Editing Dirac (video compression format) (section)

{{short description|Video compression format}}
{{Update |inaccurate=yes |reason=This needs to be rewritten to primarily describe (and possibly be renamed to) VC-2, the SMPTE standard based on a subset of the Dirac spec intended for professional studio and post-production use. The original Dirac codec is more or less abandoned, but can and should be described in a §History section |date=December 2023 }}
{{Use British English|date=December 2023}}
{{Use dmy dates|date=November 2023}}
{{Infobox file format
| name                   = Dirac
| icon                   =
| logo                   =
| extension              = drc
| mime                   =
| type code              =
| uniform type           =
| magic                  =
| owner                  = [[BBC Research & Development]]
| released               = {{Start date and age|2008|03|06|df=yes}}<ref name="dirac-sf-press">{{cite press release |title=Worlds first high performance Dirac video codec implementation available |url=http://schrodinger.sourceforge.net/press/DiracAnnounce060308.html |access-date=14 December 2021 |work=Schrödinger project |publisher=SourceForge |date=6 March 2008 |archive-date=14 December 2021 |archive-url=https://web.archive.org/web/20211214233732/http://schrodinger.sourceforge.net/press/DiracAnnounce060308.html |url-status=live }}</ref>
| latest release version = 2.2.3<ref name="Dirac-2.2.3"/>
| latest release date    = {{Start date and age|2008|09|23|df=yes}}
| type                   = [[Video coding format]]
| container for          =
| contained by           = {{hlist | [[MPEG-TS]] | [[Ogg]] | [[Matroska]] | [[QuickTime File Format|MOV]] | [[ISO base media file format|ISO/MPEG-4]] }}
| extended from          =
| extended to            = VC-2
| standard               = {{hlist | SMPTE 2042-1-2022 | SMPTE 2042-2-2017 (Level Definitions) }}
| open                   = Yes
| free                   = Yes<ref name="bbc-wp-124">{{Cite web |title=White Paper 124: Dirac video compression |last1=Davies |first1=T.J. |last2=Borer |first2=Tim |last3=Suraparaju |first3=A. |work=[[BBC Research & Development]] |publisher=[[BBC]] |date=September 2005 |url=https://www.bbc.co.uk/rd/publications/whitepaper124 |access-date=18 December 2023 |archive-date=29 June 2023 |archive-url=https://web.archive.org/web/20230629054340/http://www.bbc.co.uk/rd/publications/whitepaper124 |url-status=live }}</ref>
}}

'''Dirac''' (and '''Dirac Pro''', a subset standardised as [[Society of Motion Picture and Television Engineers|SMPTE]] '''VC-2''') is an open and [[royalty-free]] [[video compression format]], specification and software [[video codec]] developed by [[BBC Research & Development]].<ref name="bbc-wp-159">{{Cite web |title=White Paper 159: Open Technology video compression for production and post production |first=Tim |last=Borer |work=[[BBC Research & Development]] |date=November 2007 |publisher=[[BBC]] |url=https://www.bbc.co.uk/rd/publications/whitepaper159 |access-date=18 December 2023 |archive-date=11 September 2017 |archive-url=https://web.archive.org/web/20170911213042/http://www.bbc.co.uk/rd/publications/whitepaper159 |url-status=live }}</ref><ref name="FAQ">{{cite web |work=diracvideo.org |publisher=[[BBC Research & Development]] |title=Frequently Asked Questions |url= http://diracvideo.org/wiki/index.php/FAQ |access-date=30 August 2009 |archive-url= https://web.archive.org/web/20100723110316/http://diracvideo.org/wiki/index.php/FAQ |archive-date=23 July 2010 |url-status=usurped }}</ref><ref name="bbc-vc-2">{{Cite web |title=Project: VC-2 |work=BBC Research & Development |date=January 2009 |publisher=[[BBC]] |url=https://www.bbc.co.uk/rd/projects/vc-2 |access-date=18 December 2023 |archive-date=12 July 2022 |archive-url=https://web.archive.org/web/20220712195759/https://www.bbc.co.uk/rd/projects/vc-2 |url-status=live }}</ref> Dirac aimed to provide high-quality video compression for [[Ultra High Definition Television|Ultra HDTV]] and competed with existing formats such as [[H.264]].<ref name="bbc-wp-124"/>

The specification was finalised in January 2008, and further developments were only bug fixes and constraints.<ref name="Dirac-2.2.3"/> In September of that year, version 1.0.0 of an [[I-frame]] only subset known as '''Dirac Pro''' was released and was standardised by the [[Society of Motion Picture and Television Engineers|SMPTE]] as '''VC-2'''.<ref name="Dirac-1.0.0">{{cite web |url=https://lwn.net/Articles/298755/ |title=Dirac 1.0.0 released. |last=Edge |first=Jake |date=17 September 2008 |website=LWN.net |access-date=7 July 2017 |archive-date=14 September 2016 |archive-url=https://web.archive.org/web/20160914141853/https://lwn.net/Articles/298755/ |url-status=live }}</ref><ref name="bbc-wp-159" /><ref name="smpte-vc2" >{{cite web |url=https://pub.smpte.org/pub/st2042-1/ |title=SMPTE Standard: 2042-1:2022, VC-2 Video Compression |date=2022 |publisher=[[Society of Motion Picture and Television Engineers]] |access-date=18 December 2023 |archive-date=18 December 2023 |archive-url=https://web.archive.org/web/20231218230038/https://pub.smpte.org/pub/st2042-1/ |url-status=live }}</ref> Version 2.2.3 of the full Dirac specification, including [[motion compensation]] and inter-frame coding, was issued a few days later.<ref name="Dirac-2.2.3">{{cite web |title=Dirac Specification, Version 2.2.3 |date=23 September 2008 |work=diracvideo.org |publisher=[[BBC Research & Development]] |url= http://diracvideo.org/download/specification/dirac-spec-latest.pdf |access-date=5 July 2009 |url-status=usurped |archive-url= https://web.archive.org/web/20150503015104/http://diracvideo.org/download/specification/dirac-spec-latest.pdf |archive-date=3 May 2015 }}</ref> Dirac Pro was used internally by the BBC to transmit HDTV pictures at the [[2008 Summer Olympics|Beijing Olympics]] in 2008.<ref name="broadcast-2008">{{cite web |work=Broadcast Magazine |title=Dirac Pro to bolster BBC HD links |date=16 July 2008 |publisher=[[EMAP|East Midland Allied Press]] |url=https://www.broadcastnow.co.uk/dirac-pro-to-bolster-bbc-hd-links/1732462.article |access-date=18 December 2023 |archive-date=2 December 2021 |archive-url=https://web.archive.org/web/20211202155651/https://www.broadcastnow.co.uk/dirac-pro-to-bolster-bbc-hd-links/1732462.article |url-status=live }}</ref><ref>{{Cite news |title=And now, Dirac from the Olympics, a new free codec! |first=Junko |last=Yoshida |date=15 September 2008 |work=EE Times |publisher=UBM Tech |url=https://www.eetimes.com/and-now-dirac-from-the-olympics-a-new-free-codec/ |access-date=18 December 2023 }}</ref>

Two [[open source]] and royalty-free [[video codec]] software implementations, libschrodinger and dirac-research, were developed. The format implementations were named in honour of the theoretical physicists [[Paul Dirac]] and [[Erwin Schrödinger]], who shared the 1933 [[Nobel Prize in Physics]].