Editing Theora (section)

==History==
{{See also|VP3}}
Theora's predecessor ''On2 TrueMotion VP3'' was originally a [[proprietary software|proprietary]] and patent-encumbered [[video codec]] developed by [[On2 Technologies]]. VP3.1 was introduced in May 2000<ref>{{citation |url=http://www.on2.com/index.php?id=486&news_id=407  |title=On2.com Launches Next Generation of Revolutionary Broadband Video Technology |author=On2 |date=17 May 2000  |archive-url = https://web.archive.org/web/20071203064537/www.on2.com/index.php?id=486&news_id=407 |archive-date = 3 December 2007}}</ref> and followed three months later by the VP3.2 release,<ref>{{citation |url=http://www.on2.com/index.php?id=486&news_id=401 |title=On2 Introduces TrueMotion VP3.2 |author=On2 |date=16 August 2000 |access-date=23 August 2010 |archive-url=https://web.archive.org/web/20071203062255/www.on2.com/index.php?id=486&news_id=401 |archive-date=3 December 2007}}</ref> which was the basis for Theora.

===Move to free software===
In August 2001, On2 Technologies announced that they would release an open source version of their VP3.2 video compression algorithm.<ref>{{citation |url=http://www.on2.com/index.php?id=486&news_id=365 |title=On2 Technologies to Open Source VP3.2 Video Compression Technology (archived website) |author=On2 |date=7 August 2001 |archive-url=https://web.archive.org/web/20071203062120/www.on2.com/index.php?id=486&news_id=365 |archive-date=3 December 2007}}</ref><ref>{{cite web|last=Mariano|first=Gwendolyn|title=On2's video codec to go open-source|url=http://news.cnet.com/2100-1023-271254.html|work=CNET|date=7 August 2001}}</ref> In September 2001, On2 Technologies published the [[source code]] of the VP3.2 codec under the VP3.2 Public License 0.1,<ref name="vp32license-01">{{citation
  | title = VP3.2 Public License 0.1
  | year = 2001
  | author = On2 Technologies
  | publisher = Xiph.Org Foundation
  | url = https://trac.xiph.org/browser/branches/vp32/vp32/VP32_license.txt
  | access-date = 10 February 2008
  | archive-date = 4 April 2016
  | archive-url = https://web.archive.org/web/20160404101159/https://trac.xiph.org/browser/branches/vp32/vp32/VP32_license.txt
  | url-status = dead
  }}</ref> a custom open-source license.<ref>{{cite web|last=Bernat|first=Bill|title=On2 Offers Up VP3.2 Source Code|url=https://www.streamingmedia.com/Articles/ReadArticle.aspx?ArticleID=64360|work=StreamingMedia.com|date=7 September 2001}}</ref><ref>{{citation |url=http://www.on2.com/index.php?id=486&news_id=364  |title=On2 Technologies Makes Video Compression Technology Available to Open-Source Community |author=On2 |date=7 September 2001 |archive-url = https://web.archive.org/web/20071207021659/www.on2.com/index.php?id=486&news_id=364 |archive-date = 7 December 2007}}</ref> The license only granted the right to modify the source code if the resultant larger work continued to support playback of VP3.2 data.<ref name="vp32license-01" /><ref>{{cite mailing list |url=https://lists.xiph.org/pipermail/vorbis/2001-September/004554.html |title=VP3.2 video codec open sourced|mailing-list=vorbis |last=Seibert |first=Stan |date=September 2001}}</ref>

