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?

[eahm]

QAAC TVBR (v1.42) - 59.6 kbit/s (qaac --he -v56 se_ref.wav)

-v is not TVBR but CVBR. -V is TVBR and --he is not possible with it.

qaac TVBR settings:

CODE

Q0 - Q4 (0) = ~40 Kbps
Q5 - Q13 (9) = ~45 Kbps
Q14 - Q22 (18) = ~75 Kbps
Q23 - Q31 (27) = ~80 Kbps
Q32 - Q40 (36) = ~95 Kbps
Q41 - Q49 (45) = ~105 Kbps
Q50 - Q58 (54) = ~115 Kbps
Q59 - Q68 (63) = ~135 Kbps
Q69 - Q77 (73) = ~150 Kbps
Q78 - Q86 (82) = ~165 Kbps
Q87 - Q95 (91) = ~195 Kbps
Q96 - Q104 (100) = ~225 Kbps
Q105 - Q113 (109) = ~255 Kbps
Q114 - Q122 (118) = ~285 Kbps
Q123 - Q127 (127) = ~320 Kbps

BTW, qaac doesn't contain a codec: it uses AAC encoder from iTunes. So probably it's better to write:
QAAC 1.42 + iTunes 10.7
or something like this.

Even better if he adds the CoreAudioToolbox.dll version he's using it (7.9.7.9, 7.9.8.1 etc.).

This post has been edited by eahm: Oct 14 2012, 22:45