You know, the greatest reverse engineer I know is Derek B. He’s managed to RE such codecs as Canopus HQX and Cineform HD in the most efficient manner ever—saying he’ll do it and patiently waiting until somebody else does it.
So here are some words about his favourite lossless audio codec. The most interesting thing about it is that it was actively developed in 2001-2006 and then it was suddenly resurrected in 2015. Also it’s one of few non-standard codecs (i.e. not made into standard) that has several articles written about it.
The codec actually consists of two different formats, seemingly an old one and a newer one (that looks like it supports all range of sample type). The former is notable for having signal reconstruction stage using floating point math (a thing you don’t see in codecs every day), the latter seems to employ various parameter reading and reconstruction methods. Coding is done using low precision range coder (large values are decoded using chunks of 8 or 12 bits). So nothing really interesting there.
P.S. I’m definitely not going to write a decoder for it. There are too many lossless audio codecs already, let all proprietary ones (in custom containers too) die in peace.
You say that has if this Derek fellow had a plan, and was simply not a lazy, lazy person. This is, of course, speaking as someone who is definitely not him.
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Also, you’ll be pleased to know that a certain nuker of atoms is working on FFA1.
When you have a
Daala coderhammer every problem looks like acodecnail. Feel free to tell him about LTAC.There is plan that OptimFROG will be open sourced.
There was such plan for other codecs, you might remember how well opensourcing TAK went.
Your “there is too much of them already” is acceptable for unremarkable codecs IMHO, but in this case it is a codec that outperforms the current competition (it achieves better compression than maxed TAK and wavpack, nto to speak of FLAC which is pretty weak).
So I think there is value in it – while you have every right to not do it yourself, having a decoder would be beneficial. Be it by open sourcing or by REing. Another option is to get a different (future), even stronger lossless codec into ffmpeg.
@Mandarinka
> Your “there is too much of them already†is acceptable for unremarkable codecs IMHO…
I remember when I first tried playing Monkey’s Audio on my laptop it was stuttering — because it was unable to decode in realtime (while FLAC was incredibly fast on the same hardware). A lot of those experimental codecs compresses better only by a couple of percents than conventional codecs while using a lot more time to compress and decompress. I’ll write a separate post on my opinion about such codecs.
> having a decoder would be beneficial. Be it by open sourcing or by REing.
On the contrary, it will only encourage people to use it more instead of sticking to much more convenient formats one can actually encode too. That’s why I was not going to reverse engineer TAK even if it had rather interesting entropy coding.
> Another option is to get a different (future), even stronger lossless codec into ffmpeg.
You haven’t heard about Sonic then.
I like to “RE” codecs like XMA that do not reinvent wheel.