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RE: Duration of an SVG file

From: Julien Reichel <Julien.Reichel@spinetix.com>
Date: Tue, 8 Jul 2008 09:13:52 +0200
Message-ID: <364D31930BDB974AB40E22C5C2E584ED10D042@asterix.SPINETIX.local>
To: "Dr. Olaf Hoffmann" <Dr.O.Hoffmann@gmx.de>, <www-svg@w3.org>

Hi Olaf and all,

I was afraid that this would be the answer to my question :-)

Is there a specific reason why the animated SVGs are considered
differently from the other media files (video and audio) ?

The fact that it is not possible to create an animated SVG file with a
specific duration makes it difficult to use SVG for small animated movie
that would be included in other documents using the <animation> tag.

We (SpinetiX) are using a lot the <animation> tag for creating content
(playlists, multi-layers documents, ...). Final scene can be created by
combining all sorts of medias (video, images, audio files and animated
SVG files). In this condition it is necessary to be able to specify a
duration for SVG animation when included into other documents.

For this reason we have added a non-standard way to specify the duration
of an SVG file by supporting the attribute dur to the <svg> element. 

In http://idefix/www.w3.org/TR/SVGMobile12/struct.html#SVGElement add: 

dur = "<Clock-value>" | "indefinite"
 Specifies the intrinsic duration of SVG document. The attribute value
can be either of the following:
 <Clock-value>
   Specifies the length of the SVG document duration in document time.
Value must be greater than 0.
 indefinite
   Specifies the SVG document duration as indefinite.
 If the attribute is not specified, the effect is as if a value of
"indefinite" were specified. 

(of course, in this case it is allowed to specify "media" as the dur of
an <animation>)

We think this is a minor addition to SVGT 1.2 and which really helps
applications using the <animation> element. Of course there might be
better and cleaner solution to solve this problem, and I would be very
happy to discuss others views on the subject.

Julien

Visit http://www.spinetix.com/ for more information 

> -----Original Message-----
> From: Dr. Olaf Hoffmann [mailto:Dr.O.Hoffmann@gmx.de] 
> Sent: 03 July 2008 20:12
> To: www-svg@w3.org; Julien Reichel
> Subject: Re: Duration of an SVG file
> 
> Hello,
> 
> my interpretation of this issue:
> 
> For
> <animation dur="10s" ... />
> the duration of the animation element (and the active 
> duration of the referenced SVG) is simply 10s.
> The SVG file itself has no well defined simple media duration 
> in the sense, SMIL defines this for simple continuous media, 
> therefore in SMIL the dur value 'media' is not applicable and 
> no one has to compute the duration of an SVG file.
> 
> 
> SVG tiny 1.2 notes about the dur attribute:
> http://www.w3.org/TR/SVGMobile12/animate.html#TimingAttributes
> 
> 'For SVG's animation elements, if media is specified, the 
> attribute will be ignored.'
> 
> And: 
> 'If the animation does not have a 'dur' attribute, the simple 
> duration is indefinite.'
> 
> Therefore if the author does not provide a dur attribute or 
> sets it to media, this is resolved to 'indefinite'.
> 
> Repetitions cannot have a visible effect for an object with 
> indefinite duration, but for dur="10s" it can. 
> This is the same for the animation elements as for other 
> elements too, no matter what the referenced content of the 
> animation element is.
> 
> 
> Olaf
> 
Received on Tuesday, 8 July 2008 07:14:33 GMT

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