How to get the volume level from an audio file

I've got an app that repeatedly records from the mic and stores it in short bursts in a temporary 3gp file. I'd like to get the loudest volume (or even just the first part's volume) from that file. Is there a way to do this through Android?

If it's easier to do wit开发者_C百科h mpeg4, raw amr, or the default format I can do that too. I'm stuck with Android 1.5 though, so some of the newer options in MediaRecorder.OutputFormat aren't available.

Thanks!