Decryption of full disc backup

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evilmatcher
Posts: 30
Joined: Fri Apr 24, 2020 9:17 am

Decryption of full disc backup

Post by evilmatcher »

Hi all

My copy of Saving Private Ryan (the UK 3 disc version) has some small scratches on the disc that prevents MakeMKV 1.16.7 to read the disc. I have retried numerous times and it stops at the exact same place. I have managed to copy the files from the disc manually in Windows and my backup folder has the same structure as the disc.

I need to decrypt the disc/files as one of the steps to do a .TS version of the movie for my x800m2 to have the full DV FEL experience.

I open the files manually in MakeMKV but i get these errors
"
The volume key is unknown for this disc - video can't be decrypted
DEBUG: Code 0 at EVz_tTp6BRfYN?zX:29396092
DEBUG: Code 0 at EVz_tTp6BRfYN?zX:29394850
Failed to open disc
"
I have previously made a MKV-version of the movie, so I don't get why it says that the volume key is unknown.

Can anyone help here?
Ezatoka
Posts: 411
Joined: Fri Dec 06, 2019 6:55 pm

Re: Decryption of full disc backup

Post by Ezatoka »

Because just copying the files doesn't do the full trick.

Start an encrypted backup of your disc, and cancel it as soon as the file discatt.dat was created at your destination.

Copy that file into the main directory of the contents you copied from the disc. Now when you open files manually in MakeMKV you can select the discatt.dat file and should be able to decrypt the files.
evilmatcher
Posts: 30
Joined: Fri Apr 24, 2020 9:17 am

Re: Decryption of full disc backup

Post by evilmatcher »

Thanks - i was aware that just copying the files was not enough.

Unfortunately your solution didn't help.

An AACS dump file is saved C:\Users\XXXX/.MakeMKV/MKB20_v61_Saving_Private_Ryan_9F8B.tgz. I tried to start a normal MKV-extract of the movie, which runs as it should. Isn't it a bit weird.

Also this time I get the same error messages as before:

"
The volume key is unknown for this disc - video can't be decrypted
DEBUG: Code 0 at EVz_tTp6BRfYN?zX:29396092
DEBUG: Code 0 at EVz_tTp6BRfYN?zX:29394850
Failed to open disc
"
Billycar11
Posts: 4396
Joined: Sun Aug 24, 2014 5:49 am

Re: Decryption of full disc backup

Post by Billycar11 »

You have to remove buss encryption before copying the full disc you current backup is likely double encrypted so it's impossible to decrypt.
First you need to open the disc in makemkv by clicking the bluray icon then close makemkv and copy the whole disc again then you should be able to decrypt it but you will likely still have errors.
Buy a UHD drive from the guide and how to video maker: https://www.makemkv.com/forum/viewtopic ... 20&t=17831
UHD Drives Guide: https://www.makemkv.com/forum/viewtopic ... 16&t=19634
Auto flash kit $25 Email me for one Billycar5924@gmail.com
evilmatcher
Posts: 30
Joined: Fri Apr 24, 2020 9:17 am

Re: Decryption of full disc backup

Post by evilmatcher »

Billycar11 wrote:
Sun Jun 19, 2022 6:49 pm
You have to remove buss encryption before copying the full disc you current backup is likely double encrypted so it's impossible to decrypt.
First you need to open the disc in makemkv by clicking the bluray icon then close makemkv and copy the whole disc again then you should be able to decrypt it but you will likely still have errors.
Thanks.

Is this double encryption issue caused by i have copied the full disc manually in Windows explorer?
Billycar11
Posts: 4396
Joined: Sun Aug 24, 2014 5:49 am

Re: Decryption of full disc backup

Post by Billycar11 »

evilmatcher wrote:
Sun Jun 19, 2022 7:58 pm
Billycar11 wrote:
Sun Jun 19, 2022 6:49 pm
You have to remove buss encryption before copying the full disc you current backup is likely double encrypted so it's impossible to decrypt.
First you need to open the disc in makemkv by clicking the bluray icon then close makemkv and copy the whole disc again then you should be able to decrypt it but you will likely still have errors.
Thanks.

Is this double encryption issue caused by i have copied the full disc manually in Windows explorer?
Yes
Buy a UHD drive from the guide and how to video maker: https://www.makemkv.com/forum/viewtopic ... 20&t=17831
UHD Drives Guide: https://www.makemkv.com/forum/viewtopic ... 16&t=19634
Auto flash kit $25 Email me for one Billycar5924@gmail.com
evilmatcher
Posts: 30
Joined: Fri Apr 24, 2020 9:17 am

Re: Decryption of full disc backup

Post by evilmatcher »

Is this double encryption issue caused by i have copied the full disc manually in Windows explorer?

Yes
Damn - then I'm screwed, as I can't get Makemkv to backup more than ~1/3 of the movie. I need to play the disc from the x800m2, which works fine.
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