I have settled on -lc -br 64000 -2pass
To be honest, I cannot ABX between this setting and iTunes 64kbps, but 2 pass vbr has got to be better ;-) and I am glad to get rid of iTunes.
I have not been able to ABX nero against iTunes using iTunes 128k VBR and q settings around 0.43 (or whatever it takes to get a similar bitrate to iTunes). I'm wondering if others can?
I just tried on harpsichord and succeed
[!--sizeo:5--][span style=\"font-size:18pt;line-height:100%\"][!--/sizeo--]TEST#1[/size]
ABC/HR for Java, Version 0.52b, 07 mai 2006
Testname:
Tester: guruboolez
1L = C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.m4a
2R = C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.mp4
Ratings on a scale from 1.0 to 5.0
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General Comments:
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1L File: C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.m4a
1L Rating: 4.5
1L Comment: not fully transparent: harpsichord is slightly distorted
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2R File: C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.mp4
2R Rating: 2.5
2R Comment: "tremolos" and smeared
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ABX Results:
C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.m4a vs C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.mp4
11 out of 12, pval = 0.0030
---- Detailed ABX results ----
C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.m4a vs C:\MP3\NERO\S16_KEYBOARD_Harpsichord_F.mp4
Playback Range: 00.000 to 11.255
10:34:19 PM p 1/1 pval = 0.5
10:34:22 PM p 2/2 pval = 0.25
10:34:30 PM f 2/3 pval = 0.5
10:34:33 PM p 3/4 pval = 0.312
10:34:35 PM p 4/5 pval = 0.187
10:34:38 PM p 5/6 pval = 0.109
10:34:40 PM p 6/7 pval = 0.062
10:34:44 PM p 7/8 pval = 0.035
10:34:46 PM p 8/9 pval = 0.019
10:34:50 PM p 9/10 pval = 0.01
10:34:53 PM p 10/11 pval = 0.0050
10:34:56 PM p 11/12 pval = 0.0030
>> original sample <<
Nero -q 0.435 bitrate = 118 kbps [.MP4 file]
iTunes VBR 128 bitrate = 128 kbps [.M4A file]
=> difference was really obvious to my ears. But I'm tempted to say that I'm very sensitive with harpsichord sound (I often claimed to hear strong distortions that other people couldn't clearly hear) so try yourself.
Bitrate is also significantly lower. That's why I tried with a second harpsichord sample (test#2).
[!--sizeo:5--][span style=\"font-size:18pt;line-height:100%\"][!--/sizeo--]TEST#2[/size]
ABC/HR for Java, Version 0.52b, 07 mai 2006
Testname:
Tester: guruboolez
1L = C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.m4a
2L = C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.mp4
Ratings on a scale from 1.0 to 5.0
---------------------------------------
General Comments: ABX: first ~8 trials on beginning; last ~12 trials on the second part (pre-echo/smearing was easier to catch)
---------------------------------------
1L File: C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.m4a
1L Rating: 3.5
1L Comment: distorted and smeared
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2L File: C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.mp4
2L Rating: 2.8
2L Comment: both distortions and smearing are more irritating this time
---------------------------------------
ABX Results:
C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.m4a vs C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.mp4
16 out of 20, pval = 0.0050
---- Detailed ABX results ----
C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.m4a vs C:\MP3\NERO\S11_KEYBOARD_Harpsichord_A.mp4
Playback Range: 00.000 to 08.410
10:42:14 PM f 0/1 pval = 1.0
10:42:21 PM p 1/2 pval = 0.75
10:42:31 PM p 2/3 pval = 0.5
10:43:09 PM f 2/4 pval = 0.687
10:43:13 PM f 2/5 pval = 0.812
10:43:22 PM f 2/6 pval = 0.89
Playback Range: 05.681 to 08.410
10:43:45 PM p 3/7 pval = 0.773
10:43:48 PM p 4/8 pval = 0.636
10:43:52 PM p 5/9 pval = 0.5
10:43:56 PM p 6/10 pval = 0.376
10:43:59 PM p 7/11 pval = 0.274
10:44:03 PM p 8/12 pval = 0.193
10:44:06 PM p 9/13 pval = 0.133
10:44:14 PM p 10/14 pval = 0.089
10:44:18 PM p 11/15 pval = 0.059
10:44:22 PM p 12/16 pval = 0.038
10:44:26 PM p 13/17 pval = 0.024
10:44:30 PM p 14/18 pval = 0.015
10:44:34 PM p 15/19 pval = 0.0090
10:44:37 PM p 16/20 pval = 0.0050
>> original sample <<
Nero -q 0.435 bitrate = 131 kbps [.MP4 file]
iTunes VBR 128 bitrate = 129 kbps [.M4A file]
Distortions was a bit harder to catch. ABX test was clearly better when I focused on the pre-echo issue (second half of the sample). This time, the bitrate discrepancy can't be invoked to explain the difference.
But it's just and only harpsichord. I noticed this issue when Nero 7.2 was released (see the corresponding thread) while listening to 150 samples; for most of them quality was fine (or close to be so: extensive tests would be required for confirmation but I don't have time for them). Harpsichord is often problematic (and clearly not representative of the whole quality of an encoder; and of course not really a concern for people that don't listen to 17th and 18th century music) with lossy encoders with rare exceptions.
EDIT: offset & gain were corrected