IRC log of tt on 2018-05-31
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- Meeting: Timed Text Working Group Teleconference
- 14:01:18 [trackbot]
- Date: 31 May 2018
- 14:01:24 [nigel]
- Log: https://www.w3.org/2018/05/31-tt-irc
- 14:02:09 [nigel]
- Present: Nigel, Glenn, Cyril
- 14:02:15 [nigel]
- Regrets: Pierre, Andreas, Thierry
- 14:02:21 [nigel]
- Chair: Nigel
- 14:02:25 [nigel]
- scribe: nigel
- 14:02:29 [nigel]
- Topic: This Meeting
- 14:02:44 [nigel]
- Glenn: The main thing I want to do today is review #794 with a view to merging early.
- 14:03:41 [nigel]
- Nigel: Today we have some regrets, so let's make what progress we can.
- 14:04:02 [nigel]
- .. On the agenda is TTWG Charter, TTML2, and I'm not sure what else we can cover.
- 14:04:19 [nigel]
- .. Aside from #794 is there anything else you'd like to make sure we look at, or any other
- 14:04:20 [nigel]
- .. business?
- 14:04:31 [nigel]
- Glenn: #770.
- 14:04:32 [nigel]
- Nigel: OK
- 14:04:49 [nigel]
- Glenn: In the remainder of the time I'd like to go over the ones ready to go pending
- 14:05:00 [nigel]
- .. approval of recent updates to address comments, that are marked as pending re-review
- 14:05:23 [nigel]
- .. in the pull request list for TTML2. There are a couple of older ones with Nigel's name on
- 14:05:27 [nigel]
- .. that maybe we can do in realtime.
- 14:05:30 [nigel]
- Nigel: OK
- 14:05:49 [nigel]
- Glenn: #703 and #755 I think.
- 14:06:06 [nigel]
- Cyril: Nothing more from me.
- 14:06:11 [nigel]
- Topic: TTWG Charter
- 14:06:22 [nigel]
- Nigel: Just to note for the minutes we are now operating under a new Charter:
- 14:06:38 [nigel]
- -> https://www.w3.org/2018/05/timed-text-charter.html TTWG Charter 2018
- 14:06:50 [nigel]
- Nigel: Thanks everyone for contributing to that and working on it.
- 14:06:53 [nigel]
- Glenn: When does it go to?
- 14:06:57 [nigel]
- Nigel: 31 May 2020.
- 14:07:33 [nigel]
- .. One other thing for the notes only given the attendees today: there's no change in scope
- 14:07:56 [nigel]
- .. so any invited experts should _not_ be ejected and need to request re-invitation. If that
- 14:08:01 [nigel]
- .. does happen please let me know ASAP.
- 14:08:41 [nigel]
- Topic: Clean up and refactor features (#688, #763, #789, #790, #791, #792, #… ttml2#794
- 14:08:46 [nigel]
- github: https://github.com/w3c/ttml2/pull/794
- 14:09:20 [nigel]
- Glenn: Summarising the changes, there were some comments on how to factor the condition
- 14:09:35 [nigel]
- .. features and I adopted as you suggested, pretty much exactly, and also for the rubyAlign-withBase
- 14:09:48 [nigel]
- .. I adopted your proposal. On the animate you had a question about if animate covers
- 14:10:00 [nigel]
- .. everything, and it was ambiguous to me as well. In a previous meeting we had discussed
- 14:10:13 [nigel]
- .. animate-related features and I said I would do some work to tie it to the calculation mode
- 14:10:25 [nigel]
- .. and that discrete and linear would be in the minimal features, and paced and spline would
- 14:10:36 [nigel]
- .. be separate features. I refactored animate to do that and to make sure that the animate
- 14:11:02 [nigel]
- .. feature did include those things. I took out the `#animate-calcMode`, `#animate-keySplines`
- 14:11:36 [nigel]
- .. and `#animate-calcMode` and added `#animate-minimal` which includes discrete
- 14:11:55 [nigel]
- .. and linear calc modes and by virtue of that implies support for keyTimes attribute.
- 14:12:04 [nigel]
- .. We don't need a separate feature for keyTimes since it is in the minimal set.
- 14:12:25 [nigel]
- .. The second thing I added was `#animate-paced` for paced mode.
- 14:12:44 [nigel]
- .. And I added `#animate-spline` which implies supporting the keySpline attribute.
- 14:13:01 [nigel]
- .. I redefined the `#animate` feature to include all those features plus `#animate-fill` and `#animate-repeat`.
- 14:13:13 [nigel]
- .. In my mind at this point animate is all wrapped up and doesn't make use of any negative
- 14:13:16 [nigel]
- .. definitions.
