Looking at yet another game format

Since I have nothing better to do and I don’t feel a desire to write a lengthy rant about what’s wrong with this world (beside the fact that russia still exists of course), I keep looking at various games I can find in order to see if they have some interesting format. Last time I’ve managed to locate an elusive Indeo IVF sample, now it’s rather curious FMV format.

So there’s an unpublished PC game called Highlander: The Last of the MacLeods which is apparently some kind of 3D action game based on the animated series (one of those, the franchise seems to have a lot in it beside the one good movie). And it turns out that it has a three dozen of FMV clips in proprietary format (stored inside mov.dat but extracting them is trivial).

From technical point of view the format is rather simple but video compression is rather peculiar: each frame in coded independently by painting each 4×4 block with 1-16 pixels using a certain pattern. That’s common but this data is packed with a simple history-based method: depending on a flag a value is rather read raw or reused from a history buffer depending on two previously decoded values. And now there’s a twist—this compression is applied twice.

Overall, it was fun to look at the format even if I don’t care about the game itself and the video quality is rather poor (probably thanks to the rather low bitrate and fixed palette all those FMVs share despite half of them being digitised animation clips and half of them being recorded in-game 3D animation). Still, now I can play the files with NihAV if I ever get such desire.

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