Thanks to the amv-codec-tools we now have somewhat working decoder (using ffplay) and encoder (using ffmpeg) of AMV format which cheap s1mp3 players are using.
You can convert video using just Linux box which plays on hardware player (apart from glitz at the end where it sometimes reports format error), but luminance is all wrong: colors are much brighter then they should be. Oh, did I mentioned that frame is flipped so that you can't read text? ;-)
On the bright size, display on players isn't that good, so turning your player under slight angle might make picture quite good.
And player doesn't mind being turned upside-down for video playback...
Anyhow, if you wanted to quickly convert video to your player on Linux box, it has some use, at least for me...
We have part of decoder submitted into ffmpeg upstream, and home to have all part merged when we fix remaining issues. So, if you know something about jpeg, mjpeg or mpeg video, help with croma/luma issue is welcomed. Instructions for download and compile are short and sweet, so dive in!