From Web Media Text Tracks Community Group

Charter of the Web Media Text Tracks Community Group


This group will work on text tracks for video on the Web, applied to captioning, subtitling and other purposes.


The group follows the process defined for Community Groups at the W3C as per

Scope of Work

This is a community group, not a working group; not everyone is expected to work on all areas, and members are expected to be flexible, recognizing that inflexibility could lead to new groups being formed.

This group plans to work initially on:

1) Documenting a semantic model underlying the caption formats in use, notably TTML, CEA 608/708, EBU STL, and WebVTT.

2) Creating a community specification for WebVTT.

3) Defining the mappings between WebVTT and some selected formats, including at least TTML (W3C/SMPTE), and CEA 608/708.

4) Creating web developer reference and tutorial material, including worked examples.

5) Creating a test suite and/or tools.

A possible transition to REC-track for some of these document(s) is envisaged and that possibility will be used to guide the work and procedures.

The group may produce recommendations for work in other groups, such as CSS, HTML5, and TTWG.


The public mailing list at is the main forum for discussion. It is referred to as "the mailing list of the community group".

The group will also make use of the Wiki, irc, issue, action, bug tracking, and the blog as adequate.

Tools that the W3C makes available are explained at

In recognition of the global nature of the group, and the lack of Zakim bridge support for community groups, the group does not expect many all-group teleconferences, but of course anyone is free to propose or host teleconferences or face-to-face meetings for any interested participants.

Decision-Making Process

The group will strive to reach decisions by consensus. Consensus is defined as the lack of a sustained objection. Objections can be recorded, even if the individual does not sustain their objection as a result of community discussion.

Technology proposals should be supported by requirements, and requirements by use cases. Proposals supported by working code may well be more persuasive.

Any member of the group can notice a question for which they believe consensus is desirable, and ask for a consensus determination. The chair is expected to facilitate the determination of consensus (e.g. by posing a question to the group in email, with a clear indication of when the decision is expected to be made).

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, make a decision, register any objections, and move on. The matter should then be considered resolved unless and until substantial new information becomes available, such as actual implemented reality.

Note, however, that the group will strive to avoid a situation where consensus cannot be achieved.

Licenses and Patent Policy

All contributions to this CG are covered by the contributor license agreement:

All specifications produced by the CG are published under the final specification agreement: