Increase in PIE/PIF levels over time - your experiences?

vbimport

#1

Today I scanned some DVDs I burned about 6 weeks ago and was astonished by the increase in PIE/PIF levels (measured in Plextools 2.21).
(Writer/reader: Plextor 716A)

Ritek +R 8X:
PIE (avg) 5.79 => 12.25
PIF (sum) 3322 => 7632
=> over 100% increase for both PIE/PIF within 6 weeks

Verbatim/Mitsubishi -R 8x
PIE (avg) 3.14 => 4.39
PIF: didn’t measure earlier, so no comparison possible
=> 40% increase within 6 weeks

In both cases, the error level as viewed in the graph seemed the same as before (i.e. no higher max levels, but the total number increased dramatically).
I measured a CD-R (also Ritek) burned at the same time as the DVDs, and the C1 level was exactly the same as six weeks earlier.
Are DVD-R media really so much more unstable over even such a short time? I find this hard to believe, but the error counts speak for themselves
What are your experiences with DVDs burned, say, two months ago? Do you also see a conspicuous increase in PIE/PIF levels?


#2

Here’s another example: Taiyo Yuden 8X DVD-R, labeled as “Plextor”
PIE (avg): 1.34 => 3.29
=> 145% increase in 2 months

Luckily, I saved the picture of the scan from two months ago.
1st picture: Scan from 2 months ago
2nd picture: Scan from today

I can’t believe that these highly regarded DVD-R from TY can deteriorate so badly in so short time. For comparison, I checked some more CD-R from a while back, and the error rates are absolutely stable.




#3

Other possible explanations for your observations:

[ol]
[li]Temperature variations can greatly influence the PIE/PIF levels of a scanned discs (I have seen this many times, variations of a factor 2x has not been uncommon and for CDs with very high C1/C2 values I have seen a more than ten-fold increase due to temperature variations in the drive!).[/li][li]Your DRIVE (not your media) has deteriorated over two months.[/li][li]Your media has acquired some dust, scratches or fingerprints. Just a single fingerprint can make parts of your DVD unreadable![/li][/ol]


#4

I have seen this with Ritek G04s. You need to get another drive to scan these to determine if the problem is drive or media.


#5
  1. That could be possible. I’ll scan some of the discs again tomorrow and compare the values to today.
  2. Also possible, but values for CD-R scans have remained exactly the same.
  3. No, the media are in perfect condition.

Unfortunately, I don’t have another drive for scanning the discs.
I am still interested to see some other people’s comparative scans.


#6

[QUOTE=sTisTi]Today I scanned some DVDs I burned about 6 weeks ago and was astonished by the increase in PIE/PIF levels (measured in Plextools 2.21).
(Writer/reader: Plextor 716A)

I have commented on this several times ( BenQ1620) with no one showing much interest. You don’t have to wait weeks - days will do. My guess is that it is normal to test disks just after they have been burned and not do so again. Leave a disk in anordinary room for a day and the dust build up alone will give you higher figures. Even cleaning a DVD can “improve” a scan. It just goes to show that (a) good enough is good enough - that if a DVD plays and data can still be extracted thats all that matters (b) enthusiasts get a kick out of low numbers but I doubt if 150 PIF is reall better than 350 © The testing programs that we all use are not all that precise and should not be taken too seriously


#7

I agree with you that readability is by far the most important measure of quality; however, if my DVDs carry on with their present speed of deterioration (supposing the drive’s reading performance stayed the same), I fear that in, say, two years the number of errors might reach levels that will make the discs unreadable.
I’m still wondering whether DVD-R are in general less suitable for long-time archiving than e.g. CD-R. Could it be that the dyes used for DVD-R are less stable, maybe because stability has been sacrificed for a better writing performance? I have e.g. a TY-made CD-R that was burned in 1998, and it still shows an average C1 error rate below 1. THAT’S what I call stable.


#8

This would be hard to believe…unless you took the media from the scan drive and kept it in a jewel case for 6 weeks (which is possible). Your naked eye can not see the damage caused by handling.

