15:00:31 RRSAgent has joined #tt 15:00:31 logging to https://www.w3.org/2019/07/04-tt-irc 15:00:33 RRSAgent, make logs public 15:00:33 Zakim has joined #tt 15:00:35 Meeting: Timed Text Working Group Teleconference 15:00:35 Date: 04 July 2019 15:00:58 scribe: nigel 15:01:23 Present: Atsushi, Gary, Glenn, Pierre, Nigel 15:01:27 Chair: Nigel 15:01:41 Regrets: Andreas, Cyril, Philippe 15:02:07 Topic: This meeting 15:02:08 atsushi has joined #tt 15:03:24 Nigel: Hi, first of all, welcome to Atsushi, who is our new team contact 15:03:55 Atsushi: I joined W3C last November, and I am working for 50% on i18n and the other half on various other WGs 15:04:18 .. I'm still working for a bunch of other things, but hope I can work here efficiently. I'm learning about this WG and 15:04:23 .. its specifications. 15:05:20 Nigel: [introduces Gary, Glenn and Pierre as well as himself] 15:05:53 .. If you want time to run through things I am available for that Atsushi. 15:06:07 Atsushi: I'm in listening mode today, I've had an introduction from Philippe. 15:06:53 Nigel: Agenda for today: some WebVTT, TTML2 issues. We won't cover Charter status because Philippe has sent his 15:07:06 .. regrets. Is there any other business or points to make sure we cover? 15:07:17 group: [no other business] 15:07:45 Topic: WebVTT 15:08:12 Gary: I posted two issues on the agenda, we only need to talk about one. 15:08:22 .. Yesterday I opened up issues from the currently failing tests so they don't get forgotten. 15:08:46 .. One of the tests is failing because when parsing the region lines value the spec says interpret it as an integer. 15:08:58 .. Safari and Firefox interpret it differently. I'm not sure it is easy to test. 15:09:07 .. Other than this I think the current at risk proposal is good to go. 15:09:26 Topic: [IR] parsing: region lines webvtt#467 15:09:32 github: https://github.com/w3c/webvtt/issues/467 15:09:57 Gary: When parsing the WebVTT file with region lines being some very large value or very small value, that is 15:10:16 .. outside of the int range, Safari I think returns max integer but Firefox returns a zero. 15:10:32 .. I think that is technically correct based on reading the spec, because it says "interpret as an integer". 15:10:36 Nigel: Which is correct? 15:10:49 Gary: I think both of them are. I don't think one is necessarily more correct. 15:10:54 .. There's nothing beyond "interpret". 15:11:01 Nigel: Is that not an interop problem? 15:11:19 Gary: Maybe, and that's why I thought this is worth talking about, because I'm not sure. 15:11:46 Nigel: Any immediate views on this? I don't have an answer. 15:12:02 Gary: The HTML spec for parsing floating points says if too large or small to use the closest available number to it. 15:12:26 .. To me that seems like the correct decision, but at the same time, basically I guess the question to answer now is 15:12:42 .. should this hold up the current at risk CR or should we just get that out and then figure out what to do with this, 15:12:48 .. alongside everything else. 15:13:04 Nigel: It doesn't help with exiting CR because there's a failing test. 15:13:07 Gary: Yes 15:13:52 Nigel: It looks like Firefox would need to change if your instinct is right. Is it worth talking to anyone at Mozilla? 15:14:00 Gary: Yes I can try or ask Philippe to find someone. 15:14:12 Nigel: Sounds like a good way forward. 15:15:12 Atsushi: I have nothing for today, but I also work for i18n WG and would like to check with them. 15:16:19 SUMMARY: Probable proposal will be to use closest value algorithm, needs implementor input 15:16:42 pal has joined #tt 15:18:02 Topic: Emphasize null style semantics in context of ruby container spans (#1100). ttml2#1101 15:18:09 github: https://github.com/w3c/ttml2/pull/1101 15:20:42 Nigel: Summary so far is that the existing pull request is okay in most respects but Pierre asks for similar wording 15:21:01 .. to be added to 4 further style attributes, and it seems Glenn is not happy to do so. Let's iterate through them. 15:21:07 .. First up is tts:direction 15:21:19 s/direction/unicodeBidi 15:21:42 Nigel: The discussion says it can have an effect - shall we cross it off the list? 15:21:59 Pierre: No, there's an outstanding question. unicodeBidi has an effect on the child spans of an element. 15:22:12 .. I gave two examples where I think the rendering is different depending on the value of the unicodeBidi property. 15:22:27 .. But when the span is a ruby container, the two child spans, like a text container and a base container are rendered 15:22:45 .. separately and their content should not ever be reordered by the unicode bidi algorithm because they're on different lines 15:23:06 .. so I'm fairly certain that the computed value of unicodeBidi cannot have an effect on a ruby container. The two 15:23:17 .. children, the base container and the text container are rendered entirely separately. 