- 14:13:40 [nigel]
- .. And then the final comment is you had expected language about processor profiles and
- 14:13:55 [nigel]
- .. I commented that it doesn't work because there's no such thing as prohibiting a feature
- 14:14:07 [nigel]
- .. in a processor profile. If you don't require support then it is optional. If you require some
- 14:14:21 [nigel]
- .. superset of a set of features then it implies that all are present, and making them optional
- 14:14:34 [nigel]
- .. does not take them out so to speak. So there's no need to add something for processor
- 14:14:37 [nigel]
- .. profiles by my reading.
- 14:15:01 [nigel]
- .. I have a set of pulls stacked up pending this and Pierre suggested that we merge it ASAP.
- 14:15:07 [nigel]
- .. So I need it to go out quickly.
- 14:15:27 [nigel]
- Nigel: Thank you for that, good summary, it's substantive, and 8 days old.
- 14:15:48 [nigel]
- Nigel: [looks at the changes]
- 14:16:26 [nigel]
- Nigel: Did you fix `#display-version-2` too?
- 14:16:35 [nigel]
- Glenn: Yes, and I spotted and fixed a typo in one of the links too.
- 14:16:39 [nigel]
- Nigel: Thank you!
- 14:17:20 [nigel]
- Nigel: I have some concerns about merging early, because of the nature of the changes,
- 14:17:27 [nigel]
- .. but it's reasonable to ask in the circumstances.
- 14:17:43 [nigel]
- Cyril: I'm fine with it since it is early but not very early. It's been more than a week.
- 14:19:09 [nigel]
- Nigel: There's a lot to review here - I'm happy in principle with what you've described but
- 14:20:00 [nigel]
- .. need to look at the detail - if we can close the call early today then I will complete that
- 14:20:02 [glenn]
- glenn has joined #tt
- 14:20:08 [nigel]
- .. review, but don't foresee any problems.
- 14:20:49 [nigel]
- SUMMARY: @nigelmegitt to complete review and add updated review status
- 14:21:21 [nigel]
- Topic: Add features for standard and high dynamic range PNG images (#694, #6… ttml2#770
- 14:21:28 [nigel]
- github: https://github.com/w3c/ttml2/pull/770
- 14:21:53 [nigel]
- Glenn: The only outstanding piece on this is the reference. My opinion is we should make
- 14:22:08 [nigel]
- .. a normative ref to the WG Note. Given the loosening of policies from HTML5 I'm pretty
- 14:22:24 [nigel]
- .. sure that it is no longer a no-no. We can't define an HDR feature unless we can point
- 14:22:40 [nigel]
- .. to a normative reference to a format. There's no generic format. We either put it in with
- 14:23:00 [nigel]
- .. the WG Note as a normative ref or we don't include any HDR PNG feature.
- 14:23:25 [nigel]
- Nigel: Ok, @plhegar didn't get back to me.
- 14:23:39 [nigel]
- Glenn: It's been more than 14 days and we have @nigelmegitt's approval but nothing from
- 14:23:53 [nigel]
- .. Pierre or Mike. Since this is still hanging I didn't want to merge it without group input.
- 14:25:34 [nigel]
- Nigel: This is also related to a separate issue that I am not up to date on where I began
- 14:25:46 [nigel]
- .. working on a pull request and realised that we probably do not want luminanceGain
- 14:26:21 [nigel]
- .. to apply to PQ HDR image at all.
- 14:26:37 [nigel]
- Glenn: It sounds like we can't resolve this until that's worked through.
- 14:26:39 [nigel]
- Nigel: +1
- 14:27:28 [nigel]
- Nigel: I've dismissed my review.
- 14:27:45 [nigel]
- Glenn: Does IMSC 1.1 use this?
- 14:27:51 [nigel]
- Nigel: IMSC 1.1 will need to be updated too.
- 14:31:22 [nigel]
- Glenn: Is it really orthogonal?
- 14:32:23 [nigel]
- Nigel: The impact comes from the comment you made Glenn about testing luminanceGain
- 14:32:33 [nigel]
- .. without supporting PQ PNG images.
- 14:32:53 [nigel]
- .. (also there's no way to make luminanceGain have no effect, i.e. be unity, where it is known
- 14:33:06 [nigel]
- .. that images generate PQ pixels already).
- 14:33:29 [nigel]
- Glenn: If we don't resolve this soon then there's a risk of needing a CR3 which I'm wary of
- 14:33:35 [nigel]
- .. because of the time implications.
- 14:33:49 [nigel]
- Nigel: Yes me too, I hope to be able to process this by the end of tomorrow so we can progress.
- 14:35:14 [nigel]
- Nigel: Back to this particular topic, I think we may not need the png pq hdr feature at all,
- 14:35:35 [nigel]
- .. though we might need a processor feature that can support identification of pq pixels
- 14:35:48 [nigel]
- .. output from image processing, as defined by the ITU spec. That would get around the
- 14:37:04 [nigel]
- .. need to reference the WG Note.
