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Topic: Politikil sample. (Read 3756 times) previous topic - next topic
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Politikil sample.

This sample seems to have trouble with AAC at low or mid bitrates:

It's easy to ABX at -q 0.50 with Nero 1.3.3.0.

Code: [Select]
foo_abx 1.3.4 report
foobar2000 v0.9.6.9
2009/10/27 22:57:40

File A: C:\Temp\Politikil [Sample].flac
File B: C:\Temp\Politikil [Sample] Nero q 0.50.mp4

22:57:40 : Test started.
22:58:01 : 01/01  50.0%
22:58:13 : 02/02  25.0%
22:58:28 : 03/03  12.5%
22:58:36 : 04/04  6.3%
22:58:49 : 05/05  3.1%
22:59:05 : 06/06  1.6%
22:59:11 : 07/07  0.8%
22:59:19 : 08/08  0.4%
22:59:28 : 09/09  0.2%
22:59:40 : 10/10  0.1%
22:59:49 : 11/11  0.0%
22:59:57 : 12/12  0.0%
22:59:58 : Test finished.

 ---------- 
Total: 12/12 (0.0%)

Precho on the sharp electronic disortion at 0:00 - 0:00 and also smear at 0:06 - 0:07.

iTunes 9.0.1.8 160kbps VBR:

Code: [Select]
foo_abx 1.3.4 report
foobar2000 v0.9.6.9
2009/10/27 23:02:55

File A: C:\Temp\Politikil [Sample].flac
File B: C:\Temp\Politikil [Sample] iTunes 9.0.1.8 160kbps VBR.m4a

23:02:55 : Test started.
23:03:07 : 01/01  50.0%
23:03:19 : 02/02  25.0%
23:03:40 : 03/03  12.5%
23:03:59 : 04/04  6.3%
23:04:09 : 05/05  3.1%
23:04:22 : 06/06  1.6%
23:04:41 : 07/07  0.8%
23:04:57 : 08/08  0.4%
23:05:12 : 09/09  0.2%
23:05:20 : 10/10  0.1%
23:05:46 : Test finished.

 ---------- 
Total: 10/10 (0.1%)

The disortion smears on iTunes AAC.


I've noticed this sample seems to produce poor playback sound under iTunes 9 on both Nero AAC and iTunes AAC formats if the file extension is .m4a. The sample sounds fine in Mp3 and WAV or if the AAC file has the .mp4 extension instead of .m4a.

The .m4a AAC files seem to produce heavy metallic warbling sound while been played under iTunes. I am not sure how i can ABX the iTunes output against the orginal to prove my claim.
"I never thought I'd see this much candy in one mission!"

Politikil sample.

Reply #2 –
well, I know the original topic mentioned artifacts when encoding this sample using iTunes/Nero AAC, but I encoded it to QuickTime AAC True VBR/-q 86 (which averages ~160kbps over my library and falls into the low/mid-bitrate range that you mentioned) and was unable to hear any warbling or other artifacts during playback in iTunes 9.0.1...
Archive- FLAC (-v 8)
Portable- QuickTime AAC (True VBR/-q 77)