Clicks after conversion from APE to Apple lossless

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sapnho
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Clicks after conversion from APE to Apple lossless

Post by sapnho » Sat Sep 15, 2007 3:18 pm

I recently converted a lot of files from monkey audio (APE, lossless) to Apple lossless (m4a) with MAX. After the conversion I have noticed "clicks" (like dust on a vinyl!) on quite a few music files.

A absurd as it may sound, but could it be that in the course of the conversion process from lossless to lossless with MAX, something goes wrong?

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sbooth
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Re: Clicks after conversion from APE to Apple lossless

Post by sbooth » Sun Sep 16, 2007 1:35 am

This is a possibility, although I haven't heard of any issues with APE conversion.

If you convert the APE files to WAV or AIFF do they still have pops?

sapnho
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Re: Clicks after conversion from APE to Apple lossless

Post by sapnho » Sun Sep 16, 2007 4:15 pm

sbooth wrote:This is a possibility, although I haven't heard of any issues with APE conversion.
That's quite shocking. You would assume a lossless to lossless conversion whitout any glitch.

RonaldPR
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Re: Clicks after conversion from APE to Apple lossless

Post by RonaldPR » Sun Sep 16, 2007 6:49 pm

sapnho wrote:That's quite shocking. You would assume a lossless to lossless conversion whitout any glitch.
Well, I do not know if this is an issue here, but officially APE is supported on Windows only. The unofficial port to GNU/Linux and Mac OS X is not recognized or supported by Monkey's Audio. So if there are glitches with decoding or conversion on Mac OS X ...

sapnho
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Re: Clicks after conversion from APE to Apple lossless

Post by sapnho » Mon Sep 17, 2007 4:00 pm

Steve, how do you think, those clicks can get inserted in the file? Thanks, Wolf

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sbooth
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Re: Clicks after conversion from APE to Apple lossless

Post by sbooth » Tue Sep 18, 2007 7:55 am

sbooth wrote:If you convert the APE files to WAV or AIFF do they still have pops?
I need more information to figure out what is going on.

sapnho
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Re: Clicks after conversion from APE to Apple lossless

Post by sapnho » Tue Sep 18, 2007 7:57 am

I have to get my hands first on my APE backup set which is stored outside of the house. Will report back.

sapnho
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Re: Clicks after conversion from APE to Apple lossless

Post by sapnho » Sat Sep 22, 2007 8:51 am

When converting a lossless file into another lossless codes and then back, shouldn't it be the same original file?

I found out the following (using latest Max):

1) APE to FLAC to APE: identical files
2) APE to WAV to APE: non identical files
3) APE to m4a to APE: identical files

Why wav is different, I have no idea. Tried several times with same result.

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Re: Clicks after conversion from APE to Apple lossless

Post by sbooth » Sat Sep 22, 2007 4:57 pm

What are you using to determine file equality? It could be possible that the files are different, but the audio is the same. Why WAV would be different, though, I have no idea.

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Re: Clicks after conversion from APE to Apple lossless

Post by sapnho » Sat Sep 22, 2007 5:00 pm

1) The file size is different.
2) I use a little tool called MD5 to compare the files.

Strange that it only occurs with wav. Maybe my test setup is faulty, can someone reproduce?

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