In March 2002, On2 responded to the public's reception by relicensing the VP3 codec under the [[GNU Lesser General Public License]].<ref>{{cite press release |title=On2 Alters Licensing Terms for VP3; Company Responds to Open Source Community Demands. |url=http://www.thefreelibrary.com/On2+Alters+Licensing+Terms+for+VP3%3b+Company+Responds+to+Open+Source...-a084233138 |publisher=On2 Technologies |date=28 March 2002 |access-date=16 August 2009 |archive-date=4 December 2010 |archive-url=https://web.archive.org/web/20101204092727/www.thefreelibrary.com/On2+Alters+Licensing+Terms+for+VP3%3b+Company+Responds+to+Open+Source...-a084233138 |url-status=dead }}</ref> In June 2002, On2 donated VP3 to the Xiph.Org Foundation and offered it under the Ogg Vorbis [[BSD License|BSD]]-style license.<ref>{{Cite web | author=Xiph.Org Foundation | title = Theora Specification | url = https://theora.org/doc/Theora.pdf | date = 3 June 2017 | publisher=Xiph.Org Foundation | page=1}}</ref><ref>{{citation |url=http://www.on2.com/index.php?id=486&news_id=313 |title=VP3 Combines with Vorbis to Create First Open-Source Multimedia Platform |website=On2 |date=24 June 2002 |archive-url=https://web.archive.org/web/20071203061350/http://www.on2.com/index.php?id=486&news_id=313 |archive-date=3 December 2007}}</ref><ref name="linux-com-ogg">Linux.com (23 June 2002) [https://www.linux.com/news/ogg-vorbis-vp3-combining-forces-create-open-source-multimedia-package/ Ogg Vorbis, VP3 combining forces to create Open Source multimedia package], Retrieved on 2009-08-16</ref><ref>InternetNews.com (24 June 2002) [http://www.internetnews.com/bus-news/article.php/1370341 On2 Throws More Open-Source at MPEG-4], Retrieved on 16 August 2009</ref> On2 also made an irrevocable, [[royalty-free]] license grant for any patent claims it might have over the software and any derivatives,<ref name="theoraspec" /> allowing anyone to use any VP3-derived codec for any purpose.<ref name="theora-license">Xiph.org [http://svn.xiph.org/trunk/theora/LICENSE libtheora license (Subversion – Trunk)], Retrieved on 16 August 2009</ref><ref name="vp32-license">Xiph.org [http://svn.xiph.org/trunk/vp32/LICENSE VP32 codec license (Subversion – Trunk)], Retrieved on 16 August 2009</ref> In August 2002, On2 entered into an agreement with the Xiph.Org Foundation to make VP3 the basis of a new, free video codec, called Theora.<ref>The Free Library (1 August 2002) [https://www.thefreelibrary.com/ON2+SIGNS+PACT+WITH+XIPH.ORG+TO+DEVELOP%2FSUPPORT+VP3-a089067501 On2 Signs Pact With Xiph.org to Develop/Support VP3], Retrieved on 16 August 2009</ref> On2 declared Theora to be VP3's successor.{{citation needed|date=January 2012}} On 3 October 2002, On2 and Xiph announced the completion and availability of the initial alpha code release of ''libtheora'', Theora's reference implementation.<ref>{{citation |url=http://www.on2.com/index.php?id=486&news_id=298 |title=On2 and Xiph Announce Alpha Code Release of Theora, VP3-Vorbis-Based Multimedia Solution |author=On2 |date=3 October 2002 |archive-url=https://web.archive.org/web/20071204072126/www.on2.com/index.php?id=486&news_id=298 |archive-date=4 December 2007}}</ref>

There is no formal specification for VP3's [[bitstream format]] beyond the VP3 source code published by On2 Technologies. In 2003, Mike Melanson created an incomplete description of the VP3 bitstream format and decoding process at a higher level than source code, with some help from On2 and Xiph.Org Foundation. The Theora specification adopted some portions of this VP3 description.<ref name="theoraspec" /><ref name="vp3-bitstream">{{citation
 |title       = VP3 Bitstream Format and Decoding Process
 |date        = 8 December 2004
 |author      = Mike Melanson (mike at multimedia.cx)
 |publisher   = Multimedia.cx
 |url         = http://www.multimedia.cx/vp3-format.txt
 |access-date  = 27 September 2009
 |url-status     = dead
 |archive-url  = https://archive.today/20130106025121/www.multimedia.cx/vp3-format.txt
 |archive-date = 6 January 2013
}}</ref>

A successor to Theora, [[Daala]], was later merged into [[AV1]].<ref name=AOMCNet2015September>{{cite web |title=Tech giants join forces to hasten high-quality online video |publisher=[[CNET]] |author=Stephen Shankland |url=https://www.cnet.com/tech/services-and-software/tech-giants-join-forces-to-hasten-high-quality-online-video/ |date=2015-09-01 |access-date=2025-05-19}}</ref>

