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EAC C2 error correction, Use it or not?
RiskyP
post May 29 2003, 22:56
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My drive supports C2 error correction and I have been using it always since it gives the fastest rips for me, while still no errors are reported and all track qualities are above 99.5%. Using this option, I get rip speeds of 18x and I was wondering whether C2 error correction is really that reliable? I mean, I never get error messages, the track quality is always reported to be over 99.5% and I cannot hear any audible difference. Is there any incentive NOT to rip at 18x under these conditions?! Btw, my drive is a LiteOn 48x CDRW (I can't remember the model name off the top of my head)
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Pio2001
post Jun 1 2003, 18:41
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QUOTE (atici @ Jun 1 2003 - 08:22 AM)
I think terminologywise "consistent" is a better term


Thanks, I've replaced "repeatable" with "consistent"

QUOTE (atici @ Jun 1 2003 - 08:22 AM)
There're also "D) consistent (repeating) errors that C2 could not detect" that I was referring to.


I included them at the beginning, then I thought that if errors are randomly distributed among the 1000 ones. If we choose 5 of them not to be C2 detected, and 5 other to be consistent, we'll likely get none at the same place, thus statistically 0 consistent and not C2 detected

QUOTE (atici @ Jun 1 2003 - 08:22 AM)
I don't understand this. If EAC gets constant C2 errors no matter how many times it reads, wouldn't it go on indefinitely?
Or does it just give up even though C2 tells something is wrong after sufficiently many multiple reads?


Only Plextools acts like this. EAC uses C2 for detection only, then gives it up and starts it's classic set of 16 rereadings : you can see the red lines flashing.

QUOTE (atici @ Jun 1 2003 - 08:22 AM)
isn't C2 also an error correction mechanism? Is there some B type errors that could be corrected with the help of C2 information?


As I explained I don't remember where (maybe the "secure mode FAQ" thread, anyway I'm abstracting here), the data starts from the CD's surface. In the chips of the drive, errors get detected and if possible corrected at the C1 stage, then the errors left are detected (or flagged) and if possible corrected at the C2 stage. Then the errors left are interpolated (glitch removal), and a C2 flag is returned with them. Then the corrected and deglitched audio data, as well as the C2 flags, get out of the drive.
Thus B errors are not correctable by C2, by definition. Otherwise, then would not be part of the 1000 errors of the CD. They would be just valid data.

QUOTE (atici @ Jun 1 2003 - 08:22 AM)
Hmm, I've naively believed [...] that [..], Audio CDs have no error detection/correction mechanism. [...]  So what's the difference then?


CD ROMs are like audio CD with error recovery files included. An audio CDR has a capacity of 740, or 800 MB. A CD ROM records 650 or 700 MB of data and 90 or 100 MB of error recovery data. In order to benefit from them in audio, just burn wav files on data CDs.

Now CD Freaks are online. Here's the discussion about the C2 accuracy : http://forum.cdfreaks.com/showthread.php?s...&threadid=67558

Spath doesn't give very detailed answers, though he's got a deep knowledge about the matter, because he's not got the time to write long explanations, and maybe because, working as a engineer in CD drives, there are things about the drive conception that he must not tell outside of his job.

CD ROMs are designed so as to get a bit perfect reading, while audio CDs have the interpolation mechanism kicking in in case of problems. Thus the bit exact reading have not been enforced as strictly as for data CDs.
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Posts in this topic
- RiskyP   EAC C2 error correction   May 29 2003, 22:56
- - atici   Compare the CRCs of your reads with and without C2...   May 29 2003, 23:01
- - Pio2001   This CRC method only works for tracks with errors ...   May 30 2003, 00:26
- - RiskyP   I could not find info on cdrinfo.com but thanks fo...   May 30 2003, 16:17
- - RiskyP   This is a bit off topic, but how much do you think...   May 30 2003, 17:13
- - liekloo   QUOTE (Pio2001 @ May 30 2003 - 12:26 AM)This ...   May 30 2003, 18:21
- - atici   You may want to check this thread about the setti...   May 30 2003, 18:24
- - Pio2001   I meant that if you turn C2 on, then test and copy...   May 30 2003, 19:35
- - atici   Yes, you're right! I knew that. But that...   May 30 2003, 19:52
- - Pio2001   I don't know, I still must verify Tigre's ...   May 30 2003, 19:56
- - atici   But wasn't it you who said when you unset ...   May 30 2003, 20:49
- - Pio2001   When C2 is unset, the drive doesn't take C2 in...   May 31 2003, 01:09
- - liekloo   QUOTE (Pio2001 @ May 30 2003 - 07:35 PM)I mea...   May 31 2003, 21:36
- - atici   @liekloo : I think you're too much of a stickl...   May 31 2003, 23:03
- - Pio2001   QUOTE (atici @ Jun 1 2003 - 01:03 AM)I trust ...   Jun 1 2003, 01:25
- - atici   QUOTE a) 990 not repeatable and detected by C2. b...   Jun 1 2003, 06:22
- - westgroveg   If someone was to test the C2 info of their CD-ROM...   Jun 1 2003, 06:48
- - liekloo   QUOTE (atici @ May 31 2003 - 11:03 PM)the kin...   Jun 1 2003, 16:32
- - Pio2001   QUOTE (atici @ Jun 1 2003 - 08:22 AM)I think ...   Jun 1 2003, 18:41
- - moikboy   If i rip with c2, i rip the data twice, and compar...   Feb 6 2008, 21:52
- - greynol   Whoa, resurrection of a 4.5 year old thread! ...   Feb 6 2008, 22:08
- - Shamray   Hello! "CD ROMs are like audio CD with ...   Mar 30 2011, 07:36
|- - pdq   QUOTE (Shamray @ Mar 30 2011, 02:36) Hell...   Mar 30 2011, 13:53
- - JunkieXL   Sheesh... what's with the random resurrection ...   Mar 30 2011, 21:13
|- - mjb2006   The first revival of the thread was on topic and m...   Mar 30 2011, 22:35
- - greynol   My last post was a bit difficult to follow if take...   Mar 30 2011, 22:55


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