Data "changing" after burning?

vbimport

#1

I’ve got 2 homemade DVD sets for which the last VOB is always failing verification. The specific error reported by Nero is that the data does not match the original file.

Firmware or driver issue? Nope, thoroughly tested that through use of other drives/firmwares.

Nero bug? Nope, tested burning with CDBurnerXP Pro and Alcohol 120%, both as data files and IFO.

Total data size? Nope, these are burned as UDF/ISO so the menu build files can be stored on the burned disc. I’ve removed some of those files which reduces the total space required by almost 3M and will also mean the recorded data occupies differing physical space on the drive.

So…wtf causes this? Is it some off combination of data values and packet sizes?


#2

To verify a disc don’t use nero verification after burning, but prefer to test disc with CD-DVD speed. The simplest way is to do a reading curve (the first tab on the main window of dvd-speed). If you want more informations, can do a quality test (if your burner is compatible with this function).

Try to do a reading curve: if your dvd reader can read all files on the disc, then the disc is OK. If you obtain an error such as “CRC error” or other, then the disc is a coaster.

Can you give more informations about your burner? Which model is? And what media do you use?


#3

Are you thinking of burn quality and media compatability? Those are common discussion issues on this board but are not the situation I’ve described.

Nero compare reads the files off the disc and compares to the original data. The last files of the set does not match near the end of the file.

All other burns have been just fine.

The drive is a NEC ND-3500A with Liggy & Dee’s V2.TF firmware, discs are Ritek R05.


#4

This keeps getting more odd. I just tested one of the reduced-size DVDRs and the final file plays just fine, all the way through the ending credits. The Nero archive from which it was made won’t load as a virtual drive into Ultra ISO or Alcohol.

FWIW, the burning issues had happened when the data was tested from multiple source drives and multiple computers, both as raw files and as the Nero compilation. (I thought I’d saved it as an ISO. I was wrong.)

Maybe there is a checksuming function of some sort which has a bug. All the original files work just fine, it’s just this combination of files, the last one in particular. The only thing I can imagine is there is something about the packing of that last file which doesn’t play nice with DVDR.


#5

Sorry for mistake.

I suggest to do a test with cd-dvd speed because, in my experience, nero verify function after burning is totally faulty: every time I use this function I obtain an error, even if the disc is perfect.

If reading test give you a good result, then all files on the disc are readable and the disc is correctly burned. Nero CD-DVD speed allow also to do a File verification, in the tab named “Scan disc”, that is different from “disc quality test”.

I don’t remember exactly in which thread I’ve read this, but there are some softwares able to compare byte to byte files on disc with files on HD. Try to do a search on the forum.


#6

Yeah, Nero’s check is a file verification. I wonder why that fails for you. I used QuickPar to compare the files after burning. Will try CD-DVD speed to see what that tells, if anything.

The last VOB does play fully on the burned discs so I think I’ll just move on. Even if there’s some kind of instability in the final portion, it’s just the end credits so it’s no big deal.

Odd, really, almost as if a checksum routine has a bug and I was lucky enough to have the particular data set that caused it.


#7

I have also heard that Nero Verification may score far from the mark. You may want to try CDCheck for file verification, it works fine. It allows you to just check the files for readability, or to compare with original file / directory.