W3C home > Mailing lists > Public > w3c-wai-ua@w3.org > October to December 1999

"close caption" vs. simply "caption"

From: Al Gilman <asgilman@iamdigex.net>
Date: Fri, 26 Nov 1999 08:23:37 -0600
Message-Id: <199911261319.IAA21171@smtp2.mail.iamworld.net>
To: w3c-wai-ua@w3.org
At 10:31 PM 11/25/99 -0500, Denis Anson wrote:
>The difference between captioning and "closed caption," in general, is that
>a caption describes the thing above (or more generally explains it's
>relevance to the topic under discussion), while "closed caption" is
>generally thought of as the text that is displayed in synchronization with
>the visual portion of an audio-visual display.  The difference between the
>two, I think, is that the "closed caption" text is thought of as being time
>synced with other actions.  This is the difference between a closed caption
>and a transcript.

That is one way to interpret the 'closed' in "closed caption."  I believe I
have encountered at least two other versions of what the 'closed' means as
people discuss this area.

Sometimes people talk about "open captions" in video, which are just as
synchronized as closed captions would have been, but they are embedded in
the main video and are always displayed, as opposed to being displayed only
on user exercise of the CC option.

Sometimes people talk as though "closed caption" means only the
EIA-standard encoding of caption content in a video format.  This is a
definition in terms of transfer encoding, the medium of transmission as
opposed to the medium of the user interface.  In this case, a SMIL caption
track which was synchronized and normally off would still not be "closed
caption" because, to the software engineer, it is in an "open" format and
not in the "closed" video encoding.

After saying all this, however, I suspect that the way Denis explained the
term is probably the way most consumers will interpret the term.

>I would think that our language should preserve that distinction.

Saying "captions" and not "closed captions" is convenient for the future
because in a SMIL world the default-on or default-off status of the caption
track is not determined by the sender of the video alone but by the
receiver.  And the same behavior can be obtained for captions sent embedded
in the video encoding and for captions delivered by a separate stream.  The
latter case was illustrated by the captions which Trace got NCI and
Lexicast to produce for some SuperComputing 99 plenary talks last week.

Inside the industry, or when talking to implementers, there is the danger
that "closed captions" will be interpreted in the transfer-medium sense as
"encoded as hidden optional video in the video transfer medium."  This is
definitely more specific than what we wish to encourage.

So if our primary audience for the User Agent Accessibility Guidelines is
the implementer community, we may wish to say simply 'caption' and take
pains at the outset to explain how we are using the term so the lay readers
of the document won't get lost.  The generic concept is still pretty much
of a concept as opposed to settled practice, so even the implementers will
need an introduction.


>Denis Anson
>>From: Bryan Campbell <bryany@pathcom.com>
>>To: w3c-wai-ua@w3.org
>>Subject: Re: Issues: Part 2 - #16 through #43
>>Date: Thu, Nov 25, 1999, 9:33 AM
>> 24-11-99 I said
>> On "closed caption" this page
http://www.jb.man.ac.uk/research/namgallery/ I
>> just hit shows the Web uses the term caption to describe 1 photo as noted
>>>many Web pages offer display of a photo or caption that is a text
>> description of 1
>>>photo analogous a to newspaper caption of a photo
>> Following the established Web usage seems wise since TV's provision of
>> "closed caption" as moving text makes the term "closed caption" widely
>> understood
>> Regards,
>> Bryan
>> ->"It has been said the pebbles can't stop the avalanche, guess the pebbles
>> didn't have access to the Web!"
Received on Friday, 26 November 1999 08:17:46 UTC

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