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ISSUE-313 (Presented Region is informative only): Presented Region section is informative only [TTML IMSC 1.0]

From: Timed Text Working Group Issue Tracker <sysbot+tracker@w3.org>
Date: Wed, 21 May 2014 13:03:36 +0000
Message-Id: <E1Wn6BE-00048c-8k@stuart.w3.org>
To: public-tt@w3.org
ISSUE-313 (Presented Region is informative only): Presented Region section is informative only [TTML IMSC 1.0]

http://www.w3.org/AudioVideo/TT/tracker/issues/313

Raised by: Nigel Megitt
On product: TTML IMSC 1.0

The definition of Presented Region [1] appears intended to add no information relative to what is in TTML1SE. I suggest making it informative rather than normative.

However it does differ in that in TTML1SE temporally active regions with opacity=0 will be included in the intermediate synchronic document construction. Note that TTML1SE does not actually define "temporally active" directly as used in ยง9.3.2 Intermediate Synchronic Document Construction (though it may be implied by reference to SMIL semantics). Therefore another solution to this issue would therefore be to rephrase in terms of a localised definition of "temporally active" as applied to regions.

For example:

A region, as defined in [TTML1], is considered temporally active if all of the following conditions are true:
...

Arguably this should be captured in an errata to TTML1SE and not needed in IMSC 1.0 at all.

[1] http://www.w3.org/TR/ttml-imsc1/#presented-region
[2] http://www.w3.org/TR/ttml1/#semantics-region-layout-step-1
Received on Wednesday, 21 May 2014 13:03:37 UTC

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