MPEG

MPEG redirects here. For the Motion Picture Editors Guild also known as MPEG, see Motion Picture Editors Guild Mpeg.svg

The Moving Picture Experts Group (MPEG) was formed by the ISO to set standards for audio and video compression and transmission. Its first meeting was in May 1988 in Ottawa, Canada. As of late 2005, MPEG has grown to include approximately 350 members per meeting from various industries, universities, and research institutions. MPEG's official designation is ISO/IEC JTC1/SC29 WG11.

Compression methodology

The MPEG compression methodology is considered asymmetric in that the encoder is more complex than the decoder. The encoder needs to be algorithmic or adaptive whereas the decoder is 'dumb' and carries out fixed actions. This is considered advantageous in applications such as broadcasting where the number of expensive complex encoders is small but the number of simple inexpensive decoders is large. This approach of the ISO to standardization in MPEG is considered novel because it is not the encoder which is standardized; instead, the way in which a decoder shall interpret the bitstream is defined. A decoder which can successfully interpret the bitstream is said to be compliant.The advantage of standardizing the decoder is that over time encoding algorithms can improve yet compliant decoders will continue to function with them. The MPEG standards give very little information regarding structure and operation of the encoder and implementers can supply encoders using proprietary algorithms. This gives scope for competition between different encoder designs which means that better designs can evolve and users will have greater choice because of different levels of cost and complexity can exist in a range of coders yet a compliant decoder will operate with them all.

MPEG also standardizes the protocol and syntax under which it is possible to combine or multiplex audio data with video data to produce a digital equivalent of a television program. Many such programs can be multiplexed and MPEG defines the way in which such multiplexes can be created and transported. The definitions include the metadata used by decoders to demultiplex correctly.

The article is based on materials from matroska.org, wikipedia.org.