Backing up a backup?

vbimport

#1

This may be kind of an esoteric question. Say you have a backup of a video, where both the original and backup are single-layer disks (so you didn’t have to use compression–i.e. a 1:1 backup). For some reason the backup did not come out to very good quality, verified both by CD Speed Disk Quality, and simply viewing the movie: some freezing or skipping, etc.

Then say you rip and reburn from the backup–not the original-- onto a second disk. Does the low quality from the first backup get ripped and burned along w/it? Or, since the data is binary–ones and zeros–will the second rip pull all the digital data off the disk? And if the second burn produces a high quality disk, will the freezing and skipping be gone?


#2

Not necessarily. DVD drives in computers will extract data by retrying in difficult to read areas of the disc. You could copy the data from the backup to your hard-drive then re-burn using top quality media and not get playback problems in your standalone. Although you mention the original and backup are single layer, in dual-layer originals bad re-encoding may introduce skipping problems too. Obviously if your PC DVD drive can’t read the disc properly then scratches/dirt on the disc and the reading lens excluded, you won’t be able to reproduce the disc.

Regards

TZ


#3

Hello Folks,

It is unrealistic to expect that just re-recording this flawed back copy which contains verified errors that somehow magically during the re-recording process these errors are going to just disappear.

It is a different matter if a software utility program designed to repair errors is used. This software utility program might be able to retrieve the data and correct the errors making the original flawed back up copy usable.

Best Regards,
bjkg


#4

If it is bad media, that is likely to degrade, or CRC errors that appear on some drives when reading the files, but the disc reads fine in the drive you are copying from, the errors will be gone on the new copy. What you need to make sure of is that you are not reading the errors also. Fot this use something like UltraISO to check the disc.

Ben :slight_smile:


#5

backing up a dvd is a digital affair, not an analog one, so as long as there are no errors that are unrecoverable, any copy of a copy will be exactly the same.