trying to debug downstream report,
https://bugzilla.redhat.com/show_bug.cgi?id=680809
about packagekit auto-install codec feature not working lately, and came to the conclusion that gstreamer's
gst_missing_plugin_message_get_installer_detail
function, and output from 
gst-inspect --print-plugin-auto-install-info --rpm
no longer match.

This last worked for me using
gstreamer-0.10.31-1.fc14

And started not working as of
gstreamer-0.10.34-1.fc15

and retested and confirmed not working too with:
gstreamer-0.10.35-1.fc16

In particular, starting with 0.10.34 , when trying to play mp3 audio via gstreamer applications (like totem or phonon-gstreamer), 
gst_missing_plugin_message_get_installer_detail
returns
gstreamer0.10(decoder-audio/mpeg)(mpegaudioversion=1)(mpegversion=1)(layer=3)()(64bit)

but 
 gst-inspect --print-plugin-auto-install-info --rpm /usr/lib64/gstreamer-0.10/libgstmad.so
gstreamer0.10(element-mad)
gstreamer0.10(decoder-audio/mpeg)(mpegversion=1)(layer=1)
gstreamer0.10(decoder-audio/mpeg)(mpegversion=1)(layer=2)
gstreamer0.10(decoder-audio/mpeg)(mpegversion=1)(layer=3)

note the missing (mpegaudioversion=1) in the latter.