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Topic: Corrupt frames in HE-AAC files(?) (Read 6705 times) previous topic - next topic

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  • Cron
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Corrupt frames in HE-AAC files(?)
I'm using qtaacenc to transcode flac > aac and some of the resulting aac-files have audible "clicks" that are not present in the original flac-files. While decoding these .m4a to .wav in foobar2000 I get errors:

(File 1, length 16:55)
  Decoding error: Unsupported format or corrupted file, frame: 7922 of 9075
 
(File 2, length 7:01)
  Decoding error: Unsupported format or corrupted file, frame: 7922 of 21859
  Decoding error: Unsupported format or corrupted file, frame: 18493 of 21859

Trying to re-transcode doesn't help - the clicks are there again. Even when using chain flac > wav > aac I get the same corrupt files! I've tried this now on two computers.

If I cut the first second off in Audacity and encode the resulting wav-file, I get no corrupted frames at all.

What's going on? 


Software and encoding parameters:
foobar2000 v1.1.1 + qtaacenc 20101119 + QuickTime 7.69.80.9
Parameters: --cvbr 96 --he --samplerate keep --highest - %d

  • Garf
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  • Developer (Donating)
Corrupt frames in HE-AAC files(?)
Reply #1
Does this happen when using QuickTime directly?

BTW. Are you sure HE-AAC is better than LC-AAC at 96kbps?

  • IgorC
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Corrupt frames in HE-AAC files(?)
Reply #2
Apple HE-AAC is only available up to 80 kbps. Not more.
I don´t know how qtaacenc has managed to get HE-AAC at 96 kbps.
  • Last Edit: 15 April, 2011, 01:47:38 PM by IgorC

  • Cron
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Corrupt frames in HE-AAC files(?)
Reply #3
Apple HE-AAC is only available up to 80 kbps. Not more.
I don´t know how qtaacenc has managed to get HE-AAC at 96 kbps.

Aha! didn't know that. Also explains why the encoded files showed 80 kbps when I checked their Properties in Foobar.

Changing --cvbr 96 to --cvbr 80 doesn't change the error though and I get the same error even with 64 kbps.

Does this happen when using QuickTime directly?

I don't have QuickTime Pro so I can't check that sorry.

Here is a picture  showing that the flac doesn't seem to have anything odd (clipping or such) that should make QuickTime to burb like it does...



  • IgorC
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Corrupt frames in HE-AAC files(?)
Reply #4
Cron,
Can you post the short piece of this file (up to 30 seconds)?

Also you can remove --he:
--cvbr 96 --samplerate keep --highest - %d

HE-AAC is disabled for bitrates >80 kbps for a good reason. It is not beter than LC-AAC at those rates.

P.S. Not sure if --samplerate keep is compatible with --he (HE-AAC)
P.S.2.  Also LC-AAC had a bug at 80-112 kbps in past. If there is a lowpass at 15.5 kHz then everything is fine. If there is a load of frequency content over that lowpass then it's bug.
  • Last Edit: 15 April, 2011, 04:38:16 PM by IgorC

  • Cron
  • [*]
Corrupt frames in HE-AAC files(?)
Reply #5
Cron,
Can you post the short piece of this file (up to 30 seconds)?

Also you can remove --he:
--cvbr 96 --samplerate keep --highest - %d

HE-AAC is disabled for bitrates >80 kbps for a good reason. It is not beter than LC-AAC at those rates.

P.S. Not sure if --samplerate keep is compatible with --he (HE-AAC)

Removing --he does help, so the problem shouldn't be in the input file (right?). I'm interested as to what is causing the problem in he-aac though.

Removing --samplerate does not help.

Cutting the lossless file changes something that makes the problem go away. I even tried to cut the file to the multiples of AAC frame size (1024 samples) to get the samples to align same way in the frame, but couldn't reproduce the problem that way. Since the defect is at 6:07 I can't post a sample of it so that you can reproduce the problem 

It should be noted that cutting the file after the 6:07 still produces lossless files that will encode to defective aac.

All this is really weird... but I've had it now with two files and two different computers - exactly the same corrupt frames every time I try to encode.

  • IgorC
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Corrupt frames in HE-AAC files(?)
Reply #6
Confirmed.
The same issue for HE-AAC 80 kbps, VBR, iTunes 10.2.1.1, QuickTime 7.6.9 .
No problem with other AAC encoders.
  • Last Edit: 15 April, 2011, 11:51:20 PM by IgorC

  • Cron
  • [*]
Corrupt frames in HE-AAC files(?)
Reply #7
Thanks IgorC!

I'm wondering if its a new bug that has come with some new version of QT. It's so easily noticeable that it would very unlikely to go unnoticed prolonged time now that I've noticed it in two files during one day.

  • menno
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  • Developer (Donating)
Corrupt frames in HE-AAC files(?)
Reply #8
Have you tried other decoders yet?

  • Cron
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Corrupt frames in HE-AAC files(?)
Reply #9
Have you tried other decoders yet?

I've tried foobar2000, QuickTime Player and Windows Media player - all of then choke to the faulty frames.

  • Cron
  • [*]
Corrupt frames in HE-AAC files(?)
Reply #10
I recently found an CD that has three tracks encoding badly.

There obviously is a pattern here: frame 7922 encodes badly way too often for it to be an accident...


  • Cron
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Corrupt frames in HE-AAC files(?)
Reply #11
Latest QuickTime update (7.7 for Windows) seems to fix the problem and produces clean output.