Typical dvd media lifespan

[yetanotherid]

I'd wonder if it even matters. The potentially copyright infringing picture must be about four years old. I wonder if it'd look the same today.

[yetanotherid]

Well I've just finished the world's least scientific study of disc longevity. "Least" because it's a small random sample and I've not really got any idea as to the horrors the discs may have been subjected to since they were burned. All came from the "poor burn" spindle but I've no way of knowing what the quality of each was like when it was originally burned. I thought I'd find older discs (I may have to search the house for them) so these only go back a few years.

One trend which seems to have emerged, all the discs seem to have deteriorated in quality but it would appear the ones which have deteriorated the least are Verbatim.
Admittedly they've all been subjected to wear and tear but what surprised me is this..... I don't keep all the bad burns, only the ones I think should still be usable, so once the quality has dropped too low (say under around 40% according to Nero CD Speed) I throw them away. Anything between 40% and around 90% goes on the "poor burn" spindle, anything above 90%-95% goes into the archive folder.

Running quality tests again today on a random sample of these "poor burn" discs led me to the conclusion that had the burn quality of the discs I tested been as bad originally as they are now I never would have kept any of them in the first place. Therefore they must have deteriorated. Many were so bad I doubted they'd be readable at all. This includes TDK Premium discs, TDK Gold discs (or pretty much anything using CMC MAG dye) Sony, Imation, etc. The brand I checked the most was Verbatim, mainly because there's a lot more of them than other brands, but they do seem to have deteriorated the least. In fact I only found one Verbatim discs which was of such a bad quality I probably would have just thrown it away if it was burned that badly originally. I can't say the Verbatim discs haven't deteriorated (they probably have) but it would appear that it's not as much as all the other brands of disc.

I've posted some rather distressingly "typical" screen shots below. As I said this is the world's least scientific disc longevity test but it makes me wonder what the average person's collection of burned discs must be like, given most people don't run quality tests after burning and most would own discs which have been subjected to similar wear and tear. I'm going to run part 2 of the test later. It'll involve exactly the same random testing, but this time I'm going to pull random samples of discs from the "good burn" folder. Unfortunately 99% of those discs are Verbatim but there's other brands scattered in amongst them. It'll be interesting to see if there's any pattern in quality when testing discs which I know would have been of a good quality when originally burned, and which have led a sheltered life in storage and hardly ever been used.

For the record I checked 1 X Benq disc, 2 x Imation, 1 x No-Name (CMC MAG), 1 x No-Name (Prodisc), 1 x Sony, 4 x TDK Gold, 2 x TDK and 6 x Verbatim. As I said.... hardly scientific.

There was one other interesting result and I'm not sure if it's thrown a spanner into my test results. I only tried it with two of the discs.... mainly because it didn't occur to me to try until I'd almost finished.... after running the quality test on the TDK Premium disc and the No-Name (Prodisc) below with their 0% quality score I tried copying the files from the discs to my hard drive. What surprised me was the same drive I used for running the quality tests (Pioneer 112D) copied every file from the TDK disc in around ten minutes. In fact watching the copying process it appeared to pull all the files off the disc without missing a beat. It copied every file from the No-Name Prodisc as well, although it was obviously struggling towards the end of the disc.
I don't know what to make of that.... whether the drive is a really good reader, whether it's not reporting errors as accurately as I thought it did, or whether the quality of the burn really doesn't have to be anywhere near as perfect as I've assumed it does.....

Benq
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestBenqMay2009.gif?t=1299582585

Imation
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestImationOctober12005.gif?t=1299582586

No-Name (Prodisc)
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestNo-NameApril22008.gif?t=1299583826

Sony
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestSonySeptember2008.gif?t=1299582744

TDK Gold
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestTDKGoldApril12008.gif?t=1299582589

TDK Premium
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestTDKSeptember2006.gif?t=1299583017

Verbatim (Although I had to test quite a few to find one this bad)
http://i10.photobucket.com/albums/a142/dashpb1/QualityTestVerbatimJanurary2008.gif?t=1299582598

[Ghitulescu]

Excellent post.
As I said before, the maximum allowed values (280/4) are very much conservative, many drives around can read bad disks quite speedy. That's why the tests are almost irrelevant, in the sense that they are not repeatable (they are drive dependent). If one keeps a single drive and runs the test in exactly the same conditions, the results, although not official, can be considered to be a measure of quality (lower PI/PO = good, higher PI/PO = bad). How much these values can go up without adversely affecting the reading (bad sectors) depends entirely on the reader (every reader is obliged by the standard to perfectly read any DVD that has PI/PO less or equal to 280/4, less than 8% jitter and so on). What goes beyond is a courtesy of the manufacturer.
One should also consider the availability of a reader, higher speed readers generally yield higher errors than low speed ones.