- 14:38:20 [nigel]
- SUMMARY: Resolve #796 and then revisit this based on the conclusion to that issue.
- 14:39:05 [nigel]
- Topic: Remove @style from animate and set (#703). ttml2#707
- 14:39:14 [nigel]
- github: https://github.com/w3c/ttml2/pull/707
- 14:39:31 [nigel]
- Glenn: Nigel you asked for minimum two values in an animation-value-list and I did that.
- 14:39:38 [nigel]
- .. I changed the * to a + in the syntax.
- 14:41:11 [nigel]
- Nigel: Great, and I see that I made a later comment that if you do that then it would be
- 14:41:25 [nigel]
- .. consistent to complete the resolution of the issue by removing @style from the animate element.
- 14:41:31 [nigel]
- .. Did you do that as part of #707?
- 14:41:36 [nigel]
- Glenn: I did it in the schemas...
- 14:41:43 [nigel]
- .. Yes, it's been removed from both set and animate.
- 14:42:19 [nigel]
- Nigel: Looks good to me, I'll approve the pull request.
- 14:43:18 [nigel]
- SUMMARY: Discussed and agreed.
- 14:43:21 [nigel]
- github-bot, end topic
- 14:43:47 [nigel]
- Topic: Describe generically compliant processors that support only external … ttml2#755
- 14:43:53 [nigel]
- github: https://github.com/w3c/ttml2/pull/755
- 14:44:45 [nigel]
- Glenn: It's tricky - in some places we have to use TTML without qualification and in others
- 14:44:52 [nigel]
- .. it is relevant to qualify as TTML2.
- 14:44:54 [nigel]
- Nigel: Yes!
- 14:46:11 [nigel]
- .. I need a bit of offline time to check through that but I think it's fine.
- 14:46:23 [nigel]
- SUMMARY: Review to continue offline
- 14:46:27 [nigel]
- github-bot, end topic
- 14:46:58 [nigel]
- Topic: Exclude vertical length offset as 1st component in 2 component positi… ttml2#769
- 14:47:03 [nigel]
- github: https://github.com/w3c/ttml2/pull/769
- 14:47:36 [nigel]
- Glenn: I made a change in the syntax as Pierre suggested.
- 14:53:08 [nigel]
- .. Either we need to dismiss his review or wait on him for a few days. I'm willing to wait.
- 14:53:21 [nigel]
- Nigel: I assume he'll do that, and that seems like the right approach.
- 14:53:47 [nigel]
- Glenn: Basically the change was to match the CSS exclusions to syntactical combinations,
- 14:53:54 [nigel]
- .. by not allowing the excluded syntax at all.
- 14:53:58 [nigel]
- Nigel: Makes sense to me.
- 14:54:26 [nigel]
- SUMMARY: DIscussed in WG meeting, review to continue offline
- 14:54:29 [nigel]
- github-bot, end topic
- 14:54:47 [nigel]
- Topic: Add explicit exceptions to ignoring element semantics with condition … ttml2#772
- 14:54:51 [nigel]
- github: https://github.com/w3c/ttml2/pull/772
- 14:54:59 [nigel]
- Glenn: I just did a commit last night to address comments.
- 14:55:14 [nigel]
- .. Nigel you pointed out that the use of content element wasn't sufficiently inclusive and
- 14:55:25 [nigel]
- .. suggested that we bring in all timed elements including region, so I introduced the
- 14:55:38 [nigel]
- .. term timed element. I had to review all the candidates for timed elements and decide
- 14:55:54 [nigel]
- .. what the distinguishing features were. I first thought timeContainer, but animate and set
- 14:56:03 [nigel]
- .. have begin and end but not timeContainer, since they don't have timed children.
- 14:56:20 [nigel]
- .. On the other hand everything had a begin, dur and end and I picked begin as a criterion.
- 14:56:31 [nigel]
- .. Then I changed content element ref to timed element so that should address your last
- 14:56:36 [nigel]
- .. comment and this should be ready to go.
- 14:56:40 [nigel]
- Nigel: Sounds good to me.
- 14:57:06 [nigel]
- Glenn: This just needs an approval - we've already passed 14 days on this one.
- 14:57:56 [nigel]
- Nigel: OK, interesting we don't have a class that corresponds to these.
- 14:58:11 [nigel]
- Glenn: Not in the spec - in TTV we have an IsTimedElement that does that, so implementations
- 14:58:22 [nigel]
- .. have to do it. I'm loathe to add another class just for this purpose. A definition should
- 14:58:23 [nigel]
- .. suffice.
- 14:59:42 [nigel]
- Nigel: Okay, I'll review.
- 14:59:48 [nigel]
- .. There are 16 uses of "timed element" in the spec.
