Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay

The best one attribute mapping I can come up for IMSC1 to TTML2 at the
present time is:

itts:forcedDisplay='true'
  => condition='(forced)'

itts:forcedDisplay='false'
  => condition='(forced)'

given a definition of *media feature* 'forced' as being the value of an
external (application supplied) boolean parameter, which if true, allows
forced content to be a candidate for display, and if false, prevents forced
content from being a candidate for display, where by 'candidate for
display', I mean further subject to temporal activation and the computed
values of tts:display and tts:visible.




On Tue, Jun 24, 2014 at 10:26 AM, Michael Dolan <mdolan@newtbt.com> wrote:

> …it is more a matter of moving the same amount of complexity around
> between components, it is more a matter of moving the same amount of
> complexity around between components
>
>
>
> Yep.  And a different room full of a balance of consumer device
> manufacturers and content publishers (including the encoder vendors),
> weighing the complexity options, converged on the currently proposed
> solution.
>
>
>
> Regards,
>
>
>
>                 Mike
>
>
>
> *From:* Glenn Adams [mailto:glenn@skynav.com]
> *Sent:* Tuesday, June 24, 2014 8:38 AM
>
> *To:* Michael Dolan
> *Cc:* TTWG
> *Subject:* Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay
>
>
>
>
>
>
>
> On Tue, Jun 24, 2014 at 9:19 AM, Michael Dolan <mdolan@newtbt.com> wrote:
>
> The content providers rejected this since they would have to author, QA
> and maintain separate works of duplicated text (in this case 3 documents).
>
>
>
> An alternative that was considered was to author a single document with
> “forced” included and at least automate the creation of what you describe
> below, but that doesn’t remove the need for authoring with the “forced”
> attribute.
>
>
>
> And, either way, having 3 subtitles tracks for every one actual content
> track increases the complexity of subtitle track selection in the decoder.
>
>
>
> Audio and subtitle track selection in International releases containing
> half a dozen languages of both image and text subtitles (substantive
> duplicates to which this would add 2 more for each language) is already
> arguably too complex.  See § 8.3.4 at [1].
>
>
>
> Like most discussions of 'complexity', it is more a matter of moving the
> same amount of complexity around between components. In this case,
> potential complexity includes:
>
>
>
> (1) the need to create multiple TTML resources representing different
> states of inclusion/exclusion of content based on language, forced display,
> etc;
>
>
>
> (2) the need to choose between those resources at decode/render time;
>
>
>
> In contrast, merging conditionally included/excluded content into a single
> TTML resource requires:
>
>
>
> (1) correct tagging/marking of conditional content;
>
>
>
> (2) introducing new spec feature to handle conditional content;
>
>
>
> (3) requiring decoder/presenter to implement conditional content handling;
>
>
>
> From the perspective of spec writing, the latter is more complex since it
> requires defining a new relatively complex feature. From the perspective of
> decoder/presenter implementation, the latter is more complex since it must
> implement the conditional content feature.
>
>
>
> So it seems to come down to the weighing of whether specifying, supporting
> (implementing), and authoring for conditional content is more or less
> complex than authoring multiple resources each of which have already made
> all content conditionalization choices and then have the decoder/presenter
> select between them.
>
>
>
> From my perspective, authoring multiple TTML resources is less complex
> overall. Of course, one could author a master TTML resource that contains
> metadata to be used by a later transformation process that splits up that
> master into the multiple resources needed to create the actual distribution
> (interchange) resources.
>
>
>
>
>
> [1]
> http://www.uvvuwiki.com/doc/sites/default/files/PublicSpecs/Device-1.1.pdf
>
>
>
>                 Mike
>
>
>
> *From:* Glenn Adams [mailto:glenn@skynav.com]
> *Sent:* Monday, June 23, 2014 8:04 PM
> *To:* Michael Dolan
> *Cc:* TTWG
>
>
> *Subject:* Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay
>
>
>
> Why not author three documents:
>
>
>
> (1) with forced content only
>
> (2) with non-forced content only
>
> (3) with non-forced and forced content combined
>
>
>
> If subtitles are off, then if external forced parameter false, don't
> decode/present any of (1) to (3).
>
> If subtitles are off, then if external forced parameter true,
> decode/present (1).