[yetanotherid]

Maybe my overly paranoid view of the need for high burn quality comes from a DVD player I used to own years ago. It's the main reason I started on my "re-burn everything, must be good quality crusade", as it was terrible at reading anything but good quality discs (it'd stutter or the picture would become blocky etc). However despite the burn quality tests I ran today being so poor, nobody in the house has ever complained about a current DVD player not being able to play any of those discs. And my Pioneer drive could pull the files off them even though it had to slow down to read the end of the second disc.
And of course I've been given discs burned by other people on many occasions (got to love laptop DVD burners) which have presented quite a struggle to copy their files, even with a PC's drive.... oh well, I guess even if I've been overly paranoid at least I should be assured the discs I keep will last a long time..... and I'm starting to feel more confident that even the bad burns Wantangobi posted (which are excellent compared to the discs I just tested) should be readable for many years to come.

Anyway.... I'll run some more tests on my good discs a little later as I'm curious as to what the results will be.

[yetanotherid]

I just ran two more burn test on a couple of Laser discs. These were actually fakes which had a MCC ID but which didn't use MCC dye. As a result the burns were generally quite poor but I did find a couple which I'd kept to put on the "poor burn" spindle (I didn't keep even the good burns on those blanks for archiving).
Oddly enough, they don't appear to have deteriorated much at all. Go figure....

[yetanotherid]

I must have done a bit more experimenting with different brands originally than I remembered. When I pulled out the oldest folder of "good burn" discs there was more of a mixed bag inside than I expected.

Some of them actually gave me a bit of a scare. For instance a couple of discs dropped to 50% near the end of the burn, but after cleaning off the fingerprints they stayed above 90%. That then got me wondering about the previous burn tests and all the handling those discs have endured. Even though I wiped the worst of the fingerprints and smudges off before testing them, it made me wonder if they'd have tested a lot better if I'd put them through a disc cleaner first, and whether underneath the scuffed plastic the burns were actually still okay.

So after all my messing around today I'm not sure if it achieved anything. There's no point uploading screen shots of the oldest "good burns" as they still look good, and I tested Benq, Prodisc, Ricoh, Sony, Taiyo Yuden, TDK and Vebatim discs. None really showed any signs of deterioration although they're all almost the same age as the previous discs. It leaves me pretty convinced most discs, especially good quality blanks, should last a long time in storage but it's obvious discs which are being used rather than stored can in fact deteriorate quite a bit. I just don't know whether the fact that they weren't as good a quality to begin with would cause them to deteriorate quickly, or whether under the scuffed plastic they haven't deteriorated as much as the quality tests indicate they have.

[Wantangobi]

Thanks for the tests yetanotherid :)

My worst disc
http://i51.tinypic.com/qycvnq.png
Scandisc of it
http://i51.tinypic.com/2u9pwfd.png
It can still be read from. But I had to make a 3rd attempt for a few files to copy over.
The disc was never used after burning and it's only 3 months old.
It was my high speed burn test on my old drive. The other were all 2x, this one was 8x.

I had some CD-RWs almost go bad on me a long time ago(Cyclic Redundancy check errors). Unstopable Copier managed to pull the uncooperative files off them. But that only works for media. Something like a game backup would probably not work unless the flaws were in the movies or sound.

once the quality has dropped too low (say under around 40% according to Nero CD Speed) I throw them away.Where does it list this % quality anyway? I only see the PI and PIF ratings.

[burfadel]

DVD +R vs DVD -R ... :)

[Ghitulescu]

Where does it list this % quality anyway? I only see the PI and PIF ratings.

Forget about %, try to keep the errors at a minimum, and get rid of the Optiarc. Since Pioneers are no longer in the DVD business, so the Plextors, get yourself a LiteOn or an LG. LiteOn for its ability to use Kprobe2 or LGs for good burns and very good (best ??) readings.

