W3C | Submissions

Comment on HTML+TIME Submission

W3C is pleased to receive the HTML+TIME submission from Compaq Computer Corporation, Macromedia Inc. and Microsoft Corporation.

This submission proposes a set of elements and attributes to include time in a document, and a mechanism to add these to an HTML document to turn it into a time-based presentation. This has the advantage that authors do not have to learn a programming language anymore for writing timed HTML presentations.

The timing part of HTML+TIME reuses goals, concepts and techniques of the W3C recommendation "Synchronized Multimedia Integration Language (SMIL) 1.0 Specification". Compared to SMIL 1.0, this submission makes the following main contributions:

As presented, the proposal focuses on integrating time-based information into HTML only. However, other XML-based formats (e.g. vector graphics languages) could benefit from a similar integration. The submission already gives an example for VML. It thus seems interesting to examine whether the proposal can be generalized to allow integration of time-based functionality not only into HTML, but into general XML-based languages. This requires a study whether it is possible to define generic rules on how to integrate time-based functionality with XML-based formats. Of course, HTML integration is an important and necessary first step and case study in this development.

Furthermore, it may prove beneficial to include the SMIL 1.0 elements and attributes reused by HTML+TIME by reference, rather than copying them directly into the HTML+TIME specification. This would avoid redundant specification and ensure consistency between specifications.

The proposal emphasizes the use of timing attributes (in contrast to the timing structures in SMIL). This will tend to obscure the timing structure of the document. The timing relationships should be made as explicit as possible.

Timing may be intrinsically inseparable from the content, or it may be a pure styling/presentation issue, or something in between. This suggest that timing information might be provided both in content and in stylesheets.

Using style rules to apply timing information to markup elements has the benefit that when the same timing behaviour is needed for multiple elements, or even multiple documents, style sheets can be specified more compactly compared with duplicating the timing information for each effected element. Style sheets also offer the potential for selecting different presentations by switching style sheets.

The proposal touches upon transition effects in an appendix. A declarative treatment of simple transition effects would significantly enrich the user experience and would seem like a natural addition to the timing features covered in the proposal.

Capability to accelerate or decelerate a presentation is mentioned in 'Appendix D: Additional Issues to Consider' with the recommendation that the capability to adjust pace should be minimal. However the ability to significantly control the pace of a presentation is important for accommodating a variety of functional issues related to disability. Users may require a slower-paced presentation due to limitations of dexterity, cognitive processing, or less efficient input or output access through adaptive devices. Conversely someone who uses only the audio and text portions of a presentation may be accustomed to and require a much faster pace of presentation to maintain usability.

Next Steps

The integration with HTML in HTML+TIME should be reviewed within the HTML activity , the new time-related functionality HTML+TIME should be reviewed within the Synchronized Multimedia activity, and the additions to the Document Object model should be reviewed by the Document Object Model activity. The feasibility of integrating timing properties as part of style rules should be considered within the Style activity.

The W3C membership is invited to discuss the disposition of the submission in the w3c-ac-forum mailing list or to advise the director in confidence via the W3C staff contacts.

Disclaimer: Placing a Submission on a Working Group agenda does not imply endorsement by either the W3C Staff or the participants of the Working Group, nor does it guarantee that the Working Group will agree to take any specific action on a Submission.

Philipp Hoschka (ph@w3.org), W3C, Editor SMIL Specification
Dave Ragget, ( dsr@w3.org), W3C lead for HTML
with input from: Judy Brewer (jbrewer@w3.org), W3C, Director, Web Accessibility Initiative (WAI) International Program Office, Martin Duerst  (duerst@w3.org), W3C, Internationalization Activity Lead
$Date: 1998/09/28 15:52:08 $