{minutes} TTWG Meeting 2018-08-09

Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2018/08/09-tt-minutes.html

A reminder that our next call will be on August 30th at the usual time.

The minutes in text format:


   [1]W3C

      [1] http://www.w3.org/

                Timed Text Working Group Teleconference

09 Aug 2018

   See also: [2]IRC log

      [2] https://www.w3.org/2018/08/09-tt-irc

Attendees

   Present
          Glenn, Pierre, Thierry, Nigel, Cyril, Andreas

   Regrets
          none

   Chair
          Nigel

   Scribe
          nigel

Contents

     * [3]Topics
         1. [4]This meeting
         2. [5]TTML1
         3. [6]TTML1 3ED tests ttml1#361
         4. [7]TTML2
         5. [8]TTML2 implementation report
         6. [9]Clarify that #length-root-container-relative
            applies to all <length> expressions. ttml2#973
         7. [10]IMSC 1.1
         8. [11]IMSC vNext Requirements.
         9. [12]CSS actions review
        10. [13]TTML Profile Registry
        11. [14]Meeting Close
     * [15]Summary of Action Items
     * [16]Summary of Resolutions
     __________________________________________________________

   <scribe> scribe: nigel

This meeting

   Nigel: Hi everyone!
   ... Today is our last meeting for a couple of weeks. Our next
   after today is on 30th August.
   ... For today, we need to start focusing on tests since there's
   no spec work to do urgently,
   ... just editorial things.
   ... I think we will cover TTML1, TTML2, IMSC 1.1, CSS stuff. I
   don't think we have anything
   ... to cover with profile registry yet.
   ... Any particular items to cover, or any other business?

   Pierre: I think it's already on the agenda, but TTML1 3rd Ed
   tests, and also two particular
   ... TTML2 tests for luminanceGain and disparity.

   Nigel: OK, thanks.

   group: [no other points to raise]

TTML1

   Nigel: Pierre, you wanted to cover TTML1 3rd Ed Tests, but
   before that...

   Thierry: TTML1 3rd Ed CR2 is published, and the call for
   exclusion has been sent.

   Nigel: Thank you!

   Thierry: We are on track and schedule.

   Nigel: Okay, Pierre, tests?

TTML1 3ED tests ttml1#361

   github: [17]https://github.com/w3c/ttml1/pull/361/files

     [17] https://github.com/w3c/ttml1/pull/361/files

   Pierre: I just pushed it a couple of hours ago so I don't
   expect anyone to have had a
   ... thorough look. I've gone through all the substantive tests
   since 2ed and created tests
   ... for everything that can be tested and highlighted what I
   think cannot be tested.
   ... The tests are inspired by the IMSC tests so they will seem
   familiar.
   ... I'd like a review especially on the things marked as
   non-testable.
   ... From a practical perspective, if Glenn could try to render
   or check them using TTPE and
   ... TTX that would be great. Last time we spoke the plan was
   for TTPE and IMSC.js to be the
   ... two implementations for the TTML1 3ed tests.

   Cyril: How many of these tests are relevant for IMSC 1.1?

   Pierre: First, there may be zero IMSC 1.1 tests because
   everything in IMSC 1.1 is already
   ... in TTML2 or IMSC 1.0.1, so there will be no additional
   tests needed to meet the IMSC 1.1
   ... exit criteria.

   Cyril: I understand that, but how many of the tests for TTML1
   3ed are relevant for IMSC 1.1
   ... features?

   Pierre: All but one are covered by IMSC 1.1. But I think the
   purpose of those tests if I recall
   ... correctly was specifically to convince the Director that
   the substantive changes were in
   ... fact implemented.

   Nigel: That's right.

   Pierre: I created those tests specifically to demonstrate that.
   All but one are already
   ... exercised by IMSC1 tests and TTML1 tests in fact.

   Cyril: Which is the exception?

   Pierre: Anamorphic fonts. There's one test that is triggered by
   anamorphic fonts.

   Cyril: 2 value relative font size?

   Pierre: Exactly. That one is not part of IMSC1 or 1.1 and I'm
   not even sure it was part of
   ... TTML1 test suite either.

   Cyril: Ok, thank you.