PS: Was this a fake Verbatim?

[kypec]

@yetanotherid: Ghitulescu's chart of DVD burners reading abilities comes from http://www.diit.cz formerly known as http://cdr.cz. Unfortunately it's very old and I couldn't find it there but I'm sure the authors wouldn't mind him posting one summary over here ;)

[Ghitulescu]

Yes, the reading capabilities is sort of old, but I haven't seen so many new burners on the market, so it is still of a certain relevance. I don't think all of modern users have now BD-burners to burn DVDs.

Bottom line: when using a NEC ND-3540A to assess the quality of a disk, be prepared to have higher PI/PO than using a Plextor PX-750 or any LGs.

[yetanotherid]

Where does it list this % quality anyway? I only see the PI and PIF ratings.

Near the bottom right corner. It's called a quality score. Your last screenshot was 0%.
Don't necessarily forget about %, and of course the desire to keep errors at a minimum would be stating the obvious. The % figure isn't really an average or anything like that. If you watch it change while you're scanning you'll see what I mean and why I say 95% is my rule of thumb.

I own a non-Pioneer, Pioneer burner. It's as good a burner as the previous Pioneer, Pioneer burner, if not a little better. Like all newer Pioneer burners though, you can't run burn quality tests with it.

[yetanotherid]

@yetanotherid: Ghitulescu's chart of DVD burners reading abilities comes from http://www.diit.cz formerly known as http://cdr.cz. Unfortunately it's very old and I couldn't find it there but I'm sure the authors wouldn't mind him posting one summary over here ;)

It was just my little dig given copyright was the excuse given by Ghitulescu for not backing up claims made earlier in the thread, yet he later posted someone else's image.

[Wantangobi]

get rid of the Optiarc. [...], get yourself a LiteOn or an LG. LiteOn for its ability to use Kprobe2 or LGs for good burns and very good (best ??) readings.Remember that all these really bad discs are from my old Samsung drive. This Sony drive is averaging pi/pif scores that are well within what cdfeaks considers good but non-archive quality.
I'm fine with the new drive. These new discs have %2 the errors of the old ones(that still work, btw). Maybe one file won't be readable in 10+ years. I'll survive.

PS: Was this a fake Verbatim?I bought them on Newegg last year. I wouldn't know how to tell if they were fake.

Near the bottom right corner. It's called a quality score. Your last screenshot was 0%.Now I see it :eek:
Thanks.

[Ghitulescu]

@yetanotherid:
I prefer not to engage a legal debate with a company, it's much easier to fight an individual, with the same money level as I have.

Besides I don't have to explain you my assertions. And I don't wanna spend money teaching you things, mostly because you seem to be such an expert. You wanna learn, use your own money, buy yourself information. I'll give the links for the articles, have fun, they are in German.

For free: non-Pioneer Pioneer burners are made by QSI. :)

[yetanotherid]

@yetanotherid:
I prefer not to engage a legal debate with a company, it's much easier to fight an individual, with the same money level as I have.

That's a fresh excuse.

Besides I don't have to explain you my assertions. And I don't wanna spend money teaching you things, mostly because you seem to be such an expert. You wanna learn, use your own money, buy yourself information. I'll give the links for the articles, have fun, they are in German.

No, you're getting it the wrong way around again. I don't have to believe your assertions unless you offer proof, which you've failed to do, so I don't.
I'm not an expert, you're a "can't be wrong". Which is probably why you avoided yet another question and didn't explain why anybody would be expected to understand what you're referring to when you call a Sony Optiarc an NEC burner.

[yetanotherid]

This Sony drive is averaging pi/pif scores that are well within what cdfeaks considers good but non-archive quality.

The screen shot you posted can't be far off it. What do they consider to be archive quality?

I bought them on Newegg last year. I wouldn't know how to tell if they were fake.

I've not seen any fake Verbatim discs as such (although maybe they exist) but I've seen other no-name brands which have the Mitsubishi MCC ID but obviously they don't really use the Mitsibishi dye.
There's some info here regarding the different dyes used on different brands of discs.
http://www.digitalfaq.com/reviews/dvd-media.htm
You can see the disc ID near the top right side of the Speed Disc window, in the "Disc Info" section.

[Ghitulescu]

It's not your thread, it's not you the one who asked for info, I have no obligations to you. Please stop this nonsense.


