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Re: [SVGMobile12] STZLC3-3 definition of the intrinsic duration of a media

From: Dean Jackson <dino@w3.org>
Date: Wed, 7 Jun 2006 06:38:41 +1000
Message-Id: <0D4320C0-0F17-49A7-A8DC-67C142B03AE5@w3.org>
Cc: www-svg@w3.org
To: Jean-Claude Dufourd <jean-claude.dufourd@streamezzo.com>

Hello Nicolas, Erwann, Julien and Jean-Claude,

 > In many delivery scenarios, there are delays in media rendering  
due to
 > connexion and buffering. Are these times to be taken into account  
in the
 > computation of the implicit duration of the media aka simple  
duration as
 > specified in SMIL timing, section 10.3.3 ?

 > Ex: clip of duration 200s, connexion and buffering time of 15s
 > <video id="v1" begin="0s" dur="media" />
 > <video id="v2" begin="0s" dur="200s" />
 > Is the 'active end' of "v1" at 200s ou  215s ? and of "v2" ?
 > If it is 200s, then the last 15ms of the media are not rendered.
 > Are the executions of "v1" and "v2" equivalent ?

After a lot of research into the SMIL specification, we believe we
have the answer.

The buffering of media is counted as a pause of the media. The values
of syncBehavior and syncBehaviorDefault describe what the implementation
should do when the media is paused, or in the case where neither of
them are present (as in your example) the implementation is free to
decide on behavior.

See http://www.w3.org/TR/SMIL2/smil-timing.html#Timing- 
ControllingRuntimeSync

Most implementations would pause the timeline for buffering so that
all the media would be played back.

In case we're wrong, we've forwarded this comment to the SYMM
Working Group.

Dean
Received on Tuesday, 6 June 2006 20:38:57 GMT

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