>
> If subtitles are on, then if external forced parameter false,
> decode/present (2).
>
> If subtitles are on, then if external forced parameter true,
> decode/present (3).
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Mon, Jun 23, 2014 at 7:15 PM, Michael Dolan <mdolan@newtbt.com> wrote:
>
> We seem to have lost the details of the use case….
>
>
>
> The visibility (or not) of text marked as “forced” is inversely signaled *external
> to the document*.
>
>
>
> When the entire document is selected (subtitles=on), “forced” has no
> affect at all (as you note).  When it matters is when the document is “not
> selected” (subtitles=off), then only the text marked “forced” is displayed.
>
>
>
> There is no other known way to get this behavior except to author two
> separate documents – one containing all the non-forced text, and one
> containing only the forced text.  Then:
>
>
>
> 1.       Subtitles=off – decode only the “forced” document
>
> 2.       Subtitles=on – decode both of the documents simultaneously,
> effectively create merged synchronic documents and then display the
> composited result.
>
>
>
> The ramifications of #2 above were rejected by consumer device
> manufacturers as too computationally difficult.
>
>
>
> Clearer?
>
>
>
> Maybe there is a more clever way to do this, but it has not emerged
> elsewhere…
>
>
>
> Regards,
>
>
>
>                 Mike
>
>
>
> *From:* Glenn Adams [mailto:glenn@skynav.com]
> *Sent:* Monday, June 23, 2014 5:41 PM
> *To:* John Birch
> *Cc:* pal@sandflow.com; public-tt@w3.org
>
>
> *Subject:* Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay
>
>
>
> I've been contemplating the forced display logic a bit more, and I'm
> wondering why we need it at all. If any content is present in a TTML input
> document to a compliant TTML presentation processor, then it must format
> all of the content in accordance with the TTML presentation semantics.
>
>
>
> That is, if there is some content in a TTML document that someone would
> like to annotate as 'forcedDisplay', then it is already being displayed
> (modulo time activation, tts:display, and tts:visible). In other words,
> there is nothing other than these three criteria that would cause it to not
> be displayed. So there is no need for forcing anything.
>
>
>
>
>
>
>
>
>
> On Mon, Jun 23, 2014 at 9:10 AM, Glenn Adams <glenn@skynav.com> wrote:
>
>
>
> On Mon, Jun 23, 2014 at 1:43 AM, John Birch <John.Birch@screensystems.tv>
> wrote:
>
> As an aside, what would be the impact on conditional region use? Where
> would content end up if the original target region was removed by a
> condition? I can see how it might end up in a parent region, but in the
> absence of a higher level parent region it would move to a default region?
>
>
>
> We would have to address this in spec text either way. It would also be
> possible to define a ttp parameter that let the author choose the behavior:
> no region or default region.
>
>
>
>
> Best regards,
> John
>
>
>
> *From*: Glenn Adams [mailto:glenn@skynav.com]
>
> *Sent*: Monday, June 23, 2014 08:15 AM
>
>
> *To*: John Birch
> *Cc*: pal@sandflow.com <pal@sandflow.com>; public-tt@w3.org <
> public-tt@w3.org>
> *Subject*: Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay
>
>
>
> In that case, my original proposal to use @condition on content elements
> should suffice, since it would have the same effect as tts:display in the
> sense of including/excluding a content element in the layout/flow process.
>
>
>
> Nevertheless, I can fathom uses for such a conditional to be applied to
> not only content elements, but also region, as well as styling. For the
> purpose of conditionalizing styling, applying it to <set/> seems the best
> option.
>
>
>
> On Sun, Jun 22, 2014 at 11:46 PM, John Birch <John.Birch@screensystems.tv>
> wrote:
>
> Agreed re content selection. I am unaware of an example where preserving
> layout is relevant... Or would be absolutely necessary.
>
> So yes... I believe that the use case can be supported using display.
>
> best regards,
> John
>
>
>
>
> *From*: Glenn Adams [mailto:glenn@skynav.com]
> *Sent*: Monday, June 23, 2014 06:28 AM
> *To*: John Birch
> *Cc*: pal@sandflow.com <pal@sandflow.com>; public-tt@w3.org <
> public-tt@w3.org>
>
> *Subject*: Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay
>
>
>
>
>
> On Sun, Jun 22, 2014 at 11:14 PM, John Birch <John.Birch@screensystems.tv>
> wrote:
>
> Whilst it may be less problematic for IMSC to diverge from TTML1 I do have
> more problems with it not being a subset of TTML2. My preference would be
> for a solution that is compatible.
