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Yet another FLAC recovery problem thread
andoru
post Jan 25 2013, 03:33
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Just as the other thread in this sub forum, I've had accidentally deleted a FLAC collection of mine and I went to recover it. Unlike the previous user most of my FLAC files turned out undamaged when recovering them but some were overwritten. Although I decided to recover the damaged files too, it went successfully and most of the FLAC files came intact. I played a few of them and I noticed one track that had a problem. When playing it in foobar (tried VLC also), at some random points it produces a unpleasant very loud screech (white-noise like). Now, as I had quite a few FLAC files in that collection, I would like to check them all for those errors, and preferably not through playback as that could be quite painful to the ears XD
I tried to run the -t parameter in the CLI flac encoder on the file, but it reports no errors. Any suggestions on what to use to detect those mishaps? (if it can do it in batch mode that's a plus! )

Software used:

Recording/Encoding - Audacity/libFLAC 1.2.1 20070917
Playback - FooBar, VLC
Recovery - Recuva
File System - NTFS
OS - WinXP SP3 x86

If anyone needs a sample of the problematic file, I can upload it somewhere, it's not copyrighted.

Thanks in advance ^^



This post has been edited by andoru: Jan 25 2013, 03:35
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andoru
post Jan 25 2013, 16:18
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QUOTE (db1989 @ Jan 25 2013, 15:28) *
Just a bugfix release, getting FLAC to compile nicely with current compilers. The new maintainers (Erik de Castro Lopo) main concern is libFLAC. Check the mailinglists for more information: http://lists.xiph.org/pipermail/flac-dev/ They are merging support for 7 and 8 channel audio as well. edit: Josh had some unreleased fixes in cvs as well, of course these will get in the new release too.


Glad to hear that the devs are improving the libs even more, would be fun to see the new features/fixes that are added ^^


QUOTE (db1989 @ Jan 25 2013, 16:28) *
Notwithstanding that I doubt this or any other undeleting program has tailored support for FLAC or any other format, I would hope that none of them would attempt to cobble together a repair and fudge a checksum without at least asking the user – and advising them of how silly that would be. wink.gif At least, that’s my expectation based upon the assumption of a rational human world, so you never know!


I don't think I would go that far to say that, but there's definately something that Recuva/deleting those files caused those screeches to show up. My other guess is that some files (or fragments of them) were placed over the deleted FLAC files thus damaging them, and so, in a recovery attempt, Recuva tried "extracting" the damaged files with the fragments of the files that replaced the deleted ones. I hope I was descriptive enough with this...

QUOTE (EagleScout1998 @ Jan 25 2013, 16:36) *
You might have to download the component. I don't think it's installed with Foobar2000 "out of the box".

http://www.foobar2000.org/components/view/foo_verifier


Thanks for the link, I tried verifying it and it didn't report any errors.

QUOTE (ktf @ Jan 25 2013, 16:45) *
I'm pretty sure that this corruption has happened *before* converting this to FLAC, because for example the first error spans 5 FLAC blocks with start and end somewhere in a block, so it's not aligned.


That's also highly impossible, because I've listened to the audio before encoding (while recording) and after and it didn't have those screeches.

QUOTE (ktf @ Jan 25 2013, 16:45) *
[...] but it's unlikely FLAC it the culprit.


With that in mind I suppose there's no automated way to detect the files with the screeches, so I'd probably have to go through the audio files one by one and check their spectrograms X.X

Thanks for your assistance, guys!
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