To install it, open a terminal :
sudo apt-get build-dep ffmpeg
git clone GitHub - libav/libav: Libav github mirror, clone of git://git.libav.org/libav --depth 1
cd libav/
./configure --enable-static --enable-omx-rpi --enable-mmal
make -j4
Now you can launch avconv,avplay and avprobe from the directory !
Example convert some mpeg2 DVD vidéo file :
./avconv -i TRAILER_SAMPLE.VOB -c:a copy -c:v h264_omx -b:v 404k trailer-sample.mp4
Exemple lowering byterate on h264 1080p video :
./avconv -i sample-1080.mp4 -c:a copy -c:v h264_omx -b:v 404k sample.mp4
It run fast ~25fps !!!
With software encoding it run at 8 fps !
Edit : correct some errors