- 14:59:54 [nigel]
- Glenn: I just noticed that, I'll update to add links to it.
- 15:00:30 [nigel]
- Nigel: Since we refer to this before, was it deemed to be an obvious concept or did we
- 15:00:33 [nigel]
- .. inherit it from SMIL?
- 15:00:45 [nigel]
- Glenn: I don't recall inheriting it from SMIL, but our usage would be different anyway.
- 15:00:52 [nigel]
- Cyril: Timed Element is a concept in SMIL I think.
- 15:01:05 [nigel]
- Glenn: It could be but the glossary section is very weak. In any case now that we have
- 15:01:16 [nigel]
- .. introduced timed element we should link those 16 places back to the definition now that
- 15:01:19 [nigel]
- .. we've added a term.
- 15:01:20 [nigel]
- Nigel: +1
- 15:02:08 [nigel]
- Nigel: Notices we should take care with 12.4
- 15:02:34 [nigel]
- Glenn: Yes
- 15:02:41 [nigel]
- Nigel: Aside from that, I think this looks good.
- 15:03:00 [nigel]
- SUMMARY: @skynavga to update to include references to the timed element term, then review to continue.
- 15:03:02 [nigel]
- github-bot, end topic
- 15:03:26 [nigel]
- Topic: Clarify distinction between validation processing, validation process… ttml2#777
- 15:03:31 [nigel]
- github: https://github.com/w3c/ttml2/pull/777
- 15:03:50 [nigel]
- Glenn: I did a commit last night in which I think I addressed Nigel's comments.
- 15:03:53 [glenn]
- https://github.com/w3c/ttml2/pull/777/commits/4aaf65d902fc70f374e31751074a18d26389f6f2
- 15:04:57 [nigel]
- Nigel: [reviews in real time] Looks good to me.
- 15:05:28 [nigel]
- .. I've approved.
- 15:05:44 [nigel]
- SUMMARY: Pull request satisfies merge requirements.
- 15:06:04 [nigel]
- Topic: Collapse language for style application to paragraph text nodes; add … ttml2#803
- 15:06:10 [nigel]
- github: https://github.com/w3c/ttml2/pull/803
- 15:06:39 [nigel]
- Glenn: I added a comment to this.
- 15:09:17 [nigel]
- Cyril: Can we add a link from the sentence in 8.1.5 to the process for creating anonymous spans?
- 15:09:33 [nigel]
- Glenn: Yes, and come to think of it we should add the same text to the span element to
- 15:09:37 [nigel]
- .. make it complete. Right now it is incomplete.
- 15:10:31 [nigel]
- Cyril: I don't want it to look like there's a separate procedure.
- 15:10:41 [nigel]
- Glenn: That gives me a tbd on this before you sign off on it Nigel
- 15:10:44 [nigel]
- Nigel: OK
- 15:12:31 [nigel]
- .. Should we add a note pointing the reader to anonymous spans beneath the new text?
- 15:12:56 [nigel]
- Glenn: I don't want another place where we paraphrase what the construct anonymous span
- 15:12:58 [nigel]
- .. procedure does.
- 15:13:07 [nigel]
- Nigel: I was thinking of a note with a reference, but I take your point.
- 15:13:36 [nigel]
- Glenn: The terms anonymous span and span already take you to the right definitions.
- 15:13:54 [nigel]
- Nigel: Yes, if you add that anonymous span text from p to span then yes, I'm okay with that.
- 15:14:43 [nigel]
- SUMMARY: Duplicate anonymous span text from p element into span element (for @skynavga) and reference the [create anonymous span] procedure from both.
- 15:15:02 [nigel]
- Topic: Add xml:base to core vocabulary (#804). ttml2#808
- 15:15:07 [nigel]
- github: https://github.com/w3c/ttml2/pull/808
- 15:15:27 [nigel]
- Glenn: This adds `xml:base`. Previously in TTML1 the `features` and `extensions` elements
- 15:15:41 [nigel]
- .. admitted `xml:base` and those were unusual in that we defined a default value in the
- 15:16:01 [nigel]
- .. element information item that specifies using the TTML feature namespace and the extensions
- 15:16:17 [nigel]
- .. namespace respectively. Those were kind of special uses that had a default.
- 15:16:29 [nigel]
- .. This PR and issue is for, now that we have URLs in a variety of other places such as
- 15:16:51 [nigel]
- .. xlink:href and the source element and audio, data and image, we potentially have some
- 15:17:14 [nigel]
- .. uses that are related to the media query support in the condition function for media functions,
- 15:17:41 [nigel]
- .. my conclusion was we need to add `xml:base` to the core attributes list so it is everywhere.
