MPEG-4: Difference between revisions

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'''MPEG-4''', introduced in [[1998]], is the [[name|designation]] for a group of [[audio]] and [[video]] [[coding]] [[standard|standards]] agreed upon by [[MPEG]] (Moving Picture Experts Group). MPEG-4 is primarily designed to handle low [[bit rate]] content, from 4800 bit/s to approximately 4 Mbit/s. The primary uses for the MPEG-4 standard are web ([[streaming media]]) and [[Compact disc|CD]] [[distribution]], conversational ([[videophone]]) uses, and [[broadcast]] [[television]].  
'''MPEG-4''', introduced in 1998, is the designation for a group of audio and video coding standards agreed upon by the [[MPEG]] (Moving Picture Experts Group). MPEG-4 is primarily designed to handle low bit rate content, from 4800 bit/s to approximately 4 Mbit/s. The primary uses for the MPEG-4 standard are web (streaming media) and Compact disc distribution, conversational (videophone) uses, and broadcast television.  


MPEG-4 absorbs many of the features of [[MPEG-1]] and [[MPEG-2]], adding new features such as (extended) [[VRML]] support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for [[Digital Rights Management]] and various types of interactivity.
MPEG-4 absorbs many of the features of [[MPEG-1]] and [[MPEG-2]], adding new features such as (extended) VRML support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for Digital Rights Management and various types of interactivity.


Most of the features included in MPEG-4 are left to individual [[developer]]s to implement. This means that there are very few complete implementations of the MPEG-4 standard. Anticipating this, the developers added the concept of "Profiles," allowing various capabilities to be grouped together.
Most of the features included in MPEG-4 are left to individual developers to implement. This means that there are very few complete implementations of the MPEG-4 standard. Anticipating this, the developers added the concept of "Profiles," allowing various capabilities to be grouped together.


MPEG-4 consists of several standards—termed "Layers"—as follows.
MPEG-4 consists of several standards — termed "Layers" — as follows.


*''Layer 1'' describes synchronization and multiplexing of video and audio.
* ''Layer 1'' describes synchronization and multiplexing of video and audio.
*''Layer 2'' is a compression codec for video signals.
* ''Layer 2'' is a compression codec for video signals.
*''Layer 3'' is a compression codec for perceptual coding of audio signals.
* ''Layer 3'' is a compression codec for perceptual coding of audio signals.
*''Layer 4'' describes procedures for testing compliance.
* ''Layer 4'' describes procedures for testing compliance.
*''Layer 5'' describes systems for Software simulation.
* ''Layer 5'' describes systems for Software simulation.
*''Layer 6'' describes Delivery Multimedia Integration Framework (DMIF).
* ''Layer 6'' describes Delivery Multimedia Integration Framework (DMIF).
*''Layer 10'' is an advanced codec for video signals also called [[H.264]].
* ''Layer 10'' is an advanced codec for video signals also called [[H.264]].


The designated container for MPEG-4 content is [[MP4]], which was also defined within MPEG-4.
The designated container for MPEG-4 content is [[MP4]], which was also defined within MPEG-4.


[[MPEG-7]] and [[MPEG-21]] serve other purposes.
MPEG-7 and MPEG-21 serve other purposes.


====See====
====See====

Revision as of 20:43, 30 March 2005

MPEG-4, introduced in 1998, is the designation for a group of audio and video coding standards agreed upon by the MPEG (Moving Picture Experts Group). MPEG-4 is primarily designed to handle low bit rate content, from 4800 bit/s to approximately 4 Mbit/s. The primary uses for the MPEG-4 standard are web (streaming media) and Compact disc distribution, conversational (videophone) uses, and broadcast television.

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

Most of the features included in MPEG-4 are left to individual developers to implement. This means that there are very few complete implementations of the MPEG-4 standard. Anticipating this, the developers added the concept of "Profiles," allowing various capabilities to be grouped together.

MPEG-4 consists of several standards — termed "Layers" — as follows.

  • Layer 1 describes synchronization and multiplexing of video and audio.
  • Layer 2 is a compression codec for video signals.
  • Layer 3 is a compression codec for perceptual coding of audio signals.
  • Layer 4 describes procedures for testing compliance.
  • Layer 5 describes systems for Software simulation.
  • Layer 6 describes Delivery Multimedia Integration Framework (DMIF).
  • Layer 10 is an advanced codec for video signals also called H.264.

The designated container for MPEG-4 content is MP4, which was also defined within MPEG-4.

MPEG-7 and MPEG-21 serve other purposes.

See