__NOTOC__ MPEG Multichannel, also known as MPEG-2 Backwards Compatible, or MPEG-2 BC, is an extension to the

MPEG-1 Layer II MP2 (formally MPEG-1 Audio Layer II or MPEG-2 Audio Layer II, sometimes incorrectly called Musicam) is a lossy data compression, lossy audio compression format. It is standardised as one of the three audio codecs of MPEG-1 alongside MPEG-1 Audio ...

audio Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to: Sound *Audio signal, an electrical representation of sound *Audio frequency, a frequency in the audio spectrum *Digital audio, representation of sound ...

compression specification, as defined in the

MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods ...

Audio standard (

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

IEC The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronic and related technologies. IEC standards cover a vast range of ...

13818-3) which allows it provide up to 5.1-channels (

surround sound Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener ( surround channels). Its first application was in movie theaters. Prior to ...

) of audio. To maintain backwards compatibility with the older 2-channel (stereo) audio specification, it uses a channel matrixing scheme, where the additional channels are mixed into the two backwards compatible channels. Extra information in the data stream (ignored by older hardware) contains signals to process extra channels from the matrix.

Consumer electronics and broadcast use

Originally a mandatory part of the

DVD The DVD (common abbreviation for digital video disc or digital versatile disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...

specification for PAL standard discs, but was dropped in favor of competitor

Dolby Digital Dolby Digital, originally synonymous with Dolby AC-3 (see below), is the name for a family of audio compression technologies developed by Dolby Laboratories. Called Dolby Stereo Digital until 1995, it is lossy compression (except for Dolby Tr ...

in December 1997. This was largely due to delays with MPEG Multichannel encode/decode processes being available for production at the professional level, and a lack of playback products at the consumer level. These issues were later resolved by Fraunhofer IIS with key industry partners such as Koninklijke Philips N.V., but not before MPEG Multichannel lost its mandatory requirement for PAL discs, remaining on only as an optional component. The format is also supported by the

Super Video CD Super Video CD (Super Video Compact Disc or SVCD) is a Digital data, digital format for storing video on standard compact discs. SVCD was intended as a successor to Video CD and an alternative to DVD-Video, and falls somewhere between both in ter ...

(SVCD) disc standard as well. MPEG Multichannel fared better in broadcast adoption and was chosen as part of Japan's CS digital television system. Other than consumer electronics made exclusively for the Japanese domestic market, native player support for the format is exceedingly rare.

Meridian Audio Meridian Audio is a consumer Audio equipment, audio and Home cinema, home theatre equipment manufacturer based in the United Kingdom. Bob Stuart and Allen Boothroyd founded the company in 1977 under the name Boothroyd-Stuart. In 1985 the company ...

makes the only commercially available surround sound processors outside of Japan that support both MPEG Multichannel and its successor format, MPEG-4 AAC surround described in the 1999 MPEG-2 Part 7 standard. Unlike MPEG Multichannel,

Advanced Audio Coding Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. It was developed by Dolby, AT&T, Fraunhofer and Sony, originally as part of the MPEG-2 specification but later improved under MPEG-4.ISO (2006ISO/ ...

has enjoyed wide industry support in VOD/OTT mediums as well as being the surround coding format used in Japan's BS digital television standard. In the United States, MPEG Multichannel was proposed for use in the ATSC

digital TV Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adv ...

broadcasting standard, but

(aka. AC-3, A/52) was chosen instead. This is a matter of significant controversy, as it has been revealed that the organizations (The

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...

and

Zenith Electronics Zenith Electronics, LLC, is an American research and development company that develops ATSC and digital rights management technologies. It is owned by the South Korean company LG Electronics. Zenith was previously an American brand of consumer e ...

) behind 2 of the 4 voting board members received tens of millions of dollars of compensation from secret deals with

Dolby Laboratories Dolby Laboratories, Inc. (Dolby Labs or simply Dolby) is a British-American technology corporation specializing in audio noise reduction, audio data compression, audio encoding/compression, spatial audio, and high-dynamic-range television (H ...

in exchange for their votes. MPEG Multichannel–compatible equipment would bear either the MPEG Multichannel or MPEG Empowered logos, or on its packaging and documentation.

References

External links

MPiG a website critical of MPEG Multichannel

mctooLAME: An Open Source MPEG Multichannel audio encoder and decoder

Official MPEG web site
{{Webarchive, url=https://web.archive.org/web/20081109215716/http://www.chiariglione.org/mpeg/ , date=2008-11-09
web site
MPEG-2 Audio codecs

Consumer electronics and broadcast use

See also

References

External links