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

On Mon, Jul 21, 2014 at 10:39 AM, Glenn Adams <glenn@skynav.com> wrote:

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> On Mon, Jul 21, 2014 at 4:08 AM, Nigel Megitt <nigel.megitt@bbc.co.uk>
> wrote:
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>> Hi Pierre,
>>
>> s/A presented region is a region that satisfies all of the following
>> conditions are true:/A presented region is a region that satisfies all of
>> the following conditions:
>>
>> Then this is acceptable to me to close Issue-313, as discussed.
>>
>> However I note that we haven't resolved whether there is any substantive
>> difference between 'presented region' in IMSC 1 and 'temporally active
>> region' in TTML 1 SE. If they are synonymous and as a result of Issue-314
>> we add an erratum to TTML 1 SE to define "temporally active region" then
>> we should modify IMSC 1 to use that term in place of "presented region".
>>
>
> I think they are not synonymous since a temporally active region may not
> produce any renderable pixels (i.e., not be presented) for a number of
> reasons, including:
>
>    - extent is zero in some dimension
>    - origin is such that region doesn't intersect with root container
>    region
>    - display is none
>
> visible is hidden
> opacity is 1
>

correction: that should read opacity is 0



>  Also, I note from §2.3 in [1] that it is both a requirement to define
>> terms and a good practice ("Good Practice 9" also in [1]) to consolidate
>> the definitions in a glossary section. I will raise a separate issue that
>> IMSC 1 needs to meet the requirements of this document and as far as
>> possible also the good practices.
>>
>> Kind regards,
>>
>> Nigel
>>
>> [1] QA Framework: Specification Guidelines
>> http://www.w3.org/TR/qaframe-spec/#define-terms-section
>>
>>
>>
>> On 20/07/2014 23:03, "Pierre-Anthony Lemieux" <pal@sandflow.com> wrote:
>>
>> >Hi Nigel,
>> >
>> >Please indicate whether the text at [1] resolves your comment per your
>> >suggestion at [2].
>> >
>> >[1]
>> >
>> https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles
>> >.html#presented-region
>> >[2] http://www.w3.org/AudioVideo/TT/tracker/issues/313
>> >
>> >Thanks,
>> >
>> >-- Pierre
>> >
>> >On Wed, May 21, 2014 at 6:03 AM, Timed Text Working Group Issue
>> >Tracker <sysbot+tracker@w3.org> wrote:
>> >> 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 §9.3.2 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
>> >>
>> >>
>> >>
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