CELT 0.9.1 is out!, Help wanted Options

[jmvalin]

Hi,

I'd like to announce CELT version 0.9.1. There have been many quality enhancements since 0.8.x and even more so since the last version announced on HA. You can get it from the CELT website. Also, CELT is now a component of the Opus codec, which is in the process of being standardized by the IETF as a lossy audio codec for interactive applications.

Also, for those who would like to help, we are looking for volunteers to help tune the codec. The bit-stream is (finally) about to be frozen, so any quality improvements we can get before then is useful. No highly specialized skills required, just good critical listening abilities. As a first round, I'd be interested in comments and rankings of the following four audio files:

fileA.wav
fileB.wav
fileC.wav
fileD.wav

The bit-rate is fairly low (64 kb/s), so artefacts are easy to hear. This is the original (uncompressed) file. I'm interested in a quality ranking of all these four files (especially the ones that sound similar). I'll reveal the contents of these files after people have responded.

[sauvage78]

you put doubts on how much it has improved since 0.5.2

? I have no doubt it has improved a lot, the problem is more did it improve so much that it is now on par with well established competitors ? ... sorry when it come to ABXing, the only guy I trust more than myself is /mnt (because I often agree with him on bad samples, & when I don't obviously ... it means he is more skilled than me), not that I don't trust other ABXer, but when you start ABXing for yourself, except for finding new killer samples easyly, you don't need the opinion of others anymore. IIRC, it happened that I already disagreed with IgorC about the relative quality of aotuv vs. nero aac in the past, so I take his results with caution, not that I would cast a shadow on him, but IIRC using a different methodology & different samples, he ended with a different conclusion than me (using other samples & methodology). Maybe he was right & maybe I would have agreed with him if I would have run the exact same test. Maybe he is more sensitive than me on some kind of artefact, I don't know. All I know is that I trust myself, as pretentious as it may sound, simply because it's me who will listen to my own encodes, & not the ABXer with golden ears which tells me that this codec is good or bad.

because the codec has been a moving target

? I don't care about the codec being a moving target, as long as you don't request me to run after it.

... well in case I wasn't clear, I am not some kind of philantropic guy wasting my time testing codecs just for fun, if I test codecs that's because I expect some personnal benefits from using them !!! In the past I have spent some time testing experimental codecs more or less as an audio enthousiast would do, just for fun. Years ago I tested CELT out of pure curiosity (back then it happened that it was very bad but it was very experimental so in fact I didn't even considered it as a competitor), but for various reasons this time is over for me. Not that I don't want to do ABXing anymore, but it has to be worth the effort. I have no doubt that CELT did improve a LOT (specially has I know how bad it was), but the overall state of lossy codecs is rather depressing IMHO as most well established codecs have stagnated since my old test. So what I am trying to explain is that actually my personnal gain for testing it is low as I am unlikely to use it (I admit that nowadays I am more a mpeg guy, not that I particulary like patents but sadly the quality of x264 & nero AAC speaks for itself, & I like the safety of the industry support to mpeg, I also admit that I completely changed my mind on this topic as when I started ABXing (Edit: Before I started) I was a vorbis fan). In the end, even when it may have seemed that I was randomly playing at ABXing experimental codecs, I had IMHO a big personnal gain from testing so many different lossy codecs: I have learned exactly what I expect from a lossy codec & I expect so much that sadly none of them fully pleases me & ... I use lossless. But don't think it's about quality, the quality of nero aac q0.55 (~192Kbps VBR) is enought for my taste: I don't use lossy because no lossy codecs has my 3 requirements: (1:Transparent Quality)+(2:Native Robust Gaplessness)+(3:Future Proof: Big Norm). Only lossywav can almost fullfill all my (quality+features) needs, but it's twice the HDD space ...

So to come back to CELT, yes I do have some interest in testing it, the biggest question for me being how close/far it will be from aotuv & if it is slowly friendly killing vorbis in the shadow ? Answering this question alone is interesting, even if the other codecs didn't evolve, but whatever is the answer in the end I may not use CELT personnaly so I don't care if I test it here & now. Maybe Vorbis will, but I won't die if I don't test CELT soon. I known I will re-test it sooner or later anyway, my goals & my timing are just not the same as jmvalin, he would like me to test CELT before he froze the bitstream, but I expect to test it slowly within 1 or 2 months after he releases a windows binarie. I just don't want to spoil my fun.

Anyway I wanted to apologize for not answering his invitation a month ago, which was cowardice.

This post has been edited by sauvage78: Feb 5 2011, 13:59