Philips MBI DVDs: strange test results

vbimport

#1

Just started doing some detailed scanning of media stash with my new crossflashed BenQ DW1640 (thanks negritude and Quikee :flower:).

Looking at my Philips MBI DVDs (back from the days before I discovered Verbies and TY) has thrown up some very strange results.

Specifically, when I scanned one MBI DVD+R @ 16x, as the scan neared the end, the Jitter and PIF rates started to skyrocket as the scan went way into PO territory. This was prompted by an Advanced Disc Scan which showed similar results and labelled the disc Class 5.
The disc passed a BenQ TRT but the resulting speed graph was epileptic.

So as I began to think the disc had gone backside-up (as another MBI disc from the same archive had done about 6 months previously) I rechecked it in my Samsung drive and IIRC also my NEC/Optiarc, both Quality Scan and TRT.
And to my surprise, those tests didn’t agree with any of it!

For reference, this disc was most likely burned on an NEC 3550A at 16x and stock firmware.

I’ve ruled out a drive fault, as for example scanning Taiyo Yuden discs @ 8x has produced far more realistic results, (perfect trts, sensible qs graphs and Class 2 results from Advanced scanning), and also burns my Yudens as well as anything I’ve used before, so I’m wondering what to do with this MBI DVD and any others like it if any.

The main purpose for this disc is long term archival. Should I bin it or not?


#2

The samsung is not the best scanner in my opinion for two reasons:

  1. It is too tolerant of a scanner (as I have heard from various people whom I trust)

  2. Not only is it tolerant, it’s only reading at 12x!

Now my main questions are - what model of NEC/Optiarc are you using, usually they are fussy, apart from a few of them. So if that TRTs fine and is a fussy reader, the results are surprising. Also, what does a 8x scan in the BenQ look like?


#3

I don’t necessarily trust the BenQ disc quality scan, especially at high scanning speed, but the Transfer Rate Test looks terrible.

If your BenQ DW1640 is in an external enclosure, that could explain the slowdown at the end - if it happens for all DVDs.

If your BenQ shows this kind of scanning behaviour and TRT slowdowns for all DVD media, then I would ignore it as a testing tool. If your BenQ show good results for some media, then I wouldn’t ignore what it says.

So provided your BenQ doesn’t show such behaviour for all DVDs, the TRT slowdowns would make me reburn that disc, regardless of how many other drives show pretty PIE/PIF scans.


#4

Welcome to the real world or testing media and burns. :bigsmile:

There is nothing surprising, for me, in wild testing or/and reading differences between different drives (specially with MBI discs :p). I’ve had many discs like these, reading and/or testing perfectly in some drives and terribly in other drives.

That’s the “mediocre burns” territory. I generally don’t keep such discs, on the logical basis that burns/discs which pass tests in all testing drives are obviously of much higher quality then those which don’t. With such cross-checks, you start noticing the difference between really good blanks like Verbatim or TY+R 8X, and only apparently good ones like lots of stuff around that scans very well in Lite_On drives @4X. :bigsmile:

Such cases are what made me change entirely my views on scanning a couple of years ago, and drift completely from the scanning dogmas. :stuck_out_tongue:

Reason why testing in several drives is the only way to go. Testing in a single at a single speed drive is just loosing lots of time for not much gained.


#5

Thanks :slight_smile:

An update:

I just rechecked the disc today in the BenQ and my NEC/Optiarc (7203A as per my sig) and the results were even worse, this time scanning with BenQ@16x I found over 24,000 PO Failures and the PI/PO spike at about the 2.2GB mark is very noticeable. With the BenQ that one alone registers massive PI rates and even POF at 16x, even the Optiarc found Max 16 PIF at that point.
Optiarc TRT also shows a slight blip at the 2.9G mark.

Too many question marks over the disc now, methinks it’s time to reburn it to one of my TYs and check the rest of my MBI DVDs really carefully.


