If you're trying to do a videochat with a Gmail user, but it doesn't work (it connects and then disconnects directly), chances are you may see the same issue I did.
If that's the case, the list of video codecs you present will most likely consist of JPEG, THEORA and MPV (without any H264 or H263).
What you need is most likely a ffmpeg package for GStreamer. On Ubuntu karmic, gstreamer0.10-ffmpeg is the right one. After a
sudo aptitude install gstreamer0.10-ffmpeg gstreamer0.10-tools; gst-inspect-0.10
things should be better (you will need to restart Empathy/Pidgin).
