Comment 3 for bug 89999

Ok, most probably this is caused by the following:

mad and faad are currently registred to decode audio/mpeg. The former can do "audio/mpeg, mpegversion=1", the latter "audio/mpeg, mpegversion=[2,4]" though the latter part of each string is not saved in the package datebase.

Now if totem plays this file it notices that it can't play "audio/mpeg, mpegversion=4" and will ask gnome-codec-install. This will look in the database for "audio/mpeg", see that mad is installed which can handle this and is happy to tell totem that it can continue playing the file. Totem now still can't play the file and gives the error.

We definitely need proper caps intersecting in gnome-codec-install and the complete caps saved in the package/codec database to have this really working.