W3C home > Mailing lists > Public > www-svg@w3.org > May 2001

Re: Streaming animation with SVG

From: Jon Ferraiolo <jferraio@Adobe.COM>
Date: Thu, 31 May 2001 11:54:01 -0700
Message-Id: <4.3.2.7.2.20010531114018.00d03d40@mailsj>
To: Michael Foster <foster@PacketVideo.COM>
Cc: www-svg@w3.org
Michael,
The SVG timeline starts when the entire document has been downloaded. 
Therefore, having SVG 1.0 animations start while document downloading 
continues requires extra work. One way would be to have a very short root 
SVG document that has one or more <image> elements that refer to external 
SVG documents. According to my reading of the SVG 1.0 specification, so 
long as externalResourcesRequired on the <image> elements is not set to 
true, then the timeline starts once the root document has been parsed. The 
timeline does not have to wait for the external SVG documents to be fully 
parsed. To be sure that the timeline will indeed start after the root 
document is parsed (and not waiting for all referenced files to be fully 
parsed), then the <image> elements could initially be set to reference 
empty (and therefore very small) SVG documents, and an animation element in 
the root document could change the xlink:href attributes on the <image> 
elements to point to the desired external SVG documents. (Note: this 
technique won't work with the Adobe SVG Viewer version 2 because Adobe does 
not yet support <image> elements referring to external SVG files. This 
feature is high on our list for future releases.)

Regarding SVG 2.0, I am proposing that there be features in the SVG 
language that allow for streaming animations even if everything is 
contained within the same document.

Jon Ferraiolo
SVG Editor
jferraio@adobe.com


At 04:09 PM 5/30/01 -0700, Michael Foster wrote:
>I have searched the archives and spec for this topic, but haven't found
>anything other than references to 'progressive rendering'...
>
>I am wondering if there is any support in the current SVG specification (or
>in future plans) for streaming SVG animation functionality. By streaming, I
>mean SVG data arrives at the SVG player at periodic intervals, and this data
>causes the display to be updated. Basically I am interested in the same type
>of streaming animation functionality that Flash has.
>
>As I understand 'progressive rendering', parts of the SVG document are
>displayed while the rest of the document is downloaded, but I don't know if
>'Flash-like' streaming animation could be achieved using this functionality.
>
>Thanks
>
>Mike
>
>_________________________________________________
>Michael Foster  *  PacketVideo  *  (858) 731-5543
>foster@pv.com  *  www.packetvideo.com
Received on Thursday, 31 May 2001 15:11:37 GMT

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