Nero Disc Speed advice

Hi
I produce DVDs for clients and quality control is important. I want to be able to test my DVDs so I downloaded Nero Disc speed.
I have looked in the Help and Manual but can't find information regarding what is a damaged disc and what isn't. Also I'd like to know if you use the scan disc and disc quality tab for testing your DVDs?
Any advice or pointers would be greatly appreciated.
Thanks
Paul

DVDs use ECC (Error Correcting Codes) and so they can still play correctly even if there are a lot of unreadable bits on the drive. Even "good" disks normally have thousands of sectors where the data needs to be corrected by these codes. So the level of errors that's "unacceptable" is a rather nebulous determination. But according to the DVD specification the maximum number of allowable "Parity Inner Errors" (PIE) is 280 errors per 8 blocks.

More important in my opinion is the number of PIF (Parity Inner Failure) errors. Because of the way the ECC information is organized, you're guaranteed to be able to recover the data as long as there are no more than 4 PIFs per block, so that's the number I use for my own determination of what's acceptable and what isn't.

Most DVD drives can't report PIE and PIF error counts and so you won't be able to see them on the "Disk Quality" tab of Nero DiscSpeed. For my error scanning I use a Lite-On IHAS424 drive, which does have this capability.

I personally wouldn't have accepted that burn because the max PI failure count is more than 4. But I'm pretty anal about burn quality - disks can have a lot more errors than that and still be perfectly fine.

The real question is whether you're burning archival material to the disc that you want to be able to read in 10 or 20 years time (assuming computers still have DVD drives by then...). In that case you want the best possible burn right out of the gate to give you a bigger safety margin in case the disc degrades over time.