IRC log of tt on 2017-10-12

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Meeting: Timed Text Working Group Teleconference

14:00:34 [trackbot]

Date: 12 October 2017

14:01:17 [nigel]

scribe: nigel

14:01:19 [nigel]

Present: Nigel

14:01:22 [nigel]

Regrets: None

14:01:25 [nigel]

Chair: Nigel

14:01:50 [nigel]

Present+ Pierre

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Present+ Thierry

14:02:33 [mike]

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14:03:12 [nigel]

Present+ Glenn

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Present+ Mike

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Present+ Cyril

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Topic: This meeting

14:04:56 [nigel]

Nigel: Today, I don't think we have anything to discuss with TPAC today;

14:05:22 [nigel]

.. I'd like to start running the TTML2 Wide Reviews to see if we have any easy dispositions.

14:05:42 [nigel]

.. And we agreed last week to discuss publication of FPWD of IMSCvNext

14:06:06 [nigel]

.. And we have had some other issues raised this week on TTML1/2.

14:06:38 [nigel]

Mike: Request to cover backward compatibility issue in TTML

14:06:41 [nigel]

Nigel: Ok

14:07:57 [nigel]

.. I'm not expecting David to join to discuss WebVTT review today.

14:08:03 [nigel]

Thierry: I've had no confirmation.

14:08:15 [nigel]

Nigel: In that case I think we have a full agenda.

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14:08:32 [nigel]

Nigel: Any other specific points to cover?

14:08:40 [nigel]

Group: nothing else.

14:10:55 [nigel]

Topic: processor backwards compatibility #458

14:11:00 [nigel]

github: https://github.com/w3c/ttml2/issues/458

14:11:21 [nigel]

Glenn: This may be a duplicate of #442 - anyway they are related.

14:11:39 [nigel]

Present+ David_Ronca

14:12:22 [nigel]

Mike: It's hard to summarise from the issue - lots of opinions, not necessarily harmonious.

14:13:11 [nigel]

.. It boils down to how we make IMSC vNext reference TTML2 or TTML1, since we need

14:13:26 [nigel]

.. a safety net for presentation processor conformance for IMSC 1.0.1.

14:13:44 [nigel]

.. These things are all intertwined. Fundamentally we started out with what we are doing

14:13:48 [nigel]

.. in IMSC v1.1.

14:15:51 [nigel]

Nigel: Pierre recently made the comment that the presentation processor differences

14:16:26 [nigel]

.. between TTML1 and TTML2 are already proposed for TTML1 Third Edition. If we do that

14:16:37 [nigel]

.. would it address the problem for IMSC or just move the problem somewhere else?

14:17:07 [nigel]

Glenn: I don't think we can add features to TTML1 to resolve all the differences.

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14:17:21 [nigel]

Pierre: Trying to keep things simple, the first step is to determine if we all think that the

14:17:34 [nigel]

.. goal of having TTML1 and TTML2 be consistent on shared features is a good idea. Then

14:17:39 [nigel]

.. we can figure out how to make that happen.

14:18:01 [nigel]

Glenn: I agree with that as a default scenario. We could probably add a statement to the current

14:18:14 [nigel]

.. section on backward compatibility that says its an objective to achieve that modulo

14:18:20 [nigel]

.. explicit variations or exceptions.

14:18:30 [nigel]

Pierre: Anyone think it's a bad idea to have that as a goal?

14:18:41 [nigel]

Mike: No, and that's where I thought we ended up last week.

14:19:06 [nigel]

Andreas: I think it's important to make it mandatory to state this objective in the spec.

14:19:21 [nigel]

.. People will look for normative statements, otherwise it won't help much.

14:20:12 [nigel]

Glenn: It's different stating the objective to making a mandatory requirement on processors.

14:20:17 [nigel]

.. We should separate those.

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14:22:29 [nigel]

Nigel: I think there is a problem if we let edge cases drive specs, and I particularly don't

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.. want us to be held back by previous specifications and be unable to make improvements

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.. if we find them.

14:23:40 [nigel]

Cyril: Are we allowing for specific signalling of TTML2 behaviour?

14:23:51 [nigel]

Pierre: This is only for features that TTML1 and TTML2 have in common.

