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CELT 0.9.1 is out!, Help wanted
jmvalin
post Nov 16 2010, 02:56
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Xiph.org Speex developer


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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.
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sauvage78
post Feb 5 2011, 04:54
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Personnaly I have some interest in it, but I need a win32 command line encoder/decoder to test it my way. I am moderately interested in testing how it competes nowadays against aotuv & nero aac in a self-made single test, but I am not interested to help for development in the long run... specially if it doesn't compete well & specially on already encoded wavs which are not my own selection of killer samples. (In short I am interested in a very selfish test serving my own needs & I don't care what others may think of my test). Anyway I am not in a hurry to test it because if ever it would beat aotuv (which would mean it has improved a LOT since V0.52 ... which it certainly has considering how many updates there were since V0.52) then it will be frustrating to have all the aotuv zealots on my back for teaching them that Vorbis would likely be dead ... I wish that CELT would be the new messiah but having seen in the past how musepack/vorbis/aotuv development has stalled when their developer interest slowed down, I suspect that, sooner or later (hopefully later), CELT will follow the same fate, so honestly I am much more interested by an open source aac equivalent to x264 developed by a team, which I think would be more future proof, then I will ever be by a xiph codec developed by a loner (no matter how clever he is). My only problem with aac is its non-native & non-robust gapless support via tricky deletable tags. I like the robust vorbis gapless support & I think CELT might inherit this which is why I still have some interest in it. AAC already perfectly suits my needs for blu-ray audio part encoding because gaplessness is not needed there.
If ever CELT beats aotuv then we will end up with a better-then-vorbis codec with no [f2k-cuetools-eac3to-mkv-5.1-rockbox] support, which would be an annoying (but hopefully temporary) situation.

All this put together made that if I do have some interest in CELT, I always plan to test it ... later. I use flac for CD & nero aac for blu-ray & CELT alone is unlikey to change this. My small interest for CELT is due to 2 possibility both with unlikely probability:
1: I run out of HDD space because my 5 HDD sata (the 6th one is for SDD) are full, then I will need CELT. (Only if I don't favor lossywav)
2: Webm becomes better than x264, then I will need CELT. (... but I don't believe in Santa Claus anymore)

As you see CELT beeing trapped in the family of Xiph codecs, & this family of codec being non-competitive (x264 beat webm/theora, & nero aac beats aotuv), even if CELT alone would become the perfect lossy codec (the quality of nero aac with the robust gaplessness of vorbis) that doesn't mean it would be enougth for me to use it, because CELT is "bonded by blood" to a sub-optimal family of video codecs. (Using it would mean mixing mpeg with xiph in mkv which I tend to avoid.)

I know it may sound discouraging, but I only explain all that for you to understand why I didn't anwser to your request for me to test CELT one month ago.
Just like lossywav, I like CELT on paper, but I just don't use it in real life actually.

Sorry for not answering your pm directly a month ago (jmvalin), I was too lazy & short of time to write this down. Furthermore I was fearing that you wouldn't like much my opinion about the actual state of lossy codecs.

To sum up according to me, CELT is in a very paradoxal situation, where it might have become a real challenger for aotuv & nero aac, but because of its missing features/missing support/non-mpeg status, even if it would be the best codec around, I would likely not use it ... well at last not untill an eco-system was built around it.

I don't want to be the only guy on earth knowing that CELT is (maybe) the best pure lossy codec around, so I just don't test it to avoid the headache ... I know it's a vicious circle, but it's not my problem, I leave the frustration to ... IgorC [no you don't need to thks me, man wink.gif]

This post has been edited by sauvage78: Feb 5 2011, 05:20


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Secure [Low/C2/AR(2)]
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jmvalin
post Feb 5 2011, 05:20
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A few things I'd like to say here about CELT to answer some of questions and address some misconceptions. First, CELT has gone a long, long way since 0.5.2. In fact, there were more changes since 0.5.2 than there were from the beginning to 0.5.2. Among the things that changed is that CELT now supports longer frame sizes than you tested earlier (20 ms vs 5 ms) though the smaller frame size is still supported. Another difference is that it now supports VBR. On top of that, there's been a huge number of other changes. I'm sure if you tested again, the results you would get would be a lot different than with 0.5.2. I recommend you listen to the samples on Monty's CELT demo page (if you hear clicks in the samples when played from the web page, it's a browser bug and you should download them directly), which has some comparisons with Vorbis and AAC. The 32 kb/s and 48 kb/s samples aren't that useful (below the sweet spot), but the 64 kb/s ones should give a good idea of the quality. Of course, CELT also scales up to 510 kb/s for stereo. Also, if you look at IgorC's results, you'll see that CELT actually beats Vorbis aotuv on most samples, though of course the results vary from one sample to another.

