Geek Lair

By default, Firefox in Ubuntu uses totem to play video files. If you want to use mplayer instead, do this:

1. Uninstall the totem plugin:

sudo apt-get remove totem-mozilla

2. My Ubuntu installation also had a gecko mediaplayer plugin. Remove it:

sudo apt-get remove gecko-mediaplayer

3. Install mplayer plugin:

sudo apt-get install mozilla-mplayer

Now enjoy mplayer on your Firefox.