14:25:57 [nigel]

Pierre: The question is if the high level goal is for parity of processing, as a high level

14:26:06 [nigel]

.. principle, then we can come to the details later.

14:26:23 [nigel]

Nigel: My understanding is this is driven by a desire for identical presentation processor

14:26:35 [nigel]

.. output, so the details become important. I don't think that the general guiding principle

14:26:43 [nigel]

.. is controversial, and it's easy to agree with.

14:27:02 [nigel]

Glenn: There are layers that affect every feature - it's not simple than just talking about

14:27:08 [nigel]

.. individual style features.

14:27:19 [nigel]

Pierre: It would be bad if TTML1 and TTML2 compelled implementations to end up with

14:27:41 [nigel]

.. a different computed font size on an element due to differing inheritance rules.

14:27:53 [nigel]

Glenn: I recall lineHeight and ongoing discussion of this in TTML2 vs TTML1.

14:28:02 [nigel]

Pierre: That's my point - these should be aligned.

14:28:19 [nigel]

.. Again, it's the normative statements that it's important to make consistent.

14:28:41 [nigel]

Glenn: We made some explicit decisions about lineHeight="normal" - we shouldn't go back

14:28:44 [nigel]

.. to those decisoins.

14:28:52 [nigel]

s/oi/io

14:29:04 [nigel]

Pierre: I'm just asking about the general principle.

14:29:28 [nigel]

Andreas: The rendered outcome of a document only using TTML1 vocabulary should

14:29:39 [nigel]

.. generate the same outcome for TTML1 and TTML2 processors - this should be the goal

14:29:48 [nigel]

.. of our activity. It should be mandatory for processors.

14:30:02 [nigel]

Glenn: I certainly would not agree to that statement, in its entirety at least.

14:30:23 [nigel]

David_Ronca: From my perspective the primary objective for TTML2 is a robust spec that

14:30:36 [nigel]

.. will carry us into the future. Where its possible to be TTML1 compatible we should be

14:30:50 [nigel]

.. but we should not preserve ambiguous or poorly defined features in TTML1.

14:31:03 [nigel]

Andreas: That's a core question - how much is backward compatibility needed.

14:32:47 [nigel]

Nigel: We have a mechanism via the TTML profile registry for systems that use it to request

14:33:04 [nigel]

.. a specific processor type, and we should use the flexibility that gives us.

14:33:24 [nigel]

Glenn: We have never had a normative requirement to have different implementations

14:33:35 [nigel]

.. produce the same presentation as a general statement. If you throw out a lot of other

14:33:42 [atai2]

q+

14:33:46 [nigel]

.. variation axes, then you might say that modulo those variations it should be close.

14:33:57 [nigel]

ack atai2

14:34:11 [nigel]

Andreas: Following the discussions, maybe there are different business requirements here.

14:34:41 [nigel]

.. For our side, backward compatibility is a first priority. We are in the middle of uptake

14:34:52 [nigel]

.. and adoption of the spec so it's important that current implementation is not blocked by

14:35:07 [nigel]

.. a message that TTML2 is coming and may change it. That gives the message "wait for TTML2".

14:35:21 [nigel]

.. At least we want to avoid that and keep TTML adoption ongoing including IMSC1 adoption.

14:35:42 [nigel]

Nigel: Good point - my statement earlier was that in agreement with David_Ronca I think

14:35:57 [nigel]

.. it is a stronger objective to produce a future facing spec than a backward compatible one.

14:36:18 [nigel]

David_Ronca: Compare to video coders. We have to be able to make fixes and correctness

14:36:30 [nigel]

.. needs to outweigh compatibility. TTML2 implementations can still be TTML1 implementations.

14:36:44 [nigel]

.. It's just like encoders can still make AVC or HEVC. We have to be careful. I don't know

14:36:58 [nigel]

.. if there are specific cases where we need stability of features, but if TTML2 gets it right

14:37:05 [nigel]

.. and TTML1 gets it wrong then TTML2 should prevail.

14:37:11 [nigel]

Mike: Is there an example of this?

14:37:23 [nigel]

Pierre: I'm not aware of such a thing, and ironically many of those bugs were discovered

14:37:39 [nigel]

.. while implementing TTML1, so most have been logged as a bug on TTML1 and fixed in TTML2.

