Recovering data from badly burned DVD

I’m trying to recover data from an old DVD-R (Fuji/Ritek). The media
itself is dubious, and I suspect that it was probably burned at high speed.

I tried to do a byte-by-byte compare after copying original files to
hard drive, and got a few mismatches. Tried again, same thing.
This was on a Plextor 716-A. Decided to try on a Lite-On Combo
SOHC-5232K which will read DVDs. Got a different result. I suspect
that the DVD itself is at fault, though I can’t explain why the LiteOn
would give a different result.

Are there recommended programs that will try to re-read sectors
to make sure that they are correct? I know that there is a program
called ‘BadCopy Pro’ that is supposed to do this (though I don’t think
it will just read the entire DVD). Are there others?

Yes, for example IsoBuster or Unstoppable Copier.

Apparently two very different programs. Unstoppable takes a long time.
Its log file says ‘no errors’ but the files do not compare with the other
‘rescue’ versions.

IsoBuster reports lots of errors. Multiple retries do not read the sectors
so I’m forced to say ‘ignore.’ Again, the output files do not compare with
any others.

I’ve tried 4 or 5 programs now and each has a different output version
for the problem files. It would be great if at least two of them agreed.

I guess I can keep trying different programs, but some have to be
better at this than others.

Have you tried CDRoller. I had a +RW DVD,formatted with InCD which I couldn’t read. CDRoller found all the files, a few were damaged but not many. Also, the disc became readable again when I took InCD off and installed Sonic DLA.