It doesn’t take much to introduce error. Just wiping off your media with a lense cloth can introduce error…although it doesn’t appear to do any damage, a magnifying glass will show micro-scratches. If you clean off your media the wrong way, that’s big-time error, because the small scratches form in the spin direction of the media. Blowing (with mouth) on the media, will leave microscopic water droplets that deflect the laser and cause error…scenerios are endless. Most of these cannot be seen with the naked eye (unless you have kick-azz vision).

So, unless you vacuum packed your disk, I’m sure the media is not as pristine as when you first finished your burn.

Now you can see why it’s so important to get the best possible burns in the first place with quality media.


#9

My oldest disks are about 4 years old. Some have problems but some are fine.
The ones that are fine are the ones made by Quality manufacturers and the one that have problems are the ones that I bought because I thought they were a good deal price wise. Well we all make mistakes.

When CD writers first came out they had all sorts of problems and could hardly be used to archive anything. Today we take it for granted they they are reliable.
Its been years since I managed to make a CD coaster. DVD reliability is starting
to catch up.

I think that when you test these DVDs in say a year or 2 you will find that the scores have changed little. For amusement I have scanned some older disks and although the results do not look as pretty as you would expect from modern disks they are still within the generally accepted limits


#10

Which is exactly what I did. The disc is a backup of part of my MP3 collection. I stored it away immediately after burning & scanning it. In addition I always check discs for dust before inserting them in my drive. If I spot some particles, I use a small bellows to blow it away, because if you insert too many dusty discs in a drive, the drive itself will become dusty too :wink:


#11

Hmm, so have they actually become worse? Or didn’t you keep notes on their previous error levels?


#12

No I didn’t even scan in the early days - but if 9 out of 10 DVDs still play I’m hopeful that with today’s better writers and media that I will have few problems in years to come.
Just in case I always make 2 copies - old habits…


#13

That eliminates handling errors.

I wouldn’t put too much faith in PI/PO scans. I use them extensively, but playability in multiple standalones is the only true test.

I see that your versions of Plextools has changed…how about your firmware? All of these things can affect your scans. Quality scans are really only the scanning drive’s “readablility” of your burned media. You can’t even compare scans between two different drives.


#14

[PARODY]
Today I scanned a DVD I burned about 4½ months ago and was astonished by the decrease in PIE/PIF levels (measured in Plextools 2.21).
(Writer/reader: Plextor 712A)

Memorex DVD+R 4X (CMC MAG F01):
PIE (sum) 151926 => 97260
PIF (sum) 1888 => 1734
=> over 35% decrease for PIE and 8% decrease for PIF within 4½ months

At this improvement rate my DVD will be error-free in 4½ years, and already within 9 months it will have no PI Errors?! :eek:
[/PARODY]

The numbers above are completely legitimate, but of course my conclusion is faulty!!!

The DVD has been sitting unused within a DVD case for 4½ months, and both the original scans and todays scans were made on the same drive (different firmware, different PlexTools).

@sTisTi: No offense was intended - I am just using humour to make my point clear. :wink:


#15

I have also encountered big changes in errors after just a few hours.
I guess it has to do with the bearings of the reader drive. Sometimes
they are better balanced and you get better results. Just a guess.


#16

You guys just need better equipment. My scans are always exactly the same. If they aren’t I just re-scan until they are. :wink:


#17

I re-scanned one of the DVDs today directly after booting my computer to check for possible variation in scan results:
PIE avg: Yesterday: 3.29 => today 3.30
so only a minimal difference.

I completely agree with you all that readability is paramount and that PI/PO and other quality measures are probably neither very accurate nor do they tell you a lot about the readability of media provided the errors are not insanely high.
Still, I am worried by this downward trend of my DVD-R, especially as most of my CD-R are so obstinately stable even years later.


#18

As far as I can see, most changes seem to be seen after changing ‘something’.

I would expect parts of a media’s surface that has slightly marginal lands and pits to be read differently on each pass, so the average may stay the same but at any point the data read back before correction would alter slightly - spikes changing a little.