PlexTools Qchecks give poor results to media Burned on anything but a Plextor 760a!

vbimport

#1

PlexTools Qchecks give poor results to media Burned on anything but a Plextor 760a!

This was my test to back this up… :eek:

I used CD/DVD Speed to Create/Burn the identical testdata disk
on three differnet drives…the PLEX PX760A, the LG GSA-H22L and the
SONY - 830A. The media, Verbatim NC004, was Burned at 8x.

I first Q-checked errors on the Plex760-created disk using the Plex760a as the scanning drive. (Only first 2gb were checked to save time).
A pretty good scan (42k PIE 2K PIF) as you can see in the first diagram entitled…
“PLEX PX760A burneddisk - Quality tested on a Plex760a(using PlxToolsPro)”


Then I Q-checked errors on an LG-GSH22-created disk using the Plex760a as the scanning drive. This time a Very Bad scan (with 669K PIE) as you can see in the 2nd diagram entitled…
“LG GSA-H22L burneddisk - Quality tested on a Plex760a(using PlxToolsPro)”

But Then I Q-checked errors on the same LG-GSH22-created disk using the Sony830a as the scanning drive. And that show this same burn as having only 101K in PIE errors as you can see this in 3nd diagram…
“LG GSA-H22L burneddisk - Quality tested on a Sony830a(using CD-DVDSpeed)”


Then I Q-checked errors on an Sony 830A-created disk using the Plex760a as the scanning drive. Once again a Very Bad scan (425K PIE) as you can see in the 4th diagram entitled…
"SONY - 830A burneddisk - Quality tested on a Plex760a(using PlxToolsPro)

Then I Q-checked errors on the same Sony 830A-created disk using the Sony830a as the scanning drive. And that show this same burn as having only 58k PIE errors as in the 5th diagram entitled…
“SONY - 830A burneddisk - Quality tested on a Sony830a(using CD-DVDSpeed)”


What does this tell us? Plextools may not give an unbiased q-check to burns created on drives other than a plextor?

Anybody understand this? :cop:


#2

I haven’t done a cross check yet, but afaik German c’t magazine compared scanning results of a professional laboratory to those of the 716A – and they looked very much alike.


#3

Palardo, posting the same thing in two or more threads in the same or different forums is called cross-posting and it’s against our forum rules because it creates additional work for the people involved.

Please don’t cross-post again!

The other threads will be closed and this thread will remain open.


#4

IMHO you should check the Plextor burns in the Sony before coming to such a (possible) conclusion. If both the Sony and the Plextor agree it’s good quality, then the disc is very likely ok. However, if your current results show that one drive shows no problems and another one does, then there might indeed be a problem that is related to the burning drive and not to the scanning.


#5

In my experience the H22N is a much better burner in CAV than in Z-CLV, i.e. MCC004 burns far better @12X or @16X than @8X in this burner. Mainly for jitter figures. An exception among my burners…

Actually I consider my H22N as a poor (Z-)CLV (4X, 6X, 8X) burner, except with CMC MAG E01 for some reason. My feeling is that this burner has been optimized for high-speed media and they kinda let down lower speed media. :confused:


#6

That may well be possible. Creating firmware strategies costs money and manufacturers want to save cost. Me too with the Plextor PX-755/760 had the impression that 16x burning with early FW was good but lower speeds where not as good as with the earlier model PX-716. This has been cured with later FW.


#7

Another consideration:

The PIE figure above (rather high -or plain out-of-specs in the Plex scan- in the 4X part of the burn) are what I experienced with MCC004 @8X in the H22N, but on the other hand, I don’t think the dense PIF figures above are to blame on the burner only. I haven’t experienced this. I’d say this very batch of MCC004 is a little lousy. :frowning:

Is the Plextor burnt disc from the same spindle than the LG burnt disc, [B]Palardo[/B]?


#8

Franksoy - “Is the Plextor burnt disc from the same spindle than the LG burnt disc, Palardo?”

