There are pre-packaged sources for FFmpeg including building instructions for Android:

* [http://bambuser.com/opensource Bambuser]
* [http://sourceforge.net/projects/ffmpeg4android/ ffmpeg4android]

[http://ffmpeg.zeranoe.com/forum/viewtopic.php?f=5&t=1005&p=4137&hilit=android#p4137 This forum thread] describes how to strip .so.5 type names, if you want to go the all-DLL route.