14:37:55 [nigel]

.. So my technical opinion is that the probability that we can align the two is very high

14:38:01 [nigel]

.. via TTML1 Third Edition.

14:38:35 [nigel]

Glenn: I would not agree - there are specific things like displayAspectRatio that are ambiguous

14:38:39 [nigel]

.. in TTML1 but fixed in TTML2.

14:38:51 [nigel]

Pierre: That ambiguity would have to remain in TTML1.

14:38:59 [nigel]

.. The common features can be aligned.

14:39:13 [nigel]

Glenn: If it's simply a matter of fixing prose (even normative) then I think we can back-fill

14:39:19 [nigel]

.. ambiguities that don't require new featuers.

14:39:24 [nigel]

s/ers/res

14:39:33 [nigel]

Cyril: Why not deprecate ambiguous TTML1 features?

14:39:45 [nigel]

Pierre: Some of the ambiguities are in the core layout and styling algorithms. So it's not

14:39:57 [nigel]

.. deprecating a features, just correcting an ambiguity in TTML1.

14:40:15 [nigel]

Cyril: If it's ambiguous in TTML1 then noone can interoperably implement it in TTML1.

14:40:29 [nigel]

Pierre: This is core, basic things like lineHeight style inheritance.

14:40:47 [nigel]

Cyril: Two choices: either it has been demonstrated interoperably, or it has not, in which case

14:40:52 [nigel]

.. let's deprecate the feature.

14:41:05 [nigel]

Pierre: You can't do that - you can't deprecate style inheritance.

14:41:13 [nigel]

Cyril: Has it been demonstrated interoperably?

14:41:25 [nigel]

Pierre: TTPE and IMSC.js implemented it the same way.

14:41:33 [nigel]

Cyril: Why not fix the spec to reflect it?

14:41:37 [nigel]

Pierre: Exactly.

14:41:53 [nigel]

Glenn: We cannot deprecate features in TTML1. There is no requirement for rendering

14:42:03 [nigel]

.. interoperability, though it may have been a goal for some implementers.

14:42:17 [nigel]

Pierre: I agree with you Cyril, we should make it work consistently.

14:42:55 [nigel]

.. My suggestion is to fix it in TTML1 Third Edition. We could conceive of other ways, but

14:43:02 [nigel]

.. that seems like a straightforward way of doing it.

14:44:16 [nigel]

Nigel: I think if we can achieve consistency by retro-fitting to TTML1 Third Edition that makes

14:44:33 [nigel]

.. it a lot easier, but does that work for IMSC 1.0.1 which references 2nd Edition? Would

14:45:42 [nigel]

.. that resolve the original IMSC compatibility issues? Would it make TTML2 processors

14:45:53 [nigel]

.. process say IMSC1 documents in an acceptable way?

14:46:16 [nigel]

Pierre: We have a lot of resolutions in TTML1 GitHub issues reflecting TTML2 fixes, and

14:46:22 [nigel]

.. we should capture those in a TTML1 Third Edition.

14:46:38 [nigel]

.. The next step is to update IMSC 1.0.1, to give those organisations that care the opportunity

14:46:49 [nigel]

.. to update their implementations to match the updated specs.

14:47:13 [nigel]

.. W3C can't compel implementers to reference a particular version of a spec.

14:48:21 [nigel]

Nigel: I have no problem with that - making TTML1 Third Edition aligned with TTML2

14:48:36 [nigel]

.. so that TTML2 represents clean feature additions.

14:48:53 [nigel]

Pierre: I would like to go back to the general principle.

14:49:20 [nigel]

Glenn: If it's too general I might not be able to agree.

14:49:43 [pal]

https://github.com/w3c/ttml2/issues/458#issuecomment-336022891

14:49:50 [nigel]

Pierre: I proposed the text in the issue above.

14:50:06 [nigel]

Glenn: I need to contemplate that language.

14:51:03 [nigel]

.. When you say "features that the specs share" that doesn't address my point about layers.

14:51:25 [nigel]

Pierre: "given a document that contains only TTML1 syntax, a processor was compelled by the TTML2 specification to process it differently than it would have been compelled by the TTML1 specification."

