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Re: Alt-Registry Proposal

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 3 May 1999 22:19:17 -0400 (EDT)
To: Jan Richards <jan.richards@utoronto.ca>
cc: "w3c-wai-au@w3.org" <w3c-wai-au@w3.org>
Message-ID: <Pine.LNX.4.10.9905032218460.22923-100000@tux.w3.org>
This looks pretty cool to me...


On Mon, 3 May 1999, Jan Richards wrote:

  >From the document:
  2.3.1: [Priority 1] 
       Prompt the author to provide alternative content (e.g., captions,
  descriptive video). 
  2.3.2: [Priority 1] 
       Prompt the author for all missing structural information (e.g., in
       FIELDSET, OPTGROUP and LEGEND for form controls). 
  2.3.3: [Priority 2] 
       Provide pre-written alternative content for all multimedia files
  packaged with the
       authoring tool. 
  2.3.4: [Priority 3] 
       Provide a mechanism to manage alternative content for multimedia
  objects, which
       retains and offers for editing pre-written or previously linked
  alternative content. 
  2.3.5: [Priority 1] 
       Do not insert automatically generated (e.g., the filename) or
  place-holder (e.g., "image")
       equivalent text, except in cases where human-authored text has been
  written for an
       object whose function is known with certainty. 
  Jan's Alt-Text Registry Technique Proposal
  In checkpoint 2.3.4 a recommendation is made that mentions the provision
  of a "mechanism to manage alternative content". This checkpoint is
  prioritized as a level 3, meaning that in itself, it does not have a
  critical effect on an authoring tool's likelihood of producing
  accessible mark-up. However, several limited  extensions to this
  alternative content mechanism (ACM) have the potential to simultaneously
  meet several higher priority checkpoints and dramatically improve the
  usability of an access aware authoring tool . In particular:
  1. The ACM should maintain a list of associations between object file
  names and authored responses to prompts for alternative content (as per
  checkpoint 2.3.1 [Priority 1]). The alternative content may take the
  form of short strings (i.e. "alt"-text) or pointers to descriptive files
  (i.e. "longdesc", transcripts, etc.). Multiple associations for the same
  object for different languages or contexts should also be handled.
  2. The ACM would offer the associated alternative content as a default
  whenever the appropriate associated object is selected for insertion. If
  no previous association is found the field should be left empty (i.e. no
  purely rule-generated alternative content should be used). Note: the
  term "default" implies that the alternative content is offered for the
  author's approval. The term does not imply that the default alternative
  content is automatically placed without the author's approval. Such
  automatic placement may only occur when in situations where the function
  of the object is known with certainty as per checkpoint 2.3.5 [Priority
  1]. Such a situation might arise in the case of a "navigation bar
  builder" that places a navigation bar at the bottom of every page on a
  site. In this case, it would be appropriate to use the same "alt"-text
  automatically for every instance of a particular image (with the same
  target) on every page. 
  3. The alternative content mechanism should be closely integrated with
  the pre-written alternative content provided for all packaged multimedia
  files, as per checkpoint 2.3.3 [Priority 2]. This would allow the
  alternative content to be automatically retrieved whenever the author
  selected one of the packaged objects for insertion. An important benefit
  of the system would be the ease of adding a keyword search capability
  that would allow efficient location of multimedia based on their
  alternative content.
  Jan Richards
  University of Toronto

--Charles McCathieNevile            mailto:charles@w3.org
phone: +1 617 258 0992   http://www.w3.org/People/Charles
W3C Web Accessibility Initiative    http://www.w3.org/WAI
MIT/LCS  -  545 Technology sq., Cambridge MA, 02139,  USA
Received on Monday, 3 May 1999 22:19:23 UTC

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