>
> On the forcedDisplay point I do believe that this represents a content
> classification rather than a stylistic attribution... Albeit poorly named.
> I.e. Forced subtitles are content that is different to 'normal'
> subtitles... As Pierre has illustrated, they are often used for
> translations of on-screen texts, or for translations of invented languages
> (e.g. Klingon or Navi). They are a sub classification of subtitle. I am
> however struggling to think of a better term than 'forced subtitles' as
> other alternatives are narrower in scope.
>
> Consequently I suggest that these are handled as a content categorisation
> that invokes a specific style. Possibly a new style attribute value is
> needed: visibility = 'forced'.
>
>
>
> From the examples I've seen so far, this is a content selection (as in
> active or not active) issue rather than a style (visibility) issue. That
> is, I haven't seen any examples where it should map to tts:visible as
> opposed to tts:display.
>
>
>
> I think we should not disconnect this issue from that of how to treat
> content tagged with different languages. Furthermore, we could use the
> @condition approach to dynamically select different region extent/origin
> based on media device features.
>
>
>
>
> Best regards,
> John
>
>
> John Birch | Strategic Partnerships Manager | Screen
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>
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> 1473 831700 | Ext : 2208 | Direct Dial : +44 1473 834532
> Mobile : +44 7919 558380 | Fax : +44 1473 830078
> John.Birch@screensystems.tv | www.screensystems.tv |
> https://twitter.com/screensystems
>
>
> *Visit us at Broadcast Asia, Marina Bay Sands, Singapore 17-20 June, Stand
> 5E4-01*
>
> *P** Before printing, think about the environment*
>
>
>
>
> *John Birch | Strategic Partnerships Manager | Screen*Main Line : +44
> 1473 831700 | Ext : 2208 | Direct Dial : +44 1473 834532
> Mobile : +44 7919 558380 | Fax : +44 1473 830078
> John.Birch@screensystems.tv | www.screensystems.tv |
> https://twitter.com/screensystems
>
>
> *Visit us at Broadcast Asia, Marina Bay Sands, Singapore 17-20 June, Stand
> 5E4-01*
>
> *P** Before printing, think about the environment*
>
>
>
> P Before printing, think about the environment----- Original Message -----
> From: Pierre-Anthony Lemieux [mailto:pal@sandflow.com]
> Sent: Monday, June 23, 2014 04:55 AM
> To: Glenn Adams <glenn@skynav.com>
> Cc: public-tt@w3.org <public-tt@w3.org>
> Subject: Re: [IMSC] Thoughts re: issue-312 -- itts:forcedDisplay
>
>
> > If you want to define it in IMSC1 as a style attribute that will map to
> a future conditional
> > style construct in TTML2, then that is fine, but there is no guarantee
> we will directly support
> > that attribute in TTML2 (as opposed to requiring that the more general
> mechanism be used). As it is,
> > IMSC1 is likely not going to be a strict subset of either TTML1 or TTML2.
>
> Sounds like a reasonable approach.
>
> Best,
>
> -- Pierre
>
> On Sun, Jun 22, 2014 at 8:45 PM, Glenn Adams <glenn@skynav.com> wrote:
> > Do you have a real world example of where conditional content couldn't
> > handle it? In any case, I think we can define a conditional styling
> > mechanism as well as conditional content, and then author can choose the
> one
> > that makes sense.
> >
> > If you want to define it in IMSC1 as a style attribute that will map to a
> > future conditional style construct in TTML2, then that is fine, but
> there is
> > no guarantee we will directly support that attribute in TTML2 (as
> opposed to
> > requiring that the more general mechanism be used). As it is, IMSC1 is
> > likely not going to be a strict subset of either TTML1 or TTML2.
> >
> >
> > On Sun, Jun 22, 2014 at 9:42 PM, Pierre-Anthony Lemieux <
> pal@sandflow.com>
> > wrote:
> >>
> >> > In this example, the conditional content would suffice, since there
> >> > is no layout interaction between the two regions.
