Re: Definition: time-dependent presentation

At 08:39 PM 2002-06-23, Charles McCathieNevile wrote:

>Yep, I think Katie has captured an important distinction.
>On Thu, 20 Jun 2002, Katie Haritos-Shea wrote:
>  I am cross posting because this is a WCAG 2.0 definition that needs some
>  work.......
>  Currently in the latest WCAG 2.0 Draft "time-dependent presentation" is
>  defined as below......
>  <qoute>
>  Definitions (informative)
>  time-dependent presentation
>  (1)A time-dependent presentation is a presentation which
>  is composed of synchronized audio and visual tracks (e.g., a movie),

George Kercher calls it 'temporal' content.

Yes, 'presentation' is too display-smelling if you want to include the case of time-dependent
action opportunities.


Time-dependent content is content where the sense [or more generally operational 
effectiveness] of the content depends in some way on time differences as they are 
realized in the actual, concrete user interaction with the content.

Time-dependent content is sensitive to the time-flow fidelity of its realization in
the delivery context.

Audio and video streams, and time-limited promotional pricing are examples of time-dependent
content.  A synchronized bundle of time-dependent components such as a SMIL presentation may 
be regarded as one time-dependent content object, if the user perceives all the concurrent 
phenomena as part of an integrated experience relating to a common time interval such that 
time-coincidence is significant.

Playback time and nominal playback time need not be exactly one to one, but distortion of
the inter-component synchronization or playback rate beyond some limit may degrade or destroy
the comprehensibility or operability of the content when it is time-dependent.  See the
"slow playback rate" provisions in the standard talking book specification for an example
of such bounded-distortion playback.



>  OR
>  (2)a presentation which requires the user to respond interactively at
>  specific times in the presentation.
>  </quote>
>  .......I think that the (2) is a definition of "response time dependent
>  presentation", rather than "time-dependent presentation".  The response
>  time issue is very important, but different.
>  Also, I think it would be a good idea to provide language that includes
>  other sense modalities (tracks).  I realize that it is a bit premature
>  to include "synchronized smell" and "synchronized vibration" tracks,
>  but, I think we should have language that covers this eventuality.
>  Katie Haritos-Shea
>  Internet/Software/Device Accessibility and Standards
>  Strategist/Developer/Evangelist
>  #571-220-7777
>  "The best and most beautiful things in the world
>       cannot be seen or even touched.
>      They must be felt with the heart."
>                  - Helen Keller
>Charles McCathieNevile phone: +61 409 134 136
>W3C Web Accessibility Initiative fax: +33 4 92 38 78 22
>Location: 21 Mitchell street FOOTSCRAY Vic 3011, Australia
>(or W3C INRIA, Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, France)

Received on Tuesday, 25 June 2002 11:17:27 UTC