Digital Cinema Package
A Digital Cinema Package (DCP) is a collection of digital files used to store and convey digital cinema (DC) audio, image, and data streams.
The term was popularized by Digital Cinema Initiatives, LLC in its original recommendation[1] for packaging DC contents. However, the industry tends to apply the term to the structure more formally known as the composition. ("You PLAY a composition, You do NOT play a Digital Cinema Package".[2]) A DCP is a “packing crate” for compositions,[3] a hierarchical file structure that represents a title version. The DCP may carry a partial composition (e.g. not a complete set of files), a single complete composition, or multiple and complete compositions.[3]
The composition consists of a Composition Playlist (in XML format) that defines the playback sequence of a set of Track Files. Track Files carry the essence, which is wrapped using Material eXchange Format (MXF). Two track files at a minimum must be present in every composition (see SMPTE ST429-2 D-Cinema Packaging – DCP Constraints, or Cinepedia[4]): a track file carrying picture essence, and a track file carrying audio essence. The composition, consisting of a Composition Playlist and associated track files, are distributed as a Digital Cinema Package (DCP). It must be underscored that a composition is a complete representation of a title version, while the DCP need not carry a full composition. However, as already noted, it is commonplace in the industry to discuss the title in terms of a DCP, as that is the deliverable to the cinema.
The Picture Track File essence is compressed using JPEG 2000 and the Audio Track File carries a 24-bit linear PCM uncompressed multichannel WAV file. Encryption may optionally be applied to the essence of a track file to protect it from unauthorized use. The encryption used is AES 128-bit in CBC mode.