14:51:35 [nigel]

Glenn: I don't agree with that, the way it is expressed.

14:52:02 [nigel]

.. A clarification question: in some of my commentary on the issues I have pointed out

14:52:16 [nigel]

.. that an implementor may implement a processor that adheres to some subset of TTML1 or TTML2,

14:52:32 [nigel]

.. so if you're objective as stated could be used as a mandate to require a TTML2 implementation

14:52:45 [nigel]

.. to operate in a bug-for-bug compatible way with TTML1?

14:53:24 [nigel]

Pierre: W3C doesn't compel implementors to do anything. Given a TTML1-only syntax document,

14:53:37 [nigel]

.. the processors should not yield a different outcome on those features that they have in common.

14:54:22 [nigel]

Glenn: I could accept a general objective - as soon as you start hinting at touching the

14:54:27 [nigel]

.. conformance section the answer is no.

14:54:38 [nigel]

Pierre: So do you agree on the objective of making TTMl1 and TTML2 consistent on the

14:54:42 [nigel]

.. features they share?

14:54:48 [nigel]

Glenn: Yes, and we can add that language.

14:55:19 [nigel]

Andreas: Yes, that should be a clear objective. It is also important to say in the text that

14:55:36 [nigel]

.. a TTML1 document containing only TTML1 syntax, then this applies, but that if TTML2

14:55:46 [nigel]

.. syntax is present then the outcome may be different.

14:56:04 [nigel]

David_Ronca: What's a document that shares TTML1 and TTML2?

14:56:16 [nigel]

Pierre: No, the document would contain only features in common, i.e. TTML1 syntax.

14:56:43 [nigel]

Andreas: [has to drop off]

14:57:08 [nigel]

Cyril: Maybe a different perspective to the question: in terms of implementation, how do

14:57:18 [nigel]

.. you translate your design goal? To minimise the overhead of implementing both TTML1

14:57:37 [nigel]

.. and TTML2, or further, to reuse exactly the TTML1 implementation for a TTML2 renderer.

14:57:50 [nigel]

Pierre: That's not what I had in mind, though it would be awesome if one could do the latter.

14:58:19 [nigel]

Cyril: In the worst case scenario, if I have an implementation that switches based on

14:58:25 [nigel]

.. document type then it won't make any difference.

14:58:38 [nigel]

Pierre: The goal is to avoid completely different tests, code paths, authoring tools etc. We're

14:58:55 [nigel]

.. trying to make it easier for people with a limited amount of resource.

15:02:04 [nigel]

SUMMARY: General agreement that there should be compatibility where possible, and that this may be achieved in practice by publishing TTML1 Third Edition being made compatible with TTML2 where practical.

15:03:49 [nigel]

Cyril: A practical question: did this begin with a question about the processing rules for tts:disparity present in an IMSC 1.0.1 document?

15:04:17 [nigel]

Glenn: It's not simply a matter of the document using TTML1 features only, so we need to handle

15:04:22 [nigel]

.. more generally which rules to follow.

15:04:37 [nigel]

Mike: It is complicated, but we need to be clear, so if e.g. ATSC adopts one or two TTML2

15:04:51 [nigel]

.. features into TTML1-based IMSC 1.0.1 we need to be sure that the act of doing that

15:05:02 [nigel]

.. doesn't cause things to behave differently.

15:05:15 [nigel]

Cyril: We could avoid this issue by back-porting the feature to TTML1.

15:05:56 [nigel]

.. Apparently it doesn't require any other changes in TTML2.

15:06:44 [nigel]

Pierre: Conceivably we could create IMSC 1.0.2 to solve disparity.

15:06:48 [nigel]

Glenn: We cannot add it to TTML1.

15:06:53 [nigel]

Cyril: OK that's fine.

15:07:13 [nigel]

.. Are there any other features coming from TTML2 that may land in IMSC?

15:07:21 [nigel]

Mike: ATSC may adopt luminanceGain.

15:07:29 [nigel]

Cyril: That would be a path to at least solve that issue practically.