Yes it was the very next disk on the same spindle.

HWP - “you should check the Plextor burns in the Sony before coming to such a (possible) conclusion”

The Sony reads the same results on the plex burned disk as the Plex scan reveals. This is not the issue at hand. The issue is that if a disc is burned on non Plex drive then Plextools/Plex760 will give it a bad error score.

The Sony drive does give non biased scores on Media burned in other drives. The plextor does not.


#9

What program are you using to make your test with the Sony and LG drive?

If you are using Nero to burn the media with Sony and LG, what are the Nero test results for those drives?

I bet you get inconsistence test result between Nero and Plextools .

Since Nero will not let you do a PIE and PIF results with the 760A how can you make a conclusion based upon what one program burned and another did the test results? Until Nero allows to test Plextor drives and Plextools does not allow you to test any drives except Plextor, comparisons can not be drawn to conclusions between the Sony and LG drive.
Unless there is a program that is available to the public where it can test all and any DVD drives to give a far comparison.


#10

Toadyy I am on set now so can only answere briefly.You missed the point of this question.
Plextools will test any burns done on any drive but “read test” must be performed while on a 760a. And once again Plex always gives worse results to disks burned on other drives. The scans above show this conclusively. Hence Plextools must be a biased program.


#11

The Plextor drive doesn’t care what device the media was burned on. It has no “decision” making capabilities for ‘bias’. The drive is in a read operation and burning does not enter into the equation for Q check graphing. The PTP application just reports the PI/PO or C1/C2 results as read from the drive, so it cannot be biased toward one media or another. It just processes data.

The PTP Q check is designed to work with Plextor drives only, but the app will test any drive for write transfer or read transfer rates. The write transfer and read transfer are tests of the interface, laser and mechanics, and, unless the media drops off due to burnproof or PoweRec, is not a check for media quality

A better test would be to take multiple blank media and run them in the 760A to test for FE/TE at max speed. Take four or more discs with similar/identical graphs. It is possible to get varying results within a spindle, so you want to start with identical media, or as close to identical as you can get.

Burn two in the 760. Run both completed discs burned on the Plextor through a full Qcheck for beta/jitter and PI/PO sum 8 to check results. They should compare fairly closely.

Then use the Sony with Nero or other testing program to burn and test the other two discs at the same speed as the Plextor burn. They should compare closely in the test program.

You can test the Sony disc in the Plextor to see how it reads, and check the Plextor disc in the Sony to see how it reads. The results may be different, even if you started with identical discs.

You cannot compare QCheck results in the Plextor against Nero results in the Sony unless you start with a professional (CATS, Expert Magnetics, Clover, etc.) tester system that will give an ‘unbiased’ baseline. You are then comparing the PTP or Nero results against a dedicated test system, instead of one app vs another app. Each application may process the errors differently and you’ll get different results for each disc tested in each drive, simply because of media differences and hardware differences.

You may get consistent low errors in one drive with a specific media recorded at a specific speed, while the same media gives varying or high error results in another drive at the same recorded speed because of the write strategies. Try selecting the various modes of Autostrategy in the 760 if your results are not consistent from disc to disc.


#12

Bob
Thanks for the explanation. I glad someone understands my endeaver here.
What you are saying is that unless I use an “unbiased” program for qchecking
the results will differ from drive to drive app to app.
OK as for the write stategy, How can say a PCAV strategy be changed to a CAV or CLV strategy. Seems the best results are gotten on PCAV/CAV strategy and the Z-CLV produces many errors especially when the speed is trying to stabilize at 8x.
So why not use CAV at all writing speeds like 8X 4X 2X etc.


#13

I think there is some misunderstanding here, so I will try to clear it up.

PlexTools can only perform quality scans on Plextor drives but not on other drives.

Nero CD-DVD Speed can perform quality scans on many drives but not on any Plextor drives.

So there is no way to compare a PlexTools and a CDSpeed scan on the same drive.

