Archive for March, 2025

Random NihAV news

Saturday, March 8th, 2025

Since I can’t do anything about the world largest countries run by over 70-year old dictators, I try to find a distraction elsewhere. It usually works only until the next time I read next. Anyway, here’s something different for a change.

With all the work on na_game_tool I’ve been mostly neglecting the original NihAV (not that it makes much difference). So I’ve tried to improve it a bit and I have something to report.

First of all, I decided to make ARMovie support more complete (after discovering that e.g. the only thing that can play Eidos Escape 122 codec is their own DOS player). So I’ve added all three video codecs with known samples (Escape 122, 124 and 130) as well as their ADPCM codec. Sadly Escape 122 description in The Wiki is somewhat unclear, so I referred to the original DOS player for it. Similarly I looked at ADPCM decoding because what libavcodec produces is not quite right (but I guess Paul can tell you more stories about all those IMA ADPCM flavours). So I guess now my project has the most complete ARMovie formats support out there. There’s only one other third-party format I’m aware of (The Complete Animation film, it may be stand-alone or encapsulated in RPL) and I might get to it eventually.

The other thing is TrueMotion S. When you think there’s nothing unknown left about it, it manages to surprise you anyway. So I was looking at Discmaster search results for potential candidates (“aviAudio” is a good format for that—sometimes it is really AVI with audio track only, sometimes it is AVI with unknown video codec) and found three .duk files that were TM1 in AVI and which could not be decoded. It turned out to use codebook 0—which is not present in the open-sourced version of the decoder. Another thing is that it does not use so-called fat deltas (i.e. larger difference values), so code zero means eight zeroes instead of an escape value. Remarkably, this is demo of The Horde game by Toys For Bob, known to employ yet another exotic version of the codec in their 3DO version of Star Control II. It makes me wonder if they had the same relationship with Duck as JVC NWC with RAD (you know, the company which released a game with Bink-b videos not found anywhere else and bundling Bink-d decoder with one of their other games—all while others started with Bink-f or later).

Hopefully I’ll be able to do more in the future, but I wanted to share these stories while they’re still fresh.

Posted in NihAV, TrueMotion, Various Video Codecs | 7 Comments »

na_game_tool 0.3.0 released

Tuesday, March 4th, 2025

This is finally a release I’ve been wanting to make—with a format for each letter of the alphabet! It features about twenty new formats supported, a dozen of them being newly reverse engineered by me and the rest coming from NihAV, various open-source game engines and my older RE work. The games are diverse too, as some of them come from Argentina, Finland, France, Germany, Israel, Japan, Spain—beside the usual English-speaking countries (I’ve not tried to achieve it but that’s a nice thing too).

As usual, it’s available here (but who really cares?).

Considering that I’ve mostly exhausted the games to look at and the goals for the next release are at least twelve new formats and to support over hundred formats in total (i.e. about twelve in total), I’m not sure the next release will happen this year. I’ll find other stuff to do meanwhile.

Posted in NihAV | 5 Comments »

Cinepak everywhere!

Sunday, March 2nd, 2025

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).

Posted in Game Video, NihAV | No Comments »