Correcting mp3 duration

[Tony Houghton]

There's a bug which makes sound-juicer produce MP3 files which are shown
with the wrong duration. See
<https://bugzilla.gnome.org/show_bug.cgi?id=675275>. Can anyone
enlighten me with what the "profile implementation" mentioned in comment
7 means, or whether this has been fixed in gst 1.0?

I would also like to be able to correct some files I've already ripped,
especially some from obscure CDs which aren't on musicbrainz so I'd have
to enter the details all over again. I think it's fairly easy to read
the true duration from the mp3s somehow, because I'm sure I remember
seeing that when I played them in banshee it showed the true duration
by the progress bar, but still the wrong duration in the track listing.

So is there a way I can correct the files with command line tools or
something I could write with pygst?