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Re: Sounds and checkpoint 11.1

From: gregory j. rosmaita <oedipus@hicom.net>
Date: Tue, 31 Jul 2001 03:19:58 -0400
To: "Charles McCathieNevile" <charles@w3.org>, <w3c-wai-gl@w3.org>
Message-ID: <CEEMJDFDIKKPEJJLKBKJIEJECAAA.oedipus@hicom.net>
CMN: It is possible to use SVG and the Adobe plugin, but this also relies on
adobe-specific extensions. Testing Adobe's own demonstration file it worked
in Amaya (but not in iCab enabled for SVG using Adobe's own plugin - they
have some stupid browser-sniffing script they use <sigh/>) without the sound
(Amaya didn't support the extended namespace).

GJR: here's some additional cause for melancholy -- there is no tab
navigation available via the adobe plugin, nor is there currently any means
for an assistive technology to obtain alternative information from any
titles and descs which may happen to populate an individual SVG file from
any application that renders/processes/supports SVG...  nor are there any
"targeted user agents" that use the built-in conditional content mechanisms
extant in SVG to provide alternate renderings of the SVG file...  and no,
recourse to document source doesn't suffice!

as for sound support, this would be a clear case for use of the OBJECT
element, which ostensively provides for the sort of cascade that would
enable an author to provide a range of sound formats, with the "required"
format being "basic sound" -- which is precisely one of the functionalities
which OBJECT was intended to provide:

<SPEC-QUOTE1
href="http://www.w3.org/TR/html401/struct/objects.html#idx-accessibility-1">
One significant consequence of the OBJECT element's design is that it offers
a mechanism for specifying alternate object renderings; each embedded OBJECT
declaration may specify alternate content types. If a user agent cannot
render the outermost OBJECT, it tries to render the contents, which may be
another OBJECT element, etc.
</SPEC-QUOTE1>

(note the word "accessibility" in the id-reference)

the only problem (aside from the lack of support for OBJECT) is that there
are 4 different binary file types that have the mime-type "audio/basic"

	1. .aif
	2. .au
	3. .mid
	4. .snd
source: RFC 2046 - Multipurpose Internet Mail Extensions (MIME) Part Two:
Media Types
<http://www.faqs.org/rfcs/rfc2046.html>

which makes recommending that: (a) sound must be added using a mechanism
that provides a cascade or SWITCH-type mechanism; and (b) that the
"audio/basic" mime-type always be included a bit tricky...  and, yet, the
mode -- and means -- of delivering conditional content is a gaping hole
which MUST be plugged via XHTML 2.0

this will not only require elements which can point to more than one
resource (hmm -- sounds like a job for XLink to me), but will also require
that a conforming user agent MUST allow the user to select -- at least by
preferential configuration -- from amongst the available range of resources,
as well as endow the user/client with the ability to render the available
range of resources in whatever manner is most appropriate

in other words, make conformance to XHTML 2.0 for authoring tools depend
upon conformance to "at least Level Double-A" of the Authoring Tool
Accessibility Guidelines (which ensures content that is "at least Level
Double-A" compliant to WCAG), and conformance for user agents depend upon
conformance to "at least Level Double-A" of the User Agent Accessibility
Guidelines...

OBJECT may never cut it in "the real world" as it was (over-)specified in
HTML4, but with XHTML 2.0's freedom from backwards compatibility/legacy
support, we (the WAI's working groups) need to fight tooth and nail for the
inclusion of a container-based mechanism that is capable of providing
conditional content in the User Agent Accessibility Guidelines sense of the
word -- the content that is most appropriate to the requester on the basis
of media-type and other configuration preferences, such as "display images",
"show animation", "play sounds" etc. [for the actual definition, consult:
<http://www.w3.org/WAI/UA/WD-UAAG10-20010714/glossary.html#def-conditional-c
ontent>]

we should also be pushing for control over aural events in CSS3 -- that
would both: (a) provide a cascade; and (b) enable UA control over aural
events -- an important consideration, as most aural events tend to be either
scripted events (usually associated with device-dependent event handlers,
such as OnMouseOver and OnClick, even when a pointer is only one potential
mode
of initiating the event for which the sound has been defined) or intrinsic
events (such as those which occur OnLoad) or as a result of user interaction
(such as OnFocus) -- when such things are controlled by scripts, UA people
tend to say things such as "well, that's an author problem"...  if so, then
it needs to be addressed in individual specifications, before it can be
adequately addressed in WCAG, which is the reason for tying compliance to a
specification as an authoring tool to ATAG, and compliance to a
specification as a user agent to UAAG...

so, it seems as if we (that is, the W3C as a whole, that is) need to do some
work in the area of solving the author's problems with specification-based
solutions that provide a styling mechanism for adding aural events to
XHTML/XML as well as for son-of-OBJECT for those who care enough to provide
"adequate" conditional content -- or at least a SWITCH-type functionality
for multimedia objects...

oh, and did i mention a container-based mechanism for providing
alternatives?

just my 2 cents, american, on the topic,
gregory.

PS: you can find out more about XLink at:
http://www.w3.org/TR/xlink
or http://www.w3.org/XML/Linking
but for the purpose of this emessage, i think that this quotation from the
current public draft referenced above will suffice:

<QUOTE
href="http://www.w3.org/TR/xlink/#intro">
XLink provides a framework for creating both basic unidirectional links and
more complex linking structures. It allows XML documents to:
  * Assert linking relationships among more than two
    resources
  * Associate metadata with a link
  * Express links that reside in a location separate
    from the linked resources
</QUOTE>

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A man of the highest benevolence acts, but from no ulterior motive. A
man of the highest rectitude acts, but from ulterior motive. A man most
conversant in the rites acts, but when no one responds rolls up his
sleeves and resorts to persuasion by force.  -- Lao Tsu, _Tao Te Ching_
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                 Gregory J. Rosmaita, oedipus@hicom.net
            Camera Obscura: http://www.hicom.net/~oedipus/
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Received on Tuesday, 31 July 2001 03:19:03 GMT

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