Editing Data compression (section)

==== History ====
[[File:Placa-audioPC-925.jpg|right|thumb|Solidyne 922: The world's first commercial audio bit compression [[sound card]] for PC, 1990]]

Early audio research was conducted at [[Bell Labs]]. There, in 1950, [[C. Chapin Cutler]] filed the patent on [[differential pulse-code modulation]] (DPCM).<ref name="DPCM"/> In 1973, [[Adaptive DPCM]] (ADPCM) was introduced by P. Cummiskey, [[Nikil Jayant|Nikil S. Jayant]] and [[James L. Flanagan]].<ref>{{cite journal|doi=10.1002/j.1538-7305.1973.tb02007.x|title=Adaptive Quantization in Differential PCM Coding of Speech|year=1973|last1=Cummiskey|first1=P.|last2=Jayant|first2=N. S.|last3=Flanagan|first3=J. L.|journal=Bell System Technical Journal|volume=52|issue=7|pages=1105–1118}}</ref><ref>{{cite journal |last1=Cummiskey |first1=P. |last2=Jayant |first2=Nikil S. |last3=Flanagan |first3=J. L. |title=Adaptive quantization in differential PCM coding of speech |journal=The Bell System Technical Journal |date=1973 |volume=52 |issue=7 |pages=1105–1118 |doi=10.1002/j.1538-7305.1973.tb02007.x |issn=0005-8580}}</ref>

[[Perceptual coding]] was first used for [[speech coding]] compression, with [[linear predictive coding]] (LPC).<ref name="Schroeder2014">{{cite book |last1=Schroeder |first1=Manfred R. |title=Acoustics, Information, and Communication: Memorial Volume in Honor of Manfred R. Schroeder |date=2014 |publisher=Springer |isbn=9783319056609 |chapter=Bell Laboratories |page=388 |chapter-url=https://books.google.com/books?id=d9IkBAAAQBAJ&pg=PA388}}</ref> Initial concepts for LPC date back to the work of [[Fumitada Itakura]] ([[Nagoya University]]) and Shuzo Saito ([[Nippon Telegraph and Telephone]]) in 1966.<ref>{{cite journal |last1=Gray |first1=Robert M. |title=A History of Realtime Digital Speech on Packet Networks: Part II of Linear Predictive Coding and the Internet Protocol |journal=Found. Trends Signal Process. |date=2010 |volume=3 |issue=4 |pages=203–303 |doi=10.1561/2000000036 |url=https://ee.stanford.edu/~gray/lpcip.pdf |archive-url=https://web.archive.org/web/20100704113551/http://ee.stanford.edu/~gray/lpcip.pdf |archive-date=2010-07-04 |url-status=live |issn=1932-8346|doi-access=free }}</ref> During the 1970s, [[Bishnu S. Atal]] and [[Manfred R. Schroeder]] at [[Bell Labs]] developed a form of LPC called [[adaptive predictive coding]] (APC), a perceptual coding algorithm that exploited the masking properties of the human ear, followed in the early 1980s with the [[code-excited linear prediction]] (CELP) algorithm which achieved a significant [[data compression ratio|compression ratio]] for its time.<ref name="Schroeder2014"/> Perceptual coding is used by modern audio compression formats such as [[MP3]]<ref name="Schroeder2014"/> and [[Advanced Audio Codec|AAC]].