As for you comment about "As you see CELT beeing trapped in the family of Xiph codecs", you should know that CELT is actually one half of the Opus that is currently being standardized at the IETF. The other half is Skype's SILK codec. So practically speaking, CELT is likely to see very wide deployment, starting with Skype. As I've pointed out before, CELT's main focus is *interactive* audio, which means it can give very good audio quality for real-time applications (unlike MP3, Vorbis and HE-AAC). To achieve that we've had to do some sacrifices, but even despite that, the quality is competitive with that of the AAC family. And the same codec can actually work from 6 kb/s (speech) to 510 kb/s, rather than having different profiles for different bit-rates and applications (HEv1, HEv2, LC, LD, ELD). So being standardized at the IETF means we're no longer talking about just a single developer or organization.

As for the tools, don't worry, that's the next thing on the list once the bit-stream is frozen. Which brings up another point. The bit-stream is currently in soft-freeze, so there's a short window of time where the codec is in a pretty good state, but we can still fix any issue that would be discovered before the bit-stream is officially frozen. So I definitely recommend you try CELT again. If binaries are a problem, I may be able to get someone to make Win32 ones. Alternatively, I can provide you with encoded samples.
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IgorC
post Feb 5 2011, 18:39
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QUOTE (jmvalin @ Feb 5 2011, 01:20) *
If binaries are a problem, I may be able to get someone to make Win32 ones. Alternatively, I can provide you with encoded samples.

If there will be binaries than I will can do an extensive test on many samples and make detailed conclusions as performance per genres, different kind of artifacts, stereo image, soundstage, comparison with other codecs. Or you can suggest what aspects are need to be tested.

If you think that celt is ready for this kind of test then binaries are good. However if you still need some results for particular samples than you can provide these samples as well.


PS. It might also be true that comparison between CELT and Vobris, AAC at higher bitrates (128 kbps and above) can be misleading. CELT has new superior technics but Vorbis and AAC encoders are very well tuned during the years.

This post has been edited by IgorC: Feb 5 2011, 19:17
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NullC
post Feb 7 2011, 05:42
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QUOTE (IgorC @ Feb 5 2011, 09:39) *
PS. It might also be true that comparison between CELT and Vobris, AAC at higher bitrates (128 kbps and above) can be misleading. CELT has new superior technics but Vorbis and AAC encoders are very well tuned during the years.


You can say that. For example, the CELT encoder doesn't have an explicit psy-model. The format is designed so that one isn't strictly necessary, but a good one could be very helpful for VBR rate selection, right now all the VBR really does for CELT is improve transients. We haven't included an explicit psy-model because we've been focused on things that can't be done after the bitstream is final. The encoder also doesn't perform any analysis which would increase latency or which would be too computationally expensive for embedded devices, e.g. it doesn't use anything more than 2.5ms lookahead and it doesn't switch frame sizes on the fly (except the binary short/long decision). But future and alternative encoders can and will.

So there should be plenty of room for future improvements remaining.

Though I'm not so confident at comparisons with AAC and Vorbis at higher rates for another reason: This is not at all what CELT was designed to do. We built it for very low-latency, so that you could have awesome quality teleconferencing and telephony, remote music, low bandwidth digital microphones and headsets, etc. By some happy accident it's looks like its almost competitive with the best popular high latency codecs at least at some bitrates. But most implementations these codecs have the benefit of well tuned VBR engines, so on high rates with killer samples I expect that they'll do much better than CELT.

But you can not use AAC (non-LD) or Vorbis for telephony, it's a non-starter. They're useless for this. Among the codecs that can be used for low latency CELT is very good. In strict hard-CBR mode (no-bitres) CELT is very good, etc.

