MPEG Multichannel, also known as MPEG-2 Backwards Compatible, or MPEG-2 BC, is an extension to the MPEG-1 Layer II audio compression specification, as defined in the MPEG-2 Audio standard (ISO/IEC 13818-3)[1][2] which allows it provide up to 5.1-channels (surround sound) of audio.[3][4][5][6] 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.[5]
Consumer electronics and broadcast use
editOriginally a mandatory part of the DVD specification for PAL standard discs, but was dropped in favor of competitor Dolby Digital 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 (SVCD) disc standard as well. MPEG Multichannel fared better in broadcast adoption and was chosen as part of Japan's CS digital television system.[7]
Other than consumer electronics made exclusively for the Japanese domestic market, native player support for the format is exceedingly rare. Meridian Audio 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 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.[7]
In the United States, MPEG Multichannel was proposed for use in the ATSC digital TV broadcasting standard, but Dolby Digital (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 and Zenith Electronics) behind 2 of the 4 voting board members received tens of millions of dollars of compensation from secret deals with Dolby Laboratories in exchange for their votes.[8]
MPEG Multichannel–compatible equipment would bear either the MPEG Multichannel or MPEG Empowered logos, or on its packaging and documentation.
See also
editReferences
edit- ^ "ISO/IEC 13818-3:1998 - Information technology -- Generic coding of moving pictures and associated audio information -- Part 3: Audio". ISO. Retrieved 2009-10-31.
- ^ Chiariglione, Leonardo (November 6, 1992). "MPEG Press Release, London, 6 November 1992". ISO/IEC. Archived from the original on 8 November 2007. Retrieved 2008-04-03.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Chiariglione, Leonardo (October 2000). "Short MPEG-2 description". Retrieved 2009-10-31.
- ^ Thom, D.; Purnhagen, H.; MPEG Audio Subgroup (October 1998). "MPEG Audio FAQ Version 9, MPEG-1 and MPEG-2 BC". Archived from the original on 2009-11-09. Retrieved 2009-10-31.
- ^ a b Oomen, Werner; van de Kerkhof, Leon (April 2006). "MPEG-2 Audio Layer I/II". ISO/IEC. Archived from the original on Apr 30, 2010. Retrieved 2008-04-03.
- ^ Thom, D.; Purnhagen, H.; MPEG Audio Subgroup (October 1998). "MPEG Audio FAQ Version 9 - MPEG Audio". Archived from the original on Nov 1, 2009. Retrieved 2009-10-31.
{{cite web}}: CS1 maint: unfit URL (link) - ^ a b Watanabe, Karou. "Technologies and Services on Digital Broadcasting: Source Coding of Audio". NHK Japan Science & Technology Research Laboratories. Retrieved 15 May 2023.
- ^ Winstein, Keith J. (November 8, 2002). "MIT Getting Millions For Digital TV Deal". The Tech. Archived from the original on Aug 20, 2010. Retrieved 2008-04-01.