In order to watch Russian TV over the internet, I am connecting to one streaming provider which (unfortunately) broadcasts as RTSP/UDP (well, there is also RTSP/TCP and RTSP/HTTP but they are unusable - constant buffering is all I see). So... I found out that neither VLC nor mplayer can deal with it.
VLC (as far as I can see in the sources) can only work with RTSP/TCP (I sure filed a ticket in their support system, let's see how long it will take to respond).
Mplayer (using live555.com library) supports RTSP/UDP (seems so), but cannot handle the format X-ASF-PF (which is MS format, with all fairness).
Gstreamer ... "RTSP streams cannot be played yet" - that's what I got from totem..
I have to boot to XP in order to use Media Player. Sad sad...