MPEG-4, introduced in late 1998, is the designation for a group of audio and video coding standards and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG). The primary uses for the MPEG-4 standard are web (streaming media) and CD distribution, conversational (videophone), and broadcast television.

MPEG-4 absorbs many of the features of MPEG-1 and MPEG-2 and other related standards, adding new features such as (extended) VRML support for 3D rendering, object-oriented composite files (including audio, video and VRML (Virtual Reality Modeling Language) objects), support for externally-specified Digital Rights Management and various types of interactivity.

Most of the features included in MPEG-4 are left to individual developers to decide whether to implement them. 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.

MPEG-4 Parts

MPEG-4 consists of several standards—termed "parts"—including the following:

• Part 1 (ISO/IEC 14496-1): Systems: Describes synchronization and multiplexing of video and audio.
• Part 2 (ISO/IEC 14496-2): Visual: A compression codec for visual data (video, still textures, synthetic images, etc.). One of the many "profiles" in Part 2 is the Advanced Simple Profile (ASP).
• Part 3 (ISO/IEC 14496-3): Audio: A set of compression codecs for perceptual coding of audio signals, including some variations of Advanced Audio (AAC) Coding as well as other audio/speech coding tools.
• Part 4 (ISO/IEC 14496-4): Conformance: Describes procedures for testing conformance to other parts of the standard.
• Part 5 (ISO/IEC 14496-5): Reference Software: Provides software for demonstrating and clarifying the other parts of the standard.
• Part 6 (ISO/IEC 14496-6): Delivery Multimedia Integration Framework (DMIF ).
• Part 7 (ISO/IEC 14496-7): Optimized Reference Software: Provides examples of how to make improved implementations (e.g., in relation to Part 5).
• Part 8 (ISO/IEC 14496-8): Carriage on IP networks: Specifies a method to carry MPEG-4 content on IP networks.
• Part 9 (ISO/IEC 14496-9): Reference Hardware: Provides hardware designs for demonstrating how to implement the other parts of the standard.
• Part 10 (ISO/IEC 14496-10): Advanced Video Coding: A codec for video signals which is also called AVC and is technically identical to the ITU-T H.264 standard.
• Part 12 (ISO/IEC 14496-12): ISO Base Media File Format: A file format for storing media content.
• Part 13 (ISO/IEC 14496-13): Intellectual Property Management and Protection (IPMP) Extensions.
• Part 14 (ISO/IEC 14496-14): MPEG-4 File Format: The designated container file format for MPEG-4 content, which is based on Part 12.
• Part 15 (ISO/IEC 14496-15): AVC File Format: For storage of Part 10 video based on Part 12.
• Part 16 (ISO/IEC 14496-16): Animation Framework eXtension (AFX).
• Part 17 (ISO/IEC 14496-17): Timed Text subtitle format (not yet finished - reached "FCD" stage in January 2005).
• Part 18 (ISO/IEC 14496-18): Font Compression and Streaming (for OpenType fonts).
• Part 19 (ISO/IEC 14496-19): Synthesized Texture Stream.
• Part 20 (ISO/IEC 14496-20): Lightweight Scene Representation (LASeR) (not yet finished - reached "FCD" stage in January 2005).
• Part 21 (ISO/IEC 14496-21): MPEG-J Extension for Rendering (not yet finished - reached "CD" stage in January 2005).

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-2, MPEG-7 and MPEG-21 are other suites of MPEG standards.

See also

• Advanced Audio Coding (AAC)
• XviD
• DivX
• 3ivx
• Nero Digital
• SBR

External link

• MPEG-4: The Next Generation
• MPEG-4 Audio: AAC
• MPEG Industry Forum MPEG-4 page
• Moving Picture Experts Group (MPEG) Official Website