Why is Disc Quality Scanning inconsistent from one drive to another?

vbimport

#1

I’m starting to think that disc quality scanning shouldn’t really be taken too seriously cuz the disc quality varies from one drive to another. What do u think?


#2

No home scanning drive is gonna be as accurate as professional scanning equipment (CATS etc). Also, many users here like to perform scans on as many different drives as possible.

Scanning has it’s place, for instance checking deterioration periodically, but IMO shouldn’t be used by itself as a be-all and end-all.

Transfer Rate Tests on picky drives, along with real-world (playback) tests should be performed alongside wherever possible.

Just my personal opinion, I could add more but we’ve had this discussion many times. :slight_smile:

All that said, home scanning is great fun, though :wink:


#3

AFAIK both the Samsung SH-S182M and the Sony DRU-840A use the same Mediatek chipset but look at the disc quality results! I think it would be understanable if the differences between the two drives are negligible in disc quality scanning but this isn’t really the case at least on certain types of DVD+R media.




#4

I’ve seen this before. One drive was a LiteOn 165P6S, the other was a Sony - both exactly the same hardware, except one was using LiteOn firmware, the other had Sony firmware.

My bet is what you’re seeing is firmware related. :wink:


#5

[QUOTE=Auzzie Kid;2001965][B]AFAIK both the Samsung SH-S182M and the Sony DRU-840A use the same Mediatek chipset [/B]but look at the disc quality results! I think it would be understanable if the differences between the two drives are negligible in disc quality scanning but this isn’t really the case at least on certain types of DVD+R media.[/QUOTE]

:disagree:

Totally different generations of burners , the Sony 840A is actually a Samsung 202 burner .

182x series are not good for scanning while new 2xx series might be alot better and my 203B gives me comparable (sometimes even near identical PIF/PIE numbers) to LiteOn 20A4P or Benq 1640

Try to make a TRT and if it is good near the edge trust your 840A and don’t mind the 182M :slight_smile:


#6

It’s an imperfect world. You could buy 2 identical model burners and still see fairly major variation. You can burn through a whole spindle of discs and not get 2 identical scans with the same scanner. There’s still minor variation in the materials used to make the burners and discs and the manufacturing process isn’t 100% perfect. Results between different drives will vary less or more depending on the scanning speed as well.

I’d imagine firmware is the major difference but I’d think components other than the chipset also would influence the difference. I know my 203B scans entirely different than my 182D. I;ve found scanning at 18x with my 203B produces results in between my Liteys and Benqs, while 4x with my 182D is close to my Benq scans. Granted entirely different chipsets but still a vast difference.


#7

Also check the build date of your Samsung. IIRC only pre-July’06 SH-S182x units provide more or less meaningful scans. If you want some kind of a reference point for comparing with other people’s results here, you’ll have to use a more popular scanning drive like Lite-On (and even then there’s individual drive variations).


#8

Well I’ve also said that I don’t fully trust scanning. I personally use two different drives - a Liteon LH18A1P and a BenQ 1620. Sometimes I get very different results but with some really good media the results are always almost identical (even with jitter).


#9

@ [B]the original poster[/B]: I guess most of your confusion comes from the fact that you’ve originally been caught into the usual illusion that scanning is [I]measuring[/I] something on a disc. Am I wrong? :slight_smile:

I’m starting to think that disc quality scanning shouldn’t really be taken too seriously
:clap: Way to go!

Welcome to the real world, [B]scanning is not measuring anything on the disc[/B]. It’s a report of what happens in a given drive at the error correction stage while parsing ECC blocks. “Things” on the disc like jitter, surface defects, reflectivity, tilt (= flatness), tracking etc… will show (or not…) as PIE/PIF.

Different drives will choke on different kinds of “trouble” on discs, so ALL drives (and yes even of the very same make, models etc…) will report different PIE/PIF plots for the same disc. It’s only normal, and even 100% expected.

That’s why I came more and more to consider that the really best discs/burns are the ones that scan OK in [I]any[/I] scanning drive, rather than those that scan excellently in a “reference” drive like a Lite-On but possibly badly in other drives.

Professional scanning machines are tightly calibrated to give controlled, compliant and comparable PIE/PIF plots. Even so, two passes are not identical. So don’t ask too much of our cheap end-user drives… :wink: :bigsmile:

Just for the record, this post of mine doesn’t mean that I find scanning useless. Not in the least. :slight_smile:


#10

I have found very consistent scanning results comparing a liteon 20A1L with a 20A1S – usually less than 5% varience between the same disc in each drive or the same disc in consecutive tests in the same drive. Yes, I know these two drives are basically identical except for one having a LightScribe laser assembly, but I’ve read quite a few reports stating even identical burners from the same build lot showing considerably more test result varience than I found.

Out of curiosity, I also compared the Liteon test scans with a NEC 3550 and those results were within 10% of the Litey results for the same discs tested. Most importantly, the shape of the QS graph and the locations of major PIE/PIF peaks coincided with the Liteon – even though NEC drives are normally reagarded as being unreliable scanners. (And I wouldn’t recommend anyone to use one for such, either.)

My independant conclusion was that there is sufficient agreement between scans from several models and brands of ODDs to give those results reasonable credence – as long as the same discs are tested by TRT and “fussy player” tests as well, to get a more accurate indication of overall write quality of a disc.

EDIT: Looks like I posted a somewhat different conclusion at the same time as Francksoy…


#11

[QUOTE=RWP;2002380]My independant conclusion was that there is sufficient agreement [B]between scans from several models and brands of ODDs to give those results reasonable credence[/B] – as long as the same discs are tested by TRT and “fussy player” tests as well, to get a more accurate indication of overall write quality of a disc.[/quote]Not [I]that [/I]different a conclusion… :slight_smile:


#12

ughh, scaning is a pain in the butt for me, it makes me think scans don’t give any real indication of the disks state. If you scan slowly you can get close to no errors. my dw1610 with the g8t9 wouldn’t scan at more then 0.8x but it got almost no errors. then i flashed it to b8v9 and now it scans at normal speed but with many errors.

the best tests are to be are if your files transfer, your disk reads in other players and there’s negliable degradation.

but maybe i’ve missed something since well i’ve never got into this scaning business untill now it’s interesting.
i know that before i came here, i used Interaxia VDSPMSAB01. I have some that are 5 years old that all the files still copy off of. I know it’s dirt media. i stopped useing it myself after some disks became unreadable. other stuff like sony16d1’s at 8x, great burns. i’ve yet to see one fail. Won’t even finish a scan there’s so many errors.

I guess some course in scaning would be nice XD