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I used GRIP to convert my music CDs to FLAC, Now I have numerous errors
NavyJay
post Nov 8 2007, 03:38
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I used GRIP in Linux to convert my music CDs to FLAC. I didn't realize it at the time, but I have numerous CRC mismatches in the encoded files where physical scratches were located. Normally, I don't ever notice these errors during playback in Amarok or on my Squeezebox.

Since I recently bought an iPod, I had to convert all my FLAC files to MP3 using flac and lame on the command line. These mp3 files contain silent breaks anywhere there were CRC mismatches in the flac file. The same effect occurs when I use winamp to convert FLAC to mp3 in Windows. I know it's theoretically possible to interpolate through the errors, because we are oversampling with the FLAC format (~900 kbps vs. 320 kbps). But, how can I decode through errors while interpolating to get rid of silent breaks in my music??? This must be how Amarok and Slimserver deal with errors, so why is it not an option in the flac binaries?

-J
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NavyJay
post Nov 9 2007, 22:36
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Unfortunately, re-ripping would be very time consuming since I have about 200+ CDs already copied over. That may be the only option though.

GRip usually does a nice job at ripping. Some CDs that I was trying to salvage had pretty extensive damage to the outer sectors from careless handling. When GRip came to those sectors, it took many many cycles to attempt to read them. I was making an assumption that the CRC errors were caused by data corruption during ripping. If that's not possible then maybe my hard drive was failing earlier than I thought. The files were regularly backed up, but I needed to replace the primary drive at one point after ripping. I can't see any other ways the data would become corrupted after ripping.

No, I haven't tried using foobar to convert. I suspect it's the FLAC binary decoder. When I try it out, I'll let you know the results.

Off-topic: I agree that original CD quality sound is not an oversampled signal. I was referring to the audible sound that you will hear when it is played back. Mp3 encoding exploits human hearing thresholds among other tricks and so I was only referring to the fact that mp3s contain modified spectral content. Reviewing mp3-tech.org, I concede that this is not decimation in the traditional sense. That would be a gross simplification.
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