MPEG-4 Architecture & Compressions
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[edit] The Promise of Non-Proprietary Media Architectures (MPEG-4)
It is no surprise that industry players actively engaged in the research and development of digital media architectures and file formats aggressively promote their proprietary technologies, encouraging content providers and end-users to embrace their tools and players. Like most private and public sector entities, the University’s various departments each subscribe to different technologies, depending on their needs and their support and maintenance resources.
Because we are witnessing the emergence and wide adoption of the MPEG-4 standardized, non-proprietary media architecture across multiple profiles and consumption points of the New Media Ecosystem, there is an opportunity for the University to promote common methods of content preparation and distribution. The tools and best practices for exploiting the MPEG-4 architecture are either already in place or emerging quickly.
Since many existing installations of servers and media players have been updated to accommodate the MPEG-4 media architecture, adoption of a system-wide standard does not necessarily demand the purchase and implementation of new equipment.
The threat to the University, if some consistency is not promoted throughout the delivery of digital media through networks and the Internet, will be a proliferation of files and formats which cannot be played, cannot be shared, and (where appropriate) cannot be re-purposed. None of these conditions are acceptable within an academic institution (except where information must be protected for financial, privacy, patent, copyright, unpublished research, security or other similar circumstances).
[edit] ...MPEG-4 Development
Within the International Organization for Standardization (ISO), a working group was established in the late 1990s. Known as the “Moving Pictures Experts Group”, they defined an “area of work” intended to develop international standards for...
- compression,
- de-compression,
- processing, and
- coded representation
...of moving pictures, audio, and their combination, in order to satisfy a wide variety of applications.
Beginning in the early 1990s, the MPEG Working Group developed MPEG-1, followed by MPEG-2. As of 2000, they released the specification for MPEG-4, an international, standardized media architecture:
Although unrelated to media architectures and the playout of audio or video content, the MPEG Working Group is also working on standards for metadata and tracking the life cycles of intellectual content through the MPEG-7 and MPEG-21 areas of work:
[edit] ...The Advantage of a Standard
In excerpts from a description of MPEG-4, as published by Apple Computer, the architecture…
- "…provides an open playing field. As an open, industry standard, anyone can create an MPEG-4 player or encoder that will work with other manufacturer’s devices."
- "Media companies save time and resources by encoding material once for playback everywhere. No longer will content providers need to encode, host, and store media in multiple formats. Instead, a single format can reach a broad audience equipped with playback devices from not one, but a multitude of companies across a wide array of platforms."
- "Finally, content creators have a format that will reach a global audience and will stand the test of time. While other formats and versions come and go, MPEG-4 will safeguard multimedia content for a secure future."
- "Like MPEG-1 and MPEG-2 previously did for CD-ROMs and DVDs, MPEG-4 promises to create interoperability for video delivered over the Internet and other distribution channels. MPEG-4 will play back on many different devices, from satellite television to wireless devices."
- "To ensure that different products that use MPEG-4 each implement the standard in the same way, Apple, together with Cisco, IBM, Kasenna, Philips and Sun Microsystems, formed the Internet Streaming Media Alliance (ISMA). Other participants include AOL Time Warner, Dolby Laboratories, Lucent Technologies, National Semiconductor, Sony, and 25 other companies. The ISMA defines profiles that companies implement to ensure interoperability."
- "In addition to being adopted by many of the Internet’s premiere content providers, the MPEG-4 standard is receiving tremendous support in other industries. For example, the new standards for high-quality multimedia on wireless devices, 3GPP (3rd Generation Partnership Project) and 3GPP2 (3rd Generation Partnership Project 2), are based on the solid foundation of MPEG-4."
It appears that the MPEG-4 architecture, as an international standard, will be able to support the New Media Ecosystem that educational institutions, such as the University of Utah, seek to embrace. This position is further supported by a recent commentary written for Streamingmedia.com by Charlie Oppenheier (Sept 4, 2007) entitled H.264 Video--The Format of Convergence.
- Fifteen years ago, I remember talking with colleagues about a future world of multimedia where our TVs, video disc players, computers, camcorders, and portable media players would all share video using common digital formats, media, and connections. Today, we’re finally at a point where we can see the pieces coming together to form a naturally expanding ecosystem based on a common digital video encoding format: H.264.
- A common encoding format enables content created for one type of device to be easily delivered or adapted to another.
- ...A new internationally standardized encoding format known as H.264 (also known as AVC) has emerged and is poised to be a ubiquitous standard format. H.264 is already supported by many consumer electronics products, professional production tools, smartphones, wireless services, and IP set-top-boxes (STB). Most recently, Adobe announced full support for H.264 as a native format for Flash, and Google plans to transcode all of its YouTube content to H.264.
- It’s the combination of H.264 standardization, support by the leading Internet players and adoption by professional and consumer products and services, all added together, that creates a safe and stable cross-platform video format for all key platforms. With support from PCs and consumer products tied together by H.264-compliant professional products and internet delivery platforms, we will see rapid innovation leading to exciting new products and services.
- http://www.streamingmedia.com/article.asp?id=9695&page=1
[edit] ...Underlying Architecture of MPEG-4
The MPEG-4 architecture departs from many of its predecessors because of its underlying structure. It is not simply a flat stream of composited video or audio data. Instead, it accommodates individual media components, referred to as “Media Objects.” An object is a specific event or media item, such as text, image, video, audio, 2D and 3D animation, or interactivity. Individual objects are described as “Primitives” and may be acquired as either “Natural”objects (recording visuals or audio) or “Synthetic” objects (generated by software and hardware tools). When combined and synchronized, these discrete primitives form a “Compound Media Object” that contains multiple “Scenes.” Both primitives and compounds can be delivered across any of the New Media Ecosystem channels and consumption devices, each object encoded with the most appropriate codec, each object delivered at its own data rate or bit rate.
[edit] ...Conformance Points of MPEG-4
Because of its standardization and non-proprietary nature, MPEG-4 and its industry participants have defined what are known as “Conformance Points.” The manner in which content is encoded and delivered matches pre-specified degrees of complexity, otherwise called “Profiles.” Within a Profile are various “Level” descriptions, spelled out as individual parameter settings (resolutions, sizes, etc.). If media objects are distributed, matching established Levels within Profiles, then a Conformance Point has been achieved. More generally, the industry states that “Interoperability” has been realized.
Industry-wide Interoperability is the goal, without the proprietary impediments often associated with company-specific implementations of media architectures, codecs and players (such as WindowsMedia, Real Media or QuickTime).
[edit] ...AVC-Advanced Video Codec (H.264)
Ratified as part of the MPEG-4 standard is “Part 10,” also known as “AVC-Advanced Video Codec” or more popularly, “H.264.” With H.264, media objects can be encoded for optimal performance within any Profile and Level, playable from cell phones to High Definition broadcast television. With one architecture, any Conformance Point can be realized at the consumer’s Point of Presence with whatever reception device they control and interact with. More importantly, the Quality of Service is enhanced because the Profiles within H.264 deliver superior quality media, but at a third to half the data rates associated with earlier architectures, and with up to four times the frame size. A notable example is the ability to deliver digital video signals to cable and satellite subscribers using half the normal bandwidth of MPEG-2 encoded signals, but with perceptually improved quality. Examples of frame sizes, frame rates, and representative data rates are displayed in the following table of selected Conformance Points:
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