Question about less than ideal burns and loss of data

vbimport

#1

This question may have been asked before, but it’s somewhat complex so I wasn’t able to look it up on the search. My question is: say a single layer dvd is burnt “sucessfully” to a single layer dvdr, maybe while other programs are running such as the internet simulaneously downloading during the burn, & and when it is scaned the disc receives a really low score like 80 or under. Does this indicate a loss of data? If this disc is burnt to another single layer dvdr under better conditions, say with all other running programs closed prior to the burning & better quality brand of media, and this disc scans a high quality rating, is this disc as good as the first generation copy would have been had it attained the same rating? Or was there a loss of data or degration of quality as a result of the source disc for the second generation copy having a low scan rating?

Does a poor scan indicate a loss of data from the burning process?


#2

No, it generally doesn’t. There are two levels of error correction built into the DVD format [data or video, doesn’t matter, it’s all bits]. PI Failures (PIFs) indicate the failure of the inner error-correcting code; this is where the second level takes on. PO failures are where the second, outer error-correcting code fails.

However, even if an error scan has PO Failures, it doesn’t mean that the disc is unreadable. The ultimate test is to try to copy the data off the disc and let the drive do its work. When the drive hits the point of a PO Failure that caused CD-DVD Speed to give your disc a zero quality score, it will try reading the damaged area at progressively slower speeds, eventually slowing down to 1x speed, and retrying multiple times at the slowest speed. You can also tell the copying software to retry after the error dialog shows up… sometimes that helps too.

Bottom line, if the reading process completes and doesn’t come up with a fatal error in the middle, you’ve got a perfect digital copy of the data. Reburn it [on better media, hopefully] and you will have the same 4.7+ billion bytes, or 37+ billion bits that you started with.


#3

Right on man thanks a lot. Awesome contributions of knowledge like that are why I love this forum, I’ve been learning so much