- 15:18:00 [nigel]
- .. Now `xml:base` is hierarchical so you can have multiple relative levels. It can build up
- 15:18:17 [nigel]
- .. hierarchically from the most nested reference to the root level element. You need to
- 15:18:31 [nigel]
- .. populate it everywhere (ability to populate).
- 15:18:49 [nigel]
- .. Especially if you're embedding content that has some URLs in it you might nest that in
- 15:19:05 [nigel]
- .. another document and put a relative base on it at the highest level node. It turns out to
- 15:19:14 [nigel]
- .. be quite useful and is supported in SVG and SMIL as well.
- 15:19:50 [nigel]
- Nigel: Did you fix Cyril's issue about isd:css and isd:region too?
- 15:20:03 [nigel]
- Glenn: Yes. I know Cyril had suggested just supporting on the root level but as you see that
- 15:20:06 [nigel]
- .. won't quite work.
- 15:20:20 [nigel]
- Cyril: I understand the feature, I don't think it's a priority. You could default it to the base
- 15:20:24 [nigel]
- .. of the document itself.
- 15:20:42 [nigel]
- Glenn: That is the default default if there are relative URLs in the document with no xml:base specified.
- 15:20:48 [nigel]
- .. We don't have to say anything to support that.
- 15:21:02 [nigel]
- Cyril: I don't have a strong preference. It's mainly useful for images and audio content right?
- 15:21:07 [nigel]
- Glenn: Exactly.
- 15:21:51 [nigel]
- Nigel: I don't have strong view either, but don't have a particular use case. I don't think it
- 15:21:58 [nigel]
- .. is especially harmful. Is there a profile feature for it?
- 15:22:09 [nigel]
- Cyril: There is #base and #base-version-2
- 15:22:12 [nigel]
- Nigel: Ok
- 15:22:13 [cyril]
- https://rawgit.com/w3c/ttml2/0c93c4dfa88e85a61d1c2cf1bae9a530c1e7e25c/index.html
- 15:22:27 [nigel]
- Glenn: I defined it that way because we already had base in TTML1 but with no feature so
- 15:22:40 [nigel]
- .. I defined in TTML2 a feature that mapped to the original TTML1 support for base and then
- 15:22:45 [nigel]
- .. extended it with the version-2.
- 15:22:49 [nigel]
- Nigel: Makes sense.
- 15:23:29 [nigel]
- Cyril: I think we should move on from this - it was opened yesterday.
- 15:23:42 [nigel]
- .. Seems consistent, not harmful, we should approve if there's no objection. I would like
- 15:23:56 [nigel]
- .. some input from the SMPTE image users to see if they have any views on this.
- 15:24:03 [nigel]
- Glenn: Yes, I'm not asking for early merger on this.
- 15:24:14 [nigel]
- SUMMARY: Offline review to continue.
- 15:24:16 [nigel]
- github-bot, end topic
- 15:24:38 [nigel]
- Topic: Add #unicodeBidi-version-2 feature designator (#679). ttml2#759
- 15:24:49 [nigel]
- github: https://github.com/w3c/ttml2/pull/759
- 15:25:47 [nigel]
- Glenn: Nigel you made a statement about this but did not approve.
- 15:25:58 [nigel]
- Nigel: Yes, that was 2 weeks ago, pending a discussion of the approach to defining features
- 15:26:10 [nigel]
- .. by reference to their TTML1 definition. We had that discussion and agreed to proceed
- 15:26:24 [nigel]
- .. on that basis so I can now complete the review of this pull request.
- 15:27:50 [nigel]
- .. [does a rescan] Looks good to me.
- 15:28:29 [nigel]
- .. I've approved it.
- 15:28:54 [nigel]
- SUMMARY: Pull request meets criteria for merging
- 15:29:13 [nigel]
- Topic: Add and update element derivations (#380). ttml2#805
- 15:29:21 [nigel]
- github: https://github.com/w3c/ttml2/pull/805
- 15:29:26 [nigel]
- Glenn: I don't have any reviews on this yet.
- 15:29:39 [nigel]
- Cyril: The reason I didn't review it is I don't really consider it necessary. There's no impact
- 15:29:43 [nigel]
- .. if there's a bug in this one.
- 15:29:51 [nigel]
- Glenn: Exactly, this is a non-normative appendix.
- 15:30:03 [nigel]
- Cyril: I can approve it if you want but I thought Nigel was best placed to do it.
- 15:31:02 [nigel]
- Nigel: I need more time to review this.
- 15:31:21 [nigel]
- Glenn: That's fine with me - I just need a review. It's an editorial pull request that's only 2
- 15:31:30 [nigel]
- .. days old, so there's a day to go minimally before merge anyway.
- 15:32:37 [nigel]
- Nigel: OK I'll take a look.
