Totem takes over the following when totem-plugin is installed: video/quicktime QT video mov Yes application/x-mplayer2 AVI video avi, wma, wmv Yes video/mpeg MPEG video mpg, mpeg, mpe Yes video/x-ms-asf-plugin ASF video asf, wmv Yes video/x-ms-wmv WMV video wmv Yes application/ogg Ogg multimedia ogg Yes application/x-google-vlc-plugin Google VLC plugin Yes application/x-vlc-plugin VideoLAN plugin Yes audio/wav WAV audio wav Yes Yet it is not capable of playing MPEG video... when I attempt to play mpeg video with totem it locks up the browser. The same happens with quicktime. There's no error message of any kind - just locks up. On the other hand when such content is ran through totem (the standalone application) it complains about missing codecs. I know that totem uses gstreamer, and at the moment I don't have 64-bit mpeg support for gstreamer installed. However, that's not the point of this bug. mozplugger is able to successfully play all content that I'm interested in. However, totem-mozplugger overrides it when installed, which is particularly evil. Totem should know exactly what it can and can't play, and shouldn't take over file extensions it is unable to handle.
Please file this bug upstream at bugzilla.gnome.org. totem-mozplugin is highly experimental and was enabled but not installed by default because there were requests for it. Solution is to remove the packages for now and file the bug upstream as they are in a better possition to fix the issues.