Comment 38 for bug 137527

Matthew: the automated codec installation already exists in Totem actually. Just try to open a AAC file, and it will prompt you to install the codec. The Fluendo DVD plugin should just be registered with the correct information (to say: "hey, I read encrypted DVDs"), and Totem should query for such plugins. This is probably not done ATM upstream because only Ubuntu sells the Fluendo plugin by default, but would likely be easy to do.

AFAIK, Totem is already smart enough to start playing right after the codec has been installed.

For the technical details, see:
http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstpbutilsinstallplugins.html