Sustainability of Digital Formats
Planning for Library of Congress Collections
Sustainability of Digital Formats
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | Digital Cinema Initiative Package (DCP) Described in the Digital Cinema System Specification v1.0, July 20, 2005 |
| Description | The DCP is a set of encrypted files representing digital moving image content packaged for shipment to theaters. The DCP is based on the DCDM_1_0, and its files or tracks contain images, audio, subpictures and/or timed text, and auxiliary data. Only the image track is compressed in the DCP; see Notes below. The DCP consists of the package itself (with all of the track files) and a separate XML Packing List that identifies and includes file-integrity checks ("hash") for each file, as well as a public key and digital signature that is part of the overall security system. The overall Digital Cinema Initiative (DCI) system specification defines a life cycle in which content exists in a succession of states: • DSM. Content originates as a Digital Source Master; format selected by producer, not specified • DCDM_1_0. Content is shaped into a Digital Cinema Distribution Master, covered by the specification • DCP. Content is compressed and encrypted for transport to the theater as a Digital Cinema Package, covered by the specification • DCDM (again). Content is unpackaged, decrypted, and decompressed at the theater for exhibition. The overall system specification devotes considerable space to the required capabilities for playback and projection systems in theaters, and regarding security and content protection. |
| Production phase | Final-state for use in a distribution chain; may also serve as a middle-state format for archiving. |
| Relationship to other formats | |
| May contain | MXF_JP2, MXF with JPEG 2000 in Generic Container DCP image track(s) |
| May contain | Other track(s) not documented at this time; see also DCDM_1_0 |
| [Is transport format for] | DCDM_1_0, Digital Cinema Initiative Distribution Master (DCDM), Version 1.0 |
| Has earlier versions | Draft versions of overall specification: Digital Cinema System Specification v4.2 (August 2004), v4.3 (December 2004), v5.0 (March 2005), v5.1 (April 2005), and v5.2 (June 2005), not documented at this time |
| LC experience or existing holdings | None |
| LC preference | None |
| Disclosure | Fully disclosed. Developed by the Digital Cinema Initiatives. [See Notes below for information on the relationship of the DCI to the SMPTE DC28 standards-development process.] |
| Documentation | The DCP is one element defined in the Digital Cinema System Specification v5.2, June 2005. The specification is accessible to members at the Digital Cinema Initiatives Web site. |
| Adoption | This format is still under development. |
| Licensing and patent claims | None identified. The specification includes a disclaimer: "Compliance with this document may require use of one or more features covered by proprietary rights . . . no position is taken by DCI with respect to the validity of any patent of other proprietary right." (p. vii) |
| Transparency | The Packing List will be transparent. The package itself will be compressed and encrypted and not transparent; like a ZIP file, the DCP exists to support the movement of data. |
| Self-documentation | The Packing List identifies each file, includes file-integrity checks ("hash") for each file, as well as a public key and digital signature that is part of the overall security system. |
| External dependencies | See DCDM_1_0 |
| Technical protection considerations | Employs a public-private key, signature based system. |
| Video elements | |
| Normal rendering for video | Not relevant; see DCDM_1_0 |
| Clarity (support for high image resolution) | Not relevant; see DCDM_1_0 |
| Functionality beyond normal video rendering | Not relevant; see DCDM_1_0 |
| Sound elements | |
| Normal rendering for sound | Not relevant; see DCDM_1_0 |
| Fidelity (support for high audio resolution) | Not relevant; see DCDM_1_0 |
| Support for multiple sound channels | Not relevant; see DCDM_1_0 |
| Functionality beyond sound normal rendering | Not investigated at this time. |
| Tag type | Value | Note |
| Filename Extension | Not applicable | |
| Internet Media Type | Not applicable | |
| Magic numbers | Not applicable |
| General | In the DCDM_1_0, the image track consists of uncompressed data mapped to the MXF Generic Container in accord with SMPTE standard 384M, using the frame wrapping method. In the DCP, the image track consists of lossy JPEG 2000 data mapped to the MXF Generic Container in accord with SMPTE standard 422M, and using JPEG 2000 codestreams conforming to J2K_C_Profile_3 (for 2K) and J2K_C_Profile_4 (for 4K). |
| History | From the Digital Cinema Initiatives Web site: "Digital Cinema Initiatives, LLC (DCI) was created in March 2002, as a joint venture of Disney, Fox, MGM, Paramount, Sony Pictures Entertainment, Universal and Warner Bros. Studios. DCI's primary purpose is to establish and document voluntary specifications for an open architecture for digital cinema that ensures a uniform and high level of technical performance, reliability and quality control. DCI will also facilitate the development of business plans and strategies to help spur deployment of digital cinema systems in movie theaters." The formal standardization of DCI specifications is being overseen by the SMPTE technology committee DC28, made up of four working groups preparing more than 20 separate items. The relationship of this to the Digital Cinema Initiative (and a European counterpart) was articulated in 2006 by the European Federation of Cinematographers: "The establishment of a new standard for the future digital cinema projection copy has been delegated to the SMPTE [DC28 technology committee]. Both DCI (Digital Cinema Initiatives) and EDCF-T (European Digital Cinema Forum - Technical Module) are input bodies towards SMPTE DC28. . . . Now that the DCI published their specifications it is to expect that the standardisation work at SMPTE will accelerate and it is possible that SMPTE may finalize the standard in less than a year from now." |
URLs
• See DCDM_1_0
Print
URLs
• European Federation of Cinematographers (http://www.imago.org/main/public_html/_htm_digital/)
Print
• Swartz, Charles S., editor. Understanding Digital Cinema: A Professional Handbook. Amsterdam; Boston: Focal Press, 2005. LCCN: 2004021603; ISBN: 0240806174.
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