MPEG-4
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MPEG-4 is a group of
international standard An international standard is a technical standard developed by one or more international standards organization, standards organizations. International standards are available for consideration and use worldwide. The most prominent such organizatio ...
s for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related technology agreed upon by the ISO/ IEC
Moving Picture Experts Group The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by International Organization for Standardization, ISO and International Electrotechnical Commission, IEC that sets standards for media coding, includ ...
(MPEG) (
ISO/IEC JTC 1 ISO/IEC JTC 1, entitled "Information technology", is a joint technical committee (JTC) of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Its purpose is to develop, maintain and pr ...
/SC29/WG11) under the formal standard ISO/IEC 14496 – ''Coding of audio-visual objects''. Uses of MPEG-4 include compression of audiovisual data for Internet video and CD distribution, voice (
telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into ele ...
,
videophone Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio signal, audio and video signals by people in different locations for Real-time, real time communication. ...
) and
broadcast Broadcasting is the distribution (business), distribution of sound, audio or video content to a dispersed audience via any electronic medium (communication), mass communications medium, but typically one using the electromagnetic spectrum (radio ...
television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of Transmission (telecommunications), television transmission. Television ...
applications. The MPEG-4 standard was developed by a group led by Touradj Ebrahimi (later the
JPEG JPEG ( ) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image ...
president) and Fernando Pereira.


Background

MPEG-4 absorbs many of the features of
MPEG-1 MPEG-1 is a Technical standard, standard for lossy compression of video and Audio frequency, audio. It is designed to compress VHS-quality raw digital video and CD audio down to about 1.5 Mbit/s (26:1 and 6:1 compression ratios respectively) wit ...
and
MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic video coding format, coding of moving pictures and associated audio information". It describes a combination of Lossy compression, lossy video compression and ...
and other related standards, adding new features such as (extended)
VRML VRML (Virtual Reality Modeling Language, pronounced ''vermal'' or by its initials, originally—before 1995—known as the Virtual Reality Markup Language) is a standard file format A file format is a Computer standard, standard way tha ...
support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for externally specified
Digital Rights Management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted works. ...
and various types of interactivity. AAC (Advanced Audio Coding) was standardized as an adjunct to MPEG-2 (as Part 1) before MPEG-4 was issued. MPEG-4 is still an evolving standard and is divided into a number of parts. Companies promoting MPEG-4 compatibility do not always clearly state which "part" level compatibility they are referring to. The key parts to be aware of are
MPEG-4 Part 2 MPEG-4 Part 2, MPEG-4 Visual (formally International Organization for Standardization, ISO/International Electrotechnical Commission, IEC 14496-2) is a video compression format developed by the Moving Picture Experts Group (MPEG). It belongs to the ...
(including Advanced Simple Profile, used by codecs such as DivX, Xvid, Nero Digital and 3ivx and by
QuickTime QuickTime is an extensible multimedia framework A multimedia framework is a software framework that handles Electronic media, media on a computer and through a network. A good multimedia framework offers an intuitive Application programming ...
6) and MPEG-4 part 10 (MPEG-4 AVC/ H.264 or Advanced Video Coding, used by the x264 encoder, Nero Digital AVC, QuickTime 7, and
high-definition video High-definition video (HD video) is video of higher display resolution, resolution and quality than Standard-definition television, standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image wit ...
media like
Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a Digital media, digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and c ...
). Most of the features included in MPEG-4 are left to individual developers to decide whether or not to implement. This means that there are probably no complete implementations of the entire MPEG-4 set of standards. To deal with this, the standard includes the concept of "profiles" and "levels", allowing a specific set of capabilities to be defined in a manner appropriate for a subset of applications. Initially, MPEG-4 was aimed primarily at low-
bit-rate In telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves ...
video communications; however, its scope as a multimedia coding standard was later expanded. MPEG-4 is efficient across a variety of bit rates ranging from a few kilobits per second to tens of megabits per second. MPEG-4 provides the following functions: * Improved coding efficiency over MPEG-2 * Ability to encode mixed media data (video, audio, speech) * Error resilience to enable robust transmission * Ability to interact with the audio-visual scene generated at the receiver


Overview

MPEG-4 provides a series of technologies for developers, for various service-providers and for end users: * MPEG-4 enables different software and hardware developers to create multimedia objects possessing better abilities of adaptability and flexibility to improve the quality of such services and technologies as digital television,
animation Animation is a method by which image, still figures are manipulated to appear as Motion picture, moving images. In traditional animation, images are drawn or painted by hand on transparent cel, celluloid sheets to be photographed and exhibited ...
graphics, the World Wide Web and their extensions. * Data network providers can use MPEG-4 for data transparency. With the help of standard procedures, MPEG-4 data can be interpreted and transformed into other signal types compatible with any available network. * The MPEG-4 format provides end users with a wide range of interaction with various animated objects. * Standardized
Digital Rights Management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted works. ...
signaling, otherwise known in the MPEG community as Intellectual Property Management and Protection (IPMP). The MPEG-4 format can perform various functions, among which might be the following: * Multiplexes and synchronizes data, associated with media objects, in such a way that they can be efficiently transported further via network channels. * Interaction with the audio-visual scene, which is formed on the side of the receiver.


