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SMIL techniques

From: Charles McCathieNevile <charles@w3.org>
Date: Wed, 11 Oct 2000 10:24:42 -0400 (EDT)
To: WAI AU Guidelines <w3c-wai-au@w3.org>
Message-ID: <Pine.LNX.4.21.0010110953150.26600-100000@tux.w3.org>
These are the techniques that Marjolein and I worked on in the breakout
session. They are numbered by ATAG checkpoints.

Please make comments in the next week or so, and then I plan to incorporate
them and the other stuff that people did into a new draft of the techniques
document.

Cheers

Charles

1.1 For SMIL 1.0
Implement the spec - not necessary, sufficient, better
Implement the features listed in SMIL-access - necessary, sufficient See also 5.1, 5.2...

1.2
Seperate multiple imported media tracks. better

Maintain title/alt/abstract/longdesc information. Necessary

Maintain synchronisation cues. Necessary

Maintain captioning/overdub information, where possible using SMIL test attributes. Necessary

Maintain selection order (and all choices) for switch elements.

Where stuff is exported in another format, include the accessibility features (alt, title, synch, captions, etc) - if necessary as a part of the single presentation.

1.3
Synchronise explicitly where possible.

Publish in SMIL.

Provide titles for tracks.

It would be nice to have a clearer way of specifying the equivalence relationships of captions, text tracks, etc. (test attributes don't specify that something is a caption track, just that it should be played in a presentation where they are requested. Could use embedded metadata, or could use the longdesc attribute (but that's kind of tricky - most alternatives aren't really a description..)
@@CMN take this to PF (CMN - done this)

Provide consistent styling for linked elements.

SMIL 2.0: Use animation module rather than procedural scripting where possible

1.4 - Test templates for WCAG conformance. (see AERT's SMIL section ;-) Nec/suff

2.1
Generate SMIL 1.0. When SMIL 2.0 becomes available, implement it. necessary and sufficient.

Use PNG for a lossless image format. necessary for software that can produce images.

When SVG becomes a recommendation use it as an image format for vector-based images and for animations. necessary for software that produces images

@@Should images be converted? Depends on whether the SMIL tool does anything with images or just adds them.

@@Should we have a list of Working draft languages? 

2.2 - Generate content type according to spec. necessary and sufficient.

2.3
Validate documents against SMIL spec, warn if they don't validate. Necessary and sufficient
@@Does this just double 4.1? 2.1?

3.1
Ask for captions for presentations which have an audio track. Necessary P1
Ask for audio description of video tracks / slideshow presentations. Necessary P1
Ask for the above two to be marked for synchronisation. Nec P1
Ask for alt, title, for all media elements. Necessary P1
Ask for abstract, longdesc. Necessary???@@

Above are collectively sufficient for P1


@@WCAG1 - 2.1/2.2 should be for ATAG1-3.2

@@Use markup rather than images - WCAG1-3.1 how does this work in SMIL? Is it OK to have image slideshow with text alternative slideshow? @@PF is there a mechanism that would allow us to select which to have?

@@ WCAG1-6.2 how is this different from WCAG1-1.4?

@@WCAG1-7.{1,2,3} Are these requirements met by user agents?

@@WCAG1-13.2 see issue above about explicitly specifying equivalence relationships.

Prompt for a text equivalent for each active region (a element). Necessary P3 @@WCAG checkpoints on this assume HTML image maps - please fix in WCAG 2

Ask the author to provide multimedia content for text-only presentations Nec P3
Above are sufficient for P3 (are they?)

3.2
Prompt the author for language information (nec P1)
Prompt for link target information (nec P2, can be covered by having text equivalents see above, or ask author if they make sense)
Prompt for abstract for the presentation (P3)

For repeated links to the same destination ask the author to consider using the same content. (may not always make sense, may not be possible to know - e.g. time-based links)

For text elements, see text editing. Nec/suff for tools that allow generation/editing of text content

@@WCAG1-6.2 belongs with ATAG1-3.1

@@tab order - check. The assumption that there is a tab order seems not to work in SMIL elements.

3.3 - Check presupplied content - see ATAG1-1.4 Nec/Suff

@@Make it clear that this is stuff that comes with the tool.

3.4 - Do it. Necessary and sufficient.

3.5 - Do it. Necessary and sufficient. Doing this should also meet 3.4 and (a lot of? all of?) 

3.1

4.1, 4.2 see AERT SMIL section ;-)

4.3 - Do it. Nec/Suff - note that this may mean telling the author that the markup will be changed if the tool is used, and then letting them decide to go ahead.

4.4 - Do it by providing results of 4.1

4.5 - @@Does this apply???

5.1 - Do it.



5.2 - Do it.

Making this happen for all accessibility authoring, not just P1, is even
better.

6.all - Do it.

7.all - See general UI stuff.
Received on Wednesday, 11 October 2000 10:24:42 GMT

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