Kprobe Scans @ 2X and 4X

I am attaching the Kprobe scans done on my 811S at 2x and 4x. The 2x results look like an excellent burn while the 4x one has more PI errors.

I am having the 811S in an external enclosure - USB 2.0. Could that be a reason for the difference in errors in the two scans.

I know there is a FAQ on interpretting kprobe scans. But if the experts can shed some light looking at these graphs it would be very helpful.

Thanks again

4X results


Iregardless of what speed the disc is burnt at you should be scanning both discs’s @ 4x 8ECC (I see in your pics that you scanned one at 2x and the next at 4x). Scanning at different speeds does not produce and accurate comparison.

I think the scans are from the same disc, only one at 2x and other at 4x.

240SXFAN, I scan at 4x, and the discs that are above 150PI skips in my not-so-good Daewoo, so I know right away if I’ll have problems. Different speeds different results, so keep the scans at same speed and if you going to post my guess is that 4x is the speed of choice.

the slower scan speed will give a better result

with that said the 4x 8ECC on 811S seems to be an issue many get a very poor scan and when you read at 8x or max the scan looks better than 4x

no one has given a good explaination except to blame media or poor write quality(this seems ?? since a faster read gives a better result)

Originally posted by nealh

no one has given a good explaination except to blame media or poor write quality(this seems ?? since a faster read gives a better result)

I don’t have a good explanation either, but if you notice when you do max scan, it’ll start scanning at 2x and increasing toward the brim. When scanning at 4x however, it will start at 4x. That is probably one of the issues with poorly burned discs. (I assume that good disc can be scanned at 4x because when i scaned a factory pressed DVD, it gave an good result.)

On the side note, lately i’ve been scanning at max with my DATA discs. I feel that when i use it, it will read at that max speed anyway.

I have the same problem, when I scan at 4x when compared to 2x I get about 10x PI errors but the PO errors stay the same.

Both of the posted scans are perfectly good scans. In this case, a difference of 10x higher PI rates has no real meaning because it’s still well within specs. What is seen here, is that the disc is harder for the drive to read at 4x than at 2x, which shouldn’t come as a surprise to anyone. The 4x scan doesn’t even come close to being bad enough to cause concern.

well i have higher scans than he does so his average of 14 on 4x is more like 30 on mine and the errors do go out of spec by a decent amount when scanned at 4x but they are well within the specs when scanned at 2x

As long as you only care about comaring your own results you can scan at any speed you want as long as you are consistant. Although I don’t get why people scan at different speeds myself… does it make you feel better when you get lower errors or something? :confused:

Scanning at 4x is done to provide a standard with wich to judge your results against others in the DVD Media test forums as well as here.

Doesn’t ECMA state that error counts should be carried out at 1x (like AudioDev does IIRC) ?

Around here, we use 4x as some compromise between time and accuracy.

Since the Liteys (or any other drive) will read out higher error rates at higher speeds, even short excessions of the standards @ 8ECC (280/32) shouldn’t cause trouble since these excessions will most likely be gone if the drive gets into re-reading at lower speed.

So if you scan @ 4x 8ECC and the results are within the specs and the disc is recognized by the drive/standalone of your choice, there is no need to worry at all … despite the fact that no one can state anything useful about DVD long-term reliability yet.

Doesn’t ECMA state that error counts should be carried out at 1x (like AudioDev does IIRC) ?

Exactly. And also, measuring equipment should be properly calibrated as well. That is why Kprobe’s PI/PO should be taken with grain of salt.

I don’t know why people making a big deal about PIPO/C1C2 anyway. Of course, i do kprobe some, only couple first when switch brand of discs or backing up crucial data. That’s because it is just easier than getting up to the DVD player and watch the whole thing. Or for DATA, i just kprobe for data verification. If i’m gonna spend 15 minutes, i’d rather kprobe the discs. At least, the graph just looks more cool. :slight_smile:

One thing though, people will say low error discs last longer. I don’t really agree that it is necessary true. It’s more about how stable the chemical on discs are, how well is coating, thing like that. If the media is actually rotten chemically, so much error will occur on the disc thus no amount of error correction can help.

So stop scanning every single disc and get over number of PI/PO, it does not matter. As long as your DVD works as you want, you’d fine.:bigsmile:

Originally posted by simplelife
Exactly. And also, measuring equipment should be properly calibrated as well. That is why Kprobe’s PI/PO should be taken with grain of salt.

K-Probe simply counts error flags that are being transmitted by the drive itself … so your drive’s accuracy should be taken with a grain of salt.

I experienced some strange behaviour from my 411S … e.g. some discs show completely different error values when being scanned twice … but I agree that a disc which can be played flawlessly on the most picky piece of equipment should be well … although a low PI/PO (just like CD C1/C2) leaves some additional headroom for successful error correction regarding future media degradation like scratches (uh, these DVD’s are being scratched so easily) or fingerprints.

regards, sven

the pressed dvd I have scanned give similar or worse results than a disc off my liteon