title: extracting mp3 file duration using AudioQueueServices
body: <p>I have implemented a streaming mp3 player using AudioQueueServices, that downloads mp3s over an NSURLConnection.   Playback, pausing, and seeking work great, however I can't figure out how to extract the duration of the audio from the mp3 files while they are still being downloaded.  I'd like to be able to pull the info from the id3 tags but am clueless as to how to do that.  Any thoughts? </p>