You have one burner, one brand of disks, yet extrapolate the "results" to an axiom.
On the other hand, I own some 50 optical units, and burn optical media probably longer than your mental age (I witnessed each and every optical disk birth, including types you never heard of, like PD, and I think I have quite a good perception of their quality decline). I always selected the best media possible, but I also tried nonames only to check whether it's worth paying the name for Verbatim, TDK & Co. Except for one type, it was worth.
And you want me to convince you!? No way. Start your own thread and I may answer, erh, sorry, you know everything, of course, you have nothing to ask.

[yetanotherid]

It's not your thread, it's not you the one who asked for info, I have no obligations to you. Please stop this nonsense.

I never said you did. If you want to make claims you won't back up and the end result is you're not taken seriously, that's up to you. If you want to call someone dumb and then not acknowledge it when you were wrong because you're a know-it-all, that's also up to you.
Please stop playing the poor little victim because the moral high ground you seem to think you're posting from is just a delusion.

You have one burner, one brand of disks, yet extrapolate the "results" to an axiom.

Has the dementia taken a firmer grip or do you recall how many different types of discs I posted in my last lot of quality tests. I've done exactly the same experimenting as you've done even though my part of the discussion mainly involves Verbatim discs, which I use the most, and your claim Verbatim's quality has dropped. Deal with it.

On the other hand, I own some 50 optical units, and burn optical media probably longer than your mental age (I witnessed each and every optical disk birth, including types you never heard of, like PD, and I think I have quite a good perception of their quality decline).

Yeah, yeah.... and you've continually ignored requests to post burn tests which prove your claims, yet you now point out you're in a better position to do so than I am. Quack.

And you want me to convince you!? No way. Start your own thread and I may answer, erh, sorry, you know everything, of course, you have nothing to ask.

I don't care whether you convince me or not, I just won't take you seriously.
And give the "start your own thread" nonsense a rest. It just makes you look more like a know-it-all. Go and start your own forum and moderate it to your hearts content if you won't be disagreed with and always need to be right. Until then accept that you're not always going to be agreed with, especially when you selectively ignore questions and won't offer the proof you claim to have.

[Ghitulescu]

... and your claim Verbatim's quality has dropped. Deal with it. ..

I haven't said that Verbatim dropped quality, I said all DVDRs dropped quality, and Verbatim is no exception. My 20 years experience with burning told me this. And really feel sorry for you if you cannot grip that quality is more than PI/PO values, or your interesting 95% limit. As independent longevity tests showed several times, disks that cut perfectly during burning couldn't be read afterwards, while disks that were not so brilliant in terms of PI/PO, withstand much much better and be still within the specs. Which I think is exactly what the OP asked. There are not so many dyes around, (I assume) you know, so there are other factors besides who manufactured the dye, who manufactured the stamper and who relabelled it. And of course, (I assume) you know there is also Gold/Alu layers, not only Alu.

And most people that claim that the DVDR must be burned at 16x because that's why is 16x written on them, and that the burners are designed to burn at 16x, or the same argumentation for CDR, they simply measure, if, the PI/PO (E21/E31 for CDR) but they don't have access (or time) to measure the jitter, which is higher at higher speeds, especially where the writing speed changes (also higher PI/PO, too). Those people don't come back to say, well, you know, my 16x (or 24x) disk just died, two weeks ago, God know why, it had such beautiful PI/POs.

[yetanotherid]

I haven't said that Verbatim dropped quality, I said all DVDRs dropped quality, and Verbatim is no exception.

And I said in the case of Verbatim I don't agree, What's your point?

My 20 years experience with burning told me this.

It's a pity you can't post screen shots which back up your experience such as a better quality burn than what I'm getting with Verbatim today. 20 years experience, yet while making lots of generalisations you haven't actually given any examples of your own experiences with media longevity, or lack of it.

And really feel sorry for you if you cannot grip that quality is more than PI/PO values, or your interesting 95% limit. As independent longevity tests showed several times, disks that cut perfectly during burning couldn't be read afterwards, while disks that were not so brilliant in terms of PI/PO, withstand much much better and be still within the specs. Which I think is exactly what the OP asked. There are not so many dyes around, (I assume) you know, so there are other factors besides who manufactured the dye, who manufactured the stamper and who relabelled it. And of course, (I assume) you know there is also Gold/Alu layers, not only Alu.

