Digital Cinema Initiatives
The primary purpose of DCI is to establish and document specifications for an open architecture for digital cinema that ensures a uniform and high level of technical performance, reliability and quality. By establishing a common set of content requirements, distributors, studios, exhibitors, d-cinema manufacturers and vendors can be assured of interoperability and compatibility. Because of the relationship of DCI to many of Hollywood's key studios, conformance to DCI's specifications is considered a requirement by software developers or equipment manufacturers targeting the digital cinema market.
On July 20, 2005, DCI released Version 1.0 of its "Digital Cinema System Specification", commonly referred to as the "DCI Specification". The document describes overall system requirements and specifications for digital cinema. Between March 28, 2006, and March 21, 2007, DCI issued 148 errata to Version 1.0.
DCI released Version 1.1 of the DCI Specification on April 12, 2007, incorporating the previous 148 errata into the DCI Specification. On April 15, 2007, at the annual NAB Digital Cinema Summit, DCI announced the new version, as well as some future plans. They released a "Stereoscopic Digital Cinema Addendum" to begin to establish 3-D technical specifications in response to the popularity of 3-D stereoscopic films. It was also announced "which studios would take over the leadership roles in DCI after the current leadership term expires at the end of September."
Subsequently, between August 27, 2007, and February 1, 2008, DCI issued 100 errata to Version 1.1. So, DCI released Version 1.2 of the DCI Specification on March 7, 2008, again incorporating the previous 100 errata into the specification document. An additional 96 errata were issued by August 30, 2012, so a revised Version 1.2 incorporating those additional errata was approved on October 10, 2012. The previous versions are also archived on the DCI web site.
Based on many SMPTE and ISO standards, such as JPEG 2000-compressed image and "broadcast wave" PCM/WAV sound, it explains the route to create an entire Digital Cinema Package (DCP) from a raw collection of files known as the Digital Cinema Distribution Master (DCDM), as well as the specifics of its content protection, encryption, and forensic marking.
The specification also establishes standards for the decoder requirements and the presentation environment itself, such as ambient light levels, pixel aspect and shape, image luminance, white point chromaticity, and those tolerances to be kept.
Even though it specifies what kind of information is required, the DCI Specification does not include specific information about how data within a distribution package is to be formatted. Formatting of this information is defined by the Society of Motion Picture and Television Engineers (SMPTE) digital cinema standards.[b]
Image and audio capability overview
- 2048×1080 (2K) at 24 frame/s or 48 frame/s, or 4096×2160 (4K) at 24 frame/s
- In 2K, for Scope (2.39:1) presentation 2048×858 pixels of the image is used
- In 2K, for Flat (1.85:1) presentation 1998×1080 pixels of the image is used
- In 4K, for Scope (2.39:1) presentation 4096×1716 pixels of the image is used
- In 4K, for Flat (1.85:1) presentation 3996×2160 pixels of the image is used
- 12 bits per color component (36 bits per pixel) via dual HD-SDI (encrypted)
- 10 bits only permitted for 2K at 48 frame/s
- CIE XYZ color space
- TIFF 6.0 container format (one file per frame)
- JPEG 2000 compression
- From 0 to 5 or from 1 to 6 wavelet decomposition levels for 2K or 4K resolutions, respectively
- Compression rate of 4.71 bits/pixel (2K @ 24 frame/s), 2.35 bits/pixel (2K @ 48 frame/s), 1.17 bits/pixel (4K @ 24 frame/s)
- 250 Mbit/s maximum image bit rate
Stereoscopic 3D image
- 2048×1080 (2K) at 48 frame/s - 24 frame/s per eye (4096×2160 4K not supported)
- In 2K, for Scope (2.39:1) presentation 2048×858 pixels of the imager is used
- In 2K, for Flat (1.85:1) presentation 1998×1080 pixels of the imager is used
- Optionally, in the HD-SDI link only: 10 bit color, YCbCr 4:2:2, each eye in separate stream
DCI has additionally published a document outlining recommended practice for High Frame Rate digital cinema. This document discloses the following proposed frame rates: 60, 72, 96, and 120 frames per second for 2D at 2K resolution; 48 and 60 for stereoscopic 3D at 2K resolution; 48 and 60 for 2D at 4K resolution. The maximum compressed bit rate for support of all proposed frame rates should be 500 Mbit/s.
