**DRAFT** Timed Text Working Group Charter
The mission of
the Timed Text Working
Group, part of the Video in the Web Activity, is to develop W3C
Recommendations for media online captioning by developing and
maintaining new versions of the Timed Text Markup Language (TTML) and
WebVTT (Web Video Text Tracks) based on implementation experience and
interoperability feedback, and the creation of semantic mappings those
Join the Timed Text Working Group.
||30 September 2015
||Proceedings are public
|Initial Team Contact
(FTE %: 20)
|Philippe Le Hégaret,
Thierry Michel, @@tocheck
Mark Sadecki @@tocheck
|Usual Meeting Schedule
Face-to-face: 1-2 per year
This group is chartered to develop formats used for the
representation of streamable text synchronized with other timed media,
like audio and video. Such formats MUST be useable for online media
captioning, described video (aka video/audio description) and should
accessibility user requirements. Such formats MAY also be useable
for broadcast production and exchange.
The Group will:
- Publish a Recommendation for a new Timed Text Markup Language
(TTML) 1.1 specification to include the Note described above.
In the process of producing this new revision, the Group WILL:
- Address any issues found during the development of a
Simple Delivery Profile for Closed Captions.
- Consider for adoption features developed by groups such as
SMPTE, DECE and EBU.
- Produce other technical reports (Notes) on aspects of TTML
processing as appropriate.
- Address v.next issues deferred during last call.
- Seek backward compatibility with TTML 1.0 whenever possible.
- As required, produce a test suite for the above.
- Produce an implementation report, based on the test suite above.
- Publish a Recommendation for the WebVTT language, in particular
the parts that cover the syntax, semantics, and rendering of
subtitles, captions, chapter markers, and textual audio
descriptions for speech synthesis. The Group is expected to
produce annual updates for the Recommendation with previously
specified but now newly supported features by browser vendors.
In the process of producing the specification, the Group WILL:
- Address any issues found in WebVTT: The Web Video Text Tracks Format
produced by the Text Text Community Group. Some may be
deferred to v.next.
- Include all features that have at least two independent and
- Solidify the set of features through the creation of a
WebVTT test suite
- Consider the adoption of new features
Establish a semantic mapping between TTML and WebVTT in order to facilitate
browser implementation and market adoption.
- Produce a Second Edition of
Text Markup Language (TTML) 1.0 Recommendation;
In the process of producing this new edition, the Group WILL:
- Address known errata with the 1.0 specification
- Maintain a simple constrained profile for delivery of closed
captions for video content ("Simple Delivery Profile for Closed
- Produce a technical report (Note) on the application of TTML in
HTML5 (i.e. the mapping of TTML to HTML5/CSS3).
- Describe TTML intermediate synchronic document as HTML5.
- Understand how the presentation syntax and semantics
relate to CSS3.
- Produce a technical report (Note) on the application of TTML in
live production and streaming such as for video content.
The new work is expected to be broadly available and should be provided on
a timely fashion. This charter features a tightly constrained scope designed to
ensure that the Working Group will meet its schedule and objectives.
The Working Group is expected to demonstrate at least two interoperable
implementations of all available features in the recommendations.
- A W3C Recommendation for a new Timed Text Markup Language (TTML) 1.1 specification.
- A W3C Recommendation for the WebVTT specification, with further revisions as needed.
- A Second Edition of the Timed Text Markup Language (TTML) 1.0 Recommendation.
- Updates to the Working Group Note on a simple constrained profile for delivery of closed captions for video content ("TTML Simple Delivery Profile for Closed Captions (US)").
- Working Group Note on the mapping between TTML and WebVTT
- Working Group Note on the application of TTML to HTML5 (i.e. mapping of TTML to HTML5/CSS3).
- Working Group Note on the live production and streaming of video content using TTML.
