I don't know a complete answer, but part of that is you not
providing the needed details of "how" and "what" you're after.
ffmpeg is the underlying code powering programs like VLC (VideoLAN Client)
and MPlayer on desktop and laptop systems. It supports a lot of different
formats, both video and audio. There are a few porting attempts for VLC and
MPlayer to Android available, but I haven't tested any of them. There is also
a porting effort for ffmpeg itself:
https://github.com/appunite/AndroidFFmpeg
It should be a step in the right direction, but providing details on how you
expect to use it and what you want it to do should help others respond with
better answers than mine.