@ rpp3po
I did a test with those iTunes AAC files, and it seems that Nero AAC does has some issues with that sample.
iTunes
foo_abx 1.3.3 report
foobar2000 v0.9.6.3
2009/03/16 21:07:20
File A: C:\Temp\Linchpin [Edit].flac
File B: C:\Downloads\Linchpin__QtTrueVBR127.m4a
21:07:20 : Test started.
21:08:04 : 01/01 50.0%
21:08:47 : 02/02 25.0%
21:09:03 : 02/03 50.0%
21:09:08 : 03/04 31.3%
21:09:34 : 03/05 50.0%
21:09:47 : 04/06 34.4%
21:09:58 : 05/07 22.7%
21:10:07 : 06/08 14.5%
21:10:19 : 06/09 25.4%
21:10:31 : 06/10 37.7%
21:10:36 : 07/11 27.4%
21:10:44 : 08/12 19.4%
21:10:54 : 09/13 13.3%
21:11:05 : 09/14 21.2%
21:11:10 : 09/15 30.4%
21:11:20 : 10/16 22.7%
21:11:29 : 11/17 16.6%
21:11:45 : 12/18 11.9%
21:12:03 : 13/19 8.4%
21:12:05 : Test finished.
----------
Total: 13/19 (8.4%)
Am not sure about this encode, it was hard to ABX.
foo_abx 1.3.3 report
foobar2000 v0.9.6.3
2009/03/16 21:12:45
File A: C:\Temp\Linchpin [Edit].flac
File B: C:\Downloads\Linchpin__iTunesPlus.m4a
21:12:45 : Test started.
21:13:41 : 00/01 100.0%
21:13:49 : 00/02 100.0%
21:14:28 : 00/03 100.0%
21:14:48 : 00/04 100.0%
21:15:04 : 00/05 100.0%
21:15:10 : 00/06 100.0%
21:15:14 : 00/07 100.0%
21:15:18 : 01/08 99.6%
21:15:26 : 02/09 98.0%
21:15:43 : 03/10 94.5%
21:15:57 : 04/11 88.7%
21:16:03 : 04/12 92.7%
21:16:12 : 04/13 95.4%
21:16:16 : 04/14 97.1%
21:16:21 : 04/15 98.2%
21:16:22 : Test finished.
----------
Total: 4/15 (98.2%)
Seems transparent to me.
Nero AAC 1.3.3.0
q 0.50
foo_abx 1.3.3 report
foobar2000 v0.9.6.3
2009/03/16 21:17:58
File A: C:\Temp\Linchpin [Edit].flac
File B: C:\Temp\Linchpin.mp4
21:17:58 : Test started.
21:18:22 : 01/01 50.0%
21:18:34 : 02/02 25.0%
21:18:47 : 03/03 12.5%
21:19:04 : 04/04 6.3%
21:19:18 : 05/05 3.1%
21:19:31 : 06/06 1.6%
21:19:43 : 07/07 0.8%
21:19:49 : 08/08 0.4%
21:19:57 : 09/09 0.2%
21:20:07 : 10/10 0.1%
21:20:23 : 11/11 0.0%
21:20:38 : 12/12 0.0%
21:20:39 : Test finished.
----------
Total: 12/12 (0.0%)
Better then q 0.40, but still full of smearing and warbling.
q 0.55
foo_abx 1.3.3 report
foobar2000 v0.9.6.3
2009/03/16 21:21:37
File A: C:\Temp\Linchpin [Edit].flac
File B: C:\Temp\Linchpin q 0.55.m4a
21:21:37 : Test started.
21:21:53 : 01/01 50.0%
21:22:06 : 02/02 25.0%
21:22:19 : 02/03 50.0%
21:22:25 : 03/04 31.3%
21:22:35 : 04/05 18.8%
21:22:39 : 05/06 10.9%
21:22:51 : 06/07 6.3%
21:23:09 : 06/08 14.5%
21:23:14 : 07/09 9.0%
21:23:24 : 07/10 17.2%
21:23:28 : 08/11 11.3%
21:23:32 : 09/12 7.3%
21:23:40 : 10/13 4.6%
21:23:45 : 11/14 2.9%
21:23:54 : 12/15 1.8%
21:24:06 : 13/16 1.1%
21:24:14 : 14/17 0.6%
21:24:18 : 15/18 0.4%
21:24:23 : 16/19 0.2%
21:24:30 : 17/20 0.1%
21:24:45 : 18/21 0.1%
21:24:53 : 19/22 0.0%
21:24:55 : Test finished.
----------
Total: 19/22 (0.0%)
An improvement over q 0.50, smearing is gone but theres warbling on the guitars. Dammit that track is not transparent to me at q 0.55 anymore