- 15:32:44 [nigel]
- SUMMARY: Offline review to continue
- 15:32:49 [glenn]
- https://github.com/w3c/ttml2/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+milestone%3ACR2+-label%3A%22pr+open%22
- 15:32:49 [nigel]
- github-bot, end topic
- 15:33:23 [nigel]
- Topic: CR2 issues with no pr open label on them
- 15:33:29 [nigel]
- -> https://github.com/w3c/ttml2/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+milestone%3ACR2+-label%3A%22pr+open%22
- 15:33:37 [nigel]
- Glenn: I've marked a couple of them for agenda
- 15:34:31 [nigel]
- Topic: Time containment semantics for smpte time base. ttml2#377
- 15:34:39 [nigel]
- github: https://github.com/w3c/ttml2/issues/377
- 15:34:55 [nigel]
- Glenn: Nigel, you're original complaint was that we prematurely deprecated the use of
- 15:35:16 [nigel]
- .. the sequential time containment in smpte discontinuous mode and you have argued that
- 15:35:29 [nigel]
- .. there is a potential interpretation of that. I argue that even if that is the case then it
- 15:35:38 [nigel]
- .. doesn't make any sense to use it and it shouldn't be used anyway.
- 15:36:05 [nigel]
- .. In my mind smpte discontinuous indicates that there is no time container at all.
- 15:36:18 [nigel]
- Nigel: I don't think there's no time containment.
- 15:36:42 [nigel]
- Glenn: For example if you have a span in a p and the span says begin=0s and the p says begin=10s
- 15:36:57 [nigel]
- .. for me the 0s on the begin relates to the document timeline not to the p.
- 15:37:32 [nigel]
- .. Any time you find a time in a smpte discontinuous document then it relates to the
- 15:37:58 [nigel]
- .. document context. This is from markerMode. The problem with what you're suggesting
- 15:38:24 [nigel]
- .. Nigel is that it backs out that. Under markerMode it says that time expressions must not
- 15:38:46 [nigel]
- .. be calculated etc. in discontinuous mode. All time expressions are interpreted as time
- 15:39:01 [nigel]
- .. events which cause a temporal interval to begin or end accordingly.
- 15:42:33 [nigel]
- Nigel: I don't disagree with that but my point is that time expression calculation is orthogonal
- 15:44:18 [nigel]
- .. to time containment, and that there is a logical processing model for sequential time
- 15:45:22 [nigel]
- .. containment with smpte discontinuous, treating the time expressions as events.
- 15:45:39 [nigel]
- .. I don't believe that there is any data presented to deprecate this potential usage.
- 15:45:56 [nigel]
- Glenn: If we take out the deprecation, I don't really want to tweak this language or add
- 15:46:27 [nigel]
- .. more language?
- 15:47:42 [nigel]
- Nigel: I don't think we need to do anything particular to the spec and I wouldn't prioritise
- 15:48:08 [nigel]
- .. this niche use case, just back out the deprecation.
- 15:48:12 [nigel]
- Glenn: Is this editorial?
- 15:48:28 [nigel]
- Nigel: Although we apparently did not have consensus for this when #647 was merged
- 15:48:44 [nigel]
- .. in February, this is a substantive change relative to CR1 unfortunately.
- 15:48:55 [nigel]
- Glenn: Okay I can accept backing out the deprecation, I may ask for early merge next week.
- 15:49:49 [nigel]
- SUMMARY: Back out the deprecation of seq time containment in smpte discontinuous
- 15:50:31 [nigel]
- Topic: Negative feature designators aren't future proof. ttml2#697
- 15:50:36 [nigel]
- github: https://github.com/w3c/ttml2/issues/697
- 15:50:40 [nigel]
- Nigel: I still have the action on this.
- 15:50:51 [nigel]
- Glenn: To some extent #794 overtakes this because we are already backing out some
- 15:51:04 [nigel]
- .. negative feature designations. I'm not sure if there are potential action items.
- 15:51:15 [nigel]
- Nigel: Let me keep it and think further on this please.
- 15:52:14 [nigel]
- .. The action on me is to demonstrate that there is a specific problem.
- 15:52:31 [nigel]
- Glenn: The only remark I have is that one of the reasons we use the phrase "all defined values"
- 15:52:44 [nigel]
- .. is that not all values are enumerable, e.g. floating point values, and the primary condition
- 15:52:58 [nigel]
- .. expressions are infinite in their number of possibilities, so we can't enumerate every
- 15:53:01 [nigel]
- .. value set.
- 15:53:09 [nigel]
- Nigel: There are ways to group value sets finitely.
- 15:53:50 [nigel]
- Glenn: In the condition refactoring, where you suggested using "non-function" expressions,
- 15:53:57 [nigel]
- .. there probably isn't any other way to do it.
- 15:54:05 [nigel]
- Nigel: Ok the action is still with me.
