W3C home > Mailing lists > Public > public-html-a11y@w3.org > November 2009

Re: timing model of the media resource in HTML5

From: Philip Jägenstedt <philipj@opera.com>
Date: Sat, 28 Nov 2009 20:18:19 +0100
To: "Maciej Stachowiak" <mjs@apple.com>
Cc: "Eric Carlson" <eric.carlson@apple.com>, "Silvia Pfeiffer" <silviapfeiffer1@gmail.com>, "HTML Accessibility Task Force" <public-html-a11y@w3.org>
Message-ID: <op.u34c8tvhsr6mfa@worf>
On Sat, 28 Nov 2009 19:27:06 +0100, Maciej Stachowiak <mjs@apple.com>  

> On Nov 25, 2009, at 12:02 PM, Philip Jägenstedt wrote:
>> On Wed, 25 Nov 2009 18:43:39 +0100, Eric Carlson <eric.carlson@apple.com 
>> > wrote:
>>> On Nov 25, 2009, at 8:50 AM, Philip Jägenstedt wrote:
>>>> My thinking is that <overlay> should be the container of overlay  
>>>> content whether it is from an external subtitle file or from HTML.  
>>>> When an external subtitle file is used the element acts as if it had  
>>>> a single text node child with the content of the current text from  
>>>> the subtitle file.
>>>> In the absence of an external file the content of the element is  
>>>> shown as "fallback", which can then easily be set using script.
>>>   Thanks, that makes sense.
>>>   I think <overlay> should be used for internal subtitle and/or closed  
>>> caption tracks as well. Further, I think that we will want them to  
>>> "just work" so a UA should create an <overlay> element if the markup  
>>> doesn't have one and it finds that a file has internal  
>>> captions/subtitles:
>>>     <video src='my-captioned-movie'> </video>
>> Yes, that sounds good. One issue is how to style such an implicit  
>> <overlay>. Should one actually include an <overlay> in the markup and  
>> somehow indicate that it can/should be used to render in-band subtitles  
>> from the resource?
>> <video src="my-captioned-movie">
>>  <caption style="font-weight:bold" magic-attribute></caption>
>> </video>
>> Not awesome. Perhaps a new CSS pseudo-selector could be used? Other  
>> ideas?
> Can we come up with a name for the <overlay> element that sounds less  
> presentational? I think the fact that the element sounds purely  
> presentational may come up as an issue when this proposal is taken back  
> to the full Working Group.
> (Also, the name "overlay" implies that this is the only way to add an  
> overlay to video content, but in fact any content can be positioned over  
> the video and will composite properly. So it doesn't even really have  
> the presentational function that its name implies.)

It would be the only way to make an overlay that the browser understands  
so that it can e.g. display it in fullscreen and make sure that it doesn't  
interfere with native controls. I still wouldn't mind a better name though.

It can be used for any timed content including subtitles, optional  
animated mustaches for all the actors and popups with information about a  
particular object in the scene. It is completely void of semantic meaning  
except the fact that the content probably changes over time (except for  
scripted controls).

<animation>? <timeranges>? <timedcontent>? <rangelist>?

Or perhaps the concept is purely presentational and should be done using  
CSS instead?

<video src="foo">
   <div style="display:overlay"></div>

But then we still need an element for captions/subtitles (in-band or  

Philip Jägenstedt
Core Developer
Opera Software
Received on Saturday, 28 November 2009 19:19:02 UTC

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