   Glenn: Q: what did we change in the spec that that particular
   test is used to demonstrate?

   Pierre: If you recall, we added a bunch of text that discussed
   inheritance.
   ... Example, p fontSize = "1c", then child span fontSize="1em".
   The font size is calculated
   ... to be 1c, that's boring.
   ... There are two examples in the TTML1 text that describe
   this.

   [18]fontSize in TTML1

     [18] https://www.w3.org/TR/ttml1/#style-attribute-fontSize

   Nigel: The examples are in Notes?

   Pierre: Yes
   ... The 3rd and 4th note in that section.
   ... "1em 1em" can result in an anamorphic font size.
   ... The relative font size is relative to the computed parent
   font size which can be anamorphic.

   Glenn: What normative text changed that drove adding that test?

   Pierre: The entire text of that section was heavily changed.

   Glenn: I'm just wondering if we went too far in creating that
   test or if the original test
   ... suite was under-represented.

   Pierre: The 5th paragraph, "When a single relative <length>
   value is specified, ..."
   ... If that is in TTML1 2nd Ed then I agree there's no need for
   tests, but I'm thinking it was not.

   Glenn: I'll check.

   Pierre: The two that can't be tested or don't need to be tested
   are:
   ... 1. 'should' regarding the tts:lineHeight.
   ... 2. application defaults for frame rate and sub-frame rate.
   ... I don't think that's testable.

   Nigel: Presumably we could include the application settings to
   apply for testing frame rate
   ... and sub-frame rate, for example in text outside the TTML
   document instance, then the
   ... same instance would have a different evaluation in some
   way?

   Pierre: Sure, but that in itself, the decision to apply an
   application default, has no requirement
   ... so I don't think it's testable.

   Nigel: In other words we have merely made explicit the already
   existing option for an
   ... implementation to do its own thing?

   Pierre: Yes, that's right.

   Nigel: That seems like a reasonable argument to me. What about
   lineHeight.
   ... Why not be able to test that?

   Pierre: It's a should.

   Nigel: But the semantic is still testable.

   Pierre: Yes but applications can be conformant without doing
   it.

   Nigel: Yes but we can still test the semantic.

   Pierre: The syntax is unchanged, and it's a should.

   Nigel: Yes but the test needs to demonstrate implementability,
   so there needs I think to be
   ... some test that shows the should behaviour can be
   implemented.

   Glenn: If normal already appears in any of the TTML1 tests then
   we don't need a new test
   ... for this.

   Nigel: Why not?

   Glenn: If normal is already there then that test for how normal
   is used, with no normative
   ... or exemplar images...

   Pierre: I don't understand - say tts:lineHeight="normal" and an
   implementation returns to
   ... you something with a line height that is double the font
   size, what do you conclude?

   Nigel: Depending on the algorithm in the spec and the font
   resources, on balance most
   ... likely that implementation is not demonstrating that the
   spec can be implemented.

   Pierre: It's only a recommendation.

   Nigel: If the spec said "should go back in time by 10 minutes"
   then the Director would want
   ... a test to show that, but of course no time machine exists,
   so I think that text would
   ... lead to trouble.

   Pierre: Good news, there already is a test for
   lineHeight="normal".

   Glenn: As I said.

   Pierre: I wanted to agree the scope first.

   Glenn: I wonder if it would be consistent if we add an exemplar
   to a small subset of TTML1
   ... tests.

   Nigel: I don't think we need to worry about that.

   Pierre: My proposal was just to check in the test files without
   exemplars, but file the outputs
   ... generated from our implementations under the implementation
   report.

   Glenn: Ok. When is the last date for this?

   Nigel: Thanks to Thierry,

   [19]Timeline

     [19] https://www.w3.org/AudioVideo/TT/specs-timeline.html

   Nigel: Shows that implementation report needs to be finalised
   by 24th September.

   Pierre: Can we give ourselves until August 30th to review those
   tests and make changes,
   ... then freeze them then create the implementation report, and
   then start submitting results.
   ... Just a suggestion.

   Glenn: TTPE implements normal as described as well as
   anamorphic fonts so I think we're
   ... good there but I'd need to run the tests to verify that. I
   don't think there's any problem
   ... in using TTPE as one of the implementations to verify
   those.

