Sustainability of Digital Formats
Planning for Library of Congress Collections
Sustainability of Digital Formats
|
|
|
|
| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | ISO/IEC 14496-2:2004. Information technology -- Coding of audio-visual objects -- Part 2: Visual (formal name) MPEG-4, Visual Coding (common name) |
| Description | Compression encoding for video identical to ITU-T (International Telecommunications Union-Telecommunication Standardization Sector) recommendation H.263. MPEG-4_AVC based on H.264 is a sibling that appears to be more widely adopted. In order to distinguish the two, technical writers sometimes call this encoding MPEG-4 video and the other H.264 video. From the specification: "The full syntax allows coding of rectangular as well as arbitrarily shaped video objects in a scene. Furthermore, the syntax supports both nonscalable coding and scalable coding. Thus it becomes possible to handle normal scalabilities as well as object based scalabilities. The scalability syntax enables the reconstruction of useful video from pieces of a total bitstream. This is achieved by structuring the total bitstream in two or more layers, starting from a standalone base layer and adding a number of enhancement layers." The specification also describes many additional elements. MPEG-4_V profiles (some of which are listed as subtypes below) are defined in terms of bitstream characteristics. They relate to the conformance of players, and the profiles are generally given the name of the most complicated object type that a player supports. |
| Production phase | Generally a final-state (end-user delivery) format. |
| Relationship to other formats | |
| Other | Identical to the ITU-T standard H.263 |
| Used by | MPEG-4 File Format, Version 1, with Visual Encoding, not documented at this time |
| Used by | MP4_FF_2_V, MPEG-4 File Format, Version 2, with Visual Coding (All Profiles) |
| Used by | QTV_MP4_V, QuickTime Video, MPEG-4 Visual Coding |
| Used by | Other file wrappers, not documented here |
| Has subtype | MPEG-4_V_SP, MPEG-4 Visual Coding, Simple Profile |
| Has subtype | MPEG-4_V_SSP, MPEG-4 Visual Coding, Simple Scalable Profile |
| Has subtype | MPEG-4_V_ASP, MPEG-4 Visual Coding, Advanced Simple Profile |
| Has subtype | MPEG-4_V_CP, MPEG-4 Visual Coding, Core Profile |
| Has subtype | MPEG-4_V_MP, MPEG-4 Visual Coding, Main Profile |
| Has subtype | MPEG-4_V_SStP, MPEG-4 Visual Coding, Simple Studio Profile |
| Has subtype | MPEG-4 Visual Coding, Additional Profiles, not documented here |
| LC experience or existing holdings | The content produced by the NDIIPP partnership project with SCOLA consists of foreign television news broadcasts in MP4_FF_2_V, MPEG-4 File Format, V.2, with Visual Encoding. |
| LC preference |
| Disclosure | Open standard. Developed by ISO technical program JTC 1/SC 29 (WG11), aka the Motion Picture Experts Group (MPEG). See http://www.iso.org/iso/en/CatalogueListPage.CatalogueList?COMMID=148&scopelist=PROGRAMME. |
| Documentation | ISO/IEC 14496-2:2004. Information technology -- Coding of audio-visual objects -- Part 2: Visual; ISO/IEC 14496-2:2004/Cor 1:2004; ISO/IEC 14496-2:2004/Amd 1:2004. Error resilient simple scalable profile. These specifications supercede earlier versions. |
| Adoption | As of 2005, there appears to be increasing adoption of MPEG-4_AVC, Advanced Video Coding (Part 10), based on ITU-T H.264, with improved capabilities. There is no evidence of any extensive or increasing use of MPEG-4 Video Coding (Part 2). See also MP4_FF_2. The specifications for the video-capable iPod introduced by Apple in late 2005 state that device will play MPEG-4 Video in the Simple Profile, i.e., MPEG-4_V_SP. |
| Licensing and patent claims | See MP4_FF_2. |
| Transparency | Depends upon algorithms and tools to read; will require sophistication to build tools. |
