Editing Dirac (video compression format) (section)

==Software implementations==

{{Update|date=May 2010}}

{{Infobox software
| name                   = Schrödinger
| developer              = David Schleef
| latest_release_version = 1.0.11
| latest_release_date    = {{Start date and age|df=yes|2012|01|23}}
| genre                  = [[Video codec]]
| license                = {{hlist
                             | [[Mozilla Public Licence|MPL 1.1]]
                             | [[GNU General Public License|GNU GPL]] 2
                             | [[GNU Lesser General Public License|GNU LGPL]] 2
                             | [[MIT License]]
                           }}
| website                = {{URL|https://sourceforge.net/projects/dirac}}
}}

Two software implementations were initially developed. The BBC's reference implementation, initially called ''Dirac'' but renamed ''dirac-research'' to avoid confusion, was written in C++ and released under the [[Mozilla Public License]], [[GNU GPL]] 2 and [[GNU LGPL]] [[free software license]]s. Version 1.0.0 of this implementation was released on 17 September 2008 and defines the Dirac bitstream format.<ref name="Dirac-1.0.0"/>

A second implementation called ''Schrödinger'' was funded by the BBC and aimed to provide a high-performance, portable version of the codec whilst remaining 100% bitstream compatible. Schrödinger was written in ANSI [[C (programming language)|C]] and released under the same licenses as dirac-research, as well as the highly-permissive [[MIT License]]. [[GStreamer]] plugins were included to enable the library to be used with that framework. On 22 February 2008, Schrödinger 1.0.0 was released, and was able to decode HD720/25p in real-time on a [[Core Duo]] laptop.<ref name="schrodinger-1.0.0">{{Cite web |title=Schroedinger 1.0.0 released |work=LWN.net |publisher=Eklektix |date=27 February 2008 |url=https://lwn.net/Articles/271058/ |access-date=18 December 2023 |archive-date=13 March 2016 |archive-url=https://web.archive.org/web/20160313124647/http://lwn.net/Articles/271058/ |url-status=live }}</ref>

By the March 2010 release of Schrödinger version 1.0.9, it was outperforming dirac-research "in most encoding situations, both in terms of encoding speed and visual quality".<ref>{{cite web |title = ''Schrödinger-1.0.9 Released'' |date=4 March 2010 |work=diracvideo.org |publisher=[[BBC Research & Development]] |url= http://diracvideo.org/2010/03/schroedinger-1-0-9-released/ |access-date=11 March 2010 |archive-url= https://web.archive.org/web/20100308063136/http://diracvideo.org/2010/03/schroedinger-1-0-9-released/ |archive-date=8 March 2010 |url-status=usurped }}</ref> With that release, most of the encoding tools in dirac-research were ported over to Schrödinger, giving Schrödinger the same as or better compression efficiency than dirac-research. Development of Schrödinger ceased after the 1.0.11 release in 2012. 

After the standardisation of Dirac Pro as SMPTE VC-2, development began on an open source reference VC-2 encoder. The code is provided in a git repository by the BBC and is available on [[GitHub]].<ref name="vc2-ref">{{Cite web |title=VC-2 Reference Encoder and Decoder |publisher=[[BBC]] |url=https://github.com/bbc/vc2-reference |access-date=18 December 2023 |via=[[GitHub]] |archive-date=5 August 2023 |archive-url=https://web.archive.org/web/20230805002138/https://github.com/bbc/vc2-reference |url-status=live }}</ref>

An encoder quality testing system has been put in place at BBC to check how well new encoding tools work and to make sure bugs that affect quality are quickly fixed.<ref name="testing-tools">{{Cite web |title=VC-2 Video coding: Getting it right |last=Heathcote |first=Jonathan |work=[[BBC Reaearch & Development]] |publisher=[[BBC]] |date=7 April 2021 |access-date=18 December 2023 |url=https://www.bbc.co.uk/rd/blog/2021-04-vc-2-video-coding-testing-tools |archive-date=20 June 2022 |archive-url=https://web.archive.org/web/20220620224546/https://www.bbc.co.uk/rd/blog/2021-04-vc-2-video-coding-testing-tools |url-status=live }}</ref>

===Desktop playback and encoding===

Dirac video playback is supported by [[VLC media player]] since version 0.9.2 (2008), and by applications using the [[GStreamer]] framework. Support has also been added to [[FFmpeg]]. Applications which can encode to Dirac include [[FFmpeg]], [[MediaCoder]], [[LiVES]] and [[OggConvert]].<ref>{{cite web |url= http://diracvideo.org/wiki/index.php/Dirac_Compatibility_Matrix |title=Wiki: Dirac Compatibility Matrix |work=diracvideo.org |publisher=[[BBC Research & Development]] |access-date=14 January 2009 |archive-date=8 November 2008 |archive-url= https://web.archive.org/web/20081108133806/http://diracvideo.org/wiki/index.php/Dirac_Compatibility_Matrix |url-status=usurped }}</ref>