W3C Interaction

"Television and the Web" Interest Group Charter

This charter is written in accordance with section 3.2.2 of the W3C Process.

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Table of Contents

Mission Statement

W3C held a Workshop on "Television and the Web" (TVWeb) in June 1998. At this workshop, it became evident that different standardization bodies and vendors will make a significant effort over the next year to integrate Web and television technologies. This enables applications such as browsing the Web using a television set, or using Web content formats to annotate a television broadcast, making the television more interactive.

Historically, television standards tend to differ between regions of the world, and are issued by regional standardization bodies. Thus, a television receiver purchased in one part of the world is not necessarily usable in another part of the world. This is in stark contrast with the technology used by the Word Wide Web. Any Web user can read all Web pages, no matter where in the world they are stored, because the Web uses the same technology all over the world. The integration of TV and the Web should not lead to a fragmentation of the Web, even though such fragmentation is typical in the television world.

The World Wide Web Consortium is an international organisation, with branches in America, Asia and Europe. It is therefore well-positioned to avoid the regional solutions typical of TV standards when it comes to integrating the Web and television.

The participants at the "TVWeb" workshop expressed interest in W3C taking a more active role in the ongoing efforts of TV/Web integration, particularly since these efforts concern subsetting or extending some of the core W3C technologies (HTML, CSS, XML, ...).

This Interest Group has three missions:

  1. It serves as a pool of experts on TV/Web integration, some of which will participate in the W3C working groups relevant to TV/Web integration.
  2. It serves as a coordination body with the TV-specific regional standardization groups working on TV/Web integration.
  3. It will prepare and review documents related to TV/Web integration.
    These documents should be produced quickly (typically within two months). Their purpose is mainly to point out specific requirements in the area of TV/Web integration, and to give rough ideas on how these requirements can be resolved.
    It is not the main purpose of this Interest Group (or any W3C Interest Group, for that matter) to produce specifications. Production of specifications and W3C recommendations is reserved to W3C working groups (see definition of interest group in W3C process).


The W3C process defines the general scope of an interest group as follows:

"An Interest Group brings together people who wish to evaluate potential Web technologies and policies. An Interest Group does not have the goals of a Working Group -- development of specifications or code. Instead, it serves as a forum to explore cooperation and exchange ideas.

It is quite possible that an Interest Group's studies will lead to the creation of a Working Group, but this may not be known in advance nor is it guaranteed."

The following list of topics is based on discussions at the W3C workshop on "Television and the Web". Additional topics may be added during the lifetime of the Interest Group, if there is enough interest.

Coordination with TV standardization bodies

A first important mission of the TVWeb IG is to coordinate with efforts in other TV standardization groups, avoiding duplication of effort and fragmentation of the Web by incompatible standards.

TV-specific use of HTML and CSS

In the television community, there is a desire to adapt certain W3C specifications before using them in TVWeb applications. This means that only a limited set of features of these specifications may be supported, or that new, TV-specific features are added to these specifications. This requires that some members of the Interest Group represent TV-specific interests in the HTML- and CSS working groups.

"tv" URL-scheme

A new URL scheme is needed to address content that is broadcast in a TV channel. This requires to study and, potentially, harmonize existing proposals for tv-related URLs. The review must take the results URL registration Working Group in the IETF of the into account. The idea is to review the existing approaches within the W3C TV IG, after which they will be proposed to the IETF, in order to become standards-tracks RFCs, similar to other URL schemes (mailto:, ...).

The previous TVWeb Interest Group produced a W3C Note entitled "TV Broadcast URI Schemes Requirements", which should also be taken into account.