[[Discrete cosine transform]] (DCT), developed by [[N. Ahmed|Nasir Ahmed]], T. Natarajan and [[K. R. Rao]] in 1974,<ref name="DCT"/> provided the basis for the [[modified discrete cosine transform]] (MDCT) used by modern audio compression formats such as MP3,<ref name="Guckert">{{cite web |last1=Guckert |first1=John |title=The Use of FFT and MDCT in MP3 Audio Compression |url=http://www.math.utah.edu/~gustafso/s2012/2270/web-projects/Guckert-audio-compression-svd-mdct-MP3.pdf |archive-url=https://web.archive.org/web/20140124152337/http://www.math.utah.edu/~gustafso/s2012/2270/web-projects/Guckert-audio-compression-svd-mdct-MP3.pdf |archive-date=2014-01-24 |url-status=live |website=[[University of Utah]] |date=Spring 2012 |access-date=14 July 2019}}</ref> [[Dolby Digital]],<ref name="Luo">{{cite book |last1=Luo |first1=Fa-Long |title=Mobile Multimedia Broadcasting Standards: Technology and Practice |date=2008 |publisher=[[Springer Science & Business Media]] |isbn=9780387782638 |page=590 |url=https://books.google.com/books?id=l6PovWat8SMC&pg=PA590}}</ref><ref>{{cite journal |last1=Britanak |first1=V. |title=On Properties, Relations, and Simplified Implementation of Filter Banks in the Dolby Digital (Plus) AC-3 Audio Coding Standards |journal=IEEE Transactions on Audio, Speech, and Language Processing |date=2011 |volume=19 |issue=5 |pages=1231–1241 |doi=10.1109/TASL.2010.2087755|s2cid=897622 }}</ref> and AAC.<ref name=brandenburg>{{cite web|url=http://graphics.ethz.ch/teaching/mmcom12/slides/mp3_and_aac_brandenburg.pdf|title=MP3 and AAC Explained|last=Brandenburg|first=Karlheinz|year=1999|url-status=live|archive-url=https://web.archive.org/web/20170213191747/https://graphics.ethz.ch/teaching/mmcom12/slides/mp3_and_aac_brandenburg.pdf|archive-date=2017-02-13}}</ref> MDCT was proposed by J. P. Princen, A. W. Johnson and A. B. Bradley in 1987,<ref>{{cite book|doi=10.1109/ICASSP.1987.1169405|chapter=Subband/Transform coding using filter bank designs based on time domain aliasing cancellation|title=ICASSP '87. IEEE International Conference on Acoustics, Speech, and Signal Processing|year=1987|last1=Princen|first1=J.|last2=Johnson|first2=A.|last3=Bradley|first3=A.|volume=12|pages=2161–2164|s2cid=58446992}}</ref> following earlier work by Princen and Bradley in 1986.<ref>{{cite journal|doi=10.1109/TASSP.1986.1164954|title=Analysis/Synthesis filter bank design based on time domain aliasing cancellation|year=1986|last1=Princen|first1=J.|last2=Bradley|first2=A.|journal=IEEE Transactions on Acoustics, Speech, and Signal Processing|volume=34|issue=5|pages=1153–1161}}</ref>

The world's first commercial [[broadcast automation]] audio compression system was developed by Oscar Bonello, an engineering professor at the [[University of Buenos Aires]].
<ref>{{cite news|title=Ricardo Sametband, La Nación Newspaper "Historia de un pionero en audio digital" |url=https://www.lanacion.com.ar/tecnologia/la-historia-de-un-pionero-del-audio-digital-nid187775|language=es}}</ref>
In 1983, using the psychoacoustic principle of the masking of critical bands first published in 1967,<ref name="Zwicker"/> he started developing a practical application based on the recently developed [[IBM PC]] computer, and the broadcast automation system was launched in 1987 under the name [[Audicom]].
<ref name="Solidyne">{{cite web |title=Summary of some of Solidyne's contributions to Broadcast Engineering |url=http://www.solidynepro.com/nosotros-breve-historia/ |work=Brief History of Solidyne |publisher=Buenos Aires: Solidyne |access-date=6 March 2013  |archive-url=https://web.archive.org/web/20130308063719/http://www.solidynepro.com/indexahtmlp_Hist-ENG%2Ct.htm |archive-date=8 March 2013 }}</ref>
35 years later, almost all the radio stations in the world were using this technology manufactured by a number of companies because the inventor refused to patent his work, preferring to publish it and leave it in the public domain.
<ref>{{cite news|language=en|title=Anuncio del Audicom, AES Journal, July-August 1992, Vol 40, # 7/8, pag 647|url=http://www.aes.org/e-lib/browse.cfm?elib=19076}}<!-- auto-translated by Module:CS1 translator --></ref>

A literature compendium for a large variety of audio coding systems was published in the IEEE's ''Journal on Selected Areas in Communications'' (''JSAC''), in February 1988. While there were some papers from before that time, this collection documented an entire variety of finished, working audio coders, nearly all of them using perceptual techniques and some kind of frequency analysis and back-end noiseless coding.<ref name="Possibilities"/>