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RE: Timed Text Authoring Format - Distribution Format Exchange Pr ofile (DFXP) Streaming

From: Russ Wood <russ.wood@softel.co.uk>
Date: Mon, 21 Mar 2005 15:29:43 -0000
Message-ID: <0A80B31A7A69D61182420000F87E0463B8DF37@homer.softel.co.uk>
To: "'Glenn A. Adams'" <gadams@xfsi.com>, Johnb@screen.subtitling.com, shayes@microsoft.com
Cc: public-tt@w3.org
BULK OF MESSAGE DELETED see comment RW> below

"does not require dereferencing (and subsequent loading) of any resources
other than DFXP content (i.e., no embedded URIs);"

Is this just a timeliness issue?


[GA] No. Having to load any other resource may preclude direct streaming
through inline insertion, otherwise, any referenced resources would have to
be inlined and made availabe contemporaneously.


 Loading of a resource (referred to for example by a header section) would
presumably just delay the ability to decode subsequent timed fragments. A
stream decoder may then incur a 'one off' setup period where referenced
resources were dereferenced and loaded. Any timed fragment in a streaming
scenario would need to be sent some (short) time in advance of its
activation period(s) on the timebase.



RW> Another reason why the referencing of non-included resources should be
prevented is the issue of obsolescence.  If a broadcaster purchases a
programme with subtitles, he wants to know that those subtitles will work
today, tomorrow, next year and in a decade.  If a reference is made to a URI
that needs to be fetched then that resource may have moved for reasons
beyond the control of the originator.
I would prefer not to have a DFXP preload and store operation on first


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