Correction: totem plugin is okay. I've tried a trailer, it failed to be played. FF3 complained about vlc, not totem. So I removed the vlc plugin, restarted FF3 and the same trailer played perfectly.
Correction: totem plugin is okay. I've tried a trailer, it failed to be played. FF3 complained about vlc, not totem. So I removed the vlc plugin, restarted FF3 and the same trailer played perfectly.