Hi all!

My trusty old PW-1210A is pretty near to kicking the bucket now, so I need a new drive.

The 1210 managed ~99.9% C2 accuracy as tested by the "DAE Quality" software at www.exactaudiocopy.de (at the speed of 8x), and now I'm looking for a drive that is just as good.

Let's assume that either price is no object, or back in the real world, that I am not buying a pricetag, but a drive.


All suggestions welcome!

If you're concerned about extraction quality (from what you've posted so far here and at EAC forum I'm sure you are ) you should consider this:

- If a drive has near to 100% C2 accuracy this means EAC secure mode will notice all errors (and report if uncorrectable). It's great to have this security but I guess you additionally want results as good as possible, not results that are bad for sure. So ...

- A drive's internal error correction capabilities might be important for you as well. There are big differences. At http://www.cdrinfo.com/ most recent drive reviews contain error recovery tests (also audio). Best drive tested so far is Plextor PX-708A.

Additionally you might want to use the search (here and on EAC forum), there have been some similar threads recently.

I agree with tigre on the PX-708A (but price really must not be an issue with that DVD+/-R/RW ) ... I use a Plexwriter Premium for Extraction ... great drive since it overreads and overwrites Lead-In/Out and additionally comes with Plextools Professional's C1 & C2 / Jitter / FE & TE error checker (function not available with the PX708A AFAIK) that is a very handy tool for me since it allows to determine media quality (blank and written, that is) and thus write speed before the actual burn or error rates after burning ... just check the review at cdrinfo.com ...

Another drive reported to show 100% C2 accuracy by cdrinfo.com are the newer LiteOn CDRW's (I own a 52246S as well) ...

I have the PX-708A, and I'm very satisfied with it. However, there is one peculiar thing about it in EAC: No C2.

According to EAC, the drive does not support C2 info, but this is clearly wrong since e.g. Plextools and Nero DriveInfo do report C2 capabilities.

Also - possibly related to this - the drive is pretty slow in EAC: usually, my ripping speed starts at around 5.5x (start of disc).

Not that this matters much to me. I'm only interested in the quality of the rips.

Thanks for the suggestions everybody!

BUT I don't see me buying the 708 drive.

I am interested in cd-ripping and cd-ripping only, so paying double price for a drive that can do DVD recording just isn't in the cards.

Although if I shat gold bricks, I would have considered it.

I'm currently partial to the Plextor drives, so I'm thinking about the PX-W5224TA drive... do you think this is any good?

@tigre:
Yes, I am concerned with C2-reporting accuracy... hysterically so, as you may have reason to suspect.

So error correction capabilities are totally uninteresting to me, appart from considering the assumption that "a drive which aims at providing good error correction functionality must also provide accurate error detection".

I have deleted rips which had 5 errors in them, as reported by Plextools.

Do whatevery you want, it's your choice

As many ripping programs don't care about errors reported by a drive, some drive manufacturers seem to think, correction of errors, performed by the drive internally is important while reporting of uncorrectable errors to software isn't.

Maybe you'll like this: This drive is ~ 45 € here BTW. Downside (which shouldn't matter much as C2 accuracy is 1 ... 0 ... 0 ... % ): Drive caches audio data -> extraction speed in secure mode ~ 10x

Or this?This drive caches too, but extraction speed in secure mode is ~17x

Uh-huh.



Call me stupid, but I fail to see the point... as I mentioned, correction of correctable errors is irrelevant to me; a C2 error is uncorrectable.

¹: I believe this is a fair assumption.

Can anyone please tell me if there is any good "combo" drive, you know, those that read DVDs and burn CDs?

I need to replace a dying CD burner and also have a DVD reader, but I don't have enough space in my current setup to have two drives.

I want a drive that will perfom well in EAC, and maybe have desirable features such as C2 error reporting.

Thanks.

Hello DrDoogie,

I suppose that you're a person who is very careful with his CDs and treats them well, since you're more interested in 100% perfect C2 error detection than in good error concealment. Is this correct?

If I were you, I would buy a good writer (a Plextor Premium, for example) and ALSO a good reader (a LiteON LTD-166S, for example).

Then I would rip each of my CDs with BOTH drives using EAC (with the C2 error detection feature activated), and I would compare the CRCs obtained to verify they're identical.

It would be best if you buy a reader that uses a different chipset from the one used in the writer. (I think Plextor Premium uses a Sanyo chipset and LiteON 166S uses a MediaTek chipset)

Cheers.