> >>
> >> Perhaps, but this cannot be guaranteed to be always the case.
> >>
> >> -- Pierre
> >>
> >> On Sun, Jun 22, 2014 at 8:40 PM, Glenn Adams <glenn@skynav.com> wrote:
> >> > In this example, the conditional content would suffice, since there is
> >> > no
> >> > layout interaction between the two regions.
> >> >
> >> >
> >> > On Sun, Jun 22, 2014 at 9:31 PM, Pierre-Anthony Lemieux
> >> > <pal@sandflow.com>
> >> > wrote:
> >> >>
> >> >> Hi Glenn,
> >> >>
> >> >> Attached is an example inspired from an opening shot from The Muppets
> >> >> (2011) Blu-Ray.
> >> >>
> >> >> The forced subtitle is the translation of the "High School" sign. It
> >> >> appears when French is selected as the language, even if the user has
> >> >> not explicitly selected French subtitles, i.e. when 'forced mode' is
> >> >> true.
> >> >>
> >> >> The translation of the voiceover is not labeled 'forced', and thus
> >> >> shows up only when French subtitles are selected, i.e. 'forced mode'
> >> >> is false.
> >> >>
> >> >> Best,
> >> >>
> >> >> -- Pierre
> >> >>
> >> >> P.S.: in UVVU, 'forced mode'=='true' is called "Alternate Subtitling
> >> >> Presentation Mode" and 'forced mode'=='false' is called "Primary
> >> >> Subtitling Presentation Mode".
> >> >>
> >> >> On Sat, Jun 21, 2014 at 7:17 PM, Glenn Adams <glenn@skynav.com>
> wrote:
> >> >> > Could you point at or construct a real world example, i.e., images
> of
> >> >> > what a
> >> >> > mixture of forced and non-forced content looks like depending on
> >> >> > whether
> >> >> > a
> >> >> > forced display parameter is true or false?
> >> >> >
> >> >> >
> >> >> > On Sat, Jun 21, 2014 at 6:56 PM, Pierre-Anthony Lemieux
> >> >> > <pal@sandflow.com>
> >> >> > wrote:
> >> >> >>
> >> >> >> Hi Glenn,
> >> >> >>
> >> >> >> > why would one want it to occupy layout space if not selected?
> >> >> >> > that doesn't make any sense;
> >> >> >>
> >> >> >> The forced content would have been positioned with the non-forced
> >> >> >> content present. Simply removing the non-forced content from flow
> >> >> >> would potentially change the rendered position of the forced
> >> >> >> content.
> >> >> >>
> >> >> >> I will confirm this.
> >> >> >>
> >> >> >> Best,
> >> >> >>
> >> >> >> -- Pierre
> >> >> >>
> >> >> >> On Sat, Jun 21, 2014 at 5:50 PM, Glenn Adams <glenn@skynav.com>
> >> >> >> wrote:
> >> >> >> >
> >> >> >> > On Sat, Jun 21, 2014 at 6:43 PM, Pierre-Anthony Lemieux
> >> >> >> > <pal@sandflow.com>
> >> >> >> > wrote:
> >> >> >> >>
> >> >> >> >> Hi Glenn,
> >> >> >> >>
> >> >> >> >> Thanks for these initial thoughts.
> >> >> >> >>
> >> >> >> >> > 3. evaluating this sub-tree in a postorder traversal, prune
> >> >> >> >> > elements
> >> >> >> >> > if they are not a content element, if they have a condition
> >> >> >> >> > attribute
> >> >> >> >> > that evaluates to false,
> >> >> >> >>
> >> >> >> >> "Forced" does not remove the content element from layout and
> >> >> >> >> flow,
> >> >> >> >> but
> >> >> >> >> instead
> >> >> >> >> effectively sets the visibility to zero, like
> >> >> >> >> tts:visibility="hidden".
> >> >> >> >
> >> >> >> >
> >> >> >> > it should; why would one want it to occupy layout space if not
> >> >> >> > selected?
