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Re: Timed tracks

From: Ian Hickson <ian@hixie.ch>
Date: Thu, 22 Apr 2010 18:51:52 +0000 (UTC)
To: Philippe Le Hegaret <plh@w3.org>, Sean Hayes <Sean.Hayes@microsoft.com>, Geoff Freed <geoff_freed@wgbh.org>, Jonas Sicking <jonas@sicking.cc>
Cc: "public-html@w3.org" <public-html@w3.org>
Message-ID: <Pine.LNX.4.64.1004221842430.14147@ps20323.dreamhostps.com>
On Thu, 22 Apr 2010, Philippe Le Hegaret wrote:
> It seems that this is a reasonable to look at a new format since, in my
> opinion, none of the existing formats are satisfying (and yes, that
> includes Timed Text). The main problem being that none of them are based
> on HTML and CSS.

While I agree that the existing formats (or at least, the ones I've looked 
at) are't especially satisfying, I don't think basing a format on HTML+CSS 
is an especially good idea either. It would be a very bad idea to require 
every video playback device in the world to embed an HTML+CSS+DOM+JS+XML 
user agent, when subtitles are a comparatively simple issue. If we can't 
reuse an existing format directly, then at most I hope we can reuse an 
existing format in a backwards-compatible way, so that existing deployed 
tracks can be reused. Leverging network effects is a big way to ensure 
adoption -- we don't have a magic wand that causes people to automatically 
do whatever we say! If anyone has examples of "real world" usage of 
various subtitle formats, that would be great.

Also, there's a lot more to this problem than a format for timed tracks 
and cues. :-)

> I wonder however how you see this work interfacing with
> the HTML5 specification, ISSUE-9, and the work in the a11y task force.
> Is your intention to bring an alternative proposal for captions to the
> task force? If yes, do you have a timeline in mind?

My intention is to take the task force's proposal more or less wholesale; 
that was in fact more or less the request given in the bugs:

> > FYI, I've started looking at the timed track bugs:
> > 
> >    http://www.w3.org/Bugs/Public/show_bug.cgi?id=9452
> >    http://www.w3.org/Bugs/Public/show_bug.cgi?id=9471

I hope to have the first proposal for how to integrate the proposals into 
HTML5 in the next few weeks.

On Thu, 22 Apr 2010, Sean Hayes wrote:
> I'm not sure what level of integration is being considered, or why CSS 
> would necessarily be perceived as a benefit, since in my opinion there 
> will need to be a strong barrier between the HTML and the timed text 
> environments, for both security reasons and in order that the 
> video/caption author's intention is not undermined by the HTML page 
> author.


On Thu, 22 Apr 2010, Jonas Sicking wrote:
> For what it's wroth, just because CSS is used as a styling technology 
> both for the page and captions, doesn't mean that any style rules 
> applied to one of the two also applies to the other. The page 
> stylesheetes can apply just to the page, and the captions stylesheets 
> can apply just to the captions.
> It's simply a matter of specifying which style sheets are in scope 
> where.

Indeed. If we have a model where CSS applies to timed track cues, I would 
expect it to be based on pseudo-elements, not to use the main bulk of 
style rules in the page.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Thursday, 22 April 2010 18:52:22 UTC

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