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Codecs and settings for 64kbit/s SE listening test, criticism required
Serge Smirnoff
post Oct 14 2012, 21:55
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As SoundExpert now has pretty stable flow of volunteer testers it is time to update codecs in all bitrate sections. After a short discussion at Russian bit-torrent tracker we decided to update 64-96-128-192-256-320 sections first. For the 64kbit/s section five codecs were chosen:

Fhg AAC (2012-06-24) - 59.2 kbit/s (fhgaacenc --vbr 2 se_ref.wav)
QAAC TVBR (v1.42) - 59.6 kbit/s (qaac --he -v56 se_ref.wav)
Nero AAC (v1.5.4.0) - 60.1 kbit/s (neroAacEnc.exe -q 0.25 -if se_ref.wav -of out.mp4)
Vorbis (Xiph 1.3.3) - 60.3 kbit/s (oggenc2.exe -q-0.3 se_ref.wav)
Opus (libopus 1.0.1) - 59.9 kbit/s (opusenc --bitrate 59 se_ref48.wav out.opus)
Conversion chain for Opus: 44.1/16 -->> 48/24(Audition CS6) -->> opusenc -->> foobar2000(48/24) -->> 44.1/16(Audition CS6)

Bitrates are calculated on the basis of nine SE test samples concatenated. Fortunately first two codecs have close values of resulting bitrates at their corresponding discrete quality settings. Other contenders were adjusted to have close values.

Did we miss something?


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jensend
post Oct 31 2012, 05:49
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QUOTE (Serge Smirnoff @ Oct 14 2012, 14:55) *
Conversion chain for Opus: 44.1/16 -->> 48/24(Audition CS6) -->> opusenc -->> foobar2000(48/24) -->> 44.1/16(Audition CS6)

Why on earth would you do that? You should just use opusenc and opusdec. opusenc will happily accept your 44.1/16 input and running the result through opusdec will by default give you 44.1/16 output.

opusenc and opusdec will handle any resampling internally and transparently, even making sure that opusdec's output has the exact same number of samples as the input to opusenc had. Using a convoluted Audition/foobar/Audition toolchain is more likely to introduce extraneous problems.