> >> >> >> > that doesn't make any sense;
> >> >> >> >
> >> >> >> > i don't see how to handle conditional content and conditional
> >> >> >> > visibility; i
> >> >> >> > think the best you will get is the former
> >> >> >> >
> >> >> >> >>
> >> >> >> >>
> >> >> >> >> Best,
> >> >> >> >>
> >> >> >> >> -- Pierre
> >> >> >> >>
> >> >> >> >> On Sat, Jun 21, 2014 at 5:38 PM, Glenn Adams <glenn@skynav.com
> >
> >> >> >> >> wrote:
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> > On Sat, Jun 21, 2014 at 6:07 PM, Pierre-Anthony Lemieux
> >> >> >> >> > <pal@sandflow.com>
> >> >> >> >> > wrote:
> >> >> >> >> >>
> >> >> >> >> >> > What do you mean by "application" in this context?
> >> >> >> >> >>
> >> >> >> >> >> The entity that is instructing the presentation processor to
> >> >> >> >> >> render
> >> >> >> >> >> the IMSC document.
> >> >> >> >> >>
> >> >> >> >> >> > I also don't know what parameter means in this context,
> >> >> >> >> >> > e.g., what does it mean vis-a-vis a TTML parameter, i.e.,
> >> >> >> >> >> > an attribute expressing a TTML parameter.
> >> >> >> >> >>
> >> >> >> >> >> It is not a TTML parameter, as in a ttp:*, but instead a
> state
> >> >> >> >> >> variable passed to the presentation processor instructing it
> >> >> >> >> >> to
> >> >> >> >> >> render
> >> >> >> >> >> or not non-forced content, like a function argument in a
> >> >> >> >> >> procedural
> >> >> >> >> >> language.
> >> >> >> >> >>
> >> >> >> >> >> > I am opposed to a one-off solution to a special case of
> the
> >> >> >> >> >> > conditional
> >> >> >> >> >> >  content problem. And the forcedDisplay feature is exactly
> >> >> >> >> >> > such
> >> >> >> >> >> > a
> >> >> >> >> >> > special case.
> >> >> >> >> >>
> >> >> >> >> >> Can you think of a generic solution that would reduce to a
> >> >> >> >> >> single
> >> >> >> >> >> attribute controlling the rendering of forced content? If
> so,
> >> >> >> >> >> we
> >> >> >> >> >> could
> >> >> >> >> >> consider using it in IMSC.
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> > I haven't given it much thought, but if we were to introduce
> as
> >> >> >> >> > the
> >> >> >> >> > general
> >> >> >> >> > mechanism a new element type:
> >> >> >> >> >
> >> >> >> >> > <tt:switch condition="expression">
> >> >> >> >> > ... content elements ...
> >> >> >> >> > </tt:switch>
> >> >> >> >> >
> >> >> >> >> > then we could also, or as an alternative, introduce an
> >> >> >> >> > attribute
> >> >> >> >> > @condition
> >> >> >> >> > on content element vocabulary, e.g.,
> >> >> >> >> >
> >> >> >> >> > <div condition="expression"/>
> >> >> >> >> >
> >> >> >> >> > where expression uses a simple expression language such as
> >> >> >> >> > media
> >> >> >> >> > queries
> >> >> >> >> > level 4 [1] or a derivative.
> >> >> >> >> >
> >> >> >> >> > [1] http://dev.w3.org/csswg/mediaqueries4/
> >> >> >> >> >
> >> >> >> >> > For example,
> >> >> >> >> >
> >> >> >> >> > <p condition="(forced)"/>
> >> >> >> >> >
> >> >> >> >> > <p condition="not (forced)"/>
> >> >> >> >> >
> >> >> >> >> > <p condition="(locale: en)"/>
> >> >> >> >> >
> >> >> >> >> > <p condition="not (locale: en)"/>
> >> >> >> >> >
> >> >> >> >> > <p condition="(forced) or not (locale: en)"/>
> >> >> >> >> >
> >> >> >> >> > ...
