...MPEG-4 Architecture & Compressions
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[edit] Overview--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.
If some consistency is not promoted throughout the delivery of digital media through networks and the Internet, the threat to the University will be a proliferation of files and formats that 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within an academic institution (except where information must be protected for financial, privacy, patent, copyright, unpublished research, security or other similar circumstances).
In the following sections, the MPEG-4 architecture is explained. As well, you may wish to consult a separate web page reviewing the MPEG Architecture (1 ,2 , MP3, 4, 7, 21) (authored by Media Solutions, University of Utah).
[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.
[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] MPEG-4 -- Internet Streaming and Synchronized Multimedia
- Quoted from an article entitled The MPEG Video Standards-from 1 to 21, authored by Larry Bouthillier, February 18, 2004, copyrighted to StreamingMedia.com.
- "Where MPEG2 was designed to scale up to broadcast and high-definition quality and operating requirements, MPEG4 goes the other way. It's designed to scale down – down to dial-up internet bandwidths and to tiny devices like cell phones and PDAs; as well as still remain viable for high-quality desktop streaming up to 1Mbps. MPEG4's AAC audio codec is the root of the MP4 file type, recently popularized by Apple's iTunes, among others."
- "But MPEG4 is much more than just an audio and video compression/decompression scheme. It's a container for all kinds of media objects (images, text, video, animation, interactive elements like buttons and image maps, etc.) and a way to choreograph them into a synchronized, interactive presentation. (see "Interactive Authoring for MPEG4" for more info). MPEG4 also has standard interfaces to allow plugging in a DRM scheme called Intellectual Property Management and Protection (IPMP)."
- "MPEG4 is still at the frontier of media technologies. The specification is extensive, and each vendor implements it in their own way. Try a variety of MPEG4 tools and you'll find lots of incompatibilities. But some are working to smooth the landscape. The Internet Streaming Media Association (ISMA) is an industry consortium dedicated to interoperability among MPEG4 products and services. Essentially, any implementation that's ISMA-compliant will work with any other."
[edit] MPEG-4 -- Authoring Interactivity
- The next iteration of MPEG-4 will embrace the ability to author interactivity between the various "Media Objects" that comprise the components of an individual MPEG-4 file. Presently, most MPEG-4 files in distribution are simple profiles, combining video and audio tracks in a linear playback. In order to author interactivity, the tools currently available are (as of 2006) in the same raw space as the original text-based authoring tools for creating HTML pages almost a decade ago. If the industry progresses as expected, then higher level, more WYSIWYG-based authoring tools will emerge along the same lines as perhaps a DreamWeaver for HTML or Flash for time-based, interactive media objects. For the present, Larry Bouthillier states in his article Creating Interactive Video With MPEG4 from streamingmedia.com (November 26, 2003) that "...working with interactive MPEG4 at this stage is a bit like running with scissors." The future holds promise, however.
- IBM is working an a java-based set of authoring tools for interactive MPEG-4, named the IBM Toolkit for MPEG-4. The toolkit and available documentation is available from IBM's website called alphaWorks.
- Several years ago, a company called iVAST, offered a set of tools for multimedia creation. According to a brochure, "iVAST's object-oriented MPEG-4 solutions support not only digital audio and video, but also 2D and 3D graphics -- creating interactive and personalized multimedia experiences." iVAST has since been bought out by another entity called DG2L whose primary focus is "...the ability to design, deliver and install end-to-end digital media delivery systems which can support any codec across any network to any device." The original authoring tool is defunct.
- Flash Video is using the proprietary video codec ON2 VP6 to deliver its video/audio linear media in combination with the Flash authoring environment to create interactivity. Announced at the 2007 National Association of Broadcasters trade show, Adobe unveiled its new Adobe Media Player and demonstrated the merging of high quality Flash Video playback with interactivity layers enabled by Flash. In light of the lack of user-ready authoring tools for MPEG-4, Adobe may successfully disrupt the MPEG-4 interactivity potential.
- Also announced at the 2007 National Association of Broadcasters trade show was Microsoft's Silverlight interactivity environment across multiple playback profiles. In extreme "beta" as of May 2007, we shall see what unfolds.
[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:
[edit] ...Embedded DRM
Digital and Intellectual Property Rights management and acknowledgements are fast becoming a legal necessity, in addition to being a professional courtesy. The MPEG-4 media architecture is capable of embedding the rights management metadata within the structure of MPEG-4 objects and streams. Use restrictions, permissible playouts, and payment information can accompany any media item as it journeys from server to server, computer to computer, set-top device to set-top device.
[edit] ...Player Neutrality
MPEG-4 objects are for the most part “Player Neutral.” If a device, set-top, desk-top, or portable device can play ISO Standard MPEG-4 scenes matching pre-established Profiles and Levels, then the player is ISO compliant. No longer must an end-user be forced to download a Real Player and a QuickTime Player and a WindowsMedia Player or some other player in order to experience and interact with content posted in one or several media architectures.