   Nigel: I like Pierre's suggested plan, any issues with that?

   group: [silence]

   Nigel: Okay, then agenda+ for 30th August to confirm the TTML1
   3ed test suite so we can
   ... begin to create the implementation report.
   ... [discusses tests, with comments on the pull request]

   Glenn: I just double checked the anamorphic font text, and it
   turns out that it is basically
   ... present in 2nd Ed in the 4th note in §8.2.9, in the last
   sentence. So this is basically a
   ... paragraph of text in a note already, now made normative
   whereas it was more an
   ... explanation of an implication in 2nd Ed.

   Pierre: So do we need the tests still?

   Glenn: In my opinion the semantic was already there and we're
   not demonstrating a new
   ... semantic.

   Pierre: I'm not excited by it.

   Glenn: I'd be willing to have no test and point to the 2nd Ed
   text for that.

   github: [20]https://github.com/w3c/ttml1/pull/361

     [20] https://github.com/w3c/ttml1/pull/361

   Nigel: I think the Director was asking for tests to demonstrate
   the substantive changes,
   ... and this counts as one because normative text clarifies
   what may have been ambiguous
   ... before.
   ... We need to look more carefully at this to see if an
   existing TTML1 test for two value fontSize
   ... can be reused or already demonstrates this.

   Glenn: I added a comment under this pull request.

   Nigel: This needs further investigation - I see that the diff
   tool isn't helping us.
   ... in the direction test, shouldn't the direction on the first
   p be direction="ltr"?

   Pierre: That is a subtle point that 3ed clarifies - without
   bidiOverride the "natural" direction
   ... of the script is not overridden.

   Glenn: Where that comes into effect is resolving the
   directionality of weakly directional
   ... or neutral directional characters at the boundaries of the
   paragraph, like the period that
   ... ends the paragraph is neutral directionality. If the
   paragraph embedding level is ltr then
   ... a period at the end of a hebrew or arabic sentence takes on
   the direction of the previous
   ... character, but there are scenarios where it doesn't work.
   On this point, previously in
   ... 2ed and prior we didn't call out this semantic but probably
   many implementations
   ... implemented it as we have now clarified. Since we did not
   say either way, some
   ... implementations may have read between the lines and applied
   it to p which would not
   ... have been non-conformant since we had no test suite
   examplars to follow. It could have
   ... fallen through the cracks.

   <tmichel> FYI you may use the following diff tool

   <tmichel>
   [21]http://www.aptest.com/standards/htmldiff/htmldiff.pl?oldfil
   e=https%3A%2F%2Fwww.w3.org%2FTR%2F2013%2FREC-ttml1-20130924%2F&
   newfile=https%3A%2F%2Fwww.w3.org%2FTR%2F2018%2FCR-ttml1-2018042
   4%2F

     [21] http://www.aptest.com/standards/htmldiff/htmldiff.pl?oldfile=https://www.w3.org/TR/2013/REC-ttml1-20130924/&newfile=https://www.w3.org/TR/2018/CR-ttml1-20180424/

   Glenn: The XSL spec says to apply it this.

   Cyril: 2 comments about the test suite.
   ... Some tests have a copyright.

   Pierre: Yes, I thought I'd removed them and didn't. Please add
   a comment.

   Cyril: Secondly, in the pull request you've done the work to
   link the issues to the tests,
   ... but there's no link backwards. I wonder if we should put
   metadata in the tests to point
   ... to the issues or the spec sections that it is trying to
   test.

   Pierre: Yes that'd be awesome.

   Nigel: Is that information available?

   Pierre: Yes it's in the pull request. Most of the tests have a
   metadata section so it's a matter
   ... of copying and pasting the pull request info into the
   metadata header. If someone wants
   ... to spend 45 minutes doing it that'd be awesome.

   Cyril: Going a bit further, referencing the spec itself?
   ... I suppose the issue goes to the pull request goes to the
   section of the text.

   Pierre: Exactly. Copying the bullet point is all we need to do.

   Nigel: Any other points on this test suite?

   SUMMARY: Test suite to be finalised August 30th, review to
   continue until then.

