Copying Copies.... are PIE/PIF Errors Cumulative?

[ulTRAX]

So I have to wonder about these PIEs and PIFs I see in a DVD quality test such as Nero Speed. Just what am I seeing when I test a disk? Are those PIEs fully correctable? What happens to when playing a disk that has sustained spikes of over 280 PIE or sustained spikes of PIFs over 4? Is data interpolated? Or is there a momentary glitch?

I have a disk with a high PIE score. I don't feel like going though the encoding process again. I know it's supposed to be OK.... that we might find problems when a disk has sustained spikes of over 280 PIE or sustained spikes of PIFs over 4. So can I assume all the data is being perfectly reconstructed?

That leads me to my next question: Can a copy of a disk ever be made that will have LESS errors than the original? Or are the errors cumulative?

Or does it matter how it's being copied... say if it goes though Shrink... the errors are corrected but that might not happen if it were copied as a data disk?

[SweetiePie]

Does your disk play ok?

[ulTRAX]

Does your disk play ok?

To be honest I ended up reencoding and burning a new disk.... but the question remains whether a copy can EVER have lower error rates than the original.... or are they cumlative?

[jm1647]

I might be wrong but since they happen during the burning process, if the DVD can be read and plays ok, I don't think they would be cumulative. Like backing up a DVD to a standalone recorder cause of CRC errors, the source had CFC errors but the backup doesn't.

[ulTRAX]

I might be wrong but since they happen during the burning process, if the DVD can be read and plays ok, I don't think they would be cumulative. Like backing up a DVD to a standalone recorder cause of CRC errors, the source had CFC errors but the backup doesn't.

That's what I'm wondering. If a copy of a copy is made though Shrink that has an encoding phase... then the DVD error correction would kick in... and all that would be left are the new errors that creep in during the burn.

But what about direct disk to disk copies? Would they go though that error correction process? Or would they preserve all the original errors while adding new ones? The analogy would be how with analog video... video noise is cumulative.

[ulTRAX]

I've wondered if a copy of a backup could result in lower PIE/PIF tests than the original. It can. Here's some test results using Nero DVD Speed and testing at 4 X

----------------COPY---------ORIGINAL
MAX PIE---------17-------------187
AVERAGE--------.01------------44.09
TOTAL---------40800----------650908

MAX PIF----------2--------------2
AVERAGE--------.03------------.01
TOTAL----------532------------127

So knowing that both disks are acceptable given the standard that PIEs should not exceed 280 and PIFs not exceed 4.... that whatever's here is correctable...... is any disk preferable to the other? I'm thinking of the theory that errors may accumulate over time and make a disk that's readable unreadable in the future.

[blutach]

The PIs are less to worry about than the PIFs. The PI says I got an error and need to access the error correction code to fix it. ALL disks have these.

PIFs are failures to correct PIs. Too many and you will have a bad copy. This really goes to media quality. So long as the data can be read, you should be able to lay it down on better quality media and have lower PIFs.

Best idea is to ensure you verify after burning.

Regards

[blutach]

And, a disks errors CAN accumulate over time - particularly with crap media. Another good way is to put them in the sun for a bit - even a relatively short time. Optical media are VERY sensitive to UV light. Try it!

Regards

[ulTRAX]

The PIs are less to worry about than the PIFs. The PI says I got an error and need to access the error correction code to fix it. ALL disks have these.

PIFs are failures to correct PIs. Too many and you will have a bad copy. This really goes to media quality. So long as the data can be read, you should be able to lay it down on better quality media and have lower PIFs.

My understanding was that there were two levels of DVD error correction and even small numbers of PIFs could be corrected. Here's on page on the topic: http://www.cdr-zone.com/reviews/dvd_...ew_page_3.html

"A DVD has two levels of error correction. Any errors that make it through the first level are reported as PI Errors and any that make it past the second level are reported as PI Failures. PI Failures are what your DVD playback device will potentially have to correct to achieve perfect DVD Video playback or Data transfer at high speeds."

I'm wondering if this is analogous to CDs which had the ability to correct... and if disk damage was bad enough to conceal an error though interpolation.

Then there's POFs. A disk should have zero. I need to read more on the topic since it's been months and I still don't fully understand this topic.


Here's another good discussion: http://www.cdfreaks.com/article/178/3