Subtitles for Encrypted dcps

[rjtagayon]

So i have an encrypted dcp which needs a subtitle to be added to it before we release to cinemas. The client has already sent us the dcp xml file. I've tried adding it to the unencrypted version we have and it worked, I'm just worried about the encrypted one.

Here's what Im about to do.

I import the encrypted dcp into dcp o matic, and import a kdm for it so Im free to modify. I click refer to existing dcp for video and audio tabs and import the xml subs file I have. Im going to keep it unencrypted before i click Job> make dcp. Once its done im going to ingest the supplemental dcp I have created.

Now the question is, do I only need to make a kdm for the encrypted OV and the VF will play as long as the kdm is valid? Or do i have to make a kdm for the vf too. I hope you guys can help, release is next week so i still have some time to test this

[carl]

That is a tricky one. A KDM is targeted at a particular CPL so I think (although I could be wrong) you will need a KDM for the VF which contains the keys for the encrypted assets from the OV. Whether DCP-o-matic successfully creates such a KDM is another question... perhaps you could try it and see what happens!

[rjtagayon]

Hi carl, I did what I said I would step by step. Also, I made a KDM for the version file using its CPL via DCP creater thru Jobs > Make KDMs.

I ingested both OV and VF into our server, I can play OV all right. But as for the VF, the player says its running but the timecode is stuck at 00:00:00.

Keep in mind I exported the VF as an unencrypted dcp. I will try and do all this again using both encrypted OV and VF. Will update this thread immediately.

[rjtagayon]

Same case for encrypted VF, still doesn't play when ingested and license is loaded.

What to do?

[Carsten]

Is there a way to actually decrypt the encrypted DCP without recoding, so to generate a new encrypted DCP afterwards, with the subs added?

After the KDM is assigned to the encrypted DCP, would it be possible to extract the AES Key and set it as the 'new' AES Key in the project? But KDM and CPL would still need to have the proper Key-ID sequence for all assets.

- Carsten

[ale_dc711]

Same problem here. VF with subtitles refering to an encrypted OV doesn't work. Tested on Christie and Barco Servers. Is this a DCP O'matic mastering problem or a common problem on all servers? Does anyone found a solution?

[lemgeo]

Hi,
Here's what worked for me in the past with a previus version of DoM( tested on a DOLBY server):

Import the encrypted DCP and the KDM.
Make a new KDM for DoM (Jobs -make KDM)
Start a new project import the encrypted DCP and the created KDM.
Import the sub file and make a VF package ( click refer to existing dcp for video and audio tabs ) not encrtypted.
MAke a KDM using KDM creator and choose the VF's cpl.
I didn't have to make KDM for the OV package.

For me it worked. I'll make a test with the latest version and let tou know but a have access only to a dolby server

[khinkalo]

Hello!

Sorry to revive such an old thread but this is really an interesting question.

I met a person a few years ago from Germany whose company could do this but unfortunately I lost his contact. So, somehow it should be doable. Some Googling also shows that a few people offer this service without KDM/DKDM. I'd like to believe it's not about cracking the encryption, but just some kind of work-around.

I just wanted to follow up on lemgeo's reply: do you still get this to work? If not, has anyone else found a way?

[Carsten]

Simply said - if the OV is encrypted, it is not possible without a DKDM.
Unless you use completely different methods for subtitling (e.g. personal smartphone). These would be solutions highly dependent on local options, e.g. festivals, etc.

[khinkalo]

Sorry Carsten, how do you mean personal smartphone? Some fairly high profile festivals still use standalone projectors and project the subtitles separately (by clicking subtitle by subtitle), but my question here, since it's been proven to work, is: is it possible someone cracked the DCP encryption, or would it actually be possible to create a VF on an encrypted DCP?

lemgeo seemed to have one working option even though it also seemed to be some kind of a glitch. If not glitch, there obviously is a way. Unless we're not to talk about this in public. But I can't see why, because the purpose is not to view encrypted DCP:s (which isn't possible either way), just to add subtitles to them.