- 15:54:20 [nigel]
- Glenn: My point is even if you think we'd like to do this I don't think we can completely
- 15:55:22 [nigel]
- .. do what you're suggesting, in the case of some infinite value sets.
- 15:55:57 [nigel]
- Topic: tts:rubyReserve length component semantics ttml2#779
- 15:56:02 [nigel]
- github: https://github.com/w3c/ttml2/issues/779
- 15:56:17 [nigel]
- Cyril: Glenn can you clarify that we harmonised rubyReserve with rubyPosition using
- 15:56:34 [nigel]
- .. `<annotation-position>`? Looking at the CR spec I couldn't find it.
- 15:56:50 [nigel]
- Glenn: There's an optional length component in rubyReserve.
- 15:57:06 [nigel]
- .. The set of keywords that are defined there are equal to or a subset of `<annotation-position>`.
- 15:57:11 [nigel]
- .. We took out around and between.
- 15:57:35 [nigel]
- Cyril: Did we change the examples?
- 15:58:49 [nigel]
- Nigel: [checks spec] There's no mismatch between the examples in rubyReserve and the syntax.
- 15:58:58 [nigel]
- Cyril: OK, sorry, I was looking at the wrong version.
- 15:59:33 [nigel]
- Glenn: The example does need to be updated - around and between have gone.
- 15:59:42 [nigel]
- Nigel: Sorry, I also looked at the wrong version.
- 15:59:52 [nigel]
- Glenn: It looks like I just need to remove the around and between examples.
- 16:00:11 [nigel]
- Cyril: OK, now about the behaviour or ruby, line area and lineHeight.
- 16:00:27 [nigel]
- .. You clarified that the rubyReserve area is parented to the line area.
- 16:00:30 [nigel]
- Glenn: Correct.
- 16:00:48 [nigel]
- Cyril: But I remember that the CSS WG said that you also had to set the line-height and that
- 16:00:59 [nigel]
- .. ruby-reserve did not affect the line height. Is that the case in TTML2 as well?
- 16:01:10 [nigel]
- Glenn: I avoided going into the details of this in the spec.
- 16:01:15 [nigel]
- Cyril: so it's implementation specific?
- 16:01:18 [nigel]
- Glenn: Yes.
- 16:01:25 [nigel]
- Cyril: Why don't we do the same with rubyReserve?
- 16:01:41 [nigel]
- Glenn: TTP for example increases the line height based on the concept that the definition
- 16:01:52 [nigel]
- .. of normal under line height maps to the per inline height rectangle in XSL-FO and that
- 16:02:06 [nigel]
- .. is defined in such a way as to increase the line height on the per line area basis based on
- 16:02:19 [nigel]
- .. the glyph areas contained in that so that the ascender, descender and half leadings on
- 16:02:31 [nigel]
- .. both sides of every glyph area are included in the line height for that particular line.
- 16:02:46 [nigel]
- .. The height of individual areas in "normal" varies based on what is inside them. The model
- 16:03:04 [nigel]
- .. there is to extend the line height to enclose the descendants. I use the same model, if
- 16:03:18 [nigel]
- .. lineHeight="normal" (including default) it will increase the line height of a box that has
- 16:03:32 [nigel]
- .. ruby to include the ruby annotation inline areas. I avoided writing this into the spec at
- 16:03:44 [nigel]
- .. this point. One thing you are suggesting is that we add a note maybe that it is implementation
- 16:03:55 [nigel]
- .. dependent what effect rubyReserve has on lineHeight?
- 16:04:06 [nigel]
- Cyril: I'm not sure if that is what I am suggesting. I am trying to understand how it works.
- 16:04:19 [nigel]
- .. If I cannot understand it probably other readers cannot understand how it works.
- 16:04:43 [nigel]
- Glenn: Interestingly Pierre is just mapping to CSS and letting CSS do it. What I implemented
- 16:04:57 [nigel]
- .. is basically compatible with that. CSS doesn't define those details. It's basically what is
- 16:05:10 [nigel]
- .. implemented in the wild is the de facto standard.
- 16:05:17 [nigel]
- .. It would take a lot of work to define those requirements.
- 16:05:32 [nigel]
- Cyril: I'm fine with not specifying it and maybe in a future version doing that when we have
- 16:05:40 [nigel]
- .. converged on a processing model.
- 16:05:58 [nigel]
- .. Pierre is saying that the length field is over-specified?
- 16:06:04 [nigel]
- Nigel: I think we need Pierre here for that.
- 16:06:18 [nigel]
- Glenn: My interpretation is that he has some issue with how we define the default value
- 16:06:46 [nigel]
- .. for length.
- 16:09:08 [nigel]
- Glenn: We have the problem of length with lineHeight too, which is not dependent on font size either.
- 16:09:20 [nigel]
- Nigel: OK so now we have the problem in two places!