15:07:55 [nigel]

Pierre: We could follow the same path as fillLineGap in IMSC 1.0.1, by creating 1.0.2

15:08:04 [nigel]

Mike: If that solves the problem it'd be fine.

15:08:31 [nigel]

Nigel: This feels like the moment to mention that factoring out the style attributes into a

15:08:47 [nigel]

.. separate specification altogether might be quite helpful, separate from the other spec

15:08:48 [nigel]

.. semantics.

15:09:43 [nigel]

Mike: Someone needs to draft the text that reflects this discussion.

15:09:50 [nigel]

Nigel: For the TTML2 spec?

15:10:17 [nigel]

Mike: I think that's the target.

15:10:48 [nigel]

Nigel: Glenn?

15:10:56 [nigel]

Glenn: I'll draft something and send it to the list for discussion.

15:11:12 [nigel]

Nigel: I'm happy to look at that and try to make sure it reflects this discussion.

15:11:25 [nigel]

Mike: [needs to drop off the call]

15:11:58 [nigel]

Topic: IMSC

15:15:41 [nigel]

action-507?

15:15:41 [trackbot]

action-507 -- Nigel Megitt to Add imsc vnext repo to agenda, board, github-bot etc -- due 2017-10-05 -- PENDINGREVIEW

15:15:41 [trackbot]

http://www.w3.org/AudioVideo/TT/tracker/actions/507

15:15:52 [nigel]

Nigel: That's all done, and the TT board has been updated, so closing.

15:15:56 [nigel]

close action-507

15:15:56 [trackbot]

Closed action-507.

15:16:48 [nigel]

Nigel: Now what about the FPWD of IMSC 1.1?

15:16:51 [nigel]

Pierre: It's ready to go.

15:17:00 [nigel]

Thierry: There are a couple of issues to discuss offline.

15:17:13 [nigel]

Pierre: The pub-rules checker said it was okay.

15:17:24 [nigel]

Thierry: I'll send you what I've found, and then request publication for the 17th.

15:18:05 [pal]

https://github.com/w3c/imsc/blob/IMSC1.1/imsc1/spec/ttml-ww-profiles.html

15:18:22 [pal]

https://rawgit.com/w3c/imsc/IMSC1.1/imsc1/spec/ttml-ww-profiles.html

15:18:51 [nigel]

Nigel: Last week we made the proposal to publish this. Any objections?

15:19:14 [nigel]

Cyril: No objection, but I did raise a few issues on the document, mostly trying to clarify

15:19:26 [nigel]

.. the relationship between this IMSC version and the previous one. It's important that

15:19:38 [nigel]

.. people understand with simple communications what are the differences.

15:20:05 [nigel]

.. Pierre has responded to the issues.

15:21:05 [nigel]

RESOLUTION: TTWG agrees to publish FPWD of IMSC 1.1

15:21:19 [nigel]

action-509?

15:21:19 [trackbot]

action-509 -- Pierre-Anthony Lemieux to Propose liaison text for the imsc 1.1 fpwd -- due 2017-10-12 -- OPEN

15:21:19 [trackbot]

http://www.w3.org/AudioVideo/TT/tracker/actions/509

15:22:00 [nigel]

-> https://lists.w3.org/Archives/Public/public-tt/2017Oct/0087.html Proposed liaison text re: IMSC 1.1 FPWD

15:22:27 [nigel]

Thierry: Who do we want to send this to? Should we use the same list as for the wide review?

15:22:34 [nigel]

Pierre: Same as the IMSC 1.0.1 WR I would say.

15:22:41 [nigel]

Thierry: Okay I will dig into that and come up with the list.

15:23:05 [nigel]

Pierre: There's an MPEG meeting the week after next so it's important to send this soon.

15:23:16 [nigel]

Thierry: I will update the drafts and send the final one after publication.

15:23:29 [nigel]

Nigel: I notice there's a deadline for comments - why is that?

15:23:38 [nigel]

Pierre: It's arbitrary, just seems like a good idea.

15:24:19 [nigel]

Nigel: This isn't a call for wide review so I don't think it's a good idea to set a deadline for

15:24:30 [nigel]

.. comments but it would be good to indicate the proposed timeline.

15:24:39 [nigel]

Cyril: +1

15:24:46 [nigel]

Pierre: What about Wide Review in January?