   Glenn: I would note that August 30th is prior to when it is
   actually needed so we have
   ... some room to slip that if necessary.

   Nigel: Yes but there has to be time for the implementations to
   respond to the tests.

   Glenn: Yes

   Pierre: The goal is to freeze the tests so implementers can
   work on them.

   Glenn: It's a good goal, just not an absolute hard deadline.

   Nigel: It's a target, and as Cyril mentioned there is other
   work to do at the same time.
   ... If we can freeze the tests on 30th then that gives 3 weeks
   for implementations, which
   ... seems reasonable.

   Pierre: If you can run the validator that would be good, Glenn.

   Glenn: Sure I can do that, and check what TTPE does as well.

TTML2

   action-443?

   <trackbot> action-443 -- Glenn Adams to Prepare a document
   showing mapping arib ruby extension features to ttml2 for use
   as a liaison document to arib. -- due 2018-08-09 -- OPEN

   <trackbot>
   [22]https://www.w3.org/AudioVideo/TT/tracker/actions/443

     [22] https://www.w3.org/AudioVideo/TT/tracker/actions/443

   Glenn: Put that off please.

   Nigel: Okay, you asked for this and asked me to put it off
   until today.
   ... We made the transition request as per the plan, and if all
   goes well we should have
   ... TTML2 CR3 published by 14th August, with a deadline for
   comments of 11th September.
   ... We need to leave reasonable time for any response.

   Thierry: I don't expect a Director meeting because this is
   straightforward. I will ping them
   ... (Philippe and Ralph) but it should be approved tomorrow.

   Glenn: The documentation is already in the right place, so this
   is just a formality?

   Thierry: Yes, I'm waiting for the normal process to go through.

TTML2 implementation report

   Nigel: Raising this as it's the next thing to do, and I see
   that Glenn has been submitting tests.

   Glenn: I've now blessed 249 unique tests that are all in the
   validation category.
   ... They are either validity or invalidity tests, documented in
   the spreadsheet shared
   ... previously.

   <glenn>
   [23]https://docs.google.com/spreadsheets/d/1nunAY0F0bxL0nZDng2V
   xmWHv7i2RyAIvKQwDiiVzooc/edit#gid=0

     [23] https://docs.google.com/spreadsheets/d/1nunAY0F0bxL0nZDng2VxmWHv7i2RyAIvKQwDiiVzooc/edit#gid=0

   Glenn: If you don't have share access to that then request it.
   ... I'm almost finished, I expect to have 100% coverage of the
   features for validation tests
   ... by Monday, hopefully, if not earlier. That's going very
   well.
   ... Then I will begin populating presentation tests, starting
   from about 100+ tests that are
   ... in TTPE already and use those to populate presentation
   tests in this spreadsheet, and
   ... also I'll upload to the ttml2-tests repository.
   ... As I'm going through these I'm also updating either TTV or
   TTPE implementations to
   ... verify that they work and produce desirable results. There
   will be some points where
   ... I have presentation tests with no TTPE rendering code so I
   will be relying on 3rd parties
   ... to demonstrate those. For example disparity and
   luminanceGain.
   ... They are included in IMSC 1.1 that will be depending on
   others to satisfy.
   ... I would like to hear if anyone has implemented or plans to
   implement those.

   Pierre: I just submitted a couple of hours ago two proposed
   tests, one for disparity and
   ... one for luminanceGain, on the imsc-tests repo.

   <pal> [24]https://github.com/w3c/imsc-tests/pull/69

     [24] https://github.com/w3c/imsc-tests/pull/69

   Pierre: That's the pull request. Glenn do you want to look at
   those, and tell me if those
   ... would fit in TTML2 presentation test suite, and if so we
   can put them in there?

   Glenn: My thinking is that I will also draw from other tests as
   well as the TTPE ones. I took
   ... a quick look at those this morning and they look fine on
   first glance. I will check they
   ... validate, but the presentation part modulo Nigel's comments
   seem okay. Do we have
   ... anyone signed up for implementing them?

   Pierre: I will be looking into this, but before that I wanted
   to look at concrete tests and
   ... check if those tests are going to be sufficient before I
   try to figure out test results.

