Note: This document is a proposed charter from Google, Inc.

[Proposed] WebVTT Working Group Charter

The mission of the WebVTT Working Group, part of the HTML Activity, is to create a W3C specification starting from the WHATWG WebVTT (Web Video Text Tracks) language and solidify it through the creation of a WebVTT test suite and through the creation of semantic mappings of other subtitle formats to or from WebVTT in order to facilitate browser implementation and market adoption.

Join the WebVTT Working Group.

End date 31 December 2014
Confidentiality Proceedings are Public
Initial Chair @@whoever the implementors want as chair @@
Initial Editor Silvia Pfeiffer? @@or whoever the implementors want as editor @@
Team Contact
(FTE %: @@)
Usual Meeting Schedule IRC channel: #webvtt at
Teleconferences: up to 1 per week on an as-need basis
Face-to-face: up to 2 per year
Decisions are made on the Working Group mailing list


This group will work with the WHATWG to maintain 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 aim is a publication of a WebVTT recommendation that includes all features that have at least two independent and interoperable implementations in major Web browsers, and publication of annual updates of that recommendation with previously specified but now newly supported features by browser vendors.

The group will further work on new WebVTT features. It will achieve this by working on definitions of semantic mappings of other common subtitle, chapter, and audio description formats to or from WebVTT as well as working on a comprehensive test suite. Example format are the CEA-608 caption format, the EBU STL captions format, and the DAISY 3 navigation format.

The Group will construct a comprehensive test suite to help implementors of the language build interoperable tools that implement the WebVTT language and any semantic mappings defined.

Success Criteria

The WebVTT Working Group's work will be considered a success if there are multiple independent complete and interoperable implementations of its deliverables that are widely used.

End date

After creation of a recommendation for all documents, the WebVTT Working Group will continue to exist for maintenance purposes as long as there is continued participation of at least three browser vendors in the group's activities.



WebVTT Language Specification
The WebVTT language (Web Video Text Tracks) is a format for marking up external text track resources for media elements in HTML. This includes the syntax, semantics, and rendering of subtitles, captions, chapter markers, and textual audio descriptions for speech synthesis.
WebVTT Conversions
WebVTT Conversions capture semantic mappings from and to other formats for marking up external text track resources. The group is committed to delivering a conversion document for CEA-608 and EBU STL captions. Other format mappings may also be worked on by the group.

Other Deliverables

Test Suite
The Group will create and maintain a comprehensive test suite for the WebVTT format specification and the semantic mappings.
Primer/Best Practice Documents
The Group may create other documents to support developers when designing applications with WebVTT support.


Note: The group will document significant changes from this initial schedule on the group home page.
Specification FPWD LC Announcement Call for Implementations / CR Call for Proposed Recommendation / PR Rec Annual Call for Review of Edited Rec / ERec Annual Edited Rec
WebVTT Format Specification Oct 2011 Aug 2012 Dec 2013 Dec 2013 Dec 2014 every Aug every Dec
CEA-608 Conversion to and from WebVTT Jan 2012 May 2012 Aug 2012 Dec 2013 Dec 2014 every Aug every Dec
EBU STL Conversion to and from WebVTT March 2012 May 2012 Aug 2012 Dec 2013 Dec 2014 every Aug every Dec

Any other formal document that the Working Group may be working on in addition will be synchronized with this timetable as much as possible, but will follow their own timetable. This table will be updated when such a document is devised.

Only features that have at least two independent and interoperable implementations will be contained in the documents that are published as Proposed Recommendation (PR), Recommendation (Rec), and Edited Recommendation (ER).

As the Group publishes a PR document, it will create a Working Draft version of the same document containing the normative material from the PR and any other material it may be working on, but which hasn't yet had sufficient implementation. As sections in this Working Draft gain at least two independent and interoperable implementations, they will be added to the next PR, Rec, or ERec, depending on which maturity level the specification has achieved.

Dependencies and Liaison

The Group is expected to seek feedback from the broader W3C community.

Relationship to External Groups

Since this is a public group, the Group will not liaise with any other group in a manner distinct from the manner made available to any public individual. This includes interaction with other W3C Working Groups and the WHAT Working Group.

Thus, the Group's cooperation with another working group will merely consist of members of this working group participating in the other working group and inviting contributors to the other working group effort to participate in this group and vice versa.

Other groups of particular interest are:


Participation in the WebVTT Working Group consists of contributing to group discussions either on the mailing list, on IRC, or in other forums. To be successful, the WebVTT Working Group is expected to have active participation of a diverse community for its duration.

The Chairs are expected to contribute a minimum of one day per week towards the Working Group, the specification editor(s) a minimum of two days per week. There is no minimum attendance requirement on participation for other group participants.

W3C Member representatives may join the Working Group using the regular W3C process. Individuals who are in good standing with the group and whose employers are in good standing with the W3C may join the working group as well, but must first agree to Royalty-Free licensing under the W3C Patent Policy.


This group primarily conducts its technical work on a Public mailing list public-webvtt. It is referred to in the rest of this document as the Working Group mailing list. The group will not have any other mailing lists. The public is invited to post messages to this list.

Discussion may also occur in other forums, for example IRC, teleconferences and face-to-face meetings. WebVTT Working Group teleconferences will focus on discussion of particular features, and will be conducted on an as-needed basis.

The W3C may provide teleconference facilities for teleconferences if given sufficient notice. The W3C will provide a wiki and an IRC channel.

The Group will have a wiki for contributions by all participants, a bug tracker to help editors keep track of feedback, and source control repositories for the development of specifications and test suites.

Information about the group, its deliverables, and participants will be available from the WebVTT Working Group home page.

Decision Policy

As explained in the W3C Process Document (section 3.3), this group will seek to make decisions when there is consensus and with due process.

The expectation is that typically, an editor or other participant makes an initial proposal, which is then refined in discussion with members of the group and other reviewers, and consensus emerges with little formal voting being required. Decisions regarding material that is already implemented should in particular reflect implemented reality.

The chair is responsible for working with each editor to ensure that the decisions made in the development of the deliverables are of the highest possible technical quality.

If consensus does not emerge and a decision is necessary for timely progress, the chair should, after careful consideration of the range of views presented, put a question out for voting within the group (allowing for remote asynchronous participation -- using, for example, email and/or web-based survey techniques) and record a decision, along with any objections. The matter should then be considered resolved unless and until new information becomes available, such as actual implemented reality.

Patent Policy

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 Implementation.

About this Charter

This charter for the WebVTT 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.