I thought I would post this as a bit of an extension of ideas generated from a previous post, if that is ok, as some more of my recent experience.
The “dd…” post prompted me to try “ddrescue” IDK if anyone has tried that. It seemed to be able to read, though IDK if bit for bit, one on my own dvd’s that I own. I also compiled from its’ CVS system, libdvdcss. ddrescue was able to decrypt that disk, though of course I own the DVD. Now I did purchase a dvd tha tis “physically” damaged. So far my attempts at repair using ddrescue have not been successful.
Does anyone have experience with ddrescue of the dd_rescue software with Fedora 35? That’s my version anyway.
The first attempt to recover a “physically damaged” dvd should always be one of the optical disk cleaner/polisher devices and remove as many scratches as possible from the surface. If the back of the DVD (label side) is scratched through or the disk is cracked, nothing will repair the film the laser needs to read.
Note also that even one single bit missing or changed in an encrypted file will likely cause decrypting and reading that file to fail.
Note also that “owning” a DVD is not the same as having one you created. When you purchase a commercial DVD you “own” it but the data was written by their rules. When you create it the data is written by your rules. Your rules and the commercial vendors rules are usually far apart, including track structure, encryption methods, etc.
There are scratches on the back. Most of the movie is fine then it comes to the same area of the film, the same area every time, and acts up. There may be no help then. VLC software seems to read it better. At least the way I am seeing it.
The problem with dd is that it doesn’t have any verification. You might try using wodim at a low read speed and writing that to an iso file that you can verify before burning it to a new disk.
If you want a graphical front-end for this, HandBrake is available in rpmfusion-free and MakeMKV is a free-as-in-coffee (for Linux users) proprietary option that’s available in negativo17’s multimedia repo.
Note that if you choose to enable negativo17’s multimedia repo, I suggest that you specifically only include the packages you intend to install from it (ie, makemkv, etc.), since it sometimes conflicts with RPMFusion and Fedora packaged libs.