   Cyril: A clarification question for Glenn. You said you will
   have validation tests finalised
   ... maybe by end of this week, but it is unclear to me if you
   foresee gaps in what you will
   ... be submitting in tests. Do you need any help to provide the
   tests?

   Glenn: I will provide 100% coverage of validation tests.
   ... The presentation tests though I mentioned my procedure. I
   will draw from TTPE then
   ... other sources including what Pierre has done in IMSC 1.1
   and will probably be soliciting
   ... others to add to that. The only gaps I see probably are
   going to be audio related.
   ... We don't have any plans to do audio presentation work right
   now.

   Nigel: I will do that, I created the adhere column in the
   implementation report.
   ... I have begun to produce audio style attribute presentation
   tests and plan to contribute
   ... those after my vacation.

   Glenn: On that point I noticed that you did not check the box
   for #audio-description,
   ... however I think the features already cover all the features
   so you may already satisfy
   ... that one as well.

   Nigel: The difficulty with that is that the Web Speech API
   audio output is not available as
   ... an input to the Web Audio API, so if an implementation is
   required to do text to speech and apply pan and gain that is
   difficult to do.

   Glenn: Okay we'll have to come back to that.

   Nigel: But that raises a really important point.
   ... We are currently dependent on the Web Audio API Spec, and I
   had been assured by one
   ... of the Chairs of the Web Audio WG that it would be in CR
   actually before TTML2, but
   ... that hasn't happened, even though the spec is stable and
   implemented in more than
   ... one browser. I believe the hold-up is with the team support
   for the Web Audio WG, whose
   ... staff member has not been progressing this, I don't know
   why. Thierry, please could you
   ... ask Chris Lilley if he can progress it?

   Thierry: Yes I can.

   Nigel: Thank you.

   Glenn: Just doing a quick glance at the feature definition,
   audio-description is a subset
   ... of the audio-speech features, so if you have an
   implementation that can support that
   ... then it already supports audio-description.

   Nigel: OK

   Glenn: [details of the features]

   Nigel: Thanks, I'll go and look again and double-check that.
   ... Is there any requirement for continuous animation in there?

   Glenn: Not in those feature definitions.

   Nigel: Okay, we're mid-implementation of continuous animation
   of pan and gain, for information.

   Glenn: For the sake of mentioning it, we don't have any
   standards in this WG or in W3C for
   ... how many tests have to be in the test suite for some
   feature.

   Nigel: Okay, that's noted.

   Glenn: I just wanted to remind us of that fact.

   Cyril: One question about the time wallclock feature. I'm
   wondering who is going to support
   ... it, if anyone would be supporting it.

   Nigel: Remind us?

   Glenn: We added a new clock time function to the time
   expression syntax. TTV will implement
   ... validation of that, but I'm not sure who will be
   implementing presentation.

   Nigel: Oh yes, the ability to add date to clock times.
   ... What would that do?

   Glenn: The time would be synchronised to the wallclock date and
   time in a presentation.

   Nigel: I foresee that being used more for recording live events
   historically than for triggering events to occur.

   Glenn: It does have presentation semantics.

   Nigel: Right, so the CR exit criteria require a presentation
   processor for it.

   Glenn: We don't say if a presentation processor is preceded by
   multiple transformation
   ... processes. I don't know if that would be applicable here.
   If it is thought that this would
   ... mostly be used by an authoring process then you might be
   able to claim that processing
   ... up the chain has presentation semantics eventually.

   Nigel: Thank you for the reminder, I'll have to look to see how
   we can support implementation of this.
   ... Are there any other features like this?

   Glenn: I think Cyril has mentioned all of them now. Thanks for
   adding that Cyril.

   Pierre: Glenn and others, when do you think we can have a
   generic yea or nay on the
   ... disparity and luminanceGain tests?

   Glenn: By tomorrow.

   Pierre: Awesome, thank you that would really help.

   Nigel: Our timeline says implementation report finalised 27th
   September, and we need to
   ... give time for people to provide implementations against
   tests, so that means we need
   ... the tests to be finalised sufficiently far in advance. We
   said just over 3 weeks for TTML1.
   ... There are a lot more tests for TTML2.
   ... Three weeks before 27th Sep is 6th Sep. Is there any hope
   of finalising the test suite
   ... by then?

