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Topic: Artifacts at the beginning of the file (Read 3447 times) previous topic - next topic

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  • xnor
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Artifacts at the beginning of the file
Hello,

encoding the file linked below results in an artifact in the beginning of the mp3 (sounds like a click) using
$ lame --preset insane --noreplaygain B.wav
LAME 3.99.4 64bits (http://lame.sf.net)
...

B.wav
A.wav (mp3 converted to wav, edit: using lame --decode, which seems to be the cause of the problem)

Here's an overlay of the mp3 (red) and original wav (blue):


Any ideas why this is happening?
  • Last Edit: 09 February, 2012, 12:22:17 PM by xnor
"I hear it when I see it."

  • probedb
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Artifacts at the beginning of the file
Reply #1
Almost sounds like it's encoding the header as audio?

  • xnor
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Artifacts at the beginning of the file
Reply #2
The artifact is not present in the mp3 itself. I traced the problem down to lame --decode. Decoding (mp3 -> wav) the file with fb2k doesn't result in that artifact in the beginning.
  • Last Edit: 09 February, 2012, 10:23:12 AM by xnor
"I hear it when I see it."

  • adamlau
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Artifacts at the beginning of the file
Reply #3
You are a true audiophile, xnor! Hardcore, I have to be more like you. I'll check out the LAME bug tracker and build 3.99 through 3.99.3 later (I really need some sleep first), run a series of encodes/decodes, see if this issue is a regression, or a new bug.
IBM T42 2378-FZU
Audigy 2 ZS Notebook
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foobar2000 0.9 b8

  • john33
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Artifacts at the beginning of the file
Reply #4
It would seem this is a regression as I just decoded the mp3 with 3.98.4 and all was well. I'll check back and see where this may have occurred.
John
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My compiles and utilities are at http://www.rarewares.org/

  • xnor
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Artifacts at the beginning of the file
Reply #5
@adamlau: Nope, being a software developer myself I just like seeing bugs fixed.

@john33: Thanks for taking a look at this.
  • Last Edit: 09 February, 2012, 12:20:55 PM by xnor
"I hear it when I see it."

  • john33
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Artifacts at the beginning of the file
Reply #6
Hopefully, Robert will pick up on this. There was quite a lot going on in the switch from mpglib to hiplib at this time making it a little difficult to track through but Robert, perhaps, could put his finger on this quite quickly.

EDIT: I have emailed Robert to draw his attention to this.
  • Last Edit: 09 February, 2012, 02:00:40 PM by john33
John
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My compiles and utilities are at http://www.rarewares.org/

  • robert
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Artifacts at the beginning of the file
Reply #7
Thanks xnor, for finding this issue. It crept in early in 3.99 development. This will be fixed in official 3.99.5 soon.

  • xnor
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Artifacts at the beginning of the file
Reply #8
Thanks, that's good news.
"I hear it when I see it."