MPEG-4
MPEG-4, introduced in 1998, is the designation for a group of audio and video coding standards agreed upon by MPEG (Motion Pictures Coding 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).
See also
Referenced By
.asf | 3ivx | Advanced Audio Codec | Advanced Audio Coding | Advanced Streaming Format | Broadband Internet | Broadband Internet access | Broadband access | CCITT | Camcorder | Codec | Comité Consultatif International Telegraphique et Telephonique | Compression artefact | Compression artifact | Consultative Committee for International Telegraphy and Telephony | Data compression/lossy | Digital-rights management | Digital Radio Mondiale | Digital Rights Management | Digital Video | DivX | DivX ;-) | H.264 | ITU-T | List of ISO standards | List of file formats | List of standards topics | Lossy data compression | MPEG | MPEG-7 | Moving Picture Experts Group | Ogg-Theora | Ogg Theora | Olympus C-770 Movie | QuickTime | QuickTime 6 | QuickTime Player | Streaming Media | Theora | VideoLAN | Windows Media Video | Xiph.org Foundation | XviD
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