Editing Dolby Digital (section)

===Dolby AC-3===
{{Infobox file format
|name = Dolby AC-3
|extension = .ac3
|mime = audio/ac3
|uniform type = public.ac3-audio<ref>{{cite web |url=https://developer.apple.com/documentation/avfoundation/avfiletypeac3 |title=AVFileTypeAC3 |work=Apple Developer Documentation |publisher=[[Apple Inc]]}}</ref>
}}
[[File:Dolbytrailerdvd07.png|thumb|right|The former Dolby Digital logo, entitled "Aurora", that was sometimes shown at the start of broadcasts, feature films, and video games]]
[[File:Dolby Digital old logo.svg|thumb|The old Dolby Digital logo]]

'''Dolby AC-3''' (a [[backronym]] for Audio Codec 3, Advanced Codec 3, or Acoustic Coder 3), also known as '''[[ATSC]] A/52''' (name of the standard)<ref>{{cite web |url=http://www.atsc.org/cms/index.php/standards/published-standards/48-atsc-a52-standard |title=A/52B: Digital Audio Compression (AC-3) (E-AC-3) Standard, Rev. B |publisher=[[Advanced Television Systems Committee]] |access-date=2010-08-06 |archive-url=https://web.archive.org/web/20100918151932/http://atsc.org/cms/index.php/standards/published-standards/48-atsc-a52-standard |archive-date=2010-09-18 |url-status=dead }}</ref> or simply '''Dolby Digital''' ('''DD'''), is the common version containing up to six discrete channels of sound. Before 1996 it was marketed as '''Dolby Surround AC-3''', '''Dolby Stereo Digital''', and '''Dolby SRD'''.<ref name=":0">{{cite web|url=http://www.spannerworks.net/reference/10_3a.asp|archive-url=https://web.archive.org/web/20050311043636/http://www.spannerworks.net/reference/10_3a.asp|url-status=usurped|archive-date=March 11, 2005|title=Movie Sound Chronology|website=spannerworks.net|access-date=2017-04-02}}</ref>

The most elaborate mode of this codec in common use involves five channels for normal-range speakers ({{nowrap|20 Hz – 20,000 Hz}}) (right, center, left, right surround, left surround) and one channel ({{nowrap|20 Hz – 120 Hz}} allotted audio) for the [[subwoofer]] driven [[low-frequency effects]].<ref>{{cite web |url=http://www.dolby.com/uploadedFiles/Assets/US/Doc/Professional/42_DDFAQ.pdf|title=Dolby-Frequently Asked Questions |publisher=[[Dolby Laboratories]]}}</ref> [[monaural|Mono]] and [[stereo]] modes are also supported. AC-3 supports audio sample rates up to 48&nbsp;kHz.

In 1991, a limited experimental release of ''[[Star Trek VI: The Undiscovered Country]]'' in Dolby Digital played in 3 US theatres.<ref name=":0" /> In 1992, ''[[Batman Returns]]'' was the first movie to be released and presented in Dolby Digital.<ref name=":1">{{cite web|url=https://www.dolby.com/us/en/about/history.html|title=History: 50 YEARS OF INNOVATION|website=Dolby Laboratories|access-date=2017-03-22}}</ref><ref>{{Cite news|url=https://www.chicagotribune.com/1992/05/13/batman-returns-to-try-double-dolby/|title='Batman Returns' To Try Double Dolby|date=May 13, 1992|work=The Chicago Tribune|access-date=2017-03-22}}</ref> In 1995, the [[LaserDisc]] version of ''[[Clear and Present Danger (film)|Clear and Present Danger]]'' featured the first [[home theater]] Dolby Digital mix, quickly followed by ''[[True Lies]]'', ''[[Stargate (film)|Stargate]]'', ''[[Forrest Gump]]'', and ''[[Interview with the Vampire (film)|Interview with the Vampire]]'' among others.<ref>{{cite web|url=http://www.lddb.com/list.php?format=ld&list=ac3&start=75&sort=date,asc|title=Laserdisc Database Search By Date|website=Laserdisc Database|access-date=2017-04-02}}</ref><ref>{{cite web|url=http://www.lddb.com/laserdisc/21521/LV-32463-2WS/Clear-and-Present-Danger|title=LaserDisc Database Clear and Present Danger|website=LaserDisc Database|access-date=2017-04-02}}</ref>