I got curious and decided to look at RAA.
http://raa.ruby-lang.org/
mp3info claims to be able to give mp3 length.
-Carlos

On Sat, 19 Jan 2008 10:47:47 +0900, "Rick DeNatale"
<rick.denatale / gmail.com> said:
> I'm working on a project which has the requirement to automatically
> determine the runtime of audio files in several formats, right now mp3
> and aac.
> 
> I googled around to see if there might be some existing code,
> hopefully ruby code which can determine this, but I'm coming up dry.
> 
> Any ideas?
> 
> -- 
> Rick DeNatale
> 
> My blog on Ruby
> http://talklikeaduck.denhaven2.com/
>