First of all, I’m happy to announce that I’ve finally managed to reverse engineer a format for game called Wing Nuts which means I’ve finally collected formats for the whole alphabet. So I want to implement another format that I’ve REd and I can finally release na_game_tool 0.3.0 in a week.
But what I really want to talk about is the game format itself. There are no real game videos but rather game engine data files containing various kind of data, including video frames. I could also extract PCM audio but I don’t know how to synchronise it properly so I ended up with a video-only decoder. MIDI data was yet another option that I ignored.
What is curious is the video compression format. While REing it I had constant thoughts like “hmm, it stores chunk type in a byte followed by 24-bit big-endian number, just like Cinepak” or “hmm, it uses 2×2 vectors and either scales them or combines four of them in a single 4×4 block, just like Cinepak” or “wait a minute, this bitstream format—chunk markers, flags and vectors—are exactly like Cinepak”. There are some differences from the usual Cinepak we all know though: it is a paletted format (with palette stored in a similar form before actual image data) and it has some additional chunks with codes 0x60-0x62 which seem to contain some auxiliary information used by the engine.
So seeing this shortly after CinEApak and knowing that SEGA company used slightly modified Cinepak format on its consoles, it makes me wonder is the codecs was more widely licensed and tweaked than we are aware of. That would make it even more like Duck TrueMotion (which was also widely used in game videos, on consoles as well, and with a special flavours used at least in one game).