MPEG-4: Difference between revisions

Revision as of 00:29, 18 October 2004

MPEG-4, introduced in 1998, is the designation for a group of audio and video coding 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 CD 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.

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-'''MPEG-4''' is ISO's stadard for encoding audio, video and other content.
+'''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 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.
+MPEG-4 consists of several standards&mdash;termed "Layers"&mdash;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.
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