VBR mp3 length

[No One]

Hello all,
If this isn't the correct newsgroup, please redirect me.

I'm trying to extract the song length from variable bit rate mp3's.
Does anyone know of a library or bit of code that will do this?  I've
tried pymad, but it seems to grab the bitrate of the first frame and
then apply that to the the file length to come up with a total length.
Needless to say, if the bitrate of the first frame isn't close to the
overall average, it's wildly off.

Thanks,
-Steve