With this bash script one can encode videos for his Android with 480×320 screen.
for f in *.avi;
do ffmpeg -i "$f" -s 480x320 -vcodec mpeg4 -acodec libvo_aacenc \
-ac 1 -ar 16000 -r 13 -ab 32000 -aspect 3:2 `basename $f.mp4`;
done
Enjoy the videos on your commute! 🙂