Kostya's Boring Codec World

Since I still have nothing much to do (and messing with browsers is a bad idea unless the situation is desperate), I decided to make a NihAV-lite project. So announcing na_game_tool.

This is going to be a simple tool to convert various game and image formats (and related) into image sequence, WAV or raw AVI (which then can be played or processed with anything conventional). I’ve begun work on it already but the release will happen when at least when I implement all planned features (which is writing image sequence in BMP format, AVI output and porting two dozen of half-baked decoders I wrote to test if I understood the format).

Why a new project? Because I have nothing better to do, it still may be marginally useful for somebody (e.g. me) and I can do some stuff not fitting into NihAV (for example, decode 3DO version of TrueMotion video split into four files) and I don’t have to bother about other stuff that fits demuxer-decoder paradigm poorly and requires inventing ways to convey format-specific information from the demuxer to the decoder. In my case I simply feed the input name to the input plugin and it returns frames of decoded audio or video data. Some hypothetical Antons might ask a question how to deal with the formats that use variable delay in milliseconds between frames instead (and I’ve implemented one such format already). To which I can reply that one can fit a square peg in a round hole in two ways—by taking a larger hole or by applying more force. The former corresponds to having, say, fixed 1000fps rate and send mostly the same frames just to have constant rate; the latter is forcing a constant framerate and hoping for the best. I chose the latter.

The design is rather simple: there’s a list of input plugins and output plugins. Input plugin takes input name, opens whatever files it needs, outputs information about the streams and then decoded data. Output plugin takes input name, creates whatever files it needs, accepts stream information and then receives and writes frames.

Probably there’s a better alternative with librempeg but you’d better go read about it on Paul’s blog.

This entry was posted on Sunday, July 7th, 2024 at 12:47 pm and is filed under Game Video, NihAV. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.