> >> >> >> >> >
> >> >> >> >> > Where the semantics of @condition is essentially changing
> step
> >> >> >> >> > 3
> >> >> >> >> > of
> >> >> >> >> > 9.3.3
> >> >> >> >> > [construct intermediate document] to read essentially as
> >> >> >> >> > follows:
> >> >> >> >> >
> >> >> >> >> > 3. evaluating this sub-tree in a postorder traversal, prune
> >> >> >> >> > elements
> >> >> >> >> > if
> >> >> >> >> > they
> >> >> >> >> > are not a content element, if they have a condition attribute
> >> >> >> >> > that
> >> >> >> >> > evaluates
> >> >> >> >> > to false, if they are temporally inactive, if they are empty,
> >> >> >> >> > or
> >> >> >> >> > if
> >> >> >> >> > they
> >> >> >> >> > aren't associated with region R according to the [associate
> >> >> >> >> > region]
> >> >> >> >> > procedure;
> >> >> >> >> >
> >> >> >> >> >>
> >> >> >> >> >>
> >> >> >> >> >> Thanks,
> >> >> >> >> >>
> >> >> >> >> >> -- Pierre
> >> >> >> >> >>
> >> >> >> >> >> On Fri, Jun 20, 2014 at 10:56 PM, Glenn Adams
> >> >> >> >> >> <glenn@skynav.com>
> >> >> >> >> >> wrote:
> >> >> >> >> >> >
> >> >> >> >> >> > On Fri, Jun 20, 2014 at 10:33 PM, Pierre-Anthony Lemieux
> >> >> >> >> >> > <pal@sandflow.com>
> >> >> >> >> >> > wrote:
> >> >> >> >> >> >>
> >> >> >> >> >> >> Hi Glenn,
> >> >> >> >> >> >>
> >> >> >> >> >> >> Thanks for the feedback.
> >> >> >> >> >> >>
> >> >> >> >> >> >> > no, [forcedDisplayModeParameter] should not be a
> >> >> >> >> >> >> > parameter,
> >> >> >> >> >> >> > in
> >> >> >> >> >> >> > which
> >> >> >> >> >> >> > it would go into some
> >> >> >> >> >> >> > parameter namespace, but should be a metadata
> attribute,
> >> >> >> >> >> >> > ittm:forcedDisplay
> >> >> >> >> >> >>
> >> >> >> >> >> >> forcedDisplayModeParameter != itts:forcedDisplay.
> >> >> >> >> >> >> forcedDisplayModeParameter would be a parameter passed by
> >> >> >> >> >> >> the
> >> >> >> >> >> >> application to the processor, not a parameter within the
> >> >> >> >> >> >> document.
> >> >> >> >> >> >
> >> >> >> >> >> >
> >> >> >> >> >> > What do you mean by "application" in this context? I also
> >> >> >> >> >> > don't
> >> >> >> >> >> > know
> >> >> >> >> >> > what
> >> >> >> >> >> > parameter means in this context, e.g., what does it mean
> >> >> >> >> >> > vis-a-vis
> >> >> >> >> >> > a
> >> >> >> >> >> > TTML
> >> >> >> >> >> > parameter, i.e., an attribute expressing a TTML parameter.
> >> >> >> >> >> >
> >> >> >> >> >> >>
> >> >> >> >> >> >>
> >> >> >> >> >> >> > in other words, TTML will remain silent on any
> >> >> >> >> >> >> > presentation
> >> >> >> >> >> >> > semantics
> >> >> >> >> >> >> > of
> >> >> >> >> >> >> > such an attribute;
> >> >> >> >> >> >>
> >> >> >> >> >> >> How would interoperability be achieved?
> >> >> >> >> >> >
> >> >> >> >> >> >
> >> >> >> >> >> > By defining a standard mechanism for expressing
> conditional
> >> >> >> >> >> > content
> >> >> >> >> >> > contingent on external processor state, e.g., selected
> >> >> >> >> >> > language,
> >> >> >> >> >> > whether
> >> >> >> >> >> > display of some content is forced or not, etc.
> >> >> >> >> >> >
> >> >> >> >> >> > I am opposed to a one-off solution to a special case of
> the
> >> >> >> >> >> > conditional
> >> >> >> >> >> > content problem. And the forcedDisplay feature is exactly
> >> >> >> >> >> > such
> >> >> >> >> >> > a
> >> >> >> >> >> > special
> >> >> >> >> >> > case.
