longtail
setup wizard: rtmp stream, file: udp://, streamer:
rtmp:// However, the flash player
remains black and doesn't show our stream. 

Do you have any ideas where our problem might be? Is our gstreamer pipeline
Or is something missing in our sdp-file (it should be okay according to
<> Any advice is
welcome :-) 

Thank you for your help in advance, 

PS: our log file might help you finding a solution: 



Dipl.-Ing. Mag. rer.soc.oec. Gergely Rakoczi

E-Learning Web-Entwicklung, Dokumentation und Lehre


TU Wien - Teaching Support Center

Gußhausstraße 28/E015

1040 Wien

Tel:  +43 1 58801 41544

rakoczi at


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