With an ISO compliant MPEG-4 file, an end-user may choose their preferred player (or one that is already pre-installed on a computer) and play the content. Both QuickTime and Real players are ISO MPEG-4 compliant and will play ISO MPEG-4 content.
Other players, such as the VLC Player from VideoLan, are cross-platform, universal players. To date, WindowsMedia Player will not play ISO MPEG-4 compliant content without the additional installation of third-party plug-ins or functionality. Microsoft continues to develop and deploy WindowsMedia versions of MPEG-4 (known as MS MPEG-4) as a proprietary spin-off of the ISO standard. The industry hopes for a change in attitude, which would happily mean any MPEG-4 content can be played through a very ubiquitous player, WIndowsMedia Player, on a majority of end-users’ computers or Consumption Point devices. If no change occurs, then other players, such as QuickTime 7 for Windows, VLC Player, and Real Player, will need to be downloaded and installed on Windows-based computers.
For Apple Macintosh computers, QuickTime 7 or greater, the VLC Player, or the latest Real Player will all play ISO compliant MPEG-4 files. Note that the WindowsMedia Player development for the Macintosh OS has been completely abandoned by Microsoft. A plug-in is offered by Telestream, called Flip4Mac, in order to play Windows Media movies within the QuickTime player. Currently, files encoded up to Windows Media 9 are playable. The component does not support content that is protected with Windows Media digital rights management (DRM). Free and Pro versions of the component, as well as other encoding tools, are available from their Flip4Mac website.
[edit] Resources to Learn More about MPEG-4
- MPEG-4 Overview from Wikipedia Article
- http://en.wikipedia.org/wiki/MPEG-4
- MPEG Architecture (1 ,2 , MP3, 4, 7, 21)(authored by Media Solutions, University of Utah)
- http://stream.uen.org/medsol/digvid/html/2B_mediaarchmpeg1.html
- MPEG Industry Forum
- http://www.m4if.org/
- MPEG Home Page (Motion Pictures Experts Group)
- http://www.chiariglione.org/mpeg/
- MPEG Video Standards - from 1 to 21, article by Larry Bouthillier, 18 Feb 2004
- http://www.streamingmedia.com/article.asp?id=8569&page=1&c=7
- MPEG-1, Overview of the Standard
- http://www.chiariglione.org/mpeg/standards/mpeg-1/mpeg-1.htm
- MPEG-2, Overview of the Standard
- http://www.chiariglione.org/mpeg/standards/mpeg-2/mpeg-2.htm
- Article about the challenge of using MPEG-2 compressed video in non-linear editing systems
- http://www.bmserver.net/Down_SW/Tech_Paper/Challenge_MPEG2_Eng.pdf
- MPEG-4, Overview of the Standard
- http://www.chiariglione.org/mpeg/standards/mpeg-4/mpeg-4.htm
- MPEG-4 User Frequently Asked Questions
- http://www.m4if.org/resources/mpeg4userfaq.php
- MPEG-4 User FAQs as PDF Document
- MPEG-4 Video Gallery
- http://www.apple.com/quicktime/gallery/mpeg4.html
- MPEG-4, Standard for Digital Media, from Apple (with valuable links)
- http://www.apple.com/mpeg4
- MPEG-4 Fact Sheet, from Apple
- http://a320.g.akamai.net/7/320/51/cad38f4a7f9b46/www.apple.com/mpeg4/pdf/MPEG4_v3.pdf
- MPEG-4 Fact Sheet, from Apple PDF
- MPEG-4
- IBM TECHNOLOGIES PLAYER & RESEARCH
- http://www.research.ibm.com/mpeg4/indexjs.htm
- MPEG-4, Article entitled "MPEG-4 Secrets" by John Watkinson
- http://broadcastengineering.primediabusiness.com/ar/broadcasting_mpeg_secrets/index.htm
- MPEG-4.Net, The Streaming Media Technology Resource
- http://www.mpeg4.net/
- MPEG-4
- Creating Interactive Video with MPEG-4, article by Larry Bouthilliear, November 26, 2003
- http://www.streamingmedia.com/r/printerfriendly.asp?id=8544
- Introduction to MPEG-4 Workshop (Media Solutions, University of Utah)
- http://stream.uen.org/medsol/digvid/html/MPEG4Workshop/index.html
- MPEG-7, Overview of the Standard (standard for metadata, not digital video)
- http://www.chiariglione.org/mpeg/standards/mpeg-7/mpeg-7.htm
- MPEG-21, Overview of the Standard (standard for metadata, not digital video)
- http://www.chiariglione.org/mpeg/standards/mpeg-21/mpeg-21.htm
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