decrypting 4k Blu Ray files

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filmfreak2021
Posts: 2
Joined: Fri Jan 29, 2021 11:23 pm

decrypting 4k Blu Ray files

Post by filmfreak2021 » Mon Feb 22, 2021 2:02 pm

Hello

I have the digital files from the 4k Blu Ray disc of the greatest showman. I want to convert those digital files (an AACS folder, BDMV file and a CERTIFICATE folder to the MKV format, but MakeMKV tells me that it can't decrypt the files. How can I make it possible to rip the movie out of those files?

filmfreak2021

Woodstock
Posts: 10316
Joined: Sun Jul 24, 2011 11:21 pm

Re: decrypting 4k Blu Ray files

Post by Woodstock » Mon Feb 22, 2021 2:19 pm

If MakeMKV created the backup, there will be a file that holds the necessary information for decryption named discatt.dat. If you do not have that, you will have to either generate it, using the original disk, or get a decryption key independently.

filmfreak2021
Posts: 2
Joined: Fri Jan 29, 2021 11:23 pm

Re: decrypting 4k Blu Ray files

Post by filmfreak2021 » Mon Feb 22, 2021 4:51 pm

Thank you for replying!

Where can I get decryption keys independently? MakeMKV didn't create the backup and I also don't see a file named discant.dat.

I do have the original disk but my Blu Ray drive is not capable of ripping 4k Blu Ray. But I was able to copy the movie files and folders over to my hard drive.

Woodstock
Posts: 10316
Joined: Sun Jul 24, 2011 11:21 pm

Re: decrypting 4k Blu Ray files

Post by Woodstock » Mon Feb 22, 2021 6:17 pm

Searching came up with this link: viewtopic.php?f=12&t=17087&p=60530&hilit=discatt#p60530

The assumption is that you have access to the same drive that copied the files, because of bus encryption that would be involved. Start a backup (without decryption), and you can abort it after the discatt.dat file is created.

Independent would be finding a copy of keydb.cfg that has the decryption key for your particular disk in it (there can be more than one per title, for different markets). This way is a pain to deal with, though. I tried it a couple of times.

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