KDM for existing DCP

Anything and everything to do with DCP-o-matic.
Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

KDM for existing DCP

Post by Margus Voll » Fri Sep 13, 2019 6:24 pm

Hi.

Im new user here looking around so sorry for noob question.

I have pre made dcp but now i need to make KDM for it.
Can i do it with DOM or do i understand it wrong and i need to make new dcp?


I could do new as well but was a bit confused about input file format as i can make any from my Resolve project now.
I have currently at hand a version of MXF files with dnxhr 12 bit 444 rec709 2.4
Would that make any sense or some other files are preferable?

Carsten
Posts: 1397
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: KDM for existing DCP

Post by Carsten » Fri Sep 13, 2019 6:37 pm

Did you create the DCP encrypted? Only if you encrypted, you will be able to make a DCP.

Understanding encryption and KDMs/Certificates is not that easy.

Your source file should be okay. I guess you are using Resolve in Windows?

- Carsten

Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

Re: KDM for existing DCP

Post by Margus Voll » Fri Sep 13, 2019 6:47 pm

DCP is unencrypted (Kakadu in Resolve)
I really dont want to buy EasyDCP
Have Final DCP full setup but now it seems to be EOL

Yes Resolve on win.
As i have the master timeline at hand i can make other file types as well.

As i do need KDM made like one in 3 years or less it seems other options are in place this is why i started looking at DOM.

Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

Re: KDM for existing DCP

Post by Margus Voll » Fri Sep 13, 2019 7:32 pm

I will run one DCP on DOM also for test.

As i understand it i should make it encrypted and then make KDM with provided server cert later?

Carsten
Posts: 1397
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: KDM for existing DCP

Post by Carsten » Fri Sep 13, 2019 7:55 pm

You should be able to load a pre-existing DCP and encrypt it. DCP-o-matic will then only encrypt the existing J2K frames, not re-encode.

As such, it is perfectly okay to create a 'base DCP' in Resolve using the Kakadu encoder, and then add more features in DCP-o-matic.

Yes, you can encrypt first, then create KDMs later. Best is to keep the full project, but you can also create a DKDM right after encoding - that will allow you to issue KDMs even when you lost your project with the stored encryption key.

Try to understand as much as possible from here:

https://dcpomatic.com/manual/html/ch10.html

Once you start using encryption, you will see a couple of hints/warnings popping up in DCP-o-matic - read them, don't check the 'don't show hints again' checkbox!

- Carsten

Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

Re: KDM for existing DCP

Post by Margus Voll » Fri Sep 13, 2019 8:31 pm

It is one time copy but i will try to play with it a bit.

DCP is almost done i have to see how it goes.

Generally i so far understand that i need to encrypt and then make KDM with server cert on top of encrypted dcp
sort of "bind" dcp with server cert and result KDM that will open the delivery copy?

Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

Re: KDM for existing DCP

Post by Margus Voll » Fri Sep 13, 2019 9:07 pm

Carsten wrote:
Fri Sep 13, 2019 7:55 pm

Try to understand as much as possible from here:

https://dcpomatic.com/manual/html/ch10.html

Once you start using encryption, you will see a couple of hints/warnings popping up in DCP-o-matic - read them, don't check the 'don't show hints again' checkbox!

- Carsten
Thanks for the link!

I think i got the key logic. It is similar to the servers used in internet or like in movies usually they open safe deposit box with bank key and user key.

My main concern is if i can make it all in practice with the correct steps and maybe verify afterwards.

Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

Re: KDM for existing DCP

Post by Margus Voll » Sat Sep 14, 2019 12:07 am

The way to do it is described here I see

https://dcpomatic.com/manual/html/ch10s02.html

Now need to see if I manage to complete all steps according to it.

Started encryption but I have some questions.

For starters will it encrypt give dcp in same location or put it in location I state in config "place new film" or such

Carsten
Posts: 1397
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: KDM for existing DCP

Post by Carsten » Sat Sep 14, 2019 12:48 am

I don't understand that last sentence?

The good thing in DCP-o-matic is that you can actually test the full encryption and decryption chain on your own machine. You can essentially simulate the full relation between the person encrypting the feature and the cinema playing it.

If you encrypted a DCP, then at first this content is unplayable for you as well. You will notice that when you load this DCP in DCP-o-matic player, it will not play but ask for a KDM. Then you need to follow the necessary steps to make it work, and that should be the same method as you follow when dealing with a cinema. Actually, DCP-o-matic has a simpler way by it's shortcut to create a DKDM immediately from within DCP-o-matic.

However, I would advise that a first you don't go the easy route, but the formal one, exporting the cert, importing the cert, creating a cinema and screen, create a real KDM, then see if it works. If it doesn't work - start again.

So, first step is create an unencrypted Test-DCP - name it UEmyfeature. Then, from within the same project, rename it to ENmyfeature under DCP tab, and check the 'encrypted' checkbox. Create DCP again. You will find two DCPs in the project folder. These are your starting point. Try to play both in player, watch the second fail.

- Carsten
Last edited by Carsten on Sat Sep 14, 2019 9:28 am, edited 1 time in total.

Margus Voll
Posts: 10
Joined: Fri Sep 13, 2019 6:18 pm

Re: KDM for existing DCP

Post by Margus Voll » Sat Sep 14, 2019 5:52 am

Thanks for getting back to me on such regular basis!

What i was wondering was where it would put the new made dcp after encryption.
It seems that it sits in project folder now.

I got the logic of encrypting it and exporting virtual "server" cert and then by bringing it back in test.

Just have to make it now in step by step action.
This is the most complex thing now to mimic logic in actual steps that work.

I will play a little and see.

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