> >> >> >> >> >> >
> >> >> >> >> >> >>
> >> >> >> >> >> >>
> >> >> >> >> >> >> Thanks,
> >> >> >> >> >> >>
> >> >> >> >> >> >> -- Pierre
> >> >> >> >> >> >>
> >> >> >> >> >> >> On Fri, Jun 20, 2014 at 8:58 PM, Glenn Adams
> >> >> >> >> >> >> <glenn@skynav.com>
> >> >> >> >> >> >> wrote:
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > On Fri, Jun 20, 2014 at 7:05 PM, Pierre-Anthony Lemieux
> >> >> >> >> >> >> > <pal@sandflow.com>
> >> >> >> >> >> >> > wrote:
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> Hi all,
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> During our last call, I noted two concerns with the
> >> >> >> >> >> >> >> itts:forcedDisplay
> >> >> >> >> >> >> >> feature as currently drafted.
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> (a) the semantics of the itts:forcedDisplay feature
> are
> >> >> >> >> >> >> >> not
> >> >> >> >> >> >> >> sufficiently specified
> >> >> >> >> >> >> >> (b) the representation of itts:forcedDisplay as an
> >> >> >> >> >> >> >> attribute
> >> >> >> >> >> >> >> is
> >> >> >> >> >> >> >> not
> >> >> >> >> >> >> >> desirable
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > that should read as a style attribute
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> To address (a), below is proposed prose:
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> """
> >> >> >> >> >> >> >> The presentation processor SHALL accept an optional
> >> >> >> >> >> >> >> boolean
> >> >> >> >> >> >> >> parameter
> >> >> >> >> >> >> >> called forcedDisplayModeParameter, whose value may be
> >> >> >> >> >> >> >> set
> >> >> >> >> >> >> >> by
> >> >> >> >> >> >> >> the
> >> >> >> >> >> >> >> application. If not set, the value of
> >> >> >> >> >> >> >> forcedDisplayModeParameter
> >> >> >> >> >> >> >> shall
> >> >> >> >> >> >> >> be assumed to be equal to "false".
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > no, it should not be a parameter, in which it would go
> >> >> >> >> >> >> > into
> >> >> >> >> >> >> > some
> >> >> >> >> >> >> > parameter
> >> >> >> >> >> >> > namespace, but should be a metadata attribute,
> >> >> >> >> >> >> > ittm:forcedDisplay
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > i'm not sure why you wish to lengthen the name
> >> >> >> >> >> >> > unnecessarily
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> If the value of forcedDisplayModeParameter is "true",
> a
> >> >> >> >> >> >> >> content
> >> >> >> >> >> >> >> element with a itts:forcedDisplay computed value of
> >> >> >> >> >> >> >> "false"
> >> >> >> >> >> >> >> shall
> >> >> >> >> >> >> >> be
> >> >> >> >> >> >> >> assumed to have a tts:visibility computed value equal
> to
> >> >> >> >> >> >> >> "hidden",
> >> >> >> >> >> >> >> even if tts:visibility is otherwise set to "true".
> >> >> >> >> >> >> >> """
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > now, this is again placing style/presentation semantics
> >> >> >> >> >> >> > on
> >> >> >> >> >> >> > this
> >> >> >> >> >> >> > metadata
> >> >> >> >> >> >> > attribute, which is inapropriate
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> The idea is to essentially ignore the
> itts:forcedDisplay
> >> >> >> >> >> >> >> attribute
> >> >> >> >> >> >> >> unless otherwise specifically requested by the
> >> >> >> >> >> >> >> application.
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > i'm not sure what "requested by the application" means
> >> >> >> >> >> >> > here
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> This also
> >> >> >> >> >> >> >> clarifies that itts:forcedDisplay has "no effect on
> >> >> >> >> >> >> >> content
> >> >> >> >> >> >> >> layout
> >> >> >> >> >> >> >> or
> >> >> >> >> >> >> >> composition, but merely determines whether composed
> >> >> >> >> >> >> >> content
> >> >> >> >> >> >> >> is
> >> >> >> >> >> >> >> visible
> >> >> >> >> >> >> >> or not."
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > if that is the purpose, then the tts:visibility
> property
> >> >> >> >> >> >> > should
> >> >> >> >> >> >> > be
> >> >> >> >> >> >> > used
> >> >> >> >> >> >> > and
> >> >> >> >> >> >> > therefore there is no need for a new forcedDisplay
> >> >> >> >> >> >> > attribute
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> As next step, I plan to create examples.
