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Re: ISSUE-330 (Is Presented Region a synonym for temporally active region?): Is Presented Region a synonym for temporally active region? [TTML IMSC 1.0]

From: Nigel Megitt <nigel.megitt@bbc.co.uk>
Date: Mon, 28 Jul 2014 16:08:48 +0000
To: Nigel Megitt <nigel.megitt@bbc.co.uk>, Glenn Adams <glenn@skynav.com>, Timed Text Working Group <public-tt@w3.org>
Message-ID: <CFFC33F5.20948%nigel.megitt@bbc.co.uk>
Additionally I've added the following update to Issue-314:

"Thanks Glenn. This was not obvious to me, so I think it would be worth adding a definition of 'temporally active' or 'temporally active region' to TTML 1 SE as an erratum, and to TTML 2 also. The erratum may include both an addition to the definitions section and maybe 9.3.2 also, depending on how you think the information is best indicated."

Nigel

On 28/07/2014 16:55, "Nigel Megitt" <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>> wrote:

Thanks for the clarification Glenn. I've added a note to ISSUE-330 which I'll quote to save clicks:

"In that case it would make sense to define 'presented region' in terms of a 'temporally active region' that either contains visible content with opacity >0 or has showBackground="always" and a backgroundColour with opacity >0."

Nigel


On 28/07/2014 16:41, "Glenn Adams" <glenn@skynav.com<mailto:glenn@skynav.com>> wrote:

No, temporally active region and presented region are not synonymous. Further, showBackground="whenActive" does not mean "when temporally active", rather it means "when temporally active and has content selected into it". As such it is a bit of a misnomer, but we adopted the name from SMIL and repurposed it to our ends.

See my additional comments in Issues 314 and 330.


On Mon, Jul 28, 2014 at 6:56 AM, Timed Text Working Group Issue Tracker <sysbot+tracker@w3.org<mailto:sysbot+tracker@w3.org>> wrote:
ISSUE-330 (Is Presented Region a synonym for temporally active region?): Is Presented Region a synonym for temporally active region? [TTML IMSC 1.0]

http://www.w3.org/AudioVideo/TT/tracker/issues/330

Raised by: Nigel Megitt
On product: TTML IMSC 1.0

This issue is related to Issue-314 and was generated as part of the resolution to Issue-313.

TTML 1 SE 9.3.2 [1] uses the term "temporally active region" to define regions that are included in the construction of intermediate synchronic documents "for the purposes of performing presentation processing". Issue-314 covers the point that this term is not defined.

[1] http://www.w3.org/TR/ttml1/#semantics-region-layout-step-1

IMSC 1 editor's draft 4.6.1 [2] defines and uses the term "presented region" to define regions that may be presented at any moment, and in all but one case references presented region with respect to an intermediate synchronic document.

[2] https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html#presented-region

It looks as though these two terms may be synonyms, or very closely related to each other. If this is the case then IMSC 1 should reference the defined term in TTML 1 SE (if need be, after the resolution to Issue-314). If it is not the case then the difference should be clarified making reference to the similar concept.

For example, if the resolution to Issue-314 is to define temporally active region in TTML 1 SE as any region that is either temporally active or has content selected into it that is temporally active, or has showBackground="always", then Presented Region in IMSC 1 may be defined as:
   any temporally active region which satisfies all of the following conditions...,
   where those conditions include [those currently specified] and those noted additionally by Glenn in response to Issue-313 [3], i.e. the values of the attributes tts:display, tts:visibility, tts:extent and tts:opacity are such that marks may be made by the region or its contents.

[3] http://lists.w3.org/Archives/Public/public-tt/2014Jul/0036.html

This issue created as per Action-308.
Received on Monday, 28 July 2014 16:09:29 UTC

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