#6

[QUOTE=SeanW;2136829]Thanks :)[/quote]You’re very kind to take my evil welcome with a thanks. :wink:

Optiarc TRT also shows a slight blip at the 2.9G mark.
I’d very much like to see the TRT if you’d be so kind to post it. The reason is that I’m interested in how the 72XX drives behave with problematic discs: my current main drive for TRTs, a NEC 4550, is giving signs of aging and I’ll soon need a new drive for TRTs…


#7

[Off-topic]

[quote=Francksoy;2136862]I’d very much like to see the TRT if you’d be so kind to post it. The reason is that I’m interested in how the 72XX drives behave with problematic discs: my current main drive for TRTs, a NEC 4550, is giving signs of aging and I’ll soon need a new drive for TRTs…[/quote] My Optiarc A-7203A is much more tolerant to disc problems than my NEC ND-4551A (and Plextor PX-712A and Plextor PX-760A); still, I’m currently using it for TRT testing along with my Pioneer DVR-112L because it’s “good enough” most of the time, and there are good reasons not to use the other more sensitive drives.

If you like to discuss further regarding good current drives for TRT testing, please feel free to open a new thread on the subject. :slight_smile:

[Even more off-topic]
My Optiarc AD-7203A is giving me lots of problems today with bad relinking and slowdown to burning at 1.5x. I seem to have the worst luck with Optiarc drives! :doh:


#8

[QUOTE=DrageMester;2136869]If you like to discuss further regarding good current drives for TRT testing, please feel free to open a new thread on the subject. :)[/quote]Well, since we are discussing my crappy MBI DVDs and the hardware I’m using to ascertain same, it’s kinda relevant.

I just did a whole new set of scans of the same disc with the BenQ and the results are a lot better. Almost a full Trt graph and 0 or close to 0 POF …

Here are the new results

I don’t get it. It’s like I’m scanning two different discs or something! :doh: :doh:




#9

The error peak and the corresponding speed drop are still present, so I consider this disc as ready for the trashcan.


#10

Yes, I’ve already decided to reburn the disc to a Taiyo Yuden. I’m just wondering where the 17,000 PO Failures and most of the speed drops went!

@Francksoy:
Having rechecked the disc today in the NEC/Optiarc 7203a, it found a PI surge (to max 16 PIF, which put the PIF rate just over into the yellow section) and a small blip in the TRT, all at the 2.2-2.3GB mark, where the BenQ agrees there is a serious problem.

But since the disc seems to have magically recovered in the last 8 hours, I can’t really say for certain that that’s how this drive will read bad discs because I’m scratching my head trying to figured out just how bad the disc is - the only thing I know for certain at this point is that the disc needs to be replaced.


#11

[QUOTE=SeanW;2136915]I don’t get it. It’s like I’m scanning two different discs or something! :doh: :doh:[/QUOTE]It helps sometimes to go back to the basics, as the pioneers experienced this quite long ago… :wink:

Excerpt from an rdgrimes post:
"I think this is as good a place as any to discuss some of the problems people report with PI/PO scanning. A common report is that a disc will scan good (or bad) one time and the next time it will scan the opposite way, with the differences being fairly extreme.
We saw much the same thing when we first started scanning CDRs for C1/C2 errors. The situation does not appear to be all that different than it was then.
The discs that cause this weird behaviour are almost always discs that are somewhat marginal in burn quality. Those discs that are excellent in burn quality do not do this, and likewise those discs that are truly crappy do not do this."
Source: Interpreting PI/PO errors scans

What I personally add to the equation is the discs’s own inherent properties, and not only the burning quality.

Now, it’s very possible that you have TWO issues: a looney disc + a Benq going nuts… :doh: - difficult to say. ? Needs more cross-chekcs.