Check the latest combo drive from Toshiba. I have the SD R1312 at home & I'm very happy with it.

A C2 error can be uncorrectable for one drive and correctable for another. The best example is Tigre CDS200 rips (FAQ) : consistent CRC, but not the same for different drives -> uncorrectable errors of one drive are corrected by the other.
A given drive can correct up to 2 C2 errors per frame, while another will correct 4 of them (they're the min and max values)... and some drives can use different strategies at the EFM and C1 stages in order to reduce the number of C2 errors to begin with (improving C1 error correction).


Yes but for low error rates only. They didn't test high error rates, such as those caused by a deep scratch.
I showed that the C2 accuracy can competely fall down past a given error rate : http://perso.numericable.fr/~laguill2/dae/dae.htm (and also calculated the error correction of the drives using the method explained in the appendix, BTW)

We've been through this before, PIO.

A "C2 error", in error correction / detection terminology, is the detection of an error in which information in the error parity bits is erroneous.

An error in the error-correction, in other words.

"Test" until you are blue in the face, you cannot reliably correct an error when you have no reliable information (the C1 error bits are f***ed) as to what the error was.



Well, no.

I just delete the rip if I find 1 - count them, "one" - error.



I am anal, but not that anal.



The CRC generation in EAC has, in my impression, proven to be unreliable in the past.

I feel I am repeating myself as to the meaning and reliability of error correction / detection here.



That's a good point.

However, as I trust the C2 error detection capabilities of a drive that has (99.99±0.01)% accurate reporting, no.

But thanks for the tip, I might consider something similar in another situation.

Cheers mate!

> A C2 error can be uncorrectable for one drive and correctable for another.

Perfectly correct.

> A "C2 error", in error correction / detection terminology, is the detection of
> an error in which information in the error parity bits is erroneous.

No, you can get C2 errors with all C1/C2 parity bytes being correct.

> An error in the error-correction, in other words.

No, you can detect and locate C2 errors before trying to correct them.

> "Test" until you are blue in the face, you cannot reliably correct an error
> when you have no reliable information (the C1 error bits are f***ed) as to
> what the error was.

Sure can, that's what C2 parity bytes are there for.

You look a bit confused on C1/C2, better listen to Pio.

Are you raising the flame war banner on me, boy?



Perfectly wrong.
Or, hey: Prove it.



"Yes", you can have errors even when the C2 information says that the information is correct.

Do you happen to know the probability for this?

No?

Why am I not surprised?



You cannot correct C2 errors. Go take an introductory course to digital signal processing.



Sure cannot, the C2 is there to tell you:
"I'm sorry Dave, I cannot read the information properly. Would you like to keep the erroneous information, or would you like it resent?".



B) B)

2 posts does not necessarily mean newbie. Spath is not.



Already provided above. But here's the direct link : http://www.hydrogenaudio.org/forums/index....5370#entry54479

"CRC is the same all the time for each drive, but doesn't match between the drives"

Different CRC means C2 errors in at least one of the drives, and different ones in the other (or not at all), thus C2 errors corrected by one drive and not the other.



You can get C2 errors with all parity bytes correct, but data bytes wrong, if this is what Spath meant



DrDoogie, cool down. There is a confusion between C2 errors and CU errors, because of EAC's terminology ! Maybe you didn't browse this other recent thread, where I cleared up the confusion : http://www.hydrogenaudio.org/forums/index....=0&#entry146959



This is exactly the same confusion as above : we're talking here about C2 errors (=anything that C1 could not correct), that's what is relevant for error correction ability, while EAC talks about CU errors, that are uncorrectable C2, and not any C2 error.

Very well, as a moderator you have politely requested me to chill and re-check my wild claims; I will.



Um.
Ok, we're exactly at the point where we, perhaps, misunderstand eachother... or where I "just don't get it".

What error correction codes corrects C2 errors? What parity bits, exactly?

EDIT:
Ok, so you are saying that a few C2 errors (one or two) in the same 'thingy' can be corrected without redundant data from the other interleaved blocks in the CIRC-stream, but more C2 errors (three or four) need parity data from adjacent blocks, which should be errorfree... if the adjacent blocks are not errorfree, the correction fails.
And that EAC considers CU to be three or four C2, as reported by the drive.

Is above a more or less adequate understanding?

Here's a very good (IMO) overview about the topic. I hope it helps.