- 16:09:38 [nigel]
- .. Given the time and that this issue was raised by Pierre who is absent, we should not
- 16:09:41 [nigel]
- .. continue with this issue.
- 16:09:46 [nigel]
- github-bot, end topic
- 16:10:16 [nigel]
- Topic: Use of maximum descendant font size in normal line height computation. ttml2#806
- 16:10:21 [nigel]
- github: https://github.com/w3c/ttml2/issues/806
- 16:10:31 [nigel]
- Glenn: I would like to spend 5 minutes on this for the record
- 16:10:44 [nigel]
- .. The issue is lineHeight - what does "normal" mean?
- 16:11:00 [nigel]
- .. We had some language in TTML1 that said the computed value is no less than the font
- 16:11:12 [nigel]
- .. size that applies to the element and its descendant elements. When we recast that in TTML2
- 16:11:31 [nigel]
- .. we inadvertently omitted mention of the descendant elements.
- 16:11:39 [nigel]
- Nigel: No, we discussed it and decided that we didn't need it.
- 16:11:47 [nigel]
- Glenn: Thanks for reminding me, I need to go back to the notes on that.
- 16:12:05 [nigel]
- .. I decided to re-review the way that XSL-FO defines this, and the CSS semantics, and I
- 16:12:16 [nigel]
- .. concluded that TTML1 semantics do not match CSS 2 or XSL-FO and TTML2 semantics
- 16:12:31 [nigel]
- .. match none of them as defined. I marked this as a bug and something we need to deal with.
- 16:12:44 [nigel]
- .. I was going to maybe today or tomorrow post a pull request to deal with this. The main
- 16:12:57 [nigel]
- .. problem is that the current algorithm leads you to the conclusion that you can set a
- 16:13:12 [nigel]
- .. uniform line height that is resolved from normal and that it applies to every line
- 16:13:24 [nigel]
- .. irrespective of the inline areas on each line. In the XSL-FO language it says it should be
- 16:13:41 [nigel]
- .. the minimum required to enclose the paragraph's requested line height and the line height
- 16:13:55 [nigel]
- .. for each of the inline areas within the line area. In other words different line areas may
- 16:14:18 [nigel]
- .. have different heights based on lineHeight="normal". The current text does not do what
- 16:14:23 [nigel]
- .. CSS2 does or what XSL-FO says.
- 16:16:24 [nigel]
- .. We're inconsistent.
- 16:16:39 [nigel]
- Nigel: I recall Andreas making a presentation to us in a face to face meeting about this,
- 16:16:50 [nigel]
- .. and pointing out that the line stacking strategy we use in TTML means that lines can
- 16:16:53 [nigel]
- .. never overlap each other.
- 16:17:05 [nigel]
- Glenn: I dispute that, and will have to go back and check.
- 16:17:27 [nigel]
- .. "normal" is the most used value, and I'm pretty sure that the expectation would be the
- 16:17:37 [nigel]
- .. same as in CSS, but that is not how it is specified now.
- 16:17:50 [nigel]
- .. I don't know if say imsc.js would be able to do what the new language says.
- 16:19:45 [nigel]
- Nigel: I would advocate looking for line stacking strategy and go back to where we discussed this before.
- 16:20:18 [nigel]
- Glenn: In the case of "normal" you don't get bleed over between lines, but you might with a number.
- 16:20:33 [nigel]
- Nigel: I thought the same line stacking strategy applies even with a number.
- 16:20:51 [nigel]
- Glenn: If that's the case then XSL-FO would be inconsistent with CSS2. I would need to look at that.
- 16:22:07 [nigel]
- Nigel: The line-stacking-strategy is line-height, regardless of the value of tts:lineHeight.
- 16:22:55 [nigel]
- SUMMARY: @skynavga to continue investigating
- 16:22:59 [nigel]
- github-bot, end topic
- 16:23:02 [nigel]
- Topic: Meeting close
- 16:23:16 [nigel]
- Glenn: We covered a lot today so thank you for that. I look forward to the pull request reviews.
- 16:23:26 [nigel]
- .. #794 is my highest priority if you can take that into account.
- 16:23:41 [nigel]
- Nigel: OK, thanks both, next meeting same time next week. [adjourns meeting]
- 16:23:54 [nigel]
- rrsagent, make minutes
- 16:23:54 [RRSAgent]
- I have made the request to generate https://www.w3.org/2018/05/31-tt-minutes.html nigel
- 16:31:00 [Zakim]
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- rrsagent, make minutes
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- I have made the request to generate https://www.w3.org/2018/05/31-tt-minutes.html nigel
- 16:47:47 [nigel]
- nigel has changed the topic to: TTWG meetings Thursdays 1000 Boston time. Minutes for most recent meeting: https://www.w3.org/2018/05/31-tt-minutes.html