Quickly about Factor 5 VID 1

Yes, calculating that results in VID5 but in reality it’s MPEG-4 part 2 (minus some parts). Paul has asked me to look at it some time ago, so I did (which is much better than implementing a decoder for it). As I said already, this is essentially MPEG-4 part 2 with some insane parts being cut off (but not enough to turn it back into ITU H.263): there’s no support for special texture shapes, interlacing or even quarterpel motion compensation. There are still B- and S-frames to complicate things though. Bitstream format is cut down as well to remove most of the nonsense (or omgFFeatures if you have that view), so there are just frames containing basic header (or slightly less basic with GMC and S-frames) plus macroblock data. Macroblock data is almost identical to the expected format—they even still have sync pattern handling in MCBPC despite there being no need for that. So on the one hard writing decoder for it is not that hard, as you can simply hack an existing decoder for that, and…