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General discussion of future public test
post Dec 21 2011, 16:28
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Now when itís sure that Apple encoder represents AAC standard very well the next step will be a public multiformat test.
No particular date or plan. Itís a general discussion with the purpose to hear the opinions, points of view, suggestions.

Items to talk about (these numbers are first approximations):
1.The number of codecs: 4+low anchor. 4 is affordable number for one test.
2.The selection of codecs (basing on curret previous votes):

Apple LC-AAC - the most optimal AAC encoder. (Well, though FhG was quite good too).
MP3 LAME Ė 10 votes
Vorbis AoTuV Ė 8.5 votes.
Opus/CELT Ė 6 votes. (still no info when there will be Opus 1.0)

Itís possible to change your votes.

(?) USAC (working name of future AACís successor ). No information about future availability of it.
(?) low anchor
(?) Settings, versions, etc.

3. Bitrate:
VBR 96 kbps. The last AAC public test was at 96 kbps (well, it was actually 100 kbps).
Also I think it will be more interesting to compare MP3 128-135 kbps and AAC/AoTuV 96-100 kbps. Probably a lot of people are interesting to trade off between compability/compression efficiency smile.gif

4. Samples.
Last time we have applied the technic of random selection of the samples. 20 samples.

The developers are very welcome to participate in this topic.

This test should be more interesting as it will include interesting (for use) codecs. biggrin.gif
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post Mar 3 2012, 08:06
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USAC has been "released" with the confusing name "Extended HE-AAC." As one might guess from the new name, I don't think USAC is intended to replace AAC (LC or main profile) at higher bitrates; things I've read have seemed to imply that USAC (or at least its sweet spot) is supposed to top out at 64kbps.

Once somebody can get their paws on a USAC encoder I really think we should do another 48kbps (or possibly as low as 32kbps) test; I'd imagine HE-AAC encoders have come a long way in the >5 years since the last 48kbps test, and of course Opus is an important addition. Perhaps that could be the next one after the 96kbps test?

Go ahead and include Opus without waiting for a 1.0 release. The 1.0 release will likely include few changes; the reason it's long in coming has more to do with the drawn-out formalities of standard bodies than with the technical readiness of the format.

Vorbis too, partially because of its use for html5 audio.

I strongly feel that an MP3 encoder at the target bitrate should be included whenever possible, even when the target bitrate means we're confident it will be blown out of the water by the competition. My main reason is that this makes the test results more accessible to a wider audience; people are familiar with MP3 and having it as a point of comparison helps them have a better perspective on what the results mean. It's also simply interesting to see the progress made both in newer formats and in MP3 encoders. It'd be nice to include higher-bitrate MP3 as well; the space-compatibility tradeoff is real, and while "96kbps AAC=128kbps mp3" is probably roughly accurate, it's odd that a claim that's been made so frequently doesn't seem to have been definitively put to the test.

Note that Sebastian's test of MP3 encoders at 128kbps 3 1/2 years ago ended with "The quality at 128 kbps is very good and MP3 encoders improved a lot since the last test. This was the last test conducted by me at this bitrate. It's time to move to bitrates like 96 kbps or 80 kbps." Anybody who thinks that MP3 should only be tested at 128kbps or above needs a reality check; if we test at a bitrate where a significant number of codecs are practically transparent then testing is very difficult for the participants and in the end we get no worthwhile results.

As far as the LAME sample rate thing goes, I'd say we want to provide encoders the latitude to make any decisions they want to as they try to optimize audio quality. The only real reason to worry about LAME resampling the audio is questions of how people's sound cards may deal with the difference-- so just use a high-quality resampler to make all the encoders' decoded samples the same sample rate.
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post Mar 3 2012, 09:50
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Anybody who thinks that MP3 should only be tested at 128kbps or above needs a reality check.

We can use LAME@96k as a low anchor then. It should be good enough not to flatten results of the other encoders.
It could be a reality check to people who think mp3@96 can compete with vorbis/aac@96k. wink.gif

This post has been edited by knik: Mar 3 2012, 10:01
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Posts in this topic
- IgorC   General discussion of future public test   Dec 21 2011, 16:28
- - Steve Forte Rio   Nice... QUOTE Itís possible to change your votes....   Dec 22 2011, 16:45
- - IgorC   Good. Guys, propose the codecs you are intereste...   Dec 22 2011, 17:03
- - IgorC   There is a first issue if MP3 will be tested at 96...   Dec 22 2011, 20:17
|- - NullC   QUOTE (IgorC @ Dec 22 2011, 12:17) There ...   Dec 22 2011, 21:44
|- - Nick.C   QUOTE (IgorC @ Dec 22 2011, 19:17) Possib...   Dec 22 2011, 22:34
- - lvqcl   8.5 votes? then: +1 for AAC +1 for Vorbis +0.5...   Dec 22 2011, 20:37
- - Kohlrabi   I'd like to see how Opus will perform here, so...   Dec 22 2011, 21:10
- - IgorC   Not all cards support automatic switching between ...   Dec 23 2011, 14:16
- - halb27   The fact that Lame resamples to 32 kHz at 96 kbps ...   Dec 23 2011, 16:37
|- - nu774   QUOTE (halb27 @ Dec 24 2011, 00:37) The f...   Dec 23 2011, 17:24
- - IgorC   Also this time I will be glad to be just a listene...   Dec 24 2011, 00:53
- - IgorC   Some feedback was received on #Hydrogenaudio and ...   Dec 25 2011, 18:18
- - Yaztromo   +1 QT AAC +1 Vorbis (Aotuv b603?) +1 LAME 3.99 +0....   Dec 26 2011, 02:33
- - Gecko   +1 for keeping the number of codecs small. Conside...   Dec 26 2011, 12:43
- - IgorC   Very low quality low anchor permits to analyse the...   Dec 26 2011, 14:10
|- - knik   How about FAAC, I think it could be good as anchor...   Mar 2 2012, 10:44
- - Kohlrabi   Any chance to see Musepack competing against curre...   Mar 2 2012, 12:41
- - jensend   USAC has been "released" with the confus...   Mar 3 2012, 08:06
|- - knik   QUOTE Anybody who thinks that MP3 should only be t...   Mar 3 2012, 09:50
- - Pretentiousman   +1 Apple LC-AAC +1 MP3 LAME @ 128-135 kbps +1 Vorb...   Mar 7 2012, 22:03
- - Gainless   I think it would be a good idea to make another AA...   Aug 9 2012, 14:14
- - Garf   QUOTE (Gainless @ Aug 9 2012, 15:14) I th...   Aug 9 2012, 16:09
|- - jensend   QUOTE (Garf @ Aug 9 2012, 09:09) Ideally ...   Aug 10 2012, 04:09
- - IgorC   QUOTE (Gainless @ Aug 9 2012, 10:14) I th...   Aug 16 2012, 14:48

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