So independent longevity tests show some discs last better than others. This proves the quality has been dropping how? Did those same longevity tests on older discs of the same type show the same discs manufactured a few years earlier would have lasted longer?

Those people don't come back to say, well, you know, my 16x (or 24x) disk just died, two weeks ago, God know why, it had such beautiful PI/POs.

No, they don't.... do they? :D

[Ghitulescu]

You see, probably you'll understand once that companies do the products batchwise, then move to the next product. The same is true for retailers and wholesellers. They don't buy 1 Verbatim, 2 TDKs, 3 Maxells, they buy one container of Verbatim. The PC shop nearby buys them in smaller quantities, you even less. There's a great chance that your disks bought today are from the same batch as those bought 2 years ago, because of this triple buffering. And if the containers were not empty, you'll buy the same disks also in the next 2 years. I assume all disks in one production batch are equal (they are not). But a batch of product A is different from the same product, if meanwhile the production line changed.

The visible drop in quality for Verbatim occurred when they changed from DataLifePlus to DataLife. There are no longer DataLifePlus, at least not official (but a lot of fakes). The last good product from Verbatim was the Archival Type (which was not so well received, partly because it was graded only 8x, oh, gosh, I wanted burn it at 24x for the price I paid).

[yetanotherid]

You see, probably you'll understand once that companies do the products batchwise, then move to the next product......

Nice story. Sounds very unlikely though, that a wholesaler is going to buy a two year supply of discs in one hit, or whatever imaginings you're having there.

The visible drop in quality for Verbatim occurred when they changed from DataLifePlus to DataLife.

I'll eagerly await some screen shots of this visible quality drop. As I said, the burns you were getting from those blanks must have been phenomenal to be better than the burns I'm getting today.

[Ghitulescu]

When IceFiend will ask for it.

[yetanotherid]

When IceFiend will ask for it.

Wow! Now you're really being childish.

[Wantangobi]

The screen shot you posted can't be far off it. What do they consider to be archive quality?Not sure. Someone made a thread worried about having a dvd with hundreds of thousands of PI errors(PIF was 0.02 average), and one of the cdfreaks mods said it was normal. And another one said the burn was "good but not archive quality". He didn't specify what that was. He just said it was fine for normal stuff.

[Ghitulescu]

Archive quality is not measured in PI/PO values. It is measured in how well that particular disk withstand the time. I said it before, and I repeat it now, lower PI/PO are a prerequisite for long term storage, yet these are not enough. Supposingly one keeps the burned disks in the darkest darkness, in a vault that is humidity controlled, and keeps it from scratching, PI/PO are extremely relevant, lower values offer a higher buffer against ageing. In normal usage however, scratches, humidity and UV radiations are much more important.

However, no matter how low is the average, spikes (bulks of high PI/PO) are not allowed for archival purposes.

[leeperry]

Dye stability and error rates are 2 different stories...the ideal is to have a stable dye(TTH01 for instance) and burn it w/ a well adapted firmware. But a worst case scenario would be a poorly burned highly stable dye against an unstable dye w/ very low Pi/Po right after the burn. The former will not rot overtime, the latter very much will.

[Dogway]

I can't see the tab Disc Quality in DiscSpeed, instead there is ScanDisc. I checked an 8 years old DVD in scandisc and "surface scan" was 100%, everything green, surprised. Is there a way to check my discs quality, (even with my shitty drive)?

[Ghitulescu]

I checked an 8 years old DVD in scandisc and "surface scan" was 100%, everything green, surprised. Is there a way to check my discs quality, (even with my shitty drive)?

If a "shitty" drive can read your disk then it's ok. Problems are when even the best readers start having problems reading it.

[Dogway]

Yes, I know, when they are ok, they are ok. I just thought about checking the oldest ones to backup, with my laptop HL-DT-ST CT10N drive. If there's any software I can use for disc quality.

[Ghitulescu]

You missed the point.
Nobody can measure the quality of a DVDR, unless s/he uses special tools (there have to be a special drive and a special software), even then there's no 95% or the like, just OK or FAIL for each parameter (there are around 20 IIRC). Not only that that Philips optics is nowhere to be found (I mean in the consumer realm) and even then it will lack the special firmware that allows the reading of all parameters (it includes here the raw RF laser output), but also nobody will ever spend ~20+ hours (each parameter is measured once and at 1x only) for each disk.