Also, I agree with other posters that your bitrate setting selections for these codecs seems rather odd. In concluding that these are the rates that "really" give an average 64kbps output, have you really tried this with a large and diverse collection, or are you jumping to conclusions based on a few choice files? If the latter, you may well be unjustly penalizing codecs that have better VBR rate control.
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- Serge Smirnoff   Codecs and settings for 64kbit/s SE listening test   Oct 14 2012, 21:55
- - lvqcl   BTW, qaac doesn't contain a codec: it uses AAC...   Oct 14 2012, 22:22
- - Kohlrabi   QUOTE (Serge Smirnoff @ Oct 14 2012, 22:5...   Oct 14 2012, 22:36
|- - Serge Smirnoff   QUOTE (Kohlrabi @ Oct 15 2012, 01:36) Wou...   Oct 15 2012, 00:49
- - eahm   QUOTE (Serge Smirnoff @ Oct 14 2012, 13:5...   Oct 14 2012, 22:42
|- - Serge Smirnoff   QUOTE (eahm @ Oct 15 2012, 01:42) QUOTE (...   Oct 15 2012, 00:40
- - lvqcl   QUOTE (Kohlrabi @ Oct 15 2012, 01:36) It...   Oct 14 2012, 22:47
|- - Kohlrabi   QUOTE (lvqcl @ Oct 14 2012, 23:47) QUOTE ...   Oct 14 2012, 22:55
|- - saratoga   QUOTE (Kohlrabi @ Oct 14 2012, 17:55) How...   Oct 14 2012, 23:08
- - yourlord   Sounds like a useless test to me. There is nothing...   Oct 15 2012, 01:08
|- - Serge Smirnoff   QUOTE (yourlord @ Oct 15 2012, 04:08) Sou...   Oct 15 2012, 01:12
||- - yourlord   QUOTE (Serge Smirnoff @ Oct 14 2012, 20:1...   Oct 15 2012, 02:23
||- - Serge Smirnoff   QUOTE (yourlord @ Oct 15 2012, 05:23) The...   Oct 15 2012, 09:19
||- - Kohlrabi   QUOTE (Serge Smirnoff @ Oct 15 2012, 10:1...   Oct 15 2012, 12:32
||- - Serge Smirnoff   QUOTE (Kohlrabi @ Oct 15 2012, 15:32) I...   Oct 15 2012, 13:34
|||- - yourlord   QUOTE (Serge Smirnoff @ Oct 15 2012, 08:3...   Oct 15 2012, 17:38
|||- - Serge Smirnoff   QUOTE (yourlord @ Oct 15 2012, 20:38) QUO...   Oct 16 2012, 01:17
||- - saratoga   QUOTE (Kohlrabi @ Oct 15 2012, 07:32) How...   Oct 15 2012, 16:10
||- - Serge Smirnoff   QUOTE (saratoga @ Oct 15 2012, 19:10) QUO...   Oct 15 2012, 17:30
|- - Serge Smirnoff   QUOTE (yourlord @ Oct 15 2012, 04:08) As ...   Oct 15 2012, 01:19
- - LithosZA   What I would like to see one day is more CVBR test...   Oct 15 2012, 14:43
|- - Serge Smirnoff   QUOTE (LithosZA @ Oct 15 2012, 17:43) Wha...   Oct 15 2012, 17:15
- - Kohlrabi   In short, you need to understand what lossy audio/...   Oct 15 2012, 18:22
- - LithosZA   QUOTE All AAC contenders for this 64kbit/s testing...   Oct 15 2012, 20:57
|- - Serge Smirnoff   QUOTE (LithosZA @ Oct 15 2012, 23:57) QUO...   Oct 16 2012, 02:27
- - yourlord   How about, can we have a test worth performing? I...   Oct 15 2012, 21:55
|- - Serge Smirnoff   QUOTE (yourlord @ Oct 16 2012, 00:55) How...   Oct 16 2012, 01:42
|- - yourlord   QUOTE (Serge Smirnoff @ Oct 15 2012, 20:4...   Oct 16 2012, 03:21
- - greynol   This argument is nothing new here (I too am skepti...   Oct 15 2012, 22:01
- - Serge Smirnoff   The following codecs were added to 64kbit/s sectio...   Oct 28 2012, 10:32
- - C.R.Helmrich   Thanks! How does the reliability rating work? ...   Oct 28 2012, 17:43
|- - Serge Smirnoff   QUOTE (C.R.Helmrich @ Oct 28 2012, 20:43)...   Oct 28 2012, 19:49
|- - skamp   QUOTE (Serge Smirnoff @ Oct 28 2012, 19:4...   Oct 28 2012, 20:03
|- - Serge Smirnoff   QUOTE (skamp @ Oct 28 2012, 23:03) QUOTE ...   Oct 28 2012, 20:11
- - LithosZA   That must be one good MP3 encoder Who knew MP3 64...   Oct 28 2012, 19:21
- - Serge Smirnoff   It turned out that reliability of ratings in 64kbi...   Oct 29 2012, 02:14
- - Xanikseo   One thing I can't comprehend, is why each of t...   Oct 31 2012, 00:21
|- - eahm   QUOTE (Xanikseo @ Oct 30 2012, 16:21) One...   Oct 31 2012, 02:20
- - jensend   QUOTE (Serge Smirnoff @ Oct 14 2012, 14:5...   Oct 31 2012, 05:49
- - Serge Smirnoff   Bitrate issue: they are calculated on the basis of...   Oct 31 2012, 09:31
- - Xanikseo   I am also generally suspicious of the other result...   Oct 31 2012, 15:25
- - Remedial Sound   It would seem there are 10 people in the world, th...   Oct 31 2012, 16:03
- - Serge Smirnoff   Detailed results of this listening test are availa...   Apr 11 2013, 23:01
- - greynol   QUOTE (greynol @ Oct 15 2012, 14:01) I to...   Apr 13 2013, 00:25
- - LithosZA   From this I can gather that Vorbis should give abo...   Apr 13 2013, 07:10
- - Serge Smirnoff   Thanks, greynol. I still have some questions conc...   Apr 13 2013, 13:16
- - Serge Smirnoff   Below are results using slightly different statist...   Nov 28 2013, 12:23
- - Serge Smirnoff   Following this very painful but insightful discuss...   Mar 29 2014, 21:53


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