Well, I re-encoded with normal H.264 and managed to get the RasPI to play it back. Playback is kinda "klunky", both for a 640x480 and a 720p video, but it plays the video and audio. When the playback position jumping starts, all hell breaks lose (as predicted), with playback getting worse and worse with the number of consecutive jumps.
Tried encoding the video with mJpegA and B, but playback is even worse... Image freezes frequently and audio shuts off after 1 second or so of noisy playback. jpeg2000 doesn't even start playback... Quicktime movie with Photo jpeg loads the movie but freezes the app on playback.
What would be good settings to allow for decent jump-playback?
And this question now goes away from programming, I know, but everything else seems to be working, only video playback isn't that great.