Digital cinema refers to the use of digital technology to distribute and project motion pictures. The final movie can be distributed via hard drives, DVDs or satellite and projected using a digital projector instead of a conventional film projector. Digital cinema is distinct from high-definition television and in particular, is not dependent on using television or HDTV standards, aspect ratios, or frame rates. Digital projectors capable of 2K resolution began deploying in 2005, and since 2006, the pace has accelerated. HDTV and pre-recorded HD disks could put pressure on movie theaters to offer something to compete with the home HD experience.
*** 2K and 4K refer to images with 2048 and 4096 horizontal pixel resolution, respectively.
Technology
To match or improve the theater experience of movie audiences, a digital cinema system must provide high quality image, sound, subtitles, and captions. Theater managers require server controls for managing and displaying content in multiple theaters, and studios want their content encrypted with secure delivery, playback, and reporting of play times to the distribution company.
Digital Cinema Initiatives (DCI), a joint venture of the six major studios, published a system specification for digital cinema. Briefly, the specification calls for picture encoding using the ISO/IEC 15444-1 "JPEG2000" (.jp2) standard and use of the CIE XYZ color space at 12 bits per component encoded with a 2.6 gamma applied at projection, and audio using the "Broadcast Wave" (.wav) format at 24 bits and 48 kHz or 96 kHz sampling, controlled by an XML-format Composition Playlist, into an MXF-compliant file at a maximum data rate of 250 Mbit/s. Details about encryption, key management, and logging are all discussed in the specification as are the minimum specifications for the projectors employed including the color gamut, the contrast ratio and the brightness of the image. While much of the specification codifies work that had already been ongoing in the Society of Motion Picture and Television Engineers (SMPTE), the specification is important in establishing a content owner framework for the distribution and security of first-release motion picture content.
Digital cinema conforming to the DCI Standard is referred to within the film industry as D-Cinema while all other forms of digital cinema are referred to as E-Cinema. Thus, while D-Cinema is a defined standard, though one that is still partly being framed by SMPTE as of 2007, E-Cinema may be anything, ranging from a DVD player connected to a consumer projector to something that approaches the quality of D-Cinema without conforming to some of the standards. Even D-Cinema itself has evolved over time before the DCI standards were framed. However, the current DCI standards were made with the intention of standing the test of time, much like 35 mm film which has evolved but still retained compatibility over a substantial part of a century.
In addition to DCI's work, the National Association of Theatre Owners (NATO) released its Digital Cinema System Requirements. The document addresses the requirements of digital cinema systems from the operational needs of the exhibitor, focusing on areas not addressed by DCI, including access for the visually impaired and hearing impaired, workflow inside the cinema, and equipment interoperability. In particular, NATO's document details requirements for the Theatre Management System (TMS), the governing software for digital cinema systems within a theatre complex, and provides direction for the development of security key management systems. As with DCI's document, NATO's document is also important to the SMPTE standards effort.
Digital post-production
Film is scanned from camera-original film negatives into a digital format on a scanner or high-resolution telecine. Data from digital motion picture cameras may be converted to a convenient image file format for work in a facility. All of the files are 'conformed' to match an edit list created by the film editor, and are then color corrected under the direction of the film's staff. The end result of post-production is a digital intermediate used to record the motion picture to film and/or for the digital cinema release.
Digital mastering
When all of the sound, picture, and data elements of a production have been completed, they may be assembled into a Digital Cinema Distribution Master (DCDM) which contains all of the digital material needed for a show. The images and sound are then compressed, encrypted, and packaged to form the Digital Cinema Package (DCP).
Digital projection
There are currently two types of projectors for digital cinema. Early DLP projectors, which were deployed primarily in the
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