If you care about audio quality, then you should care about CELT not because it's going to be the best hifi codec for storing your music collection (These days you're crazy if you're not just using lossless for that purposes) but because you're going to find it all around you for other purposesó embedded in telephones and teleconferencing systems and in VoIP apps, used for wireless audio systems, in video games for realtime audio as well as sound effects, etc.

In any case, since people asked... I create a win32 build of the 0.11.0 encoder and decoder tools: https://people.xiph.org/~greg/celt/celt011-win32.zip

I would encourage testing at 48kHz rather than 44.1kHz because 48kHz is our officially supported and tuned sampling rate. The other rates are offered on a best effort basis for custom applications which have particular timing requirements. I'd certainly like to hear reports about other rates if you test them, but I can't promise that they work as well as 48kHz.

This post has been edited by NullC: Feb 7 2011, 05:45
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Ljubo44
post May 23 2011, 20:40
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QUOTE (NullC @ Feb 7 2011, 06:42) *
In any case, since people asked... I create a win32 build of the 0.11.0 encoder and decoder tools: https://people.xiph.org/~greg/celt/celt011-win32.zip


Link not working. Can someone upload celt encoder .. anyplace. Please.
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Posts in this topic
- jmvalin   CELT 0.9.1 is out!   Nov 16 2010, 02:56
- - punkrockdude   I think, after several listenings, that A sounds b...   Nov 19 2010, 19:18
- - Primius   In file A i noticed warbling distortion on guitars...   Nov 20 2010, 00:21
- - IgorC   logs h*tp://www.mediafire.com/?7ed142tcipntet1   Nov 21 2010, 02:25
- - jmvalin   Thanks very much guys. I guess I should start by t...   Nov 21 2010, 03:45
- - IgorC   logs h*tp://www.mediafire.com/?t8ko84f34bz8b5f Th...   Nov 22 2010, 20:32
|- - jmvalin   QUOTE (IgorC @ Nov 23 2010, 05:32) The ...   Nov 23 2010, 02:16
|- - IgorC   QUOTE (jmvalin @ Nov 22 2010, 23:16) Than...   Nov 23 2010, 04:20
|- - jmvalin   QUOTE (IgorC @ Nov 23 2010, 12:20) QUOTE ...   Nov 23 2010, 05:19
- - IgorC   All right, I will test fileL later. There was an...   Nov 23 2010, 03:38
- - IgorC   Sample I is still preferable but there is no stati...   Nov 27 2010, 04:51
- - IgorC   Description of artifacts. 1st sample. Samples H a...   Nov 28 2010, 05:00
|- - jmvalin   Thanks again for taking the time to listen to thos...   Dec 8 2010, 15:29
- - IgorC   What encoders did you used for Vorbis and HE-AAC? ...   Dec 8 2010, 20:37
|- - jmvalin   QUOTE (IgorC @ Dec 9 2010, 04:37) What en...   Dec 9 2010, 02:25
|- - jmvalin   QUOTE (jmvalin @ Dec 9 2010, 10:25) Regar...   Dec 9 2010, 02:36
- - IgorC   Chris has made tremendous work on compilation of ...   Dec 9 2010, 03:51
|- - jmvalin   QUOTE (IgorC @ Dec 9 2010, 11:51) Chris h...   Dec 9 2010, 06:01
- - IgorC   Logs h*tp://www.mediafire.com/?c54du2c2b95mjsn Ma...   Dec 9 2010, 05:07
|- - jmvalin   Thanks again for the results. I'll investigate...   Dec 9 2010, 14:47
|- - jmvalin   QUOTE (jmvalin @ Dec 9 2010, 22:47) Thank...   Dec 9 2010, 21:31
