'''Compact Disc Digital Audio''' ('''CDDA''' or '''CD-DA'''), also known as '''Digital Audio Compact Disc''' or simply as '''Audio CD''', is the [[standardization|standard]] format for audio [[compact disc]]s. The standard is defined in the ''[[Rainbow Books|Red Book]]'' [[technical specification]]s, which is why the format is also dubbed ''"Redbook audio"'' in some contexts.<ref>{{Cite web |title=Redbook Audio (Concept) |url=https://www.giantbomb.com/redbook-audio/3015-6487/ |access-date=2024-08-28 |website=Giant Bomb |language=en}}</ref> CDDA utilizes [[pulse-code modulation]] (PCM) and uses a [[44,100 Hz]] sampling frequency and 16-bit resolution, and was originally specified to store up to 74 minutes of [[stereo]] audio per disc.
The first commercially available audio [[CD player]], the [[Sony CDP-101]], was released in October 1982 in Japan. The format gained worldwide acceptance in some developed nations1983–84, selling more than a million CD players in its first two years, to play 22.5 million discs,<ref>{{cite book |last=Pohlmann |first=Ken C. |title=Principles of Digital Audio |date=2000 |publisher=McGraw-Hill |isbn=978-0-07-134819-5 |page=244}}</ref> before overtaking [[phonograph record|records]] and [[Cassette tape|cassette tapes]] to become the dominant standard for commercial music. Peaking around year 2000, the audio CD contracted over the next decade due to rising popularity and revenue from [[Music download|digital downloading]], and during the 2010s by [[Music streaming service|digital music streaming]],<ref>{{cite news |date=14 April 2015 |title=IFPI publishes Digital Music Report 2015 |url=https://www.ifpi.org/news/Global-digital-music-revenues-match-physical-format-sales-for-first-time |url-status=live |archive-url=https://web.archive.org/web/20150414194629/https://www.ifpi.org/news/Global-digital-music-revenues-match-physical-format-sales-for-first-time |archive-date=14 April 2015 |access-date=1 July 2016}}</ref> but has remained as one of the primary distribution methods for the [[music industry]].<ref name="AutoMR-2">{{cite news |last=Plambeck |first=Joseph |date=30 May 2010 |title=As CD Sales Wane, Music Retailers Diversify |url=https://www.nytimes.com/2010/05/31/business/media/31bestbuy.html |url-status=live |archive-url=https://web.archive.org/web/20170501175846/https://www.nytimes.com/2010/05/31/business/media/31bestbuy.html |archive-date=1 May 2017 |work=The New York Times}}</ref> In the United States, phonograph record revenues surpassed the CD in 2020 for the first time since the 1980s,<ref>{{cite news |date=10 September 2020 |title=Vinyl Outsells CDs For the First Time in Decades |url=https://pitchfork.com/news/vinyl-outsells-cds-for-the-first-time-in-decades/amp/ |url-status=live |archive-url=https://archive.today/20200922170131/https://pitchfork.com/news/vinyl-outsells-cds-for-the-first-time-in-decades/amp/ |archive-date=22 September 2020 |access-date=22 September 2020}}</ref><ref>{{cite web |title=Mid-Year 2020 RIAA Revenue Statistics |url=https://www.riaa.com/wp-content/uploads/2020/09/Mid-Year-2020-RIAA-Revenue-Statistics.pdf |url-status=live |archive-url=https://web.archive.org/web/20230509100235/https://www.riaa.com/wp-content/uploads/2020/09/Mid-Year-2020-RIAA-Revenue-Statistics.pdf |archive-date=9 May 2023 |access-date=2 June 2023 |website=Riaa.com}}</ref> but in other major markets like Japan it remains the premier music format by a distance<ref>{{Cite web |date=2023-10-23 |title=3 observations on… how Japan's music industry caters to (and relies on) 'superfans' more than any other market |url=https://www.musicbusinessworldwide.com/3-observations-on-how-japans-music-industry-caters-to-and-relies-on-superfans-more-than-any-other-market1/ |access-date=2024-05-03 |website=Music Business Worldwide |language=en-US}}</ref> and in Germany it outsold other physical formats at least fourfold in 2022.<ref>{{Cite web |title=Statistik {{!}} Absatz von physischen Tonträgern und digitalen Musikprodukten |url=https://miz.org/de/statistiken/absatz-von-physischen-tontraegern-und-digitalen-musikprodukten |access-date=2024-05-03 |website=miz.org |language=de}}</ref>
In the music industry, audio CDs have been generally sold as either a [[CD single]] (now largely dormant), or as full-length [[album]]s, the latter of which has been more commonplace since the 2000s.<ref>{{Cite web |title=1999: The Year the Record Industry Lost Control |url=https://theafterword.co.uk/1999-the-year-the-record-industry-lost-control/ |access-date=2024-05-03 |website=theafterword.co.uk}}</ref> The format has also been influential in the progression of [[video game music]], used in [[Mixed Mode CD|mixed mode]] [[CD-ROM|CD-ROMs]], providing CD-quality audio popularized during the 1990s on hardware such as [[PlayStation (console)|PlayStation]], [[Sega Saturn]] and [[personal computers]] with 16-bit [[sound cards]] like the [[Sound Blaster|Sound Blaster 16]].<ref>{{Cite book |last=Collins |first=Karen |title=From Bits to Hits: Video Games Music Changes its Tune |___location=School of Music, University of Windsor}}</ref><ref>{{Cite magazine |date=September 1995 |title=Group Test: 90MHz Pentiums - Sound cards |url=https://archive.org/details/PersonalComputerWorldMagazine/PCW%20199509%20September%20Created%20From%20PCW%20Cover%20CD/ |magazine=[[Personal Computer World]] |volume=18 |issue=9}}</ref>
