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Re: CSS2 & background : video possible?

From: Chris Lilley <chris@w3.org>
Date: Fri, 07 Jul 2000 01:46:55 +0200
Message-ID: <39651A6F.C32A94A9@w3.org>
To: Teemu Ropponen <troppone@tcm.hut.fi>
CC: www-style@w3c.org


Teemu Ropponen wrote:
> 
> Hi,
> 
> Section 14.2. of the CSS2 spec introduces the possibilty of using a color
> or image as the background of an element. In some of our research
> interests (e.g., digital tv) we'd like a background video (or sound). If
> we have a user agent that could handle such bg-video, would a style sheet
> that exploits this feature be in violation of the spec ??
> 
> ( i.e. BODY { background: white url("video.mpg") }

The CSS2 and CSS1 specifications do not constrain the image formats that
may be used. Its arguable that MPEG is not an image format, but then its
arguable that animated GIF isn't eirther ...

Ona more practical point, i suspect that it woulkd be useful to start and
stop the video, fast forward, have other things happen in synchronisation,
and so on. This would imply that the video should be treated as a
foreground, first class object and not just as part of the styling. I would
suggest you look at the SMIL specification for some ideas about this.

Once the video is part of the content, it is worth noticing that 

a) the initial value for the background property is transparent
b) absolute positioning can be used to place content on top of other
content

So, the visual effect of a web page superimposed on top of a streaming
video sequence would be entirely possible, with SMIL and XHTML and CSS,
without any extensions required.

--
Chris
Received on Thursday, 6 July 2000 19:47:06 GMT

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