Tutorial: Fix a broken rip with another one

2010-09-06 20:54:45

By request I share some recent experience. A severely scratched CD could not be saved with the usual polishing methods. All tracks ripped fine except for one with several nonrecoverable errors. I was lucky to find the same CD on Rapidshare, but with messed up gaps and also several ripping errors. With the following steps able to repair the broken track, so that the whole image passed an AccurateRip verification again.

Requirements:

• One secure rip of your original, damaged CD with exactly known error positions. Both EAC and dBPoweramp can provide those in their ripping logs, maybe also other rippers. Having your offset set up correctly might help with later AccurateRip checks.
• A lossless alternative rip from another source, some errors are tolerated.

Preparation:

You don't need to care about small offset differences, these will be aligned automatically. Only if the download differs significantly from your rip, and has maybe a lot of leading silence added (a few seconds) or a lot of leading silence removed, make it roughly the same. Sample precision is not necessary. Several thousand samples difference are no problem. Do only modify the downloaded sample, not your own ripped track.

To reduce the number of samples, that need to be fixed, try a brute force extraction first. If you have a C2 capable drive, you can set dBPoweramp to try a very high number of re-reads, e. g. 2000, per broken sector. EAC won't do so many retries, but you can at least set the error recovery quality to "high".

Processing:

• Open your ripped WAV track in EAC -> Tools -> Process WAV...
• Select Process File -> Compare with external WAV...

EAC will now list all different intervals, that differ in both files. Offset differences are automatically taken care of. Now for each differing interval that is also listed in your rip log click "Replace". If you blindly click replace for all entries, you might import errors from the downloaded file, which were ripped correctly in you version.

When you now save the result and check it along with the other ripped tracks in CUETools against the AccurateRip DB, with some luck, you will have an exact match. It has worked for me, despite the very bad quality of the downloaded track.

Tutorial: Fix a broken rip with another one

Reply #1 – 2010-09-07 13:34:44

Interesting. I tried with CEP something similar, like replacing (mix paste: replace) damaged part from scratched CD track with one provided by "massive distributed backup system" but no matter what I did (and I correctly worked in sample units with regard to start offset etc), there was always power burst at left side on pasted range. OTOH my knowledge is limited and maybe this can be done comfortably in CEP/Au, but the way EAC editor finds diffs and corrects them is great tip. Thanks again

EAC is mystery in itself

Tutorial: Fix a broken rip with another one

Reply #2 – 2010-09-07 18:52:55

http://www.hydrogenaudio.org/forums/index....showtopic=83418

Make sure options to smooth are disabled.  I don't think you need to disable options to dither, but I could easily be wrong.

Tutorial: Fix a broken rip with another one

Reply #3 – 2010-09-07 19:11:37

Thanks. I just gave up on Audition in the end, but didn't know why it had failed. The smoothing option is very likely. But I'm also somewhat helpful that it failed, else I wouldn't have found EAC's one-click solution.

Tutorial: Fix a broken rip with another one

Reply #4 – 2010-09-08 09:43:00

Somehow I never noticed that option. "Smooth Delete and Cut boundaries" was offender

I tried this on a deteriorated CD with a good small scratch, then ripped problematic track (2:22 s length) with EAC high quality (it took around 6 h on TEAC W58E, C2 capable) and then quick burst rip without EC.
Bursted rip had less corrections to be made: http://db.tt/hF5uA19 and greater time saver - at least I didn't went to 2000 repeats with dBP
Also I could continue that bursted rip needed overall 8.7 s replacements against 9.5 s with EC, while max interval is 66 ms (~3 K samples) and min 0 ms (< 44 samples) (sorry but I was bored)

Then, I didn't feel like taking picture from the CD (main reason) then upload it on my PC then on net, so I googled for picture and guess what - I found it on HA wiki article: http://wiki.hydrogenaudio.org/index.php?ti...CDex_SecureMode

So in such cases, pasting larger part from confident correction file with CEP also works fine (although in this extreme case where scratch is over whole track, some other method is more reasonable)