XMV

XMV is the audio/video container format used on the Microsoft Xbox console. It is reportedly similar to ASF and typically contains video at 640x480 29.97, and CBR audio at 128k.

Working legal source code for a decoder/demuxer can be found here but it is copyrighted and without open source licence: http://sourceforge.net/tracker/index.php?func=detail&aid=1097094&group_id=53761&atid=471491 also look at http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/25207/focus=25224 and http://www.maxconsole.net/?mode=news&newsid=411 for hints/tips