Re: Media Requirements: Structural Navigation (plus some misc reqs)

Janina,

I have worked through the content navigation section on the wiki at
http://www.w3.org/WAI/PF/HTML/wiki/Media_Accessibility_Requirements#Content_Navigation_by_Content_Structure
extracting the requirements.

It might be good if you have a look through and see if I missed something.

Thanks,
Silvia.


On Wed, May 19, 2010 at 9:22 AM, Janina Sajka <janina@rednote.net> wrote:
> The following is a draft. Comments, edits, etc., most welcome.
>
> These will be in the Wiki soon, so you may want to follow developments
> there at the following URI:
> http://www.w3.org/html/wg/wiki/Accessibility_Requirements_of_Media
>
>
> Sec. 1.10
> Content Navigation by Content Structure
>
> Most people are familiar with fast forward and rewind in media content.
> However, fast forward and rewind, because they progress through content based
> only on time, are ineffective particularly when the content is being used for
> other than entertainment purposes. People with disabilities are also
> particularly disadvantaged if forced to rely solely on time-based forward and
> rewind to study content.
>
> Fortunately, most content is structured, and appropriate markup can expose this structure to forward and rewind controls:
>
> *       Books generally have chapters and perhaps subsections within those
> *       chapters. They also have structures such as page numbers, side-bars,
> *       tables, footnotes, tables of contents, glossaries, etc.
>
> *       Short music selections tend to have versus and repeating choruses.
>
> *       Larger musical works have movements which are further dividable by
> *       component parts such as "Exposition, Development, and Recapitulation;"
> *       or "Theme and Variations."
>
> *       Operas, theatrical plays, and movies have acts and scenes within those
> *       acts.
>
> *Television programs generally have clear divisions, e.g.
> *       newscasts have individual stories usually wrapped within a larger
> *       structure called "News, Weather, and Sports."
>
> *       A lecturer may first lay out the issue, then consider a series of
> *       approaches or illustrative examples, and finally the lecturer's
> *       conclusion.
>
> Just as the structures introduced particularly by nonfictional titles make
> books more usable, media is more usable when its inherent structure is exposed
> by markup. And, markup-based access to structure is critical for persons with
> disabilities who possess less ability to infer structure from purely
> presentational queues.
>
> Structural navigation has proven highly effective internationally in various
> programs of electronic book publication for persons with print disabilities.
> Nowadays, these programs are based on the ANSI/NISO Z39.86 specifications, (see
> http://www.daisy.org/daisy-standard). Z39.86 structural navigation is also
> supported by e-publishing industry specifications (see
> http://www.idpf.org/).
>
> Structural navigation markup must support both global navigation by the larger
> structural elements of a media work, and also the most localized atomic
> structures of that work, even though authors may not have marked-up all levels
> of navigational granularity.
>
> Structural navigation must be possible through third-party provided
> navigational markup files.
>
> Structural navigation must keep all content representations in sync, so that
> moving to any particular structural element in media content also moves to the
> corresponding point in all provided alternate media representations (captions,
> described video, transcripts, etc) associated with that work.
>
> /end 1.10
>
>
> Sec. 1.11
> Miscellaneous Requirements
>
> 1.11.1  Direct Device Control
>
> Multiple user devices must be directly addressable. It must be assumed that
> many users will have multiple video displays and/or multiple audio output
> devices attached to an individual computer, or addressable via LAN. It must be
> possible to configure certain types of media for presentation on specific
> devices, and these configuration settings must be readily overwritable on a
> case by case basis by users.
>
> 1.11.2 Time Scale Modification
>
> While all devices may not support the capability, a standard control API must
> support the ability to speed up or slow down content presentation without
> altering audio pitch.
>
>
> --
>
> Janina Sajka,   Phone:  +1.443.300.2200
>                sip:janina@asterisk.rednote.net
>
> Chair, Open Accessibility       janina@a11y.org
> Linux Foundation                http://a11y.org
>
> Chair, Protocols & Formats
> Web Accessibility Initiative    http://www.w3.org/wai/pf
> World Wide Web Consortium (W3C)
>
>
>

Received on Wednesday, 26 May 2010 10:23:55 UTC