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Topic: RK Audio codec reverse engineered (Read 2199 times) previous topic - next topic
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RK Audio codec reverse engineered

Just to report here that RK Audio codec (.rka) decoding/demuxing will be available in ffmpeg codebase soon.
Please remove my account from this forum.

Re: RK Audio codec reverse engineered

Reply #1
Just as a follow-up, ffmpeg 6.0 has been released. Besides RK Audio, decoders/demuxers for quite a few other oddball formats have been merged.

Quote
February 28th, 2023, FFmpeg 6.0 "Von Neumann"

A new major release, FFmpeg 6.0 "Von Neumann", is now available for download.

[...]

New decoders featured are Bonk, RKA, Radiance, SC-4, APAC, VQC, WavArc and a few ADPCM formats.

Many thanks. Reverse-engineering such formats isn't easy.

edit: of course, there have been many other improvements besides these. See https://ffmpeg.org/ for a list of 'some highlights'
Music: sounds arranged such that they construct feelings.

Re: RK Audio codec reverse engineered

Reply #2
@mycroft :
I see you posted this in the "Lossless" section of the forum, but from a few testings, it seems to me that one of the lossy modes is covered and the other is not - and unfortunately, ffmpeg gives no warning no nothing about the latter, and decode to something unplayable. Could I suggest that you make ffmpeg detect&reject any "-v" encodeded input file?

* A "-q"-encode did decode to same audio with ffmpeg as with rkau.exe . I could do further testing with -q, but I have a hunch then that -q makes files that "decode like the lossless"?
* A "-v"-encode decoded by ffmpeg (either to file or by ffplay) is unlistenable, and close to all samples are wrong.

rkau.exe version 1.07, ffmpeg version 6.0-essentials_build-www.gyan.dev

Also, out of curiosity: You can demux, but is there any container that these could ever be remuxed into?