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Re: Assumption in the SVG specifications

From: Dave Singer <singer@apple.com>
Date: Thu, 31 Aug 2006 18:04:37 +0200
Message-Id: <p062309b1c11cb68be2f1@[]>
To: Chris Lilley <chris@w3.org>
Cc: Cyril Concolato <cyril.concolato@enst.fr>, Robin Berjon <robin.berjon@expway.fr>, www-svg <www-svg@w3.org>

At 17:38  +0200 31/08/06, Chris Lilley wrote:
>On Thursday, August 31, 2006, 3:46:28 PM, Dave wrote:
>>>So we ended up saying that image should not point to vector graphics
>>>because otherwise, the same content would have led to different
>>>behaviors in  a 1.1 Full and 1.2 Tiny player.
>DS> so you forbid what 1.1 allowed?  I got lost here.
>SVG 1.1 was not a timed specification.
>When we added timing in 1.2, we split out what had been on image 
>into two, static raster on image and animated vector stuff on 
>animation (and added audio and video).
>image is not a timed element in SVG 1.2 (and it wasn't in 1.1 
>either, of course). video, audio and animation are timed elements.

Got it.  And that this wasn't a perfectly backward-compatible change 
was acceptable, presumably.

OK, we are back to interesting cases.  Here are some questions in a 
matrix, grouped together for convenience (though no doubt the answers 
vary in some cases).

1. An un-timed, un-animated image that is drawn with (a) SVG vectors 
(b) some foreign vector drawing or (c) a raster codec, which 
otherwise looks and behaves identically to the viewer is (i) an 
animation (ii) an image?

2. A timed, animated sequence that is drawn with (a) a raster codec 
(e.g. video codec) (b) a foreign vector codec or (c) SVG vectors, 
where these appear identically, is (i) a video (ii) an animation?

3. An (admittedly degenerate) SVG scene that only makes sound is (i) 
audio (ii) animation?

4. An 'opaque' (a) SMIL file or (b) SVG file, whose contents are 
unknown is probably a 'ref' in SMIL;  it is (i) audio (ii) video 
(iii) image (iv) animation, in SVG?

5. A medium which is neither audible nor visual but is time-based 
(e.g. haptic feedback, odor generator) is an 'animation'?

I could get it if we said that SVG may only be embedded in an 
'animation' node, and nothing but SVG can be embedded in an 
'animation'.  That means I can have special handling of SVG and the 
animation construct, and not have general MIME dispatching and 
possibly codec loading either behind animation or in front of my SVG 
code.  But is it that tight?
David Singer
Apple Computer/QuickTime
Received on Thursday, 31 August 2006 16:06:55 UTC

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