Digital Cinema Initiatives

Digital Cinema Initiatives, LLC (DCI) is a joint venture of major motion picture studios, formed to establish a standard architecture for digital cinema systems.

The organization was formed in March 2002 by Metro-Goldwyn-Mayer,[lower-alpha 1] Paramount Pictures, Sony Pictures Entertainment, 20th Century Fox, Universal Studios, The Walt Disney Company and Warner Bros.

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.[1] 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.

Specification

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"[2] 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."[3]

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. DCI approved DCI Specification Version 1.3 on June 27, 2018, integrating the 45 errata issued to the previous version into a new document. [4] 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 and related documents.[lower-alpha 2]

Image and audio capability overview

2D image

  • 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 imager is used
    • In 2K, for Flat (1.85:1) presentation 1998×1080 pixels of the imager is used
    • In 4K, for Scope (2.39:1) presentation 4096×1716 pixels of the imager is used
    • In 4K, for Flat (1.85:1) presentation 3996×2160 pixels of the imager 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

Audio

  • 24 bits per sample, 48 kHz or 96 kHz
  • Up to 16 channels
  • WAV container, uncompressed PCM

DCI has additionally published a document outlining recommended practice for High Frame Rate digital cinema.[5] This document discloses the following proposed frame rates: 60, 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.[6] 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.

The Academy Film Archive houses the Digital Cinema Initiatives, LLC Collection, which includes film and digital elements from DCI’s Standard Evaluation Material (StEM), a 12-minute production shot on 35mm and 65mm film, created for vendors and standards organizations to test and evaluate image compression and digital projection technologies.[7]

Notes

  1. ↑ Metro-Goldwyn-Mayer withdrew as a member of DCI in May 2005, prior to the release of the DCI Specification.
  2. ↑ As of 1 January 2018, the following fifty-six SMPTE engineering guidelines, recommended practices, registered disclosure documents and standards had been adopted and published: • EG 432-1 Digital Source Processing - Color Processing for D-Cinema • EG 432-2 Digital Source Processing - D-Cinema Low Frequency Effects (LFE) Channel Audio Characteristics • RDD 20 Cinelink 2 Specification • RP 200 Relative and Absolute Sound Pressure Levels for Motion-Picture Multichannel Sound Systems - Applicable for Analog Photographic Film Audio, Digital Photographic Film Audio and D-Cinema • RP 428-4 D-Cinema Distribution Master - Audio File Format and Delivery Constraints • RP 428-5 D-Cinema Distribution Master - Mapping of Images into Constrained Tag Image File • RP 428-6 D-Cinema Distribution Master - Digital Leader • RP 431-2 D-Cinema Quality - Reference Projector and Environment • ST 336 Data Encoding Protocol Using Key-Length-Value • ST 337-1 Material Exchange Format (MXF) - File Format Specification • ST 377-4 MXF Multichannel Audio Labeling Framework • ST 379-1 Material Exchange Format (MXF) - MXF Generic Container • ST 379-2 For Television - Material Exchange Format (MXF) - MXF Constrained Generic Container • ST 382 Material Exchange Format - Mapping AES3 and Broadcast Wave Audio into the MXF Generic Container • ST 390 Material Exchange Format (MXF) - Specialized Operational Pattern OP-Atom (Simplified Representation of a Single Item) • ST 400 SMPTE Labels Structure • ST 410 Material Exchange Format - Generic Stream Partition • ST 422 Material Exchange Format - Mapping JPEG 2000 Codestreams into the MXF Generic Container • ST 427 Link Encryption for 1.5 Gb/s Serial Digital Interface • ST 428-1 D-Cinema Distribution Master (DCDM) - Image Characteristics • ST 428-2 D-Cinema Distribution Master - Audio Characteristics • ST 428-7 Digital Cinema Distribution Master - Subtitle • ST 428-9 D-Cinema Distribution Master - Image Pixel Structure Level 3 - Serial Digital Interface Signal Formatting • ST 428-10 D-Cinema Distribution Master - Closed Caption and Closed Subtitle • ST 428-11 Additional Frame Rates for D-Cinema • ST 428-12 D-Cinema Distribution Master Common Audio Channels and Soundfield Groups • ST 428-19 D-Cinema Distribution Master - Additional Frame Rates Level AFR2 and Level AFR4 - Serial Digital Interface Signal Formatting • ST 428-21 Archive Frame Rates for D-Cinema • ST 429-2 D-Cinema Packaging - DCP Operational Constraints • ST 429-3 D-Cinema Packaging - Sound and Picture Track File • ST 429-4 D-Cinema Packaging - MXF JPEG 2000 Application • ST 429-5 D-Cinema Packaging - Timed Text Track File • ST 429-6 D-Cinema Packaging - MXF Track File Essence Encryption • ST 429-7 D-Cinema Packaging - Composition Playlist • ST 429-8 D-Cinema Packaging - Packing List • ST 429-9 D-Cinema Packaging - Asset Mapping and File Segmentation • ST 429-10 D-Cinema Packaging - Stereoscopic Picture Track File • ST 429-12 D-Cinema Packaging - Caption and Closed Subtitle • ST 429-13 D-Cinema Packaging - DCP Operational Constraints for Additional Frame Rates • ST 429-14 D-Cinema Packaging - Aux Data Track File • ST 429-16 Additional Composition Metadata and Guidelines • ST 430-1 D-Cinema Operations - Key Delivery Message • ST 430-2 D-Cinema Operations - Digital Certificate • ST 430-3 D-Cinema Operations - Generic Extra-Theater Message Format • ST 430-4 D-Cinema Operations - Log Record Format Specification • ST 430-5 D-Cinema Packaging - Security Log Event Class and Constraints • ST 430-6 D-Cinema Operations - Auditorium Security Messages for Intra-Theater Communications • ST 430-9 D-Cinema Operations - Key Delivery Bundle • ST 430-10 D-Cinema Operations - Auxiliary Content Synchronization Protocol • ST 430-11 D-Cinema Operations - Auxiliary Resource Presentation List • ST 430-12 D-Cinema Operations - FSK Synchronization Signal • ST 430-14 D-Cinema Operations - Digital Sync Signal and Aux Data Transfer Protocol • ST 430-15 D-Cinema Operations - Facility List Message Exchange Protocol • ST 430-16 D-Cinema Operations - Extended Facility List Message • ST 431-1 D-Cinema Quality - Screen Luminance Level, Chromaticity and Uniformity • ST 433 D-Cinema - XML Data Types

References

  1. ↑ DCI (home page)
  2. ↑ Stereoscopic DC (PDF) (addendum), DCI .
  3. ↑ Cohen, David S (2007-04-15). "DCI announces digital, 3-D specs". Variety. Retrieved 2017-06-10.
  4. ↑ DCSS Version 1.3 (PDF), DCI, 2018-06-27 .
  5. ↑ High Frame Rates Digital Cinema Recommended Practice, DCI .
  6. ↑ DCinemaToday
  7. ↑ "Digital Cinema Initiatives, LLC Collection". Academy Film Archive.

Bibliography

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