The Working Group will update the test suites intended to promote
implementations of the above specification(s) and to assess interoperability between
these implementations. The Group will also produce an implementation report for each
|Note: The group will document significant
changes from this initial schedule on the group home page.
|Timed Text Markup Language (TTML) 1.0 (Second Edition)
|TTML in HTML 5 Note
|TTML Live Update Note
|Timed Text Markup Language (TTML) 1.1
As part of the Video in the Web Activity, the Timed Text Working Group will
be represented in the Hypertext Coordination Group.
Dependencies with W3C Groups
- HTML Working Group
- The HTML specification is intended to provide a semantic-level markup
language and associated semantic-level scripting APIs for authoring
accessible pages on the Web ranging from static documents to dynamic
applications. It includes media elements to present video, audio and video
text tracks and their associated APIs.
- CSS Working Group
- The work of the Working Group coordinates with this group on
presentation and layout issues.
- Protocols and Formats Working Group
- The PFWG looks at the formal Web technologies (protocols, formats,
etc.) from an accessibility perspective.
- Web Content Accessibility Guidelines Working Group
- This Group aims to make Web content accessible for people with
Liaisons with W3C Groups
- Scalable Vector Graphics (SVG) Working Group
- The Scalable Vector Graphics language allows authors to describe
two-dimensional vector and mixed vector/raster graphics. It includes
support for multimedia: audio, video and animation.
- Hypertext Coordination Group
- The purpose of this group is to identify technical areas where
different working groups may overlap, encourage discussion, and to
coordinate their work.
- Web Media Text Tracks Community Group
This group developed the first Community report for the WebVTT format and will continue to explore new features.
- ISO/IEC JTC-1/SC-29 WG 11 Moving Picture Experts Group (MPEG)
- This group is developing standards for coded representation of digital
audio and video, including MPEG-4.
- Society of Motion Picture and Television Engineers (SMPTE)
- This organization was founded to advance theory and
development in the motion imaging field. SMPTE produced
extensions to TTML 1.0 that are part of SMPTE-TT.
- European Broadcasting Union (EBU)
- EBU is a confederation of national broadcasting organisations,
facilitate exchange of audiovisual content. This Group has
developed an XML -based format for use in subtitling production
and exchange, based on TTML 1.0.
- Digital Entertainment Content Ecosystem (DECE)
- DECE is a consortium chartered to develop standards for the
digital distribution of premium content.
To be successful, the Timed Text Working Group is expected to have 5 or more
active participants for its duration. Effective participation to Timed Text
Working Group is expected to consume one half-day per week for each
participant; one day per week for editors. The Timed Text Working Group will
allocate also the necessary resources for building Test Suites for each
Participants are reminded of the Good Standing requirements of the W3C Process.
This group primarily conducts its work on the public mailing list
A Member-only mailing list, firstname.lastname@example.org (archive) is available
for administrative purposes such as liaison with Member-only Working Groups.
Information about the group (deliverables, participants, face-to-face
meetings, teleconferences, etc.) is available from the Timed Text Working Group home
As explained in the Process Document (section 3.3), this group will seek to make decisions when
there is consensus. When the Chair puts a question and observes dissent, after
due consideration of different opinions, the Chair should record a decision
(possibly after a formal vote) and any objections, and move on. This charter is
written in accordance with Section
3.4, Votes of the W3C Process Document and includes no voting procedures
beyond what the Process Document requires.
This Working Group operates under the W3C
Patent Policy (5 February 2004 Version). To promote the widest adoption of
Web standards, W3C seeks to issue Recommendations that can be implemented,
according to this policy, on a Royalty-Free basis.
For more information about disclosure obligations for this group, please see
the W3C Patent Policy
About this Charter
This charter for the Timed Text Working Group has been created according to
section 6.2 of the Process Document.
In the event of a conflict between this document or the provisions of any
charter and the W3C Process, the W3C Process shall take precedence.
charter is also available.
Philippe Le Hégaret, and al.
Copyright© 2013 W3C
, Keio, Beihang),
All Rights Reserved.
$Date: 2013-05-14 23:49:43 $