| Self-documentation | Pertains to the file format; see MP4_FF_2. |
| External dependencies | None |
| Technical protection considerations | Pertains to the file format; see MP4_FF_2. |
| Video elements | |
| Normal rendering | Good support. |
| Clarity (support for high image resolution) | Moderate to very good, given that sampling is limited to 4:2:0 (in contrast, MPEG-2 has a 4:2:2 profile), and that MPEG-4 is a format for compression. Both progressive and interlaced video are supported, at resolutions from sub-QCIF to HDTV.1 The outcome will depend on the type and extent of compression, and the encoder used. MPEG-4_AVC (MPEG-4 Advanced Video Coding, part 10) is more efficient than the Visual Coding (part 2) described on this page; MPEG-4_AVC provides better quality at the same data rate, or equal quality at a lower data rate. |
| Functionality beyond normal video rendering | The specification discusses features like composition (the mixing or matrixing of tracks), random access, and fragmented movie files. |
| Sound elements | |
| Normal rendering | Not relevant; see MP4_FF_2. |
| Fidelity (support for high audio resolution) | Not relevant; see MP4_FF_2. |
| Support for multiple sound channels | Not relevant; see MP4_FF_2. |
| Functionality beyond normal rendering | Not relevant; see MP4_FF_2. |
| Tag type | Value | Note |
| Filename Extension | See MP4_FF_2 | |
| Internet Media Type | See MP4_FF_2 | |
| Magic numbers | See MP4_FF_2 | |
| Profile and level indicators | A list of codes for profile_and_level_indication for a variety of profiles and levels is provided in Annex G of Part 2 of the standard, pp. 454-55. | |
| File type brand | See note | Indicated in file wrapper and relates to "brands" defined in ISO_BMFF. Wrapping MPEG-4_V bitstreams in MP4_FF_1 would occasion the use of mp41; in MP4_FF_2, use mp42. See Part 15 of the standard, pp. 2-9, 13. |
| General | See MP4_FF_2. |
| History | MPEG began developing video compression standards in the 1980s. The group was founded by two men described by one commentator as "the fiery Leonardo Chiariglione (CSELT, Italy)" and "the peaceful Hiroshi Yasuda (JVC, Japan)." The initial motivation to develop MPEG-4 was to improve on the compression efficiency of MPEG-2 video, a standard for the transmission of video via broadcast, cable, and satellite that received its first approvals in 1994. This goal, however, was largely achieved by the ITU-T (International Telecommunications Union-Telecommunications Standardization Sector) Low Bit-Rate Encoding (LBC) group as they developed the H.263 standard at about the same time. The group working on MPEG-4, therefore, embraced the concepts expressed in H.263 and focused on additional functional requirements desired by those interested in delivering video via online networks, mobile audio-visual services, and the like. These additional requirements include an architecture for interactivity, the representation of natural and synthetic scenes, coding of concurrent data streams, robustness in error-prone environments, and scalability. Work on MPEG-4 began in 1995, with first approvals in 1998. Later efforts incorporated H.264 or MPEG-4_AVC, Advanced Video Coding, with the first ISO specification published in 2003. |
URLs
Print
From the ISO web site (http://www.iso.ch/ISO/en/):
• ISO/IEC 14496-2:2004 Information technology -- Coding of audio-visual objects -- Part 2: Visual
• ISO/IEC 14496-2:2004/Cor 1:2004
• ISO/IEC 14496-2:2004/Amd 1:2004 Error resilient simple scalable profile
Supercedes earlier versions.
URLs
See MP4_FF_2.
Print
See MP4_FF_2.
1 QCIF is Quarter Common Intermediate Format (176 pixels by 144 lines), CIF is Common Intermediate Format (352 pixels by 288 lines), while HDTV is High Definition Television (various, including 1920 pixels by 1080 lines).
|
|