Why not just allow people to record replays as special video files called .WAVideo? It would be a format that would require a specialized app that could play it (although if it gets REALLY popular, VLC might be able to play it). It would be simple: Just record the screen and put in a few optimizations, and then put it into a video file, and voila! You've got your video file, ready to play on any device with the compatible codec!