15:24:49 [nigel]

NIgel: Why not!

15:24:53 [nigel]

s/NI/Ni

15:25:45 [nigel]

Pierre: We could just notify that we've started work and invite contributions.

15:25:47 [nigel]

Nigel: Perfect.

15:26:21 [nigel]

Cyril: Yes, what about just dropping the "by 13 December 2017"

15:26:23 [nigel]

Nigel: +1

15:26:29 [nigel]

Pierre: I'll fix the "submits" typo too.

15:26:42 [nigel]

Nigel: I'll take the action to update this and respond.

15:26:47 [nigel]

Pierre: OK great.

15:27:34 [cyril]

https://github.com/w3c/imsc/issues/263

15:27:46 [nigel]

Topic: itts:fillLineGap is unclear about what it is filling between exactly #263

15:27:52 [nigel]

github: https://github.com/w3c/imsc/issues/263

15:28:29 [nigel]

Pierre: Were you happy with the renders Nigel?

15:28:32 [nigel]

Nigel: Yes I think so.

15:28:48 [nigel]

Pierre: My proposal is not to make any normative changes in IMSC 1.0.1 but to add

15:29:02 [nigel]

.. informative text and those examples, as well as maximising the chances of using

15:29:11 [nigel]

.. roll-up harmoniously with fillLineGap, would resolve this issue.

15:29:37 [nigel]

.. It was not completely intuitive to me, but since fillLineGap didn't exist before, just saying

15:29:41 [nigel]

.. how to use it should work.

15:30:23 [nigel]

Cyril: Nigel you said line areas can be generated without `<br>`s?

15:30:29 [nigel]

Nigel: Yes, line areas can be generated by line wrapping.

15:30:42 [nigel]

Pierre: I agree with your interpretation Nigel, by the way.

15:31:17 [nigel]

SUMMARY: @palemieux to attempt to exemplify this without substantive changes.

15:32:27 [nigel]

Topic: What fillLineGap does/ affects #254

15:32:33 [nigel]

github: https://github.com/w3c/imsc/issues/254

15:33:02 [nigel]

Pierre: I didn't understand this, but maybe the new examples for #263 will help.

15:33:04 [nigel]

Nigel: Maybe!

15:33:09 [nigel]

.. I didn't understand either.

15:33:23 [nigel]

Pierre: If we get to a point ready to move past CR we will need to ping @r12a.

15:33:47 [nigel]

Cyril: A side comment - for rubys in TTML2 would fillLineGap apply?

15:33:59 [nigel]

Glenn: The presentation of the ruby is an annotation on a line area effectively so it would

15:34:10 [nigel]

.. be simply covered by the line gap as well. The height of the line gap would be predicated

15:34:22 [nigel]

.. on the height of the line area, which would in turn be predicated on any annotations and

15:34:27 [nigel]

.. the space that they need.

15:35:42 [nigel]

Cyril: Would the line gap between the ruby and the base text be filled by fillLineGap?

15:36:05 [nigel]

Glenn: Yes it's part of the line area already. It's a bit like the dot on an i.

15:37:34 [nigel]

Topic: Should UTF-8 'as specified in' point to the Encoding spec? #253

15:37:40 [nigel]

github: https://github.com/w3c/imsc/issues/253

15:38:07 [nigel]

Nigel: I see you asked @r12a a question, @palemieux, so I think we're just waiting for that.

15:38:10 [nigel]

Pierre: That's right.

15:38:44 [nigel]

Topic: TTML2 Wide Review Issues

15:39:33 [nigel]

Topic: SMPTE backgroundImage annotation #460

15:39:38 [nigel]

github: https://github.com/w3c/ttml2/issues/460

15:41:29 [nigel]

Nigel: [describes call from yesterday that generated this issue]

15:41:38 [nigel]

Glenn: If we're talking about an informative note I don't see any issue there.

15:41:40 [nigel]

Nigel: Yes that's it.

15:41:54 [nigel]

Glenn: I'd probably say something like it's motivated by smpte:backgroundImage and

15:42:00 [nigel]

.. extended to make it more compatible with ... whatever.

15:42:05 [nigel]

Pierre: It's more than that.