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> Re: (b), I am not comfortable rejecting a solution
> that
> >> >> >> >> >> >> >> users
> >> >> >> >> >> >> >> have
> >> >> >> >> >> >> >> devised and implemented based on actual use cases and
> in
> >> >> >> >> >> >> >> the
> >> >> >> >> >> >> >> absence
> >> >> >> >> >> >> >> of specific guidance and/or prohibition in TTML 1.0.
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > if those users expect that the TTWG would simply adopt
> a
> >> >> >> >> >> >> > solution
> >> >> >> >> >> >> > as
> >> >> >> >> >> >> > a
> >> >> >> >> >> >> > fait
> >> >> >> >> >> >> > accompli, then they are naive; an appropriate process
> >> >> >> >> >> >> > would
> >> >> >> >> >> >> > have
> >> >> >> >> >> >> > been
> >> >> >> >> >> >> > to
> >> >> >> >> >> >> > bring use cases and requirements to the TTWG first, not
> >> >> >> >> >> >> > bring a
> >> >> >> >> >> >> > solution
> >> >> >> >> >> >> > as
> >> >> >> >> >> >> > a given
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > at this point, I think the best that can be hoped for
> >> >> >> >> >> >> > IMSC
> >> >> >> >> >> >> > is
> >> >> >> >> >> >> > to
> >> >> >> >> >> >> > define
> >> >> >> >> >> >> > a
> >> >> >> >> >> >> > metadata attribute ittm:forcedDisplay which is
> described
> >> >> >> >> >> >> > as
> >> >> >> >> >> >> > a
> >> >> >> >> >> >> > hint
> >> >> >> >> >> >> > that
> >> >> >> >> >> >> > the
> >> >> >> >> >> >> > associated content is intended to be selected as a
> >> >> >> >> >> >> > candidate
> >> >> >> >> >> >> > for
> >> >> >> >> >> >> > display
> >> >> >> >> >> >> > by
> >> >> >> >> >> >> > a higher level protocol (outside the scope of formally
> >> >> >> >> >> >> > defined
> >> >> >> >> >> >> > TTML
> >> >> >> >> >> >> > processing); in other words, TTML will remain silent on
> >> >> >> >> >> >> > any
> >> >> >> >> >> >> > presentation
> >> >> >> >> >> >> > semantics of such an attribute;
> >> >> >> >> >> >> >
> >> >> >> >> >> >> > on the other hand, we may choose in TTML2 to define a
> >> >> >> >> >> >> > conditional
> >> >> >> >> >> >> > content
> >> >> >> >> >> >> > mechanism similar to the SMIL or SVG switch element,
> that
> >> >> >> >> >> >> > could
> >> >> >> >> >> >> > address
> >> >> >> >> >> >> > this
> >> >> >> >> >> >> > use case
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> Best,
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >> -- Pierre
> >> >> >> >> >> >> >>
> >> >> >> >> >> >> >
> >> >> >> >> >> >
> >> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >
> >> >> >> >
> >> >> >
> >> >> >
> >> >
> >> >
> >
> >
>
> This message may contain confidential and/or privileged information. If
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> any action based on this message or any information herein. If you have
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> Screen Subtitling Systems Ltd. Registered in England No. 2596832.
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> Suffolk, IP6 0EQ
>
>
>
>
>
> This message may contain confidential and/or privileged information. If
> you are not the intended recipient you must not use, copy, disclose or take
> any action based on this message or any information herein. If you have
> received this message in error, please advise the sender immediately by
> reply e-mail and delete this message. Thank you for your cooperation.
> Screen Subtitling Systems Ltd. Registered in England No. 2596832.
> Registered Office: The Old Rectory, Claydon Church Lane, Claydon, Ipswich,
> Suffolk, IP6 0EQ
>
>   ­­
>
>
>
>
>
> This message may contain confidential and/or privileged information. If
> you are not the intended recipient you must not use, copy, disclose or take
> any action based on this message or any information herein. If you have
> received this message in error, please advise the sender immediately by
> reply e-mail and delete this message. Thank you for your cooperation.
> Screen Subtitling Systems Ltd. Registered in England No. 2596832.
> Registered Office: The Old Rectory, Claydon Church Lane, Claydon, Ipswich,
> Suffolk, IP6 0EQ
>
>   ­­
>
>
>
>
>
>
>
>
>