Optional Work Items

The following work items have been suggested at the W3C workshop on "Television and the Web". They are listed in no particular order. It depends on whether there is sufficient interest and commitment within the group to pursue them:

Accessibility of program guides
The Interest Group should address the issue of access to HTML-based electronic programm guides for disability groups such as the visually impaired
Authoring guidelines
These authoring guidelines should describe in layman-terms how to use HTML and CSS so that you can do "author-once - display anywhere", instead of having to redevelop every site several times for different display environments.
Default style sheet for TV
A television set has different display characteristics than an PC. Consequently, the default presentation rules for HTML on PCs cannot be transformed without modification into the TV world. But TVs can also benefit from the existence of a well-defined default style sheet. This requires analysing existing products, and distilling common rules used in these products for displaying HTML on a TV screen. The result should be a document produced by the TV IG, documenting existing practice and recommending (but not necessarily standardizing) empirical default settings to implementors of new products. A first draft of a default style sheet is available.
Metadata description
There is an opportunity to harmonize work in the television community on MPEG-7 with W3C's RDF work.
Device profiles
To avoid that the set-top box tries to display content with features that it does not support, a mechanism for describing device profiles is needed. W3C has started work in this area in the CC/PP Working Group.
Guidelines for re-processing color palettes
Guidelines on how to translate between different color palettes of different devices will help content authors to know what color transformations will take place.
Transition effects
CSS is one possible vehicle to express an enumerated set of transition effects, as it is concerned with presentation. Another possibility is expressing transition effects in SMIL, since this language takes into account temporal aspects. The TVWeb interest group should review the work on transitions in the W3C CSS and SYMM activities.
Accurate layout control/Accurate Timing Control
Accurate layout and timing control are important issues when integrating Web content with television content. The interest group should review W3C's work on CSS and SMIL to make sure that these goals are achieved.
API to VCR controls (and other devices)
A Web page can provide functionality to control devices such as a VCR used to register a television program. This requires a standardized API.
Flexible temporal synchronization using CSS
Expressing temporal synchronization in CSS allows reuse of certain kinds of Web content. This effort should be aligned with the SMIL approach to synchronization. Properties should be added to CSS that allow expressing temporal aspects of presenting information. These properties should be aligned with the SMIL attributes and time model. The TVWeb interest group should review the work on temporal synchronization in the W3C SYMM activity.
Unidirectional HTTP
Unidirectional HTTP as proposed by the Advanced Television Enhancement Forum (ATVEF) mainly defines a subset of headers used in http responses that should be transmitted together with the web-content in the television signal.


This Interest Group is scheduled for one year, from end of January 2000 to end of January 2001.

Success Criteria

The Interest Group has fulfilled its mission if it succeeds in unifying the efforts of different TV standardization bodies for Web integration, and in avoiding a fragmentation of the Web.

Release Policy

By defaults, all documents developed by the IG are public.

Documents have a date at which they will be declared stable. Any remaining issues at this date will be described in the document, and not delay of making the document stable.

Documents that are prepared by the Interest Group will be published on the W3C site.

Documents that do not fulfill the criterion above (e.g. longer documents describing specific technical solutions brought up by one member of the IG) have to be submitted to W3C before they can be published on the W3C site.


This Interest Group does not have any deliverables, and consequently, no milestones.


To facilitate cooperation with the TV community, this charter and the archives of the Group's mailing list (www-tv@w3.org) will be open to the public.

Relationship with other W3C Activities

The TVWeb IG will have to take into account technologies developed by other groups within W3C, and to advise them about the requirements of television. At the time of writing, the following ongoing W3C activities are concerned:

Coordination with External Groups

The following is a list of groups that are known or presumed to be working on or interested in integration of Television and Web technology, including pointers to the respective projects.

Communication Mechanisms

The participants of the "Television and the Web" IG communicate via a public, archived mailing list, www-tv@w3.org (archive). Teleconferences and face2face meetings to discuss particular issues may be scheduled at the discretion of the chair.


Membership in the IG is open to the public. All subscribers to the mailing list www-tv@w3.org are IG members. There are no minimum requirements, neither in terms of expertise, not in terms of time dedicated to the group. If the IG decides to prepare a document, the editor(s) will be asked to commit to a certain percentage of their time.

W3C Team

The TVWeb IG will be chaired by a W3C Team member, which will also be W3C team contact. Resources of additional W3C team members may be required for some activities  (review of "tv" URL schemes, TV-specific subsets of HTML and CSS, Authoring guidelines etc.).

Philipp Hoschka (ph@w3.org) Last modified: $Date: 2000/01/20 15:06:21 $