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Re: Liaison Statement to W3C (SC 29 N 13268)

From: Jean-Claude Dufourd <jean-claude.dufourd@telecom-paristech.fr>
Date: Thu, 21 Feb 2013 10:02:22 +0100
Message-ID: <5125E29E.2060800@telecom-paristech.fr>
To: public-web-and-tv@w3.org
Le 20/2/13 23:30 , Vickers, Mark a écrit :
>>>> 2.The ability to address devices with multiple screens, allowing 
>>>> the content author to request rendering some parts of the document 
>>>> in a view/frame that is to be displayed at a specific time on a 
>>>> secondary screen.
>>> I would think this could be done via two windows that communicate. 
>>> Thoughts?
>> Yes – a Web page in one window causing DOM elements (presumably no JS 
>> objects since no scripting) to render in another window in another 
>> browser. Various mechanisms (Web Intents, Network Discovery API, Web 
>> Sockets) could be used to create the connection. The underlying 
>> question is how the one window identifies the specific target window 
>> on the specific secondary screen. It's not clear this could be done 
>> in a declarative manner. Even with script, this is a complex task.
> Where the use case says "ability to address devices with multiple 
> screens," I interpreted that as each of the devices has multiple 
> screens, not multiple devices with single screens. In this case, it's 
> one app and one browser, like this example [1], so we don't have to 
> worry about discovery and networking. I don't know of a standard 
> way to position a window on a particular screen. I suppose that could 
> be just using a continuous coordinate system to cover all the screens 
> of the device.
> http://stackoverflow.com/questions/5277482/can-i-control-two-browser-windows-with-one-html5-app
JCD: Knowing the people involved, I am sure they intend to address 
whatever combination, one device with one screen or multiple screens, 
multiple devices with any number of screens. The liaison text was not 
written by a technical person, so do not rely on the precision of its 
Again, MMT is about transport, the use cases in question are about some 
other layer entirely (multiple layers actually), so it would cripple any 
media to embed information about multiple screens in a transport format.

In any answer, we should insist on the fact that the use cases (1) are 
being worked on in the W3C and (2) in very separate standards that have 
nothing to do with transport. MMT should be compatible with these use 
cases, but NOT address them.

Best regards

JC Dufourd
Directeur d'Etudes/Professor
Groupe Multimedia/Multimedia Group
Traitement du Signal et Images/Signal and Image Processing
Telecom ParisTech, 37-39 rue Dareau, 75014 Paris, France
Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
Received on Thursday, 21 February 2013 09:02:51 UTC

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