If you had one of these every day more affordable and really cheap mitzui and others DVD players that also reproduce vidx and xvid video and read USB sticks/Memory Cards, but not MP4 with AC3. Sure you want to be able to reproduce without have to burn a CD with something like nero or similar to convert between formats.
I tried ffmpeg on Debian and found some interesting things:
- Build lacks MP3 sound codec, cause patent problems on several countries
- Also DivX is not included as is commercially owned and the legal of this is not gray but more like black so not included (even when its a implementation of H264/MPEG-4VC, same or worse problem for DivX ;) (MPEG-4 version 3)
- Strange enough never can make Xvid output, I found this is because patent issues on several countries…
So even transforming to AVI, Indeo/M$/H264/MPEG-4, the audio where in mp2 or AC as cant make use of liblame without make a mess o compile my own ffmpeg.
In any case the magic incantation to get what I need was:
ffmpeg -i movie.mp4 -vcodec xvid -acodec mp3 movie.avi
This is cause before I have done a really big file with MPEG-1 video and mp2 sound (terrible if you wonder), to just found that my decoder reads well, but don’t support external subtitles on mpg files :( bummer.
Finally found that even in win you can use ffmpeg for free with WinFF (that regardless of the name runs on Linux and Win)  that gives nice menus and combos, yes I know that for win exist a monstrous encoder called Super  but that thing is really big, useful when you need FFmpeg , MEncoder , MPlayer , x264 , MusePack (mpc) , Monkey’s Audio (ape) ,Shorten Audio (shn) , Tom’s Audio Kompressor (tak) , True Audio (tta) , WavPack (wv) ,libavcodec library (compiled inside FFmpeg and MEncoder) & the theora/vorbis RealProducer’s plugIn… but normally FFmpeg is just enough.
By the way searching for info I reached 19 ffmpeg commands for all needs  that gives you a very good cheat sheet and examples of how craft ffmpeg switches and options.