- - IgorC   Sample X did better on speech but still has low fr...   Dec 10 2010, 04:30
|- - jmvalin   Wow, thanks very much for all these results. I...   Dec 10 2010, 15:38
|- - SebastianG   Hi Jean-Marc, I just skimmed through some parts o...   Dec 10 2010, 16:10
|- - jmvalin   QUOTE (SebastianG @ Dec 11 2010, 00:10) I...   Dec 10 2010, 19:34
|- - SebastianG   QUOTE (jmvalin @ Dec 10 2010, 19:34) QUOT...   Dec 10 2010, 20:40
|- - jmvalin   QUOTE (SebastianG @ Dec 11 2010, 05:40) I...   Dec 10 2010, 20:48
- - IgorC   Jean-Marc, How does CELT scale with higher bitrat...   Dec 10 2010, 19:01
|- - jmvalin   QUOTE (IgorC @ Dec 11 2010, 03:01) How do...   Dec 10 2010, 19:25
|- - jmvalin   QUOTE (IgorC @ Dec 10 2010, 13:01) How do...   Feb 15 2011, 02:04
- - jmvalin   OK, so I've worked a bit on improving some of ...   Dec 10 2010, 23:36
- - IgorC   Jean-Marc, What do you plan for test of CELT? If...   Dec 13 2010, 22:01
|- - jmvalin   QUOTE (IgorC @ Dec 13 2010, 16:01) What d...   Dec 13 2010, 22:25
- - IgorC   Jean-Marc, I see that version 0.10.0 has been rel...   Dec 24 2010, 00:34
|- - NullC   QUOTE (IgorC @ Dec 23 2010, 16:34) Jean-M...   Dec 24 2010, 02:02
- - IgorC   The differences are small. The results with HD650...   Dec 24 2010, 19:35
|- - C.R.Helmrich   QUOTE (IgorC @ Dec 24 2010, 20:35) Fatboy...   Dec 25 2010, 21:23
- - IgorC   Hi, Chris. Actually the question was about the po...   Dec 26 2010, 04:32
- - IgorC   I think it can be worth to redo the last test or d...   Dec 26 2010, 09:39
- - IgorC   I've tried several time with HD650 and HD447. ...   Dec 29 2010, 23:26
- - IgorC   Aparently CELT scales good with higher bitrates. ...   Dec 30 2010, 20:55
|- - jmvalin   QUOTE (IgorC @ Dec 30 2010, 14:55) Aparen...   Dec 31 2010, 05:34
|- - IgorC   QUOTE (jmvalin @ Dec 31 2010, 01:34) If y...   Dec 31 2010, 06:00
- - IgorC   96 kbps: LC-AAC info: iTunes 9.0.0.70, 96 kbps, VB...   Dec 31 2010, 08:43
- - IgorC   Maybe CELT should compete not only with LD-AAC but...   Dec 31 2010, 18:44
- - rt87   I wonder if someone can do 48kbps tests comparing ...   Jan 1 2011, 01:59
- - IgorC   You can have an idea basing on results of 64 kbps ...   Jan 1 2011, 14:32
- - NullC   Anyone following along with the CELT technical dev...   Jan 26 2011, 02:09
- - jmvalin   OK, so we've been a bit quiet lately but worki...   Jan 28 2011, 00:36
- - IgorC   The artifacts of both files have very similar natu...   Jan 28 2011, 14:48
|- - jmvalin   QUOTE (IgorC @ Jan 28 2011, 08:48) The ar...   Jan 29 2011, 06:24
- - IgorC   0.11.0 has been released. Good news. I wonder tha...   Feb 5 2011, 02:50
- - sauvage78   Personnaly I have some interest in it, but I need ...   Feb 5 2011, 04:54
|- - jmvalin   A few things I'd like to say here about CELT t...   Feb 5 2011, 05:20
|- - IgorC   QUOTE (jmvalin @ Feb 5 2011, 01:20) If bi...   Feb 5 2011, 18:39
|- - NullC   QUOTE (IgorC @ Feb 5 2011, 09:39) PS. It...   Feb 7 2011, 05:42
|- - jmvalin   QUOTE (NullC @ Feb 6 2011, 23:42) I would...   Feb 7 2011, 05:53
|- - Ljubo44   QUOTE (NullC @ Feb 7 2011, 06:42) In any ...   May 23 2011, 20:40
- - sauvage78   One of the reason why I wait for a CLI encoder/dec...   Feb 5 2011, 06:20
|- - IgorC   QUOTE (sauvage78 @ Feb 5 2011, 02:20) Sor...   Feb 5 2011, 06:34