The LGs are quite good readers, far from being shitty. For a shitty result try a NEC (Optidrive), except for the 4550 model which stands out in this respect.

[hello_hello]

I can't see the tab Disc Quality in DiscSpeed, instead there is ScanDisc. I checked an 8 years old DVD in scandisc and "surface scan" was 100%, everything green, surprised. Is there a way to check my discs quality, (even with my shitty drive)?

Maybe you have an OEM version of Nero which includes cut-down versions of some programs?

You can download the latest version here but I'm not sure if it's a full free version.
http://www.nero.com/enu/tools-utilities.html

It seems odd someone would claim you can't test the quality of a disc given the availability of software for just that purpose, and given the same person has posted screen shots of tests they've run on their own discs. Nero doesn't actually give the quality as a percentage as has been mentioned earlier but it does give a disc a "quality score". Anything over 90 should be easily readable.

Maybe quality tests aren't 100% accurate, and of course not all drives are capable of reporting errors correctly, but they're certainly a pretty good guide as to the quality of the disc.

There's another program for running disc quality checks here, but I don't think it's free.
http://www.cdspeed2000.com/

[Ghitulescu]

It seems odd someone would claim you can't test the quality of a disc given the availability of software for just that purpose, and given the same person has posted screen shots of tests they've run on their own discs. Nero doesn't actually give the quality as a percentage as has been mentioned earlier but it does give a disc a "quality score". Anything over 90 should be easily readable.

If the person that doesn't understand why "someone" says it's virtually impossible to assess the quality of a DVDR being so many SW around, that "someone" would add, because it was clearly not understood:

One can have a sort of quality index for a DVDR for a particular reader. The same disc may be 96% (Nero) when read by an LG, and 56% when read by a NEC. Values invented.

[hello_hello]

It was understood. Maybe you missed my point when I said that even though testing for errors mightn't be 100% accurate it's still a pretty good guide as to the quality of the disc? Which obviously it must be, given you posted burn test results yourself and requested others do the same earlier in the thread. Why would you do that, only to argue later it's not possible to test the quality of a disc?

Some drives are better readers than others and different drives will no doubt report different errors. Claiming one drive will report a quality score of 96 while another will report a quality score of 56 seems to be inventing exaggerated values to me. I'd imagine a good quality burn will still test as a good quality burn in both drives while a poor quality burn will test as a poor quality burn in both drives even if the reported errors aren't exactly the same, so it'd still be possible to assess the burn quality even if it's not an exact science. Chances are the good quality burn will test as good quality in both drives (because it's good quality and easy to read) while the poor quality burn might look worse when tested in one drive than it does in the other (because one drive is better at reading poor quality burns).

Do you have any examples you can post of a disc which appears to be of a good quality in one drive while bad in another, or where the reported quality is different enough to show there's no point to testing discs for quality?

[Ghitulescu]

Some drives are better readers than others and different drives will no doubt report different errors. Claiming one drive will report a quality score of 96 while another will report a quality score of 56 seems to be inventing exaggerated values to me.

http://www.cdrhard.cz/srovnavaci_testy/dvd-rw/016.gif

Not at all. See NEC ND-3540 vs. Plextor PX-750. The percentages represent the good sectors (green) vs. the unreadable ones (red). In the green zone are also included the corrected sectors (ie sectors that were faulty but the drive used the CRC algorithm to recover the valid data).

As long as one uses the same drive to check the discs, no problems, s/he has at least a reference. But combining data from various drives, with various discs, and various programs (I use Plextools and pxscan, some use KProbe, other use CDSpeed and so on) is not a good practice IMHO.

[hello_hello]

Not at all. See NEC ND-3540 vs. Plextor PX-750. The percentages represent the good sectors (green) vs. the unreadable ones (red). In the green zone are also included the corrected sectors (ie sectors that were faulty but the drive used the CRC algorithm to recover the valid data).

Have you got an example which is relevant to the discussion? Or one which means something? So, some drives could read a bad disc better than others. No news flash there. What disc? Why was the quality bad? Was it just because the disc was scratched, was it a bad burn, was it actually a burned disc or was it a pressed disc?

