deterining duration of a sound file.

This is a two part question:

1. Is there a method of determining the length of a sound file (mp3 primarily);

   in bytes, elapsed time, before the file is played? (the file could be played against

   a stop watch and the elapsed time record after the fact, programmatically).

2. Is it possible to set markers and fast forward/rewind to markers corresponding

   to the file?

What I am thinking of is a feature allowing the user to play a file to a point and pause, set a marker, rewind

and play to the marker and stop, or fast forward from the beginning and play from the marker, or even play

past the marker and rewind to the marker.

Setting a marker would be the easy part: just record the elapsed time when the pause function is called.

Getting the sound file to start playing from that point without the previous part played at normal speed;

(with volume off) is the essential part of this question.

Thank you

JK