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Topic: Bought the same CD twice, got THE SAME C2 errors twice!!! (Read 1421 times) previous topic - next topic
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Bought the same CD twice, got THE SAME C2 errors twice!!!

Weird thing.

I had bought a CD many years ago which had ~27ish C2 errors which were audible for ~11 seconds at track 9.
Two days ago, I found the same CD at a bazaar and bought it again.

Tried to copy it and found out it has THE SAME C2 errors as my first one!!!
Same LBAs!

The discs were copied using Redumper with a Plextor 5224 which creates logs if you'd be interested in reading it, but I also had the same results with EAC and other drives (used 3 Lite-Ons, a NEC and a Sony).

I can already guess the answer is "manufacturing defect", probably on the master but...

AccurateRip and CDDB both identify the disc and CueTools can even "repair" it.
However, after the repair, CDDB finds the repair as accurate but AccurateRip STILL finds it as "No Match".

Bit annoyed, thanks for letting me vent :p

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #1 –
Did you check the other 2 pressing offsets (6, -664) for AccurateRip v2 results?
korth

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #2 –
Quote from: korth on
Did you check the other 2 pressing offsets (6, -664) for AccurateRip v2 results?

Yep, same thing...

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #3 –
Looks like the same verify offset

This is how to verify v2 at different pressing offsets in CUETools
X
korth
 

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #4 –
Quote from: korth on
Looks like the same verify offset[attach type=image]36225[/attach]
Had attached the wrong file. I have already corrected it so please check again, but basically, my offset and -664 are identical while +6 is different and fails both on CDDB and AR but it only has a confidence of 2 so...

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #5 –
Please try to copy the CD without applying the AccurateRip offset correction - "offset correction value = 0".

Decades ago I had some stange C2 errors with a CD copy - that turned out to be a "cd-recorder software issue" - So a manufacturing error is quite possible.
https://hydrogenaud.io/index.php/topic,26162.0/prev_next,prev.html#new

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #6 –
Quote
CueTools can even "repair" it.
Maybe there was a good batch and a bad batch.   (I don't know that would give these results.)

Is it repaired?   No audible errors?

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #7 –
Quote from: .halverhahn on
Please try to copy the CD without applying the AccurateRip offset correction - "offset correction value = 0".

Decades ago I had some stange C2 errors with a CD copy - that turned out to be a "cd-recorder software issue" - So a manufacturing error is quite possible.
https://hydrogenaud.io/index.php/topic,26162.0/prev_next,prev.html#new
Yeah, the C2 errors are identical and both CD surfaces are immaculate so I cannot possibly imagine it being anything OTHER than manufacturing error in the master.
Quote from: DVDdoug on
Quote
CueTools can even "repair" it.
Maybe there was a good batch and a bad batch.   (I don't know that would give these results.)

Is it repaired?   No audible errors?
CueTools has three "repair" options, I tried all three and all of them produce tracks that "sound right" but don't "CRC check right".

In all cases the CDDB database finds it "accurate" but AccurateRip does not "no match".

All other tracks are always a match though so is it due to a differing offset? Dunno

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #8 –
You have tried one drive only? I would guess that the reason that AccurateRip doesn't have it, is that it is read inconsistently from user to user - depending on drive and ripping application / settings.

I got the file, and the "repair" altered 2139 samples over a span of total 11 seconds. I isolated a segment of 617 samples where the peak difference was located, and there is nothing suspicious in the spectrogram. Yes I know that the spectrogram doesn't audio quality, but sometimes it can reveal that one is likely wrong even if you cannot hear it. But no sign here.

I don't anymore remember precisely how CTDB submissions are accepted/rejected ( @korth , you do?) but it accepts scores without the physical disc. Would it be then, that the "repair" could be just another rip that is tested through a different computer (for example, if it was shared over the 'net)? And essentially, there is no "correct" way to rip it, the only reason for the "repair" having higher score, is that the same file exists on two computers and CUETools has been run from both?

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #9 –
CUETools can only submit (without a physical CD) when:
- ZERO rips currently exist under that TOCID
- AccurateRip confidence for ALL tracks must be at least 2 (from same pressing offset)

This feature of CUETools was slated for removal by @Gregory S. Chudov  but wasn't done before he became less active. The feature was originally added to help repopulate the database when submissions were lost after track one pregaps, etc. were removed from TOCID calculation.
korth

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #10 –
Quote from: korth on
CUETools can only submit (without a physical CD) when:
Submit repair data or submit a result which will increase score? (I am quite sure that some time in the past, my results went up by one upon running two scans after one another.)

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #11 –
The submission should include everything that a never submitted before CD would and as the TOCID did not exist before submission, the score would increase from none to 1.

I don't recall any issues with the feature where CUETools would submit to an existing record.
Also by default CUETools is supposed to ask before submitting (but that can be disabled with a setting).
korth

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #12 –
I have tried dumping the disc using multiple drives, however since there are actual C2 errors during read, I'd expect that different drives would read the data differently, kinda like what happens (on purpose) with the Cactus Data Shield "protection" scheme.

I'll try dumping the two discs using other drives and see if the data matches the drives and discs.

EDIT: NOPE! The data doesn't even match across re-dumps of the same disc using the same drive and also doesn't match the other disc.
All the dumps have trouble with specific LBAs but across all reads, BUT other LBAs MIGHT be read right or not as well, adding to the uncertainty.

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #13 –
One of my frequently-used drives doesn’t support C2 error detection at all; it’s actually useful explicitly because of that. That drive has been able to rip a number of discs to the point where the rip was CTDB-repairable, when none of my other drives could. It’d be interesting to see what it’d spit out for this disc.

Re: Bought the same CD twice, got THE SAME C2 errors twice!!!

Reply #14 –
Aren't EAC's "Fast" and "Burst" modes supposed to do the same?

Indeed, for badly damaged discs and/or "copy-protected" discs I've found these modes to actually produce better results.

I also tried it on this disc but it created similar results to the other drive/mode TBH.