These two programs only present what the drive is reporting, so any “bias” is strictly to blame on the drive and firmware (aside from actual bugs in the programs).

The difference you’re seeing in your scans is the result of your drives having different opinions about the quality of your media burns. This is a very common phenomenon.

It’s pointless IMO to try to decide which drive is right and which drive is wrong. It’s better to consider the tests as subjective and that the drives each have a different point of view.

Unless one of the drives is defective or an unreliable scanner, I would consider a burn to be good only if all reliable scanning drives think it’s good. Otherwise I would consider the burn bad or marginal.

Nothing I have seen so far makes me think that Plextor PX-760 drives in general are unreliable for scanning. Any individual drive can potentially be very picky, however, like my Plextor PX-712A which reports approx. 3x as many PIE/PIF as some other PX-712A drives.


#14

You beat me to it (again). :clap:


#15

“So there is no way to compare a PlexTools and a CDSpeed scan on the same drive”

I am only testing burns created on different burners on the Plextor 760a.
I probably shouldn’t have posted those CDSPEED results it just confused you all,.

I realize Plextools doesn’t really know what drive originally created the burns but it still gives those burns a worse score than the disks created on other drives.

( Anyways If another scanner gives those burns equal scores why shouldn’t the Plextor? I don’t buy the personalitiy of the drive idea. An error is an error. And all testing programs should catch these the same way)


#16

I’m afraid you’ve misunderstood a basic fact about disc quality “scanning” - the scan isn’t measuring the disc itself but rather the interaction between the disc and the scanning drive.

So an error isn’t an error as you’re claiming. :disagree:

An error is just what the drive is experiencing while reading/scanning the disc, and the same error may be gone the next time the disc is scanned in the same drive or in another drive, and there may be new errors that weren’t there before.


#17

I’ll second [B]DrageMester[/B] and phrase it differently:

PIE/PIF errors are not errors on a disc. They are [I]reading[/I] errors. They are the result of the burning quality, the disc’s physical characteristics, and the drive’s reading behaviour.

PIE/PIF tests [B]are not measuring anything on a disc[/B] (with the possible exception of jitter but even this isn’t clear). PIE/PIF tests only shows what error correction a drive has to apply when parsing the ECC blocks of a disc.

I highly recommend that you read this article:
http://www.cdfreaks.com/reviews/CATS-vs_-Home-made-scans
[B]Excerpt:[/B]
When testing disc or drive quality it is first important to realize that such tests do not deliver absolute values : a PI/PO plot always results from a combination of factors, which are a given media, a given drive and a set of operating conditions.[B] Indeed, PI and PO errors are not values read from a disc like the book type or a logical sector number, but the result of a calculation performed by a DVD drive[/B] during a standard reading of the disc;

You may also find this interesting: http://www.cdrinfo.com/forum/tm.asp?m=65963&mpage=2


#18

This is not an accurate way to put it, as a drive is not actually reading user data when performing a PIE/PIF scan, but due to my limited knowledge of the english language I can’t come up with a better formulation, sorry. :slight_smile:


#19

All this aside – Re-examine my test burns Plextools SCANS using the LG and Sony as the originating burner. Wouldn’t you say these errors are the result of a write strategy that Plextools cannot handle the reading of?

the LG uses a Z-CLV strategy thats starts at 4x and jumps up to 8x. The 4x errors are tremendous and the 8x errors are minimal.

The Sony uses a P-CAV strat that starts at 5x climbs to 6x and suddenly drops to 4x.
In this case the errors during the climb are minimal but when it drops to 4x they become abundant (inverse of the LG)

The Plex on the other hand uses a P-CAV that steadily climbs to 8x and stays linear from that point on. Resulting in the best score according to PTP.

So would you agree that PTP just doesn’t like the strats that the LG and SONY use to write. . The create disk charts for these three burns are below.





#20

No, I’d rather say that there’s some problem with those write strategies that produce burns which aren’t that great, and the Plextor drive is picky enough to show this problem in PlexTools scans.