Editing MPEG-1 Audio Layer II (section)

{{short description|Lossy audio compression format}}
{{more footnotes|date=December 2016}}
{{Distinguish|MPEG-2}}{{Infobox file format
| name          = MPEG-1 or MPEG-2 Audio Layer II
| icon          = 
| logo          = 
| caption       = 
| extension     = .mp2, .mpa, .m2a, .mp2a
| mime          = audio/mpeg,{{ref RFC|3003}} audio/MPA{{ref RFC|3555}}
| type code     = 
| uniform type  = 
| magic         = 
| owner         = [[Philips]] and others
| released      = {{Start date and age|1991|12|06|df=yes}}<ref name="11172-draft-cite">{{Cite book |vauthors=Patel K, Smith BC, Rowe LA |title=Proceedings of the first ACM international conference on Multimedia - MULTIMEDIA '93 |chapter=Performance of a software MPEG video decoder |date=1993-09-01 |chapter-url=https://dl.acm.org/doi/10.1145/166266.166274 |series=ACM Multimedia |location=New York City |publisher=Association for Computing Machinery |pages=75–82 |doi=10.1145/166266.166274 |isbn=978-0-89791-596-0|s2cid=3773268 }} Reference 3 in the paper is to Committee Draft of Standard ISO/IEC 11172, December 6, 1991.</ref>
| latest_release_version = ISO/IEC 13818-3:1998
| latest_release_date = {{start date and age|1998|04|df=y}}
| type          = [[Lossy compression|Lossy]] [[Audio file format|audio]]
| container for = 
| contained by  = [[Elementary stream|MPEG-ES]]
| extended from = 
| extended to   = 
| standard      = [[ISO/IEC 11172-3]],<ref name="11172-3">{{cite web |url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22412 |title=ISO/IEC 11172-3:1993 – Information technology — Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s — Part 3: Audio |publisher=ISO |year=1993 |access-date=2010-07-14}}</ref> [[ISO/IEC 13818-3]]<ref name="13818-3">{{cite web |url=http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=22991 |title=ISO/IEC 13818-3:1995 – Information technology — Generic coding of moving pictures and associated audio information — Part 3: Audio |publisher=ISO |year=1995 |access-date=2010-07-14}}</ref>
| open          = Yes
| free          = Expired patents<ref>{{cite tech report |publisher=Library of Congress |location=Washington, D.C. |series=Sustainability of Digital Formats |type=Partial draft |title=MPEG-1 and MPEG-2 Layer II Audio Encoding |date=17 May 2012 |url=https://www.loc.gov/preservation/digital/formats/fdd/fdd000338.shtml |access-date=1 December 2021}}</ref>
| url           = http://mpeg.chiariglione.org/standards/mpeg-1/audio.html
}}

'''MP2''' (formally '''MPEG-1 Audio Layer II''' or '''MPEG-2 Audio Layer II''', sometimes incorrectly called '''Musicam'''<ref name="mpegfaq">{{cite web |year=1998 |title=MPEG Audio FAQ Version 9 |url=http://mpeg.chiariglione.org/faq/mp1-aud/mp1-aud.htm#16 |access-date=2010-08-22}}</ref>) 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 Layer I]] (MP1) and [[MPEG-1 Audio Layer III]] (MP3). The MP2 abbreviation is also used as a common [[Filename extension|file extension]] for files containing this type of audio data, or its extended variant MPEG-2 Audio Layer II. 

MPEG-1 Audio Layer II was developed by [[Philips]], [[Centre commun d'études de télévision et télécommunications|CCETT]] and [[Institut für Rundfunktechnik|IRT]] as the MUSICAM algorithm, as part of the European-funded [[Digital Audio Broadcasting]] (DAB) project.<ref>{{Cite web |date=2002-04-06 |title=Audio Coding |url=http://www.public.asu.edu/~rampriya/audiocoding.htm |access-date=2025-04-17 |archive-url=https://web.archive.org/web/20020406172256/http://www.public.asu.edu/~rampriya/audiocoding.htm |archive-date=6 April 2002 }}</ref> Alongside its use on DAB broadcasts, the codec has been adopted as the standard audio format for [[Video CD]] and [[Super Video CD]] media, and also for [[HDV]].<ref>{{cite web |author=Techopedia |date=16 February 2015 |title=MPEG-1 Audio Layer II (MP2) |url=https://www.techopedia.com/definition/964/mpeg-1-audio-layer-ii-mp2 |access-date=2022-03-17 |publisher=techopedia.com}}</ref> On the other hand, MP3 (which was developed by a rival collaboration led by [[Fraunhofer Society]] called ASPEC) gained more widespread acceptance for [[personal computer|PC]] and [[Internet]] applications. MP2 compresses less than MP3, but therefore also has less computational demands.<ref>{{Cite web |title=MPEG-1 Audio Layer II - Glossary |url=https://www.devx.com/terms/mpeg-1-audio-layer-ii/ |access-date=2025-04-17 |website=DevX |language=en-US}}</ref>