www.makemkv.com

So I have 2 physical discs of the same bluray. Both are damaged, but with ddrescue I am able to make a complete image of the disc. If I try to specify makemkv on the iso it doesn't work (as I expected)
is there a way to force specifying the volume key for the disc (especially as I have both damaged physical discs still) and can even keep it in the drive at the same time

http://www.makemkv.com/faq/item/12 (although the directory mentioned SHOULD be whatever you have in Preferences->General for your MakeMKV data directory)

Getting the database can be problematic; when I last looked for a copy of it, the most recent was a year old.

"First, you need to set an "AACS keys directory" in preferences"

I don't see that in my preferences (Linux)

and I know see your coment about makemkv directory

But I guess my main point was that shouldn't MakeMKV be able to generate that key data needed if I have the physical disc, (i.e. out of date internet downloadable key db's shouldn't matter) i.e. it might be damaged and a backup might not be able to be completed, but as long as it can be started the key data should be able to be generated for the ISO I'll then create via ddrescue.

so made progress, but makemkvconf doesn't work with backup and an iso (it should, see the use case I'm describing)
but it looks like if I use /dev/loop (0 in my case) it works. Or at least is doing something, I'll see the results later.

and I was wrong, it wasn't working off of /dev/loop0, it was working off the physical disc. oh well, so I'd have 2 feature requests

1) Generate/Store the keys from a physical disc
2) allow backup to work off an ISO using those keys.