   Glenn: We can have tests by then, whether they are finalised or
   not is a different question.

   Nigel: As a goal, I mean, not necessarily locked down.

   Glenn: 6th Sep leaves about 3-4 weeks from today. It's
   possible, it's aggressive.

   Nigel: We have to be aggressive to meet our timeline.

   Glenn: Absolutely!

   Nigel: Implementers may come back with issues on the tests, but
   we need a line in the sand
   ... to go to potential implementers and say here's the test
   suite.

   Glenn: It depends who will provide implementations. Skynav and
   Netflix will provide a lot
   ... of coverage, and BBC and maybe IRT will provide some
   implementations too.

   Andreas: IRT will implement IMSC 1.1 validation.

   Glenn: Thank you, Andreas. There are 25 features out of 135 new
   features that are in IMSC1.1.
   ... That leaves 110 features not included in IMSC 1.1.
   ... If the audience for our testing effort is primarily those
   of us here I'm presuming that
   ... we're keeping track of what's being proposed for tests and
   being able to be responsive.

   Nigel: You may be right, but we have to offer the test suite to
   others also.

   Glenn: Absolutely. That's why Sep 6 is okay with me for a
   "beta" version, which gives
   ... people something to work with, right?

   Nigel: Yes.

   Cyril: I counted 141 new features not 135. Is there an issue
   here?

   Glenn: Let me double check that. There may be some where all of
   the tests are a subset
   ... of something else that is already tested. I think the 6 are
   primarily new feature labels
   ... for things already in TTML1, like #set, which is an alias
   for #animation in TTML1. I think
   ... the remaining 6 come under that category.

   Cyril: Thank you.
   ... Another question on the implementation report. Do we expect
   implementers to provide
   ... renderings?

   Glenn: It's not required.

   Nigel: It's not required, it's nice to have.

   Glenn: It's not part of the implementation report review
   process. The Director can't require
   ... there to be images, because it is not a requirement.
   ... We operate on an honour system for implementation reports,
   since no public demonstration
   ... is needed.

   Nigel: That's right.
   ... Of course it is nice when people do provide one. Also
   remember that implementations
   ... can be anonymous, as long as the team can have a reasonable
   belief that it does exist
   ... and does what it says.

   Glenn: Testing is different from HTML where the tests are
   targeted at browsers. We have
   ... to allow for implementation reports from walled garden
   contexts where the report may
   ... be anonymised, right.

   Nigel: Yes.

   Glenn: There were a couple of TTML2 issues, #945 and #950 that
   were substantive, where
   ... I have implemented the deferral procedure. I just wanted to
   note that.
   ... For #950 the group agreed it as a resolution.
   ... For #945 the commenter agreed to defer it in an email to
   the list, which I used as the
   ... basis for the deferral.
   ... I wanted to note it for the minutes.

   Nigel: Thanks for reminding me of that.

   Glenn: At the moment there are 0 pull requests on TTML2 and 12
   open issues, all of them
   ... marked for PR.

   Nigel: And editorial.

   Glenn: Yes, and editorial. I will be implementing pull requests
   for those over the next
   ... few weeks as we go towards PR.
   ... You also put #973 on the agenda Nigel.

   Nigel: Thank you for reminding me.

Clarify that #length-root-container-relative applies to all <length>
expressions. ttml2#973

   github: [25]https://github.com/w3c/ttml2/issues/973

     [25] https://github.com/w3c/ttml2/issues/973

   Nigel: This might affect tests. It is not obvious. It also
   could potentially impact IMSC, where
   ... some constraints may be needed on where rw and rh units can
   be used, so they are not
   ... on every length expression.
   ... If for example a document instance requires processor
   support for rw and rh but that
   ... processor doesn't actually support it in every context,
   does that make the processor
   ... unsuitable or non-conformant?

   Glenn: We don't qualify the feature definitions, we don't say
   "anywhere" or "everywhere"
   ... in the text. I don't think we qualify its context anywhere,
   and we don't say that if there
   ... is no constraint on context then it applies everywhere.

   Nigel: That might be counter-productive!

