DCDMs/DCPs/KDMs

DCP

A digital cinema package is a bundle of files (video, audio and subtitles) that are used by cinemas to screen a film and is effectively the digital equivalent of a 35mm print. Typically, these are delivered to theatres on a CRU (a hard drive in a metal carrier) and a peli case. The CRU drive we provide slots straight into the drives at the cinema and are the only type they's accept. The DCP is generally 24fps and 1.89:1 or 2.39:1 ratio with 5.1 audio.

What is a KDM?

A 'Key Delivery Message' contains the encrypted key for the content as well as the certificate and a signature for verification purposes. KDMs are used for the playback in a Digital Cinema system. The purpose of the KDM is designed for the security and control of the content. An important process involving the Digital Rights Management. If we have created the DCP here at The Look, we can, if given the server serial number at the cinema you are screening at, issue the projectionist or you a KDM via email for £25.

What is a DKDM?

DKDM stands for "Distribution KDM"

A DKDM can fully control the DCP for copying & modification and future creation of KDMs and are not specific to a given playback device. DKDM utilize a one key system while KDM utilize a two key system. DKDMs are usually issued by a company who are going to make multiple copies later or issue KDMs themselves, they are often international companies with 24/7 KDM issuing abilities for worldwide screening support (examples might be Deluxe or Technicolor and often clients use them).

Should I Encrypt DCP?

A provocative question that should be discussed with your investors, distributors and exhibitors. Most festivals and small movie houses prefer an Un-Encrypted DCP. Dealing with keys can be troublesome for some theaters. Furthermore, the DCP file is not an easy file to read and pirate from. The file is quite large and the image color space is significantly different than most files, the only issue is that an unencrypted DCP can be played indefinitely on a cinema server as no time limit will be in place and someone could copy the DCP off the DCP player/server on to another drive. Once a DCP is encrypted, modifying the contents may not be possible. KDMs will be issued to each projector/server at a cost of £25 per KDM.

What is DCDM?

A DCDM is the post-production step prior to a DCP. The frames are in XYZ 16bit TIFF format (usually in reels with leaders) and both sound and picture (24bit 48khz wav) are not yet wrapped into MXF files. A DCP can be encoded directly from a DCDM. XYZ refers to the specific colour space of the file, the bit depth is the amount of colour information present and TIFF is a type of image file type (like JPEG).

A DCDM is useful for archiving purposes and also facilities can share them for international re-versioning purposes. They can easily be turned into alternative version DCPs for foreign territories. For smaller release films, the facility will usually skip the creation of a DCDM and instead encode directly from the DSM (Digital Source Master which is on the grading and finishing systems).

Creating DCPs of existing films or commercials

The majority of DCPs shown in cinemas are 24 frames per second, and in the aspect ratio of either 1.85:1 or 2:39:1

Is your project 25fps?

A commercial or short film will often be at 25 frames per second and also be 16x9 ratio (aka 1.78:1).
This means you may have to make some compromises and check with your distributor or festival if they can accept 25 frames per second DCPs. The rule of thumb is older cinema servers may not be able to play anything other than 24 frames per second so there is the potential to run in to problems.
If you do want to convert your 25 frames per second films (fps) to 24 fps then the film and its audio will play back slower and so audio can sound a little odd. We can fix the pitch sounding odd but the actual speed of music and duration of the film will be longer by 4%

Cinemas don't have lenses for 16x9 so we have two choices of how to present in to 1.85.

We just fit the edges and you lose 4% of picture top and bottom (2% of each)
If you are concerned you might have heads of other crucial detail top and bottom of frame (and cinemas always lose a little more that they spec) we can size top and bottom in leave you with black bars either side (again only 2% extra on both sides)So we need to know:

So the questions to answer (copy and paste this list with your answers in your email to us at bookings@thelooklondon.com ):

1) What is the frame rate you're delivering?

2) What frame rate do you want back being mindful of compatibility of 25fps in certain cinemas?

3) If changing from 25 to 24 do you want us to do the audio pitch correction (added cost) or ask your original audio company to do this (usually a better option)

4) If your project is 16x9 do you want us to crop the top and bottom (CUT) or fit original full picture but have black bars on left and right (BOX)?

5) We can screen your DCP at The Look first if this is useful but there is an additional cost of £100 per 30min (minimum charge)?

6) If your project is a film, do you want it Encrypted? (see above info) KDMs are charged at £25 with each issue?

7) What are you supplying us with? (i.e. ProRes, DPX etc.) And what is it's resolution?

8) Is your audio 5.1?