W3C home > Mailing lists > Public > public-html@w3.org > March 2012

Re: CP, ISSUE-30: Link longdesc to role of img [Was: hypothetical question on longdesc]

From: Janina Sajka <janina@rednote.net>
Date: Thu, 22 Mar 2012 10:07:59 -0400
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Cc: John Foliot <john@foliot.ca>, David Singer <singer@apple.com>, Sean Hayes <Sean.Hayes@microsoft.com>, "'"'xn--mlform-iua@målform.no'"'" <xn--mlform-iua@xn--mlform-iua.no>, rubys@intertwingly.net, laura.lee.carlson@gmail.com, mjs@apple.com, Paul Cotton <Paul.Cotton@microsoft.com>, public-html-a11y@w3.org, public-html@w3.org
Message-ID: <20120322140759.GI4686@sonata.rednote.net>
Silvia Pfeiffer writes:
> On Thu, Mar 22, 2012 at 6:05 PM, John Foliot <john@foliot.ca> wrote:
> > Silvia Pfeiffer wrote:
> >>
> >> <track> is a timed resource. Neither transcript, nor description, nor
> >> posterdescription are timed - they cannot be parsed into cues and
> >> displayed time-synchronously over the video. You cannot misuse the
> >> track element in this way.
> >
> > Hmmm... I don’t recall seeing anywhere where it states that @kind="metadata"
> > was required to be a timed resource - is that specifically stated somewhere?
> It's kinda hard to find, but it's there.
> For example, the definition of what a text track is in
> http://www.w3.org/TR/html5/the-iframe-element.html#text-track-model
> lists what a track consists of.
> One part of that is a list of cues:
> http://www.w3.org/TR/html5/the-iframe-element.html#text-track-list-of-cues
> i.e. each track consist of a list of cues. This is independent of what
> kind of text track we're dealing with.
> And a little further on the actual definition of a text track through its cues:
> "A text track cue is the unit of time-sensitive data in a text track,
> corresponding for instance for subtitles and captions to the text that
> appears at a particular time and disappears at another time."
> http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#text-track-list-of-cues
> The whole concept of text tracks is built around timed cues.
In retrospect perhaps calling them "text" tracks is an unfortunate
misnomer. "Timed" tracks might have been better, less readily

I suppose the term "text" tracks is a holdover from the early days when
some of the HTML 5 people hadn't yet grocked the extensive range of
alternative media required to support accessibility, i.e. a "sign
language translation" is not a "text" track, though a caption certainly

I recall our meeting at Stanford some years hence. Those of us from
accessibility who were just joining the HTML 5 work effort found
ourselves rather concerned at how disability support was being called
"captioning," causing us to start insisting on a requirements gathering

Would future authoring be assisted by changing this to "timed" tracks
now? Some pain, of course, but future gain?

I don't see this as important as other discussions recently in this
thread, but it did seem worth noting.


> > A quick check of the spec simply defines metadata as "Tracks intended for
> > use from script. Not displayed by the user agent." I do not see a definition
> > of "track" as used in this context.
> >
> > Just curious.
> Yeah, fair enough.
> Silvia.


Janina Sajka,	Phone:	+1.443.300.2200

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 Thursday, 22 March 2012 14:08:46 UTC

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