BCi Digital: What is DCP?


What is a Digital Cinema Package (DCP)?

A: Simply put, a DCP is the digital equivalent of a 35mm film print. It is what you give to a commercial theatre so they can screen your movie on a digital (also known as “D-Cinema”) projector. Like a 35mm print, a DCP is a world-wide standard. If you walk into any Digital Cinema (DC), anywhere in the world, they can play your DCP without any problems.

A picture paints a thousand words. Here in a nut shell is how the system works:

DCP_graphic2

 

Mastering is the generation of the original video / audio material, the essence as it’s termed. Parameters defined include bit depth, sample rate, minimum channel count, channel mapping and reference levels, and the format of a Digital Cinema subtitle track file. A subtitle track file contains a set of instructions for placing rendered text or graphical overlays at precise locations on distinct groups of motion picture frames. The resolution can be either 2k or 4k but the DCP must allow for the content to be playable on either 2k or 4k projection systems.

Transport is the process of packaging up the essence in such a way that it can be easily and securely transported be this via an Internet network, satellite or some type of physical media such as a hard disk drive

Storage refers to the file format required for storage to disk or other physical media

Projection is the actual ‘unpacking’ of the DCP files for ultimate display at a theatre with consistent and repeatable colour image
quality

The components of the DCP are MXF, CPL, PKL and optionally KDM files.

Q: How Does a DCP Work?
A: A DCP usually arrives at a cinema theater on a CRU hard-drive or USB Flash drive. The DCP is ingested into the theatre’s Digital Cinema Server. Once verified, it is played off the server through a Digital Cinema Projector.

Q: What are MXF Files?
A: MXF is an acronym for Material Exchange Format. It is a file wrapper enclosing both the content and associated metadata. Picture and sound content may be stored as one or more MXF files. Each file contains JPEG2000 compressed image information and corresponding 12-channel, 24-bit, 48/96 kbps audio information.

Q: What is a CPL?
A: CPL is an acronym for Composition Playlist. A Composition Playlist consists of an ordered sequence of reels each referencing sound or picture files. Each reel is analogous to a film reel. The CPL controls the order and timing of the play-out of the reels.

Q: What do DCPs cost to make?

A: These seem to vary based on how much you wish to spend.  The consensus on the internet is that a professionally encoded feature DCP typically costs between $1400-$3000 (depending on runtime and options), with additional copies running about $170-$300 each. When comparing prices, be sure all of the following are included in your quote:

Quality Check or ‘QC’ – this is where the final product is checked for glitches, drop-out, sync problems, gamma, colour, etc. by an experienced technician. This step is absolutely crucial. There is too much that can go wrong in the mastering process not to make sure the final product is as flawless as possible. Small mistakes look huge on a 30 foot theatre screen.

Transfer to USB or CRU drive. This is the final step when the mastered files (collectively called the DCP) are transferred to an EXT 2/3 formatted Linux hard drive. The actual drive can be a standard portable USB available in any computer store, or a professional “DX115” drive carrier, which is called a CRU. Both USB and CRU have the exact same information on them.

Q: How long do DCPs take to produce?

A: There does not seem to be a precedent. It takes as long as it takes; although obviously the shorter the better.

Q: What is DCI?
A: DCI is an acronym for Digital Cinema Initiatives. The DCI was created in 2002 as a joint venture between the major motion-picture studios (Disney, Fox, Metro-Goldwyn-Mayer, Paramount Pictures, Sony Pictures Entertainment, Universal Studios, and
Warner Bros. Studios) to establish and document specifications that would insure uniform, high-quality technical performance, reliability and quality control. The formal standardization of the DCI specifications is overseen by the Society of Motion Picture & Television Engineers (SMPTE).

Q: What is DCI Compliance?
A: DCI Compliance refers to products and services that conform to DCI specifications.

Q: What is a KDM?
A: KDM is an acronym for Key Delivery Message. A KDM is a special electronic key that contains a code which “unlocks” an encrypted film

Q: What is a KDM encryption?
A: Encryption is a security measure used to prevent films from being stolen and duplicated. DCP’s are encrypted in a manner that allows them to be played only on a specific Digital Cinema server at a predetermined time. A KDM is sent to the projection site to unlock the DCP for the screening engagement. It is not a necessity to have a DCP encrypted

Q: Where can I find more complete technical specifications for DCPs?

A: Complete DCP specifications are contained in the following: SMPTE 428-1-2006 D-Cinema, ISO/IEC 15444-1, SMPTE 428-2-2006 D-Cinema, SMPTE 428-3-2006 D-Cinema. These standards documents are sold by SMPTE and other organizations such as ISO. See diagram here:

DCP_specs

If you would like to know more about how DCP works please download our white paper.

James Hart and Mark Massel – BCi Digital

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