15:42:08 [nigel]

Glenn: It is, yes.

15:42:24 [nigel]

Pierre: I think what Nigel said is it's important to state equivalence.

15:42:37 [nigel]

Glenn: It goes beyond smpte:backgroundImage

15:42:51 [nigel]

Pierre: But there's a mapping from smpte:backgroundImage.

15:42:54 [nigel]

Glenn: Yes that would be fine.

15:43:08 [nigel]

Nigel: Yes that's a fair representation of the proposal.

15:44:13 [nigel]

.. I think we need to say something like "The semantics of the smpte:backgroundImage

15:44:25 [nigel]

.. attribute may be achieved by [whatever the equivalent is]".

15:44:47 [nigel]

Glenn: Recall that there are two mechanisms in TTML2 - backgroundImage and image,

15:44:58 [nigel]

.. serving different purposes, one for content, the other for background styling.

15:45:13 [nigel]

.. In effect backgroundImage in SMPTE was ambiguous about whether it was for content

15:45:22 [nigel]

.. or styling - I suspect both, but mainly for content.

15:45:35 [nigel]

Nigel: I think it is clear it's for content.

15:45:43 [nigel]

Pierre: It is intended to be content, that's established.

15:46:04 [nigel]

Glenn: It's not stated in the SMPTE spec.

15:46:17 [nigel]

Nigel: I thought you weren't supposed to have text in an element with backgroundImage,

15:46:26 [nigel]

.. which settles it for me - worth checking though.

15:49:56 [nigel]

Topic: [HTML5] reference should be informative. #461

15:50:00 [nigel]

github: https://github.com/w3c/ttml2/issues/461

15:50:40 [nigel]

RESOLUTION: HTML5 needs to be made an informative reference in TTML2.

15:50:53 [nigel]

Topic: [SSML] reference should be informative. #462

15:50:58 [nigel]

github: https://github.com/w3c/ttml2/issues/462

15:51:05 [nigel]

RESOLUTION: SSML needs to be made an informative reference in TTML2.

15:51:20 [nigel]

Topic: [WEBAUDIO] reference should be informative. #463

15:51:34 [nigel]

github: https://github.com/w3c/ttml2/issues/463

15:51:50 [nigel]

Nigel: The normative status of WebAudio may change in the future but we can make it

15:51:54 [nigel]

.. informative for now I guess.

15:52:01 [nigel]

RESOLUTION: WEBAUDIO needs to be made an informative reference in TTML2.

15:52:13 [nigel]

Topic: [XML 1.1] reference should be removed. #464

15:52:20 [nigel]

github: https://github.com/w3c/ttml2/issues/464

15:52:38 [nigel]

RESOLUTION: No use is made of the XML 1.1 reference so remove it.

15:52:55 [nigel]

Topic: Examples in section S use an unusual tts:displayAlign setting #459

15:53:01 [nigel]

github: https://github.com/w3c/ttml2/issues/459

15:53:14 [nigel]

Glenn: That's a simple fix.

15:53:27 [nigel]

Nigel: Yes, I commented in support of this on the TTML1 issue too.

15:53:44 [nigel]

RESOLUTION: Add tts:displayAlign="after" to examples.

15:54:00 [nigel]

Topic: Examples in section O use an unusual tts:displayAlign setting #254

15:54:06 [nigel]

github: https://github.com/w3c/ttml1/issues/254

15:54:09 [nigel]

RESOLUTION: Add tts:displayAlign="after" to examples.

15:54:21 [nigel]

Topic: Question about #background-color vs #backgroundColor. #455

15:54:30 [nigel]

github: https://github.com/w3c/ttml2/issues/455

15:54:54 [nigel]

Glenn: I can see that the two feature designators could be confusing. The background-color

15:55:11 [nigel]

.. was added in TTML2. Pierre has pointed out that backgroundColor includes the same

15:55:23 [nigel]

.. things as background-color pulled in, namely the block, inline and region versions. I think

15:55:35 [nigel]

.. the resolution is to remove background-color and possibly add some text to #backgroundColor

15:55:47 [nigel]

.. to say that it includes those as well, informatively.