Not exactly as far as I understand. From the link above:
This means a frame consists of 24 audio bytes (= 3 samples x 16bit x 2 channels) + 4 parity bytes. Because of C1 error detection it's known which ones are right/wrong, so up to 4 wrong ones can be corrected. AFAIK some drives are not able to correct 4, but only 3 or 2 wrong bytes.
So if there are more wrong bytes than a drive can correct (5, 4 or 3, depending on the drive) a CU error is reported. The more reliably this happens, the higher is the drive's "C2 accuracy".

> "Yes", you can have errors even when the C2 information says that the information is correct.
>
> Do you happen to know the probability for this?
>
> No?
>
> Why am I not surprised?

Blah, is this a joke ? You are clueless about how this "thingy" works and you
challenge me on the miscorrection probability ? The formula is right in front
of me from Vries&Odaka AEC 1982, can you describe it to me, "boy" ?

I'll try to sum up :

From the CD to the user, after the EFM decoder, the data comes in the C1 error correction stage. The data consists in frames inside which error correction is performed.
Data it is made of 28 bytes, plus 4 "P" parity bytes, (not to be mistaken with a P subcode), for each frame. These 4 P bytes acts as a PAR file for error recovery, or as the "CRC" of the 28 other bytes, if you prefer. If there are too much errors (detected comparing the 28 data bytes with the 4 P bytes), they can't be corrected, and something wrong is outputted.
Then there is an interleaving stage, that takes bytes in different frames to reconstruct other ones, and the 28 bytes, right or wrong, come into the C2 error correction stage. For this stage; the 24 first bytes are data (audio), and the 4 last are "Q" parity bytes (not to be mistaken with Q subcodes).

If, comparing the 24 data bytes with the 4 Q bytes, some inconsistencies appear, then we know that something is wrong somewhere in these 28 bytes. This is a C2 error. It's called E12 if one byte is wrong, E22 if two are wrong. I don't know if it is still called C2 error if all data bytes are correct, and some parity bytes only are corrupted.
E12 and E22 errors are always correctable. They are correctable C2 errors.
Only E32 (and further ) errors can lead to uncorrected data. E32 means that there are at least three corrupted bytes among the 28 ones in the frame in the C2 stage.
Some chipset then interpolate the affected audio samples. Some can still correct 3 or 4 wrong bytes among 28. I had no clear info about this, but I think, from some suggestions by people who know better than me (Spath and BobHere) that they manage it because they kept track of what C1 frames could not be corrected, thus, looking at the interleaving table, can know for sure that bytes coming from correct C1 frames are themselves correct. Mixing the parity information with the knowledge of what bytes are correct, they must be able to correct more than 2 wrong bytes per frame without mistake.

Anyway, when there are too much corrupted info, error correction can't take place in the C2 frame. The C2 erors are then "uncorrectable". They are called "CU" errors. The drive should then report it to the software. That's what is called "C2 error reporting". It seems that some drive report all C2 errors that took place, even E12 and E22, where the data is correct. That's what Minix says about his Plextor drives : http://www.hydrogenaudio.org/forums/index....=0&#entry147181
I never tested this with my drives. After all, the red curves in the DAEquality reports must stand for correctable C2 info (in red : C2 flags on correct data). Maybe all drives report both correctable and uncorrectable C2 (when they manage it ).

In this case, having 100 % quality in EAC, or no error in CD Speed means that the CD is in good state, because not only no errors occured, but the C2 stage was not even sollicited. But after all, C1 takes care of random errors. C2 is for burst errors.

Docs :
http://www.ee.washington.edu/conselec/CE/k...audio2/95x7.htm (beware : C1 and C2 are inverted in the text )
http://www.ecma-international.org/publicat...ds/Ecma-130.htm

No joke, simply ignorance and arrogance. Combined with the perception that "most people" have a hard time understanding the concepts of errors and correction of said.

In this case, "most people" was me.

My I offer my sincerest apologies for shooting my mouth off?


DrDoogie

Dr. Doogie ...

think about how Plextools handle error correction ... C1 (E11, E21) & C2 (correctable E12 & E22, that is) are not even reported in the logfile, only encountered CU errors (E32) will be written to the logfile with the drive reporting uncorrectable errors ... these errors can, in most cases, be corrected using speeddown and excessive calculus with adjacent data ...

EAC's terminology on that point (like PIO already stated) is not exact ... this might be due to the fact that Andre Wiethoff is not a native english speaker ...

Or, as Spath said, because the MMC standard is unclear... http://forum.cdfreaks.com/showthread.php?s...=&postid=480032

> My I offer my sincerest apologies for shooting my mouth off?

Alright, case closed.