playing m4a files with totem

Suppose you just got some .m4a files. For example, you just read this review of three M.I.A. albums and noticed it had downloads (with permission!) for two of the albums.

Totem officially plays m4a files, but mine didn't. It uses gstreamer for the backend. The plugin you need is "faad", so apt-get install gstreamer0.8-faad worked for me.