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RE: ASUS E616P2 Scan Features vs CATS - 10/20/2004 7:39:17 AM   
Halcyon

 

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BTW, what chipset does E616P2 use?

(in reply to Halcyon)
Post #: 17
RE: ASUS E616P2 Scan Features vs CATS - 10/20/2004 6:24:10 PM   
emperor


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Halc i think you covered most of my midnight worries about how we should do proper testing of media with commercial testers (liteon/etc..), i think there is still mystery about various elements....

I think minos can identify which chipsets ASUS E616P2 uses!

(in reply to Halcyon)
Post #: 18
RE: ASUS E616P2 Scan Features vs CATS - 10/23/2004 3:03:01 PM   
muchin

 

Posts: 24
Joined: 7/11/2003
From: Taiwan
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Halcyon,

Thank you very much for spending so much time to respond to my immature opinions, I feel being honored.

quote:

The loss with bigger than >1ECC sampling size are:

- loss of true minima and maxima (they become rounded-off estimates)
- The above also leads to a more smooth graph overall (removing spikes)
- Inability to check for reading of the disc to be within DVD speficiation (<=4 PIF/1ECC)

Granted, those are not neseccarily big losses in overall compatibility scanning.

I can only wish that I could explain things as clear and sound as you did.

quote:

I've been trying to find a suitable test method for cd- and dvd-/+r scanning as well (for the past three years).

I've also entertained the idea of finding a one 'picky' reader.

However, here's where the problem starts.

1) There is not just one way to make an 'incompatible' disc or a 'picky' reader. A disc may be readable in drive A, not in B. With another disc the roles are reversed. There is NO 'universal picky' reader that I've been able to find. This is due to way the dvd reading is left to the implementation of the drive more than that of cd reading. There are more than one way to read a dvd disc 'correctly', leading to different compatibilities and incompatibilities.

The information is invaluable to me. Being music oriented, I have limited experience with DVDRs, but I knew the possibility is low from the start. It is good to get the answer much less than three years, and to save money also. But do we still have a chance if the +R or -R drives are considered separately? If not, then I will turn my search instead to drive/disc combinations that will produce DVDRs playable by most or all drives. Do you know any such a writer? How about CD drives?

quote:

Remember, errors are not on the disc. One cannot expect results between drives to be similar, because the drives influence how many errors are produced in the reading process.

I take issues with the opinion that all of the errors are not on the disc. Jitter errors, eccentricity, asymmetry, etc. may be largely on the disc. The cases with C1/C2 errors are more complicated, as they are mostly the results of disc/reader combination. I did not say that the errors are on the disc in the present case, but for some types of copy protections, C2 errors are incorporated into the disc. And there are cases where C1/C2 errors are primarily due to defects on the disc. If you want some examples, I can show you.

quote:

Erik has not stated that the unit of measurement for error rates on DVD discs within CD Speed is bytes. It's just that one drive that is known to report each erroneous byte in a PO row.

We don't really know what CD speed reports.

This has been asked from Erik, but no straight answer has been gotten yet.

Does it report the basic sampling size error counts without calculation? Apparently not, because Erik has started 'calibrating' results across various drive models.

However, do they all report 8ECC floating window SUM for PIE and 1ECC PIF - or statistical averages of those?

Apparently not, because there are no units on the graphs and Erik hasn't replied on this issue either :)

I have re-read Erik's post about this matter, and both of us are not entirely correct. I have extended Erik's statement of the unit of measurement too far. I am waiting for his words about the units for other chipsets. On the other hand, it is clear to me that CD-DVD Speed plots each 64 ECC sum returned by the chipset in this case; you seem to have overlooked this point. Perhaps previously I should have also mentioned another post I came across. It is obvious then that PI errors reported by ASUS E616P2 at 5X are not significantly higher than those given by CATS when normalized, even if we assume that both use row/sample as the unit for error rate. It is unfortunate that the ASUS drive does not return PIF.

quote:

I think Erik has stated that E616P2 drive reports not PIF (or even PO), but erroneous bytes in PO columns (summed for 64 ECC blocks).

I do not understand what you mean. Erik said that it reports PO errors.

quote:

To put it shortly: I think the motives are pure and the goal is lofty, but overall I think it is folly.

Why?

Drives will see different amounts of errors in reading of a disc. Some drives are good at reading certain types of discs, other drives other types of discs.

There is NO WAY that both drive types can report the same error rates for the two different types of discs.

Yes, it is possible to somewhat correct for these differences, but it makes no sense, imho.

The point is to show how many errors did a drive see in the reading, while letting the characteristics of the drive show through in the error rates.

But showing somewhat 'universal' quality score is impossible, because there is no known universal one correct way to read a dvd disc (and as such, to measure it for errors in reading).

Also, basing this calculation on PIF is also false, imho. NIST has already shown with their testing that the crucial indicator of disc compatibility is it's reading error rates being below 280 PIE (in a CATS scanner).

So, there are two problems.

1) Disc quality score is not _disc_ quality. It is _disc compatibility in the drive doing the testing_. Errors are not on the disc.