#12

[OT]

[QUOTE=DrageMester;2136869] My Optiarc A-7203A is much more tolerant to disc problems than my NEC ND-4551A (and Plextor PX-712A and Plextor PX-760A); [/quote]Thanks :slight_smile:

If you like to discuss further regarding good current drives for TRT testing, please feel free to open a new thread on the subject. :slight_smile:
I’ll do that soon, I’ll simply have to…
My Optiarc AD-7203A is giving me lots of problems today with bad relinking and slowdown to burning at 1.5x. I seem to have the worst luck with Optiarc drives! :doh:
Indeed… :frowning:
[/OT]


#13

I just began checking some of my archived video DVD-Rs with Nero DiscSpeed today and also had such a strange result with an MBI disc! You can see it in the attached image below. It was burned by a Sony DVD recorder in 2004, but it’s my only MBI disc, so I can’t compare it with other MBIs. I can play back the video from the disc well, so the scan result may just be some kind of incompatibility between the Sony burned MBI disc and my BenQ DW1640… or there could be some real issue with the disc that just isn’t noticeable during video playback because of MPEG-II error correction.

I guess I’ll reburn the disc on a Verbatim though, just to be on the safe side.



#14

Holy cats BobaFett. 31258 PO failures? I wouldn’t think it would read at all if that figure is correct.


#15

Honestly, I think your BenQ scanner is flipping out… it can do so very easily when scanning discs with so-so to bad jitter levels, and more so after it’s heated up. If you can copy the data to your HDD without CRC errors, I’d say your POFs are imaginary.


#16

SeanW,

I don’t get it. It’s like I’m scanning two different discs or something!

Differences in disc temperature when scanning a disc at different times or on different days can also severely affect test results, particularly with the marginal disc.


#17

Ok after seeing the follow up posts with pics, it does indeed look like a bad disc. The BenQs 16x scan and TRT [B]perfectly[/B] correlate too. In post #8 you can see the BenQ only shows a slowdown where the TRT reaches 92PIF. The blip in the TRT is also somewhat small. So I assume the BenQ can read past this amount of PIF with only a small slowdown. Seeing as the PIF only reaches about 65-70 towards the end, the BenQ can read past this without slowdowns.

In post #1 you can see the MAX PIF reported towards the end is nearing well over 300 and slowdowns are also encountered in the TRT.

This could come down to heat of the drive etc. But one thing is for sure and that’s the TRT and Quality scans when done @ 16x one after another agree with each others results.


#18

[QUOTE=tropic;2137050]If you can copy the data to your HDD without CRC errors, I’d say your POFs are imaginary.[/QUOTE]That’s a fact, Nexperia/Benq drives notoriously have totally unreliable POF reporting.
This doesn’t mean, though, that the disc isn’t crap just because the Benq wrongly reports POFs. It may report PIF reliably just the same. (I stress: may)

you mean the POFs? Because the “strange” result that started this thread was more about the wild scanning variation than the POF reporting issue.

About Nexperia/Benq POF reporting, I suggest visiting the Benq forum or the testing sub-forum. Also, read the article Home PI/PIF scanning - Who to believe? which uncovers the Benq POF reporting issue. I don’t know who was the first to report this quirk, but I remember that I learned it from DrageMester (who always seems to know the new stuff before anyone else even notices).

@cd pirate: I do share your opinions about how to interpret the data at hand, thus that the disc is a problematic one, but as I mentioned above, it’s still possible that the drive itself has reporting issues as well.


#19

[QUOTE=tropic;2137050]Honestly, I think your BenQ scanner is flipping out… it can do so very easily when scanning discs with so-so to bad jitter levels, and more so after it’s heated up. If you can copy the data to your HDD without CRC errors, I’d say your POFs are imaginary.[/QUOTE]
Not necessarily, since a PO Failure doesn’t mean the affected sector is unreadable (though it can) just that it cannot be read at that speed with that drive at that time.
A Quality Scan on it’s own isn’t enough, in the case of a disc with PO Failures, copying files off it may work - albeit slowly - but what’s really needed is a Transfer Rate Test.


#20

Well, I consider such a high POF value strange for a disc that seems to play back well.

I’ve made a transfer rate test now, which you can see on the attached image. The transfer rate goes down at the end of the disc… what does this tell me about the disc now? I’d think that at least there must be some kind of fault near the end…

I’ve also made a second transfer rate test afterwards, which confirms the speed drop at the end.