|- - jmvalin   QUOTE (sauvage78 @ Feb 5 2011, 00:20) Sor...   Feb 5 2011, 12:53
- - [JAZ]   @sauvage: I don't understand you. First, you...   Feb 5 2011, 11:40
- - sauvage78   QUOTE you put doubts on how much it has improved s...   Feb 5 2011, 13:28
|- - jmvalin   If you want to see how far CELT has come, there...   Feb 5 2011, 15:18
- - list   any future improve towards 32kbps range?   Feb 6 2011, 19:25
|- - jmvalin   QUOTE (list @ Feb 6 2011, 13:25) any futu...   Feb 7 2011, 04:00
- - list   I found some samples in which @64 kbps,48 khz , CE...   Feb 7 2011, 12:52
|- - jmvalin   QUOTE (list @ Feb 7 2011, 06:52) I found ...   Feb 7 2011, 13:03
|- - NullC   QUOTE (jmvalin @ Feb 7 2011, 04:03) QUOTE...   Feb 7 2011, 16:30
- - IgorC   I have a job to do until 10th of March. After that...   Feb 9 2011, 10:26
- - IgorC   Very short test on difficult eig sample Big surp...   Feb 13 2011, 21:09
- - IgorC   Single result for one random sample. Test of scala...   Feb 13 2011, 23:37
- - IgorC   The first sample that wasn't transparent at 19...   Feb 14 2011, 16:32
- - IgorC   CELT performs not enough well and worse than Vorbi...   Feb 14 2011, 22:21
- - IgorC   ~67 kbps test: CELT 0.11.2 (complexity 10, bitrate...   Mar 15 2011, 16:02
|- - NullC   QUOTE (IgorC @ Mar 15 2011, 07:02) ~67 kb...   Mar 16 2011, 13:27
- - LaserSokrates   Hey jmvalin, thank you and the team behind CELT fo...   Mar 16 2011, 14:27
- - Anakunda   Hello there, tried to compile celtenc with library...   Jun 2 2011, 14:35
|- - 2304p   QUOTE (Anakunda @ Jun 2 2011, 15:35) Hell...   Jun 3 2011, 07:16
- - Anakunda   Thanks much, that's work. I'd be intereste...   Jun 3 2011, 07:26
- - klonuo   You can get 0.11.2 also from here: http://listenin...   Jun 3 2011, 08:01
- - lvqcl   version 0.11.4 available at http://git.xiph.org/?...   Jun 3 2011, 10:43
|- - klonuo   QUOTE (lvqcl @ Jun 3 2011, 11:43) version...   Jun 3 2011, 11:35
|- - 2304p   QUOTE (lvqcl @ Jun 3 2011, 11:43) version...   Jun 4 2011, 15:09
|- - klonuo   QUOTE (2304p @ Jun 4 2011, 16:09) I have ...   Jun 4 2011, 19:37
|- - 2304p   QUOTE (klonuo @ Jun 4 2011, 20:37) QUOTE ...   Jun 4 2011, 22:42
- - Anakunda   celt.c violates the C standard several times in th...   Jun 3 2011, 11:45
|- - lvqcl   QUOTE (Anakunda @ Jun 3 2011, 14:45) celt...   Jun 3 2011, 11:57
|- - Anakunda   QUOTE (lvqcl @ Jun 3 2011, 12:57) QUOTE (...   Jun 3 2011, 12:09
- - lvqcl   Either I cannot compile CELT 0.11.4 correctly, or ...   Jun 4 2011, 16:28
- - klonuo   run automation bash script provided and then as re...   Jun 4 2011, 23:03
- - 2304p   can you compile celt-0.11.4.tar.gz and upload as c...   Jun 5 2011, 12:46
- - Anakunda   I can compile but for me it doesnot encode anythin...   Jun 5 2011, 13:38
- - lvqcl   Celt 2011-04-21: (re-uploaded: compiled with CUS...   Jun 5 2011, 16:38
|- - 2304p   QUOTE (lvqcl @ Jun 5 2011, 17:38) Celt 20...   Jun 5 2011, 17:59
- - darkbyte   Hi! First, thanks for this truly amazing code...   Nov 13 2011, 10:00
|- - NullC   QUOTE (darkbyte @ Nov 13 2011, 02:00) I...   Nov 14 2011, 09:23
- - darkbyte   QUOTE (NullC @ Nov 14 2011, 10:23) For fi...   Nov 14 2011, 17:57
- - Gainless   Can someone re-compile the celt version 0.11.4 to ...   Dec 12 2011, 22:37


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