How to copy data from damaged DVD.
 

Hello,
I have some movies on a data dvd. I can play the movies using mplayer or vlc. However, if I try to copy to the hard disk using the cp command, or the GUI, or a program using read() system call, there is an error. I therefore conclude that the dvd is damaged - indeed there are scratches on it. How do I copy the files from the dvd so that I have an acceptable quality movie on my hard disk?
Thanks

I would try making an image of the disk using dd_rescue. Then try mounting that image on loopback and copying the files from the image.

This may sound funny, but I found a colleague today in the kitchen pouring very hot water over the shiny side of a DVD. On my question, he said that it might help to get the dvd readable again. And he was very serious about it.

Haven't followed up yet, but if it worked I'll let you know.

dd + mount --- what he said...

Just cp from the loop mounted image. In theory it should function. It may not correct any errors / damage, but it should get you past the hardware read() issues. dd has a few tricks to recover inspite of errors. You might also try a different drive / computer, it could be hardware as in drive related, not hardware as in disc related. I have to clean the lens on my optical drives every year+. But there's a smoker in the house. Pet dander doesn't help much either.

dar includes a continue-on-read-error version of the cp command called dar_cp. From its man page: dar_cp is similar to the standard 'cp' command, except it does not stop copying when an I/O error is met. Instead, it skips a bit further and continues to copy the rest of the file, as much as possible.

Could work; it may smooth scratches or remove dirt. It may also be possible to polish out scratches using progressively finer abrasive.

Another trick...

You can, at your own risk, use Brasso, the brass polish, to remove scratches on a DVD. Use a soft cloth and polish across the disk, first on one axis, then on an axis perpendicular to the first. Polish firmly, with the DVD on a flat surface, using an equal number of strokes on all parts of disk. When the Brasso dries, wipe off the residue.

This works well, but cannot correct for damage that is so deep that it reaches below what can be reasonably removed by the abrasive material in the polish.

You can practice first on a CD/DVD that would otherwise be discarded.

I would try to clone/read, polish a bit, try to clone/read, polish some more. Of course, this assumes that it is the physical readability of the medium that is the problem.

Any other polish which will buff plastic or a painted surface to a high gloss should work as well, but Brasso is cheap, easy, and mostly harmless.

Spoke with the guy today. Hot water did not work but Brasso did the trick.

PS He did this independent from this thread

Brasso to the rescue!

Sometime I add butter to the disk before trowing it to trash. It fill the crack and if the layer is very thin, will become 100% transparent at 40C+ so it kind of melt inside of a computer. It is bad for the drive, but have good chance of giving a good result. Fro standard scratches, it work well enough well I don't have polishing paste around.