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Re: Timed Text roles

From: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>
Date: Thu, 11 Oct 2007 14:32:11 +0100
Message-ID: <470E25DB.1020708@googlemail.com>
To: "Glenn A. Adams" <gadams@xfsi.com>
CC: public-tt@w3.org, w3c-wai-ig@w3.org

Glenn A. Adams wrote:
> The TTWG discussed this need, and concluded it would be exceedingly
> difficult or impossible to define them in a way that would retain their
> utility while not overly constraining such use.

Thanks kindly for the response, but I don't understand at all. :( Could 
you please explain the WG's reasoning a bit more? Given that authors can 
always create a new role in the x- prefixed space, how would defining 
the standard roles constrain authoring? What is the real-world utility 
of a standardised set of roles that aren't defined in any way? It seems 
to me that not defining "transcription", for example, means that TT 
fails to provide "clear indications in the format of what text 
corresponds to speech in some corresponding audio segment" as requested 
by Alfred S. Gilman:


> It was recognized that
> some existing standards, such as the US Digital Television Closed
> Captioning (DTVCC) standard, CEA-708, similarly enumerated such a list
> but without providing any further definition.

Are the standard roles precisely the same as CEA-708? If they are, why 
doesn't the TT spec say they are? And if they aren't, then what is the 
relevance of this apparent anti-pattern in CEA-708?

Might it not be better to specify cea- prefixed roles for mapping 
CEA-708 roles to Timed Text?

> Notwithstanding the above, we may consider adding informative examples
> to the text of DFXP during the process of transitioning from CR to REC.
> If you would like to submit such examples, possibly with descriptions,
> then that would be most welcome.

Well, I'd be happy to do that, but I can't submit examples or 
descriptions when I can't tell what the roles are for! If existing data 
in CEA-708 form is to be mapped to such roles, then we need to know how 
such labels are currently used by people who use CEA-708: I can't just 
make things up. And if they use them in utterly incoherent ways, then 
shouldn't a new format provide a set of coherent roles?

As things stand, I would have to recommend that authors don't make any 
use of these ambiguous standard roles, but instead publish some sort of 
microformat using the x- space. At least then one could find out what 
the author intended.

Has the WG considered allowing people to specify a URI that defines the 
the roles they are using so that there is no possibility of confusion? 
Compare the approaches of HTML 4.01, the draft XHTML 2.0 Role Attribute 
Module, and GRDDL:




(PS Apologies to w3c-wai-ig for the noise. I mistook public-tt latest 
for the whole public-tt archives: turns out that thankfully there are 
people on this list.)

Benjamin Hawkes-Lewis
Received on Thursday, 11 October 2007 13:32:28 UTC

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