   Glenn: I'm okay with not adding such a note. It was the
   intention of how we authored them
   ... that they would apply everywhere.
   ... We do have language about unsupported values for most
   properties to say what the
   ... correct behaviour should be.
   ... How does the language of nearest supported value apply to
   the definitions of features?
   ... That's not a question we've entertained before I think.

   Pierre: I think we do what we have done in other places, say
   that this particular feature
   ... is permitted in IMSC 1.1 but add constraints like "it shall
   not be used in these circumstances".

   Glenn: We have a few of those in TTML2 like extent on the tt
   element, which must be in px units.
   ... There are a couple of places where the units must be the
   same if there are multiple values.
   ... That does not abregate the semantics of the original
   feature.

   Pierre: My current plan, we added
   #length-root-container-relative to IMSC 1.1 at the last
   ... minute and marked it as at risk, I will be submitting as an
   issue a set of proposed
   ... constraints and if folks have thoughts about what is really
   important vs less important
   ... then please forward me your data and I will try to propose
   a strawman.

   Nigel: Okay, thank you.
   ... Okay, so coming back to this issue, a claim of support for
   #length-root-container-relative
   ... implies support on all length expressions in the absence of
   any other caveats.

   Glenn: That's correct.

   Pierre: That's the only logical interpretation.

   Nigel: That's fine, do we need some editorial text that
   explains that, or is it unnecessary?

   Glenn: I don't think we need anything absolutely in TTML2. I
   would not object to adding a
   ... note somewhere or eventually making it a normative general
   rule.
   ... I don't think we have to do anything in TTML2 1st edition
   if we don't want to.
   ... I would oppose saying anything specific to one feature, I
   wouldn't mind a general
   ... note.

   Nigel: Yes, that makes sense.
   ... Any other views?

   group: [none]

   SUMMARY: WG generally accepting of a general note explaining
   non-normatively that features like this apply universally or
   not at all, in the absence of any other caveat.

IMSC 1.1

   Nigel: Is there anything to discuss here?

   Pierre: I don't think so. I may have found a bug in the IMSC
   test suite - please review it
   ... if you are interested.
   ... Other than that, modulo luminanceGain and disparity, and
   root container length, the only other at risk
   ... feature is lineShear.
   ... Other than that, nothing to report. I'm nearly done with
   the IMSC 1.1 test suite, not
   ... intended for exit criteria, just to be useful for the
   industry.

   Glenn: TTPE will include TTML2 support for lineShear
   presentation semantics, so there's
   ... a potential that we could be able to claim support for IMSC
   1.1 lineShear.

   Pierre: Thanks for that. I expect we would formally be able to
   include lineShear in IMSC 1.1.
   ... We'll meet the exit criteria. My question is more if we
   want to do that. I'm still trying to
   ... see what is the right thing. There's a thread on the CSS WG
   issue. Hopefully we can gather
   ... the right data to make the decision there.

IMSC vNext Requirements.

   Pierre: I have some editorial work to do there.

   Nigel: Thank you.
   ... The CfC for publishing a WG Note ends today, but until the
   issues are resolved that
   ... decision cannot be enacted.
   ... That's pretty straightforward.

CSS actions review

   Nigel: Note that we have a new relevant CSS issue as Pierre
   mentioned a moment ago.

   [26]#2983 Support for shearing of lines and inline elements

     [26] https://github.com/w3c/csswg-drafts/issues/2983

   Nigel: Also, yesterday, the CSS WG agreed a name for the
   equivalent property to fillLineGap,
   ... which from memory I think is inline-box-sizing or something
   like that, with property values
   ... "normal" and "stretch".

TTML Profile Registry

   Nigel: The question has been raised with EBU, and I hope there
   will be some feedback
   ... on new profiles to add to the registry. We haven't had time
   to discuss the approach
   ... regarding processor profiles and content profiles yet.
   Something to look forward to,
   ... maybe for the agenda for TPAC?

Meeting Close

   Nigel: Thanks everyone. Reminder next meeting 30th August.
   Enjoy the break (from meetings!).
   ... [adjourns meeting]

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


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Received on Thursday, 9 August 2018 16:15:10 UTC