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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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C.R.Helmrich
post Oct 28 2012, 17:43
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Thanks! How does the reliability rating work? How many listeners are needed for, say, 5 percent? And why is Opus graded worse than mp3?

Chris

This post has been edited by C.R.Helmrich: Oct 28 2012, 17:44


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Serge Smirnoff
post Oct 28 2012, 19:49
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QUOTE (C.R.Helmrich @ Oct 28 2012, 20:43) *
How does the reliability rating work?

Each time a device under test receives a grade the rating is recalculated. A sequence of such ratings tends to some final value. ((Max-Min)/Last value)*100% over last N values is reliability. Now N = number of test files for a device. For low bitrates when artifacts amplification is not applied the number of test files equals to 18 (9samples*2).

QUOTE (C.R.Helmrich @ Oct 28 2012, 20:43) *
How many listeners are needed for, say, 5 percent?

Usually 5-7 grades are necessary for each test file in order to achieve 5% reliability of rating. Due to above mentioned nature of the parameter there is no strict relationship between accuracy of ratings and number of returned grades.


QUOTE (C.R.Helmrich @ Oct 28 2012, 20:43) *
And why is Opus graded worse than mp3?

At the moment Opus received 9 grades only and its rating is completely unreliable. I will check now why it shows 4%


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skamp
post Oct 28 2012, 20:03
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QUOTE (Serge Smirnoff @ Oct 28 2012, 19:49) *
Usually 5-7 grades are necessary for each test file in order to achieve 5% reliability of rating. [] At the moment Opus received 9 grades only and its rating is completely unreliable. I will check now why it shows 4%


I don't understand unsure.gif


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Posts in this topic
- 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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