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Media--Additional Requirement for Sec. 2.6 Captioning?

From: Janina Sajka <janina@rednote.net>
Date: Thu, 7 Oct 2010 21:35:05 -0400
To: HTML Accessibility Task Force <public-html-a11y@w3.org>
Message-ID: <20101008013505.GF2221@sonata.rednote.net>
Conversations with the consumers of captions who were in attendance at
the Open Subtitles Conference in New York City last week have exposed a
potential additional requirement clause for CC-23, and have raised concerns
regarding some of our explanatory text in Sec. 2.6 Captioning:
http://www.w3.org/WAI/PF/HTML/wiki/Media_Accessibility_Requirements#Captioning

1.)	The additional requirement -----

There was great concern about keeping captions synchronized with spoken
dialog in primary media resources. Some participants even proposed
schemes relying on tracking db variations in the primary media resource
audio in order to resync captions.

The several participants were in strong agreement that a realtime
control to nudge captions forward (and backward) during media play would
be very helpful. Their experience is that captions are frequently
noticably out of sync, and that this is distracting. They referred to a
media player which supports this today, but I've forgotten which--I'll
have to grep the conference notes for that datum.

PROPOSED ADDITION: Add a clause to CC-23 so that CC-23 would now read:

Ascertain that captions are displayed in sync with the media resource.
Provide a realtime control to allow users to adjust the caption forward and back
against the primary resource.

2.)	Explanatory Text Questions

	a.)	Open vs. Closed Captions

	The relevance of open and closed captioning in an HTML 5 context
proved confusing. Indeed, I don't believe we have a mandate to somehow
specify either or both. Rather, either can and should be achieved by the
consumer using their chosen client browser. If this is correct, the
third and fourth sentences in our first paragraph are confusing people.
They confused people in NYC last week.

SUGGESTION: Rewrite sentences 3 & 4 of our first paragraph in Sec. 2.6
to read:

Historically, captions have been either closed or open. Closed captions
have been transmitted as data along with the video but were not visible
until the user elected to turn them on, usually by invoking an on-screen
control or menu selection. Open captions have always been visible; they
had been merged with the video track and could not be turned off.

	b.)	Is our 3rd paragraph correct?


Our third paragraph currently reads:

  "The timing of caption text can coincide with the mouth movement of the
speaker (where visible), but this is not
   strictly necessary. For timing purposes, captions may sometimes
precede or extend slightly after the audio they
   represent. Captioning should also use adequate means to distinguish
between speakers as turn-taking occurs during
   conversation; this is commonly done by positioning the text near the
speaker, although in some countries color is used
   to indicate a change in speaker."

Do we stand by our assertion that synchronizing captions to spoken
dialog is not strictly necessary? Given #1 above, do we still believe
this? Is the wider experience of caption users different from what we
heard in NYC? Were our NYC consumers unrepresentative of caption users
as a whole?

Also, our NYC consumers strongly opposed colorizing caption text to
identify speakers, and strongly opposed positioning caption text next to
the person speaking. Again, did we draw nonrepresentative consumers at
the NYC event? Or is our text incorrect?

Janina

PS: Some useful NYC conference URIs:

http://universalsubtitles.org/opensubtitles2010
http://subsummit.universalsubtitles.org/index.php?title=CART-09-29
http://subsummit.universalsubtitles.org/index.php?title=CART-09-30
 

-- 

Janina Sajka,	Phone:	+1.443.300.2200
		sip:janina@asterisk.rednote.net

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 Friday, 8 October 2010 01:35:36 GMT

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