I run this command on an Ubuntu 10.4 32 bit system with gstreamer version 0.10.28-1 and it works: gst-launch udpsrc port=5000 caps="application/x-rtp, media=$string$video, clock-rate=$int$9 0000, encoding-name=$string$H264, payload=$int$96, ssrc=$guint$2396357661, clock-base=$guint $2297066863, seqnum-base=$guint$49439" ! rtph264depay ! decodebin ! xvimagesink sync=false I run the same command on an Ubuntu 10.10 64 bit system with gstreamer 0.10.30-1build2 and I get the following error: morris@ubuntu:~/gst-commands$ gst-launch udpsrc port=5000 caps="application/x-rtp, media=$string$video, clock-rate=$int$9 0000, encoding-name=$string$H264, payload=$int$96, ssrc=$guint$2396357661, clock-base=$guint $2297066863, seqnum-base=$guint$49439" ! rtph264depay ! decodebin ! xvimagesink sync=false WARNING: erroneous pipeline: could not link udpsrc0 to rtph264depay0 morris@ubuntu:~/gst-commands$ Is there a difference in the gstreamer versions? A problem with Ubuntu versions or a problem between 64 bit / 32 bit? Morris