The idea for DCI was originally mooted in late 1999 by Tom McGrath, then COO of Paramount Pictures, who applied to the U.S. Department of Justice for anti-trust waivers to allow the joint cooperation of all seven major motion picture studios.
Universal Pictures made one of the first feature-length DCPs created to DCI specifications, using their film Serenity. Although it was not distributed theatrically, it had one public screening on November 7, 2005, at the USC Entertainment Technology Center's Digital Cinema Laboratory in the Pacific Theatre, Hollywood. Inside Man was Universal's first DCP commercial release, and, in addition to 35mm film distribution, was delivered via hard drive to 20 theatres in the United States along with two trailers.
- Metro-Goldwyn-Mayer withdrew as a member of DCI in May 2005, prior to the release of the DCI Specification.
- As of 1 September 2010, the following thirty-one SMPTE standards had been adopted and published: • SMPTE 428-1-2006 D-Cinema Distribution Master (DCDM) – Image Characteristics • SMPTE 428-2-2006 D-Cinema Distribution Master – Audio Characteristics • SMPTE 428-3-2006 D-Cinema Distribution Master Audio Channel Mapping and Channel Labeling • SMPTE 428-7-2007 D-Cinema Distribution Master - Subtitle • SMPTE 428-9-2008 D-Cinema Distribution Master - Image Pixel Structure Level 3 - Serial Digital Interface Signal Formatting • SMPTE 428-10-2008 D-Cinema Distribution Master - Closed Caption and Closed Subtitle • SMPTE 428-11-2009 Additional Frame Rates for D-Cinema • SMPTE 428-19-2010 D-Cinema Distribution Master - Additional Frame Rates Level AFR2 and Level AFR4 - Serial Digital Interface Signal Formatting • SMPTE 429-2-2009 D-Cinema Packaging - DCP Operational Constraints • SMPTE 429-3-2006 D-Cinema Packaging – Sound and Picture Track File • SMPTE 429-4-2006 D-Cinema Packaging – MXF JPEG 2000 Application • SMPTE 429-5-2009 D-Cinema Packaging - Timed Text Track File • SMPTE 429-6-2006 D-Cinema Packaging – MXF Track File Essence Encryption • SMPTE 429-7-2006 D-Cinema Packaging – Composition Playlist • SMPTE 429-8-2007 D-Cinema Packaging - Packing List • SMPTE 429-9-2007 D-Cinema Packaging - Asset Mapping and File Segmentation • Amendment 1-2010 to SMPTE 429-9-2007 • SMPTE 429-10-2008 D-Cinema Packaging - Stereoscopic Picture Track File • SMPTE 429-12-2008 D-Cinema Packaging - Caption and Closed Subtitle • SMPTE 429-13-2009 D-Cinema Packaging - DCP Operational Constraints for Additional Frame Rates • SMPTE 430-1-2006 D-Cinema Operations – Key Delivery Message • Amendment 1-2009 to SMPTE 430-1-2006 • SMPTE 430-2-2006 D-Cinema Operations – Digital Certificate • SMPTE 430-3-2008 D-Cinema Operations – Generic Extra-Theater Message Format • SMPTE 430-4-2008 D-Cinema Operations - Log Record Format Specification • SMPTE 430-5-2008 D-Cinema Operations - Security Log Event Class and Constraints • SMPTE 430-6-2010 D-Cinema Operations - Auditorium Security Messages for Intra-Theater Communications • SMPTE 430-7-2008 D-Cinema Operations - Facility List Message • SMPTE 430-9-2008 D-Cinema Operations - Key Delivery Bundle • SMPTE 431-1-2006 D-Cinema Quality – Screen Luminance Level, Chromaticity and Uniformity • SMPTE 433-2008 D-Cinema - XML Data Types