2) PIF Is not the only or not even necessarily the best indicator of disc compatibility. PIE should be included as well. It could even be the determining factor, because it is a lower level error rate, not taking into account the PI row error correction strategy of the drive (which PIF/PO do).

That's all for now. I hope I didn't bore you.

As a final note, I have great respect for Erik. He's doing something I don't know how to do.

Still, that doesn't stop me from disagreeing with some of his assumptions, when I see them being clearly in opposition to the best scientific data I've been able to find on the issue.

I have not seen any discussion on Erik's attempt to normalize quality scores before, have you? I have doubts about its accuracy, too. But before his effort, with error test what being measured were reading abilities of readers rather than qualities of disc in most cases. So I welcome his endeavor. It is beyond me to comment on its feasibility. He has been responsive to requests and questions, including our concerns about units of measurements. I believe that he needs feedback to make improvements, if possible. Undoubtly he will cancel it if proven to be useless.

quote:

Of course, I'm fallible myself too, so I can be wrong as well. I don't want a flame war, just a bigger understanding of the issues involved.

Flame war? No. I am interested only in finding the truth. Besides, I am still in the process of learning and I have learned a great deal from you here and elsewhere.


< Message edited by muchin -- 10/24/2004 1:33:48 AM >

(in reply to Halcyon)
Post #: 19
RE: ASUS E616P2 Scan Features vs CATS - 10/28/2004 10:13:28 AM   
Halcyon

 

Posts: 172
Status: offline
Thanks for the comments Muchin.

Some quick further comments:

- I don't think there is a hope of finding a single drive that will be usable to for testing _universal_ _disc_ quality. Pulsetec drives (calibrated at regular intervals) come closest, but even they offer only one way of implementing the reading. Still, they are probably the best 'compromise' to assess disc burn quality / compatibility with a single drive scan (for now). However, even this is an
assumption (Pulsetec being best compromise), I have not seen it proven publicly.

- If you want drive/disc combination that produces the most compatible burns, then my personal suggestion (based on my research) is using a Nec 3500/BenQ 1620 burner with latest firmware to burn a Plextor DVD+R (Taiyo Yuden manufactured) at no faster than 8x speed and using bit-setting to set it to be in dvd-rom state. This is the best I know of (as a general rule of thumb). For CD burning I'd again use probably Nec (at no higher than 24x and no faster than 16x) and probably again on Plextor (TY) cd-r media.

- You are right, that some errrors can be considered to be on the disc. However, causal errors that I tried to refer to (PIE, POE, PIF, POF) are not 'on the disc', unless artifically manufactured there using a stamping process (i.e. with a known 'bit incorrect' stamper). Also, on DVD, the jitter measured/specified by the dvd standard is data-to-clock jitter. This is also a combinatory measure of pit-land transition frequency-amplitude-modulation and the jitter of the clock of the drive. Thus, not a true disc measure. Just to sort out what I meant :)

- The units for other chipsets I know are: Mediatek c. 1ECC, ALI c. 32ECC/64ECC, Philips c. 8ECC, Via c. 3ECC and Ricoh 16ECC (now verified by Erik).. This is what I meant with differences. Also, we don't still know if that's the sampling size AND the scanning interval or not (mostly likely only sampling size, as some chips are passive and cannot be queried at every interval the size of the sample).

- Your are right Asus does report POE. Which is the same as the nubmer of erroneous bytes per outer parity column (summed for each sample window size which is 64ECC).

I hope you didn't take the 'flame war' argument the wrong way. It was just a standard disclaimer and meant as 'I mean no harm' comment. Sometimes people misunderstand my motives due to my bad argumentation and think I'm looking for a fight :)

Cheers,
halcyon


PS All this information above I owe to such great sources like CDR-Info, c't magazin, NIST, OSTA, CISD, CDFreaks, CDRLabs, etc. I don't know it all, so all of the above may not be the most accurate portrayal of the issues dealt within :)


< Message edited by Halcyon -- 10/29/2004 7:30:42 AM >

(in reply to muchin)
Post #: 20
RE: ASUS E616P2 Scan Features vs CATS - 10/29/2004 6:29:58 AM   
muchin

 

Posts: 24
Joined: 7/11/2003
From: Taiwan
Status: offline
Many thanks for providing so much useful information again, Halcyon. Those are exactly what I have been searching for quite some time. Your knowledge and research on this subject are exceedingly impressive. I have recently found that you have addressed some of the issues in more details at Hydrogenaudio, which I did not visit in the past few weeks.

Digit-life also gives rave reviews on NEC NR-7800, 7900, and 9100 recorders, but not as good on 9300. That was the only information I could found about these drives previously. I wonder why CDRInfo has never reviewed any NEC CD-RW.

I became aware of the difference between the jitters for CD and DVD after I put last post. It is good that you have corrected my mistake, so that no people will be mislead.

We have talked about different matters with regards to units. What I said is about total error counts, and you meant error rates.

Things have become clearer through our discussions, and we no longer have differences concerning these issues. So


Cheers.

muchin


< Message edited by muchin -- 10/29/2004 6:34:48 AM >

(in reply to Halcyon)
Post #: 21
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