15:56:36 [nigel]

Pierre: In TTML1 did #backgroundColor include those three things?

15:56:44 [nigel]

Glenn: Yes by implication but not explicitly.

15:56:59 [nigel]

Pierre: That was my conclusion too. In that case I would file an issue in TTML1 to make

15:57:02 [nigel]

.. that explicitly.

15:57:16 [nigel]

Glenn: I would do this as a note in TTML2 and TTML1.

15:57:44 [nigel]

RESOLUTION: Remove #background-color and add an informative note that it includes block, inline and region and raise an issue to do the same on TTML1 Third Edition.

15:58:21 [nigel]

Topic: Examples in section S use an unusual tts:displayAlign setting #459

15:58:28 [nigel]

github: https://github.com/w3c/ttml2/issues/459

15:59:10 [nigel]

Pierre: It would be good to change the examples also to put the timing on spans rather than p elements, in S.2

15:59:12 [nigel]

Nigel: +1

15:59:40 [nigel]

Pierre: That might avoid people adding fillLineGap in a copy of the example and not understanding

15:59:43 [nigel]

.. why it doesn't work!

15:59:46 [nigel]

Nigel: Agreed.

16:01:01 [nigel]

RESOLUTION: In S.2 Modify the example to put the timing on span elements and separate lines with `<br/>` inside those timed spans.

16:02:02 [nigel]

Topic: Meeting round-up

16:02:25 [nigel]

Glenn: Next week I'd like to talk about TTML2 issues #437, #438, #439 and maybe #435

16:02:38 [nigel]

.. and possibly a couple of others that are editorial fixes.

16:02:48 [nigel]

Nigel: Yes, I'd like to tackle some TTML issues next week.

16:03:12 [nigel]

Glenn: We could also discuss #428 and #429 which are about activeArea and fillLineGap

16:03:18 [nigel]

.. making them the same as IMSC 1.0.1

16:03:39 [nigel]

.. Then the other question in my mind is what we do with namespaces...

16:04:06 [nigel]

Pierre: That's my proposal. I don't disagree that it's unfortunate. In the future we can

16:04:23 [nigel]

.. maybe add new things directly into TTML2.

16:04:38 [nigel]

Glenn: Another possibility is in 1.0.2 change to tts: namespace?

16:05:04 [nigel]

Pierre: It would break implementations that look for the existing namespace.

16:05:18 [nigel]

.. This is less than ideal, but it will cause the least amount of pain overall for implementers

16:05:20 [nigel]

.. and users.

16:05:31 [nigel]

Glenn: I'm not suggesting that we have a reference from TTML2 to IMSC, but that we

16:05:41 [nigel]

.. incorporate the syntax identically and the prose to the extent that we can.

16:05:45 [nigel]

Pierre: I agree with that proposal.

16:06:02 [nigel]

Glenn: Nigel where are we with #427?

16:06:26 [nigel]

Nigel: I've made a lot of progress - the umbrella issue is #406, and #427 lays the structural

16:06:30 [nigel]

.. groundwork, and that's done.

16:10:02 [nigel]

Glenn: I would prefer to make the table row say "Derivation:".

16:17:32 [nigel]

Nigel: Okay, when you see it, it might make sense. I'll remove the "(informative)" though.

16:17:39 [nigel]

Nigel: Thanks everyone [meeting adjourned]

16:17:44 [nigel]

rrsagent, make minutes

16:17:44 [RRSAgent]

I have made the request to generate http://www.w3.org/2017/10/12-tt-minutes.html nigel

16:34:57 [nigel]

s/if you're objective as stated/if your objective as stated

16:40:20 [nigel]

s/groundwork, and that's done/groundwork, and that's done in the issue-0406- branch.

16:40:28 [nigel]

rrsagent, make minutes

16:40:28 [RRSAgent]

I have made the request to generate http://www.w3.org/2017/10/12-tt-minutes.html nigel

16:44:07 [nigel]

ScribeOptions: -final -noEmbedDiagnostics

16:44:09 [nigel]

rrsagent, make minutes

16:44:09 [RRSAgent]

I have made the request to generate http://www.w3.org/2017/10/12-tt-minutes.html nigel

16:53:12 [Zakim]

Zakim has left #tt