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Nigelmegitt (talk | contribs) Primarily, add more detail about adoption |
VulcanSphere (talk | contribs) m Adding local short description: "XML-based file format", overriding Wikidata description "file format" |
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{{Short description|XML-based file format}}
{{Infobox file format
| name = TTML
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| extended_from = [[XML]]
| standard = [https://www.w3.org/TR/ttml1/ W3C TTML1]
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}}
'''Timed Text Markup Language''' ('''TTML'''), previously referred to as '''Distribution Format Exchange Profile''' ('''DFXP'''), is an [[XML]]-based [[W3C]] standard for [[timed text]] in online media and was designed to be used for the purpose of authoring, transcoding or exchanging timed text information presently in use primarily for [[
TTML Content may also be used directly as a distribution format and is widely supported in media players, with the exception of major web browsers, where [[WebVTT]], the second [[W3C]] standard for [[timed text]] in online media, has better built-in support in connection with the [[HTML5]] <code><track></code> element; many organisations nevertheless use TTML content on web video using their own player code.
== History ==
The idea of adding timing information on the Web by extending HTML <ref>{{cite web |url=https://www.w3.org/TR/NOTE-HTMLplusTIME |title=Timed Interactive Multimedia Extensions for HTML (HTML+TIME)|accessdate=2019-08-09}}</ref> came very early on, out of the work done on the [[Synchronized Multimedia Integration Language]]. Based on [[XML]], the work on TTML started in 2003 <ref>{{cite web |url=https://www.w3.org/blog/news/archives/1571 |title=W3C Launches Timed Text Working Group|accessdate=2019-08-09}}</ref> and an early draft was released in November 2004 as '''Timed Text (TT) Authoring Format 1.0 – Distribution Format Exchange Profile (DFXP)'''
In 2010, after discussions about its adoption in HTML5, [[WHATWG]] opted for a new but more lightweight standard based on the popular [[SubRip|SRT]] format, now named [[WebVTT]].<ref>{{cite web
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|title=WebVTT versus TTML: XML considered harmful for web captions?
|accessdate=16 February 2015
}}</ref>
}}</ref>In February 2012 the [[Federal Communications Commission|FCC]] declared the [[Society of Motion Picture and Television Engineers|SMPTE]] closed-captioning standard for online video content, a superset of TTML, as a "safe harbor interchange, delivery format".<ref>{{cite web |url=https://www.smpte.org/news-events/news-releases/fcc-declares-smpte-closed-captioning-standard-online-video-content-safe |title=FCC Declares SMPTE Closed-Captioning Standard For Online Video Content As Safe Harbor Interchange, Delivery Format |accessdate=20 February 2015}}</ref>▼
▲
In 2015, [[Netflix]], Home Box Office ([[HBO]]), [[Telestream]], [[SMPTE]], and [[W3C]] received a [[Technology_%26_Engineering_Emmy_Award#2015_Awards|Technology & Engineering Emmy Award]] for the category “Standardization and Pioneering Development of Non-Live Broadband Captioning,” for their work on TTML.▼
▲In 2015, [[Netflix]], Home Box Office ([[HBO]]), [[Telestream]], [[SMPTE]], and [[W3C]] received a [[
[https://www.w3.org/TR/ttml2/ TTML2], the second version of TTML started in February 2015, was finalized in November 2018, along with a new revision of [https://www.w3.org/TR/ttml1/ TTML1].
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=== EBU-TT ===
The [[European Broadcasting Union]] (EBU) defined several related profiles. EBU-TT Part 1 (Tech3350) uses a subset of [https://www.w3.org/TR/ttml1/ TTML1] constraining the features to make it more suitable for archive, exchange and use with broadcast video and web video applications.<ref>{{cite web | url=https://tech.ebu.ch/publications/tech3350 |title=Part 1: EBU-TT Part 1 - Subtitle format definition (EBU Tech 3350) |date=24 May 2017}}</ref> EBU-TT Part 3 (Tech3370) extends and constrains Part 1 further, in particular adding functionality to support live streaming of subtitles from the subtitle author to a distribution encoder.<ref>{{cite web | url=https://tech.ebu.ch/publications/tech3370 |title=Part 1: EBU-TT Part 3 Live Subtitling (EBU Tech 3370) |date=24 May 2017}}</ref> EBU-TT-D (Tech3380) is highly constrained profile of TTML1 intended specifically for distribution to players, and has been adopted by HbbTV, DVB and Freeview Play for example.<ref>{{cite web | url=https://tech.ebu.ch/publications/tech3380 |title=EBU-TT-D Subtitling Distribution Format (Tech3380) |date=22 May 2018}}</ref>
=== IMSC ===
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=== DVB ===
[https://www.etsi.org/deliver/etsi_en/303500_303599/303560/01.01.01_60/en_303560v010101p.pdf ETSI EN 303 560 v1.1.1 (May 2018)] is the DVB TTML Subtitling Systems specification. It defines a default conformance point that is the common intersection of conformance between EBU-TT-D and IMSC 1 Text Profile, and allows for subtitle and caption documents conformant to EBU-TT-D, IMSC1 Text Profile or other profiles of TTML to be sent and signalled within DVB MPEG-2 transport streams, and includes the ability to embed fonts for subtitle presentation, also within the transport stream.
=== HbbTV 2 ===
[https://www.etsi.org/deliver/etsi_ts/102700_102799/102796/01.05.01_60/ts_102796v010501p.pdf ETSI TS 102 796 V1.5.1 (2018-09)] is the HbbTV 2.0.2 specification. It specifies that conformant players must be able to play back EBU-TT-D subtitles delivered online for example in ISO BMFF via MPEG DASH, as well as allowing for other existing broadcast subtitle formats.
At [https://developer.apple.com/videos/play/wwdc2017/504/# WWDC 2017] Apple announced support for IMSC 1 Text Profile in HLS, and shortly after shipped systems that include presentation support, including [[iOS]] and [[tvOS]].▼
=== Freeview Play ===
[http://www.digitaluk.co.uk/__data/assets/pdf_file/0004/93118/Freeview_Play_-_Technical_Specification_V3.0.9_2018.pdf Freeview Play — Technical Specification 2018 Profile Version: 3.0.9 (14/07/2017)] defines the application requirements for the [[
=== MPEG CMAF ===
CMAF is the Common Media Application Format published by MPEG as part 19 of [[MPEG-A]], also published as [https://www.iso.org/standard/71975.html ISO/IEC 23000-19:2018 Information technology -- Multimedia application format (MPEG-A) -- Part 19: Common media application format (CMAF) for segmented media]. The format specifies CMFHD presentation profiles in which subtitle tracks shall include at least one "switching set" for each language and role in the IMSC 1 Text profile, while also allowing for other representations of subtitles in WebVTT.
▲==== HLS ====
▲At [https://developer.apple.com/videos/play/wwdc2017/504/# WWDC 2017] Apple announced support for IMSC 1 Text Profile in HLS, and shortly after shipped systems that include presentation support, including [[iOS]] and [[tvOS]].
== References ==
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