Android: Using MediaRecorder to crop an existing audio file?

Question

Hi,

I'd like to take an existing mp3 file located on an SD card and arbitrarily crop it (e.g. crop from 0:12 to 1:14 in a 3 minute song).

The only class that I've seen that seems remotely relevant to do this is the MediaRecorder class. My 'hope' would be to "record" an existing file like this:

MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(###some magical way of specifying an existing file??###);

But this obviously doesn't work (setAudioSource() takes an int and seems to default to the phone's microphone).

Is there a class or an approach that can be used to crop audio on the phone itself?

TKS!!