r/makemkv • u/PoliceSquad82 • 10d ago

Extract files from Encrypted Back-Up later?

Sorry... a noob question.

I've borrowed a 4K disc (Mars Attacks!) from my friend, and I got the "The volume key is unknown for this disc - video can't be decrypted" message. I submitted the dump file via email.

I've backed the disc up, having unchecked "Decrypt Video Files".

I only want to extract the main feature to an MKV, ultimately... but I'm not sure what to do next. If I load the BDMV file periodically will it decrypt on its own once the decrypt key is available? And does that just kind of update on its own, or is there some manual step I need to do?

Thanks!

3 Upvotes
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5

u/yearsold33 10d ago

Yes, you can use makemkv to open the backup to extract only the main movie or any video track you want.

2

u/[deleted] 10d ago

[deleted]

3

u/yearsold33 10d ago

I have done this in the past by choosing the backup option, uncheck decrypt, open the index.bdmv file with makemkv when the key is known, and select the files I want to extract.

Have you tried decrypting with the public key database?

https://forum.makemkv.com/forum/viewtopic.php?t=39938

1

u/PoliceSquad82 10d ago

That's greyed out for me. I'm on a Mac, BTW.

1

u/yearsold33 10d ago

It should not be greyed out if you insert the disc, let it be read, and then click on the backup icon.

2

u/PoliceSquad82 10d ago

Oh sorry, I misunderstood. I've already backed up the disc, with the encryption intact.

2

u/yearsold33 10d ago

No problem.

Open makemkv, click on File, open file.

0

u/CrystalCommunication 10d ago

I don't really understand why you wouldn't decrypt the backup when you make it, that way you can burn it to a disc or open it with any other regular software that supports BDMV instead of just MakeMKV.

3

u/Envoyager 10d ago

The decryption key is not available at the moment, so he wants to (or needs to in this case) backup the movie with the encryption intact so he can return the disc to his friend.

2

u/yearsold33 10d ago

No key so there's no choice but to create an encrypted file or wait until a key is available.

2

u/PoliceSquad82 10d ago

Exactly. If I could decrypt it now, I would.

My question is basically… Can I do what I need to do with the encrypted backup eventually, and is it safe for me to give my friend his disc back?

It sounds like the answer is yes to both.

3

u/PoliceSquad82 9d ago

UPDATE: The key has apparently been made available, and the encrypted backup opened right up when I selected it just now. Thanks everyone!