Looking at Q Format

For the lack of anything better to do I took a second look at Shannara game from Legend Entertainment (yes, I was that bored). And while it failed to captivate me once again, at least I have discovered yet another video format.

Actually I like old adventure games of theirs, especially the fact that they use RealSound technology (even if it’s just a way to play PCM on PC Speaker). But Shannara is a hybrid game with all the map travelling and fighting monsters. And I could not get into Terry Brooks’s books either, the first Shannara book reminded me of Lord of the Rings but in post-apocalyptic setting with magic appearing for some reason so I dropped it halfway.

In either case, the game featured full-motion animations and of course I had to look at them. As one would expect, all of them could be found in FLICS subdirectory and some of them even were in FLIC format. The rest were sporting rather rare .q extension and I doubted those were Quantum archives. After looking closer it turned out to be quite interesting format.

Video is compressed by splitting frame into 4×4 blocks, usually coding those blocks either as a block filled with two colours using a pattern or by copying some previous block (it does not try to motion search up to a pixel precision but it can reuse any block from a frame). There is an additional coding mode for coding either raw 4×4 block or block filled with 3-8 colours in a pattern. And additionally 128 of the most commonly used patterns for a group of frames are transmitted in a separate chunk before those frames, in result you can use just one byte to code that index instead of two bytes for a full pattern.

Even if I haven’t managed to figure out all details from it and there may be other flavours of it in other games, it was a surprisingly original format and it was fun looking at it.

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