Here’s a good place to start… http://club.cdfreaks.com/f96/cdfreaks-presents-home-pi-pif-scanning-article-193873/
Which was found in this forum… http://club.cdfreaks.com/f96/
You should read as much in there as possible.
Just for basic starters…
[ul][li]Most NEC drives are not good for scanning DVD media, as they are not consistent.[/li]
[li]No 2 consumer DVD drives scan alike, so you will get different results.[/li]
[li]Quality score is based on the max PIF. Depending on how a drive series scans, you can easily get a higher quality score with more errors than other drives.[/li]
[li]Right now, mainly BenQ, Plextor, LiteOn, and Samsung drives are good for scanning, and having any of the first 3 makes is good. Samsung drives can scan, but aren’t held as highly as the first three when it comes to scanning.[/li]
[li]For the drive you’re using [the NEC], a Transfer Rate Test is better, as it is pretty picky on sub-standard burns and will be a bit more useful than PIE/PIF scanning on that drive.[/li]
[li]General scanning says that you usually want a lower TOTAL number of errors, as long as the maximums are not too high. There is a point at which a super-high maximum [such as a spike] will result in an unreadable file at that spike. However, some drives may show phantom spikes or increases in errors that will not show up in playback or affect data recovery [which is the case for a lot of NEC drives].[/li]
[li]PIF [PI failures] are more serious than PIE [PI errors]. Every disc will have some of both, and drives’ error correction abilities are meant to compensate for this. You want as few PIF as possible.[/li]
[li]PIE and PIF are not the only factors of disc quality, but they are a start.[/ul][/li]
With that said, your scans are pretty good. General rule of thumb says to not overspeed, though. If you have to go by the results from the NEC, they match this rule, as you have more total errors at 16x than 8x, and the differences in PIE max. are great [with the 16x being worse], while the difference in PIF max. are not so great.