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Re: [a11y-metadata-project] Schema.org accessibility proposal Review...

From: Charles Myers <charlesm@benetech.org>
Date: Mon, 9 Sep 2013 10:58:24 +0000
To: Emmanuelle Gutiérrez y Restrepo <emmanuelle@sidar.org>
CC: Dan Scott <dan@coffeecode.net>, Madeleine Rothberg <madeleine_rothberg@wgbh.org>, Charles McCathie Nevile <chaals@yandex-team.ru>, Andy Heath <andyheath@axelrod.plus.com>, "a11y-metadata-project@googlegroups.com" <a11y-metadata-project@googlegroups.com>, "<public-vocabs@w3.org>" <public-vocabs@w3.org>, Gerardo Capiel <gerardoc@benetech.org>, Dan Brickley <danbri@google.com>, Alexander Shubin <ajax@yandex-team.ru>, Egor Antonov <elderos@yandex-team.ru>, Liddy Nevile <liddy@sunriseresearch.org>, "Richard Schwerdtfeger" <schwer@us.ibm.com>, George Kerscher <kerscher@montana.com>, Jason Johnson <jasjoh@microsoft.com>, Matt Garrish <matt.garrish@bell.net>
Message-ID: <383FED51-9D5F-4962-AD03-B3EE30EF41F0@benetech.org>
This property has had three names over the editorial history of the spec.

hasFeature was the start (going fro AfA, I believe).  That was too generic to fit into creating work (it would confuse almost anyone)
accessibilityFeature was next, which at least told the use
adaptationFeature followed that, which told was it was useful for.

However, there were three items that were neither just for accessibility or adaptations.  These were MathML, ChemML and Latex.

mediaFeature followed that That caused us to say that the features were not limited to just accessibility.  And they are not alternatives.

Now we propose mediaAlternative and AccessAlternative.  Or even AccessFeature.  These all have the same problem.  As someone pointed out, mediaFeature has the advantage of being extensible for expressing semantics beyond just accessibility, which may improve the chance of widespread adoption.

All that history aside, I do like the lumping of accessMode and the features/alternatives (whatever name you use).  But note that many of the features, like tactilegraphic and ChemML defy that a bit.

I'd want to work it out in a chart, much like the practical properties guide https://wiki.benetech.org/display/a11ymetadata/Practical+Properties+Guide does for the current method.

On Sep 8, 2013, at 3:48 PM, Emmanuelle Gutiérrez y Restrepo <emmanuelle@sidar.org<mailto:emmanuelle@sidar.org>> wrote:

Hi all,

What about "mediaAlternative", or "accesAlternative"?

Because, for me, the captions or audiodescription, etc. are not a "feature" of the media nor a description.

In the example given by Dan, appears "accesFeature" which also seems appropriate, to me. I get the feeling that he did not mean to write it that way, but in that case it's a happy accident.


2013/9/9 Dan Scott <dan@coffeecode.net<mailto:dan@coffeecode.net>>
On Sun, Sep 08, 2013 at 02:36:22PM +0000, Madeleine Rothberg wrote:
> (Gerardo's reply, which arrived when I was almost done writing this,
> covers some of the same issues, but I will send this anyway in case a
> differently worded explanation is helpful to anyone.)
> The solution to knowing which of the accessModes listed for a given
> resource are required for understanding the resource and which are not has
> traditionally (in Access for All usage) been that the matching system
> analyzes several pieces of metadata together to draw a conclusion. Here's
> the example of a video with captions and audio description, which Charles
> McN correctly marks up as:
> <div itemscope=²² itemtype=²http://schema.org/Movie²>
> <meta itemprop=²accessMode² content=²visual²/>
> <meta itemprop=²accessMode² content=²auditory²/>
> <meta itemprop=²mediaFeature² content=²audioDescription²/>
> <meta itemprop=²mediaFeature² content=²captions²/>
> </div>
> We have resources like this in Teachers' Domain. And the solution there to
> deciding which resources are well-suited a particular user's requirements
> is to analyze the whole of the metadata in comparison to the user's
> preferences. If a user cannot see, then if a resource contains "visual"
> media we look to see if there is a mediaFeature that can substitute for
> visual. "audioDescription" is an auditory substitute for visual material,
> so this resource taken as a whole meets this user's needs.

Perhaps, instead of having repeated accessMode and mediaFeature
properties repeating directly under http://schema.org/Movie, which (if I
understand correctly) makes it hard to correlate accessMode=visual with
mediaFeature=audioDescription, these properties should be subsumed under
a new Type.

For example, let's call this new type AccessibilityMode and propose that
the associated property name be accessDescription, just as a placeholder:

<div itemscope itemtype="http://schema.org/Movie">
  <div itemprop="accessDescription" itemscope itemtype="http://schema.org/AccessibilityMode">
    Accessible to sighted users
    <meta itemprop="accessMode" content="visual"/>
    <meta itemprop="accessFeature" content="audioDescription"/>
  <div itemprop="accessDescription" itemscope itemtype="http://schema.org/AccessibilityMode">
    Accessible to hearing users
    <meta itemprop="accessMode" content="auditory"/>
    <meta itemprop="mediaFeature" content="captions"/>

This would enable you to keep the mode & feature meaningfully connected,
which is I think what you're looking for. And now that we're
distinguishing the accessibility mode as a separate Type, all of the
standard Thing properties are available to us without being associated
with the Movie itself, so you could go also use the "description"
property to note any particular restrictions, etc, for each access mode.

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Emmanuelle Gutiérrez y Restrepo
Fundación y Seminario SIDAR
URL: www.sidar.org<http://www.sidar.org/>
email: emmanuelle@sidar.org<mailto:emmanuelle@sidar.org>
Received on Monday, 9 September 2013 10:58:55 UTC

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