MPEG-4

MPEG-4 is a patented collection of methods defining compression of audio and visual digital data. It designate a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC "Moving Picture Experts Group" (MPEG) under the formal standard ISO/IEC 14496.

Uses of MPEG-4 include compression of AV data for web (streaming media) and CD distribution, voice (telephone, videophone) and broadcast television applications.

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 objects), support for externally-specified Digital Rights Management and various types of interactivity.

MPEG-4 is divided into a number of parts. The key parts to be aware of are:

• MPEG-4 part 2, including Advanced Simple Profile, used by codecs such as DivX, Xvid, Nero Digital, 3ivx and by QuickTime6
• MPEG-4 part 10 – MPEG-4 AVC/H.264 or Advanced Video Coding, used by the x264 codec, by Nero Digital AVC, by QuickTime 7, and by next-gen video mídia formats like Blu-ray Disc.

Initially, MPEG-4 was aimed primarily at low bit-rate video communications; however, its scope was later expanded to be much more of a multimedia coding standard.

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 functionalities:

• Improved coding efficiency
• 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