It seems to me you've only offered a graph which shows some drives can read a poor quality disc better than others, and there's nothing to say it was even a burned disc or what sort of quality would have been reported by each drive. No doubt the drives which could read more of the disc would have reported a better quality than those which could read less, but do you really think your graph proves any of the drives would have reported the disc quality as being anything but low?

I think you'll find I've already acknowledge some drives can read poor quality discs better than others and quality scores will vary as a result, but I still maintain it doesn't negate being able to test discs for quality even though it's not an exact science and your graph does nothing to prove otherwise.

Do you have anything which actually relates to testing a disc for quality and which shows the results vary so much between drives a disc quality test is meaningless? i.e. reporting PI errors and failures etc.

As long as one uses the same drive to check the discs, no problems, s/he has at least a reference. But combining data from various drives, with various discs, and various programs (I use Plextools and pxscan, some use KProbe, other use CDSpeed and so on) is not a good practice IMHO.

Well I'd assume most people would generally be using the same drive and the same software to test their discs.
However there seems to be no logical argument offered as to why combining data from various drives, discs and programs is not good practice. If disc testing isn't an accurate science, surely having more than one reference makes it somewhat more accurate than only having a single reference, the accuracy of which is unknown?

[hello_hello]

I use Plextools and pxscan, some use KProbe, other use CDSpeed and so on.....

You're still yet to explain why you use Plextools and pxscan to test for disc quality when you've claimed "Nobody can measure the quality of a DVDR".
If you can't test for quality, what are you trying to achieve when you test the quality of your discs?

[Ghitulescu]

There are pressed (ie original) DVDs that do not pass the standard testing procedure, they have at least one FAIL for some parameters.

That is testing. The rest is approximations.

They are good as long as one uses only one drive, and only one software, and only one measure. Some people say 95% in nero. Perfect, be happy. But as long as the drives are required only to play DVDs that comply with the specs (ie only OKs, not a single FAIL), a particular disc may have playback problems on other systems. The drive manufacturers gave us a gift actually, as most drives can read also out-of-specs discs (I had once a DL with some 1300 PI for about the whole second layer, yet perfectly readable with no speed-down), but this is no guarantee.

[hello_hello]

Some drives can read poor quality discs better than others. Most drives can read discs which are way out of spec. Nobody's arguing about it. Time to move on.

When you've got something which relates to the subject of testing a disc for quality I'll be keen to read it.

[Ghitulescu]

You're still yet to explain why you use Plextools and pxscan to test for disc quality when you've claimed "Nobody can measure the quality of a DVDR".
If you can't test for quality, what are you trying to achieve when you test the quality of your discs?

I use plextools to check whether the discs according to my standards. I burn one DVDR from an unknown manufacturer then test it. From the graph I draw my own conclusions. Besides, for CDRs it happens that I have the optics used in the standard measurement device, so I'm pretty sure the C1/C2 values are closely matching the standard ones.

So I don't care whether someone else using a certain burner burned a certain DVDR with 40/2 errors, as long as my burns are ok. I may not have that particular burner, I may not have that particular DVDR.

[hello_hello]

So you're saying you can test the quality of your discs then?
Why did you tell another poster he can't do the same?

[Ghitulescu]

I said he can't have comparable results.
And that the results he will eventually obtain do not represent the values that are standardised. In other words, if he gets 280 PI these are not the 280 PI of the standard, because he didn't use the standard device nor the standard procedure.

[hello_hello]

I said he can't have comparable results.

Twaddle.
Dogway asked how he could check his older discs for quality, and this is what you said. Offering such academic nonsense as an answer to a simple question is what led to this discussion.

You missed the point.
Nobody can measure the quality of a DVDR, unless s/he uses special tools (there have to be a special drive and a special software), even then there's no 95% or the like, just OK or FAIL for each parameter (there are around 20 IIRC). Not only that that Philips optics is nowhere to be found (I mean in the consumer realm) and even then it will lack the special firmware that allows the reading of all parameters (it includes here the raw RF laser output), but also nobody will ever spend ~20+ hours (each parameter is measured once and at 1x only) for each disk.

[hello_hello]

And that the results he will eventually obtain do not represent the values that are standardised. In other words, if he gets 280 PI these are not the 280 PI of the standard, because he didn't use the standard device nor the standard procedure.