===Theora I specification===
[[File:I-15bis.ogg|thumb|Example of a Theora video used on [[Wikipedia]], showing a [[Polikarpov I-15]] biplane at an aerobatic display.]]
The Theora I bitstream format was [[Freeze (software engineering)|frozen]] in June 2004 after the libtheora 1.0alpha3 release.<ref name="theora-freeze"/> Videos encoded with any version of the libtheora since the alpha3 will be compatible with any future player.<ref name="theora-freeze" /><ref name="theora-news">{{citation
  | title = Theora.org : news | date = 24 September 2009
  | author = Xiph.Org Foundation  | publisher = Xiph.Org Foundation
  | url = https://theora.org/news/ | access-date = 19 May 2025
}}</ref> This is also true for videos encoded with any implementation of the Theora I specification since the format freeze. The ''Theora I Specification'' was completely published in 2004.<ref name="theoraspec-2004">{{Cite web | author=Xiph.Org Foundation | title = Theora I Specification, Xiph.org Foundation, September 17, 2004 | url = http://www.theora.org/doc/Theora_I_spec.pdf  | access-date=26 September 2009 | date = 17 September 2004 |archive-url = https://web.archive.org/web/20040928224506/www.theora.org/doc/Theora_I_spec.pdf |archive-date = 28 September 2004}}</ref> Any later changes in the specification are minor updates.

The Theora reference implementation libtheora spent several years in [[Software release life cycle#Alpha|alpha]] and beta status.<ref name="theora-news" /> The first alpha version was released on 25 September 2002 and the first beta version was released on 22 September 2007.<ref name="CHANGES">{{cite web |title=CHANGES file |url=https://gitlab.xiph.org/xiph/theora/-/blob/master/CHANGES |accessdate=19 May 2025 }}</ref> The first stable release of libtheora was made in November 2008.<ref>{{cite mailing list | url = http://lists.xiph.org/pipermail/theora-dev/2008-November/003736.html | title = Theora 1.0 final release! | mailing-list = theora-dev | date = 3 November 2008 | last = Giles |first = Ralph |access-date=4 November 2008}}</ref><ref>{{cite press release
  | title = The Xiph.Org Foundation announces the release of Theora 1.0
  | publisher = Xiph.Org Foundation | date = 3 November 2008
  | url = https://www.xiph.org/press/2008/theora-release-1.0/ | access-date = 19 May 2025
}}</ref> Work then focused on improving the codec's performance in the ''"Thusnelda"'' branch, which was released as version 1.1 in September 2009 as the second stable libtheora release.<ref name="theora-news" /><ref>{{cite mailing list | url = https://lists.xiph.org/pipermail/theora-dev/2009-September/003985.html | title = libtheora 1.1 (Thusnelda) stable release | mailing-list = theora-dev | date = 24 September 2009 | last = Giles |first = Ralph |access-date=19 May 2025}}</ref> This release brought some technical improvements and new features, such as the new rate control module and the [[two-pass encoding|two-pass rate control]].

The codename for the next version of libtheora was ''Ptalarbvorm''.<ref name="ptalarbvorm">{{Cite web | author=Monty | title = Theora: Ptalarbvorm project update 20100518 | url = http://people.xiph.org/~xiphmont/demo/theora/demo9.html | access-date=1 July 2010 | date = 18 May 2010 }}</ref>

Theora was well established as a video format in [[open-source software|open-source applications]], and became the format used for [[Wikipedia]]'s video content before replaced by [[VP9]]. However, the proposed adoption of Theora as part of the baseline video support in HTML5 [[Use of Ogg formats in HTML5|resulted in controversy]].<ref>{{cite web
  | last = McLean | first = Prince | title = Ogg Theora, H.264 and the HTML 5 Browser Squabble
  | publisher = AppleInsider | date = 7 July 2009
  | url = https://appleinsider.com/articles/09/07/07/ogg_theora_h_264_and_the_html_5_browser_squabble | access-date = 1 November 2020
}}</ref>

=== Legacy ===
In October 2023, Google announced intent to remove Theora support from Chromium (finalizing removal by Google Chrome 123),<ref>{{Cite web |last=Larabel |first=Michael |date=2023-10-29 |title=Google Chrome To Remove Theora Video Codec Support |url=https://www.phoronix.com/news/Google-Chrome-Dropping-Theora |access-date=2023-11-01 |website=Phoronix |language=en}}</ref> with Firefox following suit. Google developers claimed that despite lack of adoption, Theora made a case for open and royalty-free codecs like [[AV1]].<ref>{{Cite web |title=Intent to Ship: Deprecate and remove Theora support. |url=https://groups.google.com/a/chromium.org/g/blink-dev/c/qqDdLkeyk7Y/m/ajHePzglAwAJ |access-date=2023-11-01 |website=groups.google.com}}</ref>{{Better source needed|reason=The current source is primary ([[WP:NOTRS]]).|date=November 2023}}