In order to compile the FFmpeg for Android, you will need to download the Android NDK. After that, open the 'build.sh' script and replace the path to the NDK (variable NDK_DIR) with yours.

Before compile, you need to update the FFmpeg repository. To do that, execute:

git submodule init
git submodule update

Then execute 'sh build.sh', and after that the compiled libraries will be at 'libs/armeabi/'.