Nobody said otherwise.
This means Dogway can't test his discs for quality how exactly?

[Ghitulescu]

Twaddle.
Dogway asked how he could check his older discs for quality, and this is what you said. Offering such academic nonsense as an answer to a simple question is what led to this discussion.

He can find some values, ok, but when the quality is defined and it is, one needs to use that precise method to find out this quality.

[hello_hello]

He can find some values, ok, but when the quality is defined and it is, one needs to use that precise method to find out this quality.

Yippeee.
How many times do I have to acknowledge checking for disc quality isn't an exact science before you'll move on to offering another excuse for telling Dogway "Nobody can measure the quality of a DVDR" in the middle of a thread where disc quality is being discussed and quality test results are being offered.

Actually don't worry about it. I think I'll join everyone else who's posted here in not taking you seriously, and just move on myself.

Bye.

[Ghitulescu]

It's always nice to talk about quality when this is a nice and vague notion. Yet, when it's standardized, oops, yeah, sure, well, you know, that's good for me...
The only way to asses the quality is described. And it's an ON/OFF issue (compliant/not compliant). Do you have the possibility to compare at home the quality of your HiFi-chain with that of the neighbor's? Which one is louder probably yes, you could, although not immediately evident.

The OP could use any of the SW indicated and any of the HW he has, but the results are not quality as it is defined, they are just numbers. And based on his experience he may say whether this numbers mean something or not, whether the value of 1000 or that of 300 or the one of 20 do really mean something (plays everywhere in the world, plays on his own DVDplayer, can be read only by his LG drive).

That nero gives 100% quality for a disc, that doesn't automatically that it would be played everywhere, as I said, I had once that DL with some 1300 PIs, yet it was played flawlessly (perfect reading curve) on the PC, yet had problems with a standalone. No wonder.

[hello_hello]

And once again, nobody has argued that quality results won't vary a little according to the drive used to test the disc. Nobody has argued about the way discs are checked for quality.

It's fairly simple. A disc checked for quality using drive "A" will show the disc has a "X" amount of errors and is of "X" quality. Checking the same disc in a different drive will probably give slightly different results, but generally the quality will still be roughly the same. A disc which looks good in one drive will still look good when tested in another. A disc which looks bad when tested using one drive will still look bad in another. When you've got something which proves otherwise, let me know.

....as I said, I had once that DL with some 1300 PIs, yet it was played flawlessly (perfect reading curve) on the PC, yet had problems with a standalone. No wonder.

No wonder???
You mean you weren't suprised after you tested the disc quality, found it to be poor, and then discovered it wouldn't play in a standalone which isn't as good at reading poor quality discs as the PC's drive? Why weren't you surprised if the disc quality test didn't mean anything?

Once again, we're not talking about a drive's ability to read a poor quality disc, we're discussing being able to test a disc for quality. Your example of a drive still being able to read a disc after the same drive reporting the disc as having a high number of PIs proves they're not the same thing.

There's no need to repeat the information regarding disc quality being a "standard", or repeat the need for precise information to obtain the "real" quality etc. I get it, and repeating it again as though I don't will only have me thinking you must be stupid. Testing for quality isn't an exact science when using the average PC drive and testing software. I get it. I really do.

Dogway asked how he could test the quality of his discs. You told him in no uncertain terms nobody can measure the quality of a disc. I, on the other hand, maintain that while testing a disc for quality is not an exact science, anyone can test a disc for quality and obtain results which are still a very good indication as to the quality of the disc (as long as you're using a drive which reports errors etc). You do it, I do it and everyone else in this thread has done it. Except for Dogway of course, because you've told him he can't.
Maybe you're simply incapable of understanding this alternative viewpoint, or maybe you really don't agree with it, but either way you've offered nothing to prove it's not correct.

[ad1mt]

Hi,
I have run 3 significant tests of optical media, and can make very specific recommendations about the lifespan of the various types.
The reports of my tests are here: http://mark-taylor.me.uk/?Optical_Media_Life_Expectancy
The quick summary points about long-term data storage are:-
1. Do not use standard recordable DVD (with purple dye) under any circumstances.
2. Use either BD-R or CD-R for good lifespan at low cost.
3. Use MDISC for best lifespan at higher cost.
4. Always keep optical discs in darkness (i.e. in an opaque box with a lid).