The stopping problem occurs when using "xv" output with the n800. To fix it, upgrade to the latest version of mplayer. If you have the latest version ( currently maemo.10 released feb 14 ) make sure you are using "nokia770" for video output.

The built-in media player is very picky about what files it will play. The exact error message from the media player and the report from mplayer will be very helpful in determining why your videos don't play.

Canola is just a pretty fontend for the same framework used by the "media player."