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ISSUE-367 (#textAlign clarification): Clarify initial value override for tts:textAlign [TTML IMSC 1.0]

From: Timed Text Working Group Issue Tracker <sysbot+tracker@w3.org>
Date: Tue, 27 Jan 2015 17:01:29 +0000
Message-Id: <E1YG9W5-0002qp-7U@stuart.w3.org>
To: public-tt@w3.org
ISSUE-367 (#textAlign clarification): Clarify initial value override for tts:textAlign [TTML IMSC 1.0]

http://www.w3.org/AudioVideo/TT/tracker/issues/367

Raised by: Nigel Megitt
On product: TTML IMSC 1.0

The feature list in §7.4 of the IMSC 1 CR specifies for #textAlign: 

> MAY be used. The initial value of tts:textAlign shall be "center" for the default region. NOTE: This is consistent with [ST2052-1].

This is somewhat subtle, and doesn't indicate that it's a variation from TTML1SE. I propose the following edited version:

> MAY be used. The initial value of tts:textAlign shall be "center" for the default region only. NOTE: This is consistent with [ST2052-1] but differs from TTML1SE. Document authors are recommended not to rely on the initial value for text alignment in the default region but to specify the tts:textAlign attribute explicitly to generate the expected presentation by both generic TTML1SE and IMSC 1 presentation processors.

I also propose appending this wording to the #layout feature in §6.10:

> NOTE: Authors are recommended to define and reference a region rather than relying on the default region, to avoid inconsistent presentation between generic TTML1SE and IMSC 1 presentation processors resulting from the different initial value of tts:textAlign for the default region. See also #textAlign.

This is an editorial clarification rather than a substantive change.
Received on Tuesday, 27 January 2015 17:01:33 UTC

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