Profiles and Levels

MPEG-4 provides a large and rich set of tools for encoding. Subsets of the MPEG-4 tool sets have been provided for use in specific applications. These subsets, called 'Profiles', limit the size of the tool set a decoder is required to implement. In order to restrict computational complexity, one or more 'Levels' are set for each Profile. A Profile and Level combination allows:. * A codec builder to implement only the subset of the standard needed, while maintaining interworking with other MPEG-4 devices that implement the same combination. * Checking whether MPEG-4 devices comply with the standard, referred to as conformance testing.


MPEG-4 Parts

MPEG-4 consists of several standards—termed "parts"—including the following (each part covers a certain aspect of the whole specification): Profiles are also defined within the individual "parts", so an implementation of a part is ordinarily not an implementation of an entire part.
MPEG-1 MPEG-1 is a Technical standard, standard for lossy compression of video and Audio frequency, audio. It is designed to compress VHS-quality raw digital video and CD audio down to about 1.5 Mbit/s (26:1 and 6:1 compression ratios respectively) wit ...
,
MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic video coding format, coding of moving pictures and associated audio information". It describes a combination of Lossy compression, lossy video compression and ...
, MPEG-7 and MPEG-21 are other suites of MPEG standards.


MPEG-4 Levels

The low profile levels are part of the MPEG-4 video encoding/decoding constraints and are compatible with the older ITU H.261 standard, also compatible with former analog TV standards for broadcast and records (such as NTSC or PAL video). The ASP profile in its highest level is suitable for most usual DVD medias and players or for many online video sites, but not for Blu-ray records or online HD video contents. More advanced profiles for HD media have been defined later in the AVC profile, which is functionally identical to the ITU H.264 standard but are now also integrated in MPEG-4 Part 10 (see H.264/MPEG-4 AVC for the list of defined levels in this AVC profile).


Licensing

MPEG-4 contains patented technologies, the use of which requires licensing in countries that acknowledge software algorithm patents. Over two dozen companies claim to have patents covering MPEG-4.
MPEG LA MPEG LA is an American company based in Denver, Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as ...
licenses patents required for MPEG-4 Part 2 Visual from a wide range of companies (audio is licensed separately) and lists all of its licensors and licensees on the site. New licenses for MPEG-4 System patents are under development and no new licenses are being offered while holders of its old MPEG-4 Systems license are still covered under the terms of that license for the patents listed
MPEG LA – Patent List
. The majority of patents used for the MPEG-4 Visual format are held by three Japanese companies:
Mitsubishi Electric , established on 15 January 1921, is a Japanese Multinational corporation, multinational electronics and electrical equipment manufacturing company headquartered in Tokyo, Japan. It is one of the core companies of Mitsubishi. The products from ...
(255 patents),
Hitachi () is a Japanese multinational conglomerate corporation headquartered in Chiyoda, Tokyo, Japan. It is the parent company of the Hitachi Group (''Hitachi Gurūpu'') and had formed part of the Nissan ''zaibatsu'' and later DKB Group and Fuy ...
(206 patents), and
Panasonic formerly between 1935 and 2008 and the first incarnation of between 2008 and 2022, is a major Japanese multinational corporation, multinational Conglomerate (company), conglomerate corporation, headquartered in Kadoma, Osaka, Kadoma, Osaka P ...
(200 patents).


See also

*
MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by International Organization for Standardization, ISO and International Electrotechnical Commission, IEC that sets standards for media coding, includ ...
* MPEG-4 Structured Audio *
MPEG-4 SLS MPEG-4 SLS, or MPEG-4 Scalable to Lossless as per International Organization for Standardization, ISO/International Electrotechnical Commission, IEC 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding), is an extension to the MPEG-4 Part 3 (MPEG-4 ...
*
ISO/IEC JTC 1/SC 29 ISO/IEC JTC 1/SC 29, entitled ''Coding of audio, picture, multimedia and hypermedia information'', is a standardization subcommittee of the Joint Technical Committee ISO/IEC JTC 1 of the International Organization for Standardization (ISO) and the I ...


References


External links


MPEG-4 vs AVC/H.264 vs MP4. What is the difference?


at the MPEG Official Website * *
JM MPEG-4 AVC /H.264 Reference Code

OpenIPMP: Open Source DRM Project for MPEG-4
{{DEFAULTSORT:Mpeg-4 Audio codecs ISO/IEC standards Video codecs Videotelephony