Codecs and settings for 64kbit/s SE listening test, criticism required Options

[Serge Smirnoff]

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?

[Serge Smirnoff]

It turned out that reliability of ratings in 64kbit/s section was calculated according to old parameter N=9 which was in use before 2006. The last codec was added to the section in 2008 and since that time the section was a bit neglected. Probably because of that old N remained unnoticed. Fixed now. As all other codecs in the section have outdated reliability parameter we decided to put all of them on rotation for several days at least. Codecs with confirmed reliability (<5%) will be returned on hold. Testing of devices in other sections have been suspended as well. So now only codecs from 64kbit/s section are tested. Test files of newly added codecs will be given out more frequently because the old test files have more grades.