15:23:42 Glenn: That discussion ignores the fact that there are 3 different containers we are talking about, the top level, 15:23:59 .. the base and the text. It clearly applies to the base and text containers because they can contain multiple bases and texts. 15:24:18 .. In edge case scenarios potentially the top level container arguably does not have a semantic application. 15:24:22 Pierre: I don't agree with that. 15:24:38 Glenn: The other point is that even if the top level container does not have that effect normally, if you are actually 15:24:53 .. rendering two separate inline boxes for the ruby text, that argument ignores the fact that the delimiter function and 15:25:08 .. the fallback functions make use of inline ruby in which one does have a potential bidirectional semantic. In that case 15:25:31 .. it does apply. The same thing is true for wrapOption and direction. All three of those style attributes have cases 15:25:37 .. where they could have a semantic application. 15:25:53 .. In any case I thought we had a compromise from a few weeks ago to go ahead with the 15 styles where I did add the 15:26:11 .. note even though I was extremely unhappy to do so. Now in the last couple of weeks Pierre has come back and asked 15:26:18 .. for more and still seems to ask for more with color. 15:27:54 .. At this point I will not accept any new notes in any other style attributes. 15:28:16 Nigel: Entrenching your position is really unhelpful for getting to a resolution. We can discuss the technical merits 15:29:30 Pierre: If there are multiple base containers and text containers within a ruby container I don't think unicodeBidi should 15:29:44 .. apply across the text containers because each is only associated with one base container. 15:30:03 Glenn: There is a base container and a base ruby. 15:30:32 Pierre: Sorry, if there are two base containers and they each have a different bidi position before and after then it 15:30:36 .. doesn't apply, right? 15:30:53 Glenn: There are technical scenarios where based on context you could come up with a theory that there isn't anything 15:31:10 .. to apply it to, but does that require a note to the reader? I strongly disagree with that, and that's been my contention 15:31:24 .. from the beginning, that none of these notes is making any different whatsoever. 15:32:19 .. This is a note about optimisation. I'm not going to move on this. If you want to add more I prefer going nowhere. 15:35:20 Nigel: I've asked once, please don't restate or entrench position, let's have a technical basis for the decisions we make. 15:35:36 .. Pierre, you don't seem to have responded to the point about there being no delimiter. 15:35:44 Pierre: It's complicated [shares screen] 15:36:04 -> https://www.w3.org/TR/ttml2/#style-attribute-ruby ruby attribtue 15:36:34 Pierre: The note shows the nesting model 15:36:41 Glenn: The fallback scenario is well defined. 15:36:54 Pierre: You should never reorder across ruby text and base ever though. 15:37:01 Glenn: Users may want to. 15:37:26 .. The purpose of the style property unicodeBidi and direction is to provide an alternate way to override the unicode characters 15:37:36 .. for bidi. There's nothing to stop users using those unicode characters. 15:37:52 .. We have to make sure that both representations can translate to each other for example TTPE. 15:38:03 Pierre: Unicode reordering does not apply across divs, right? 15:38:14 Glenn: It does apply divs, yes, and across boundaries. 15:38:31 .. I don't know a good user case for it. You can do it in CSS, and in plain text characters you can do it using explicit bidi controls. 15:38:48 Pierre: Today unicodeBidi does not apply to div, so how can a property apply across divs but not to divs. 15:39:06 Glenn: I agree that's not a good one to talk about. Let's say p. 15:39:16 .. You're right about divs. But we don't say they don't apply to div 15:39:22 Pierre: unicodeBidi does not apply to div 15:39:28 Glenn: I'm sorry I was wrong, you're correct. 15:39:46 .. Reminder about the "presentation related element" term that is used in one of the algorithms. 15:40:04 .. We defined it as something that affects the presentation of content, but we did not define an algorithm for how to 15:40:13 .. determine whether an element can affect the presentation of content. 15:40:30 .. When we adopted this language we discussed the issue of how to determine it and we agreed that unless 15:40:44 .. an implementation can prove it does not affect presentation then it should assume it does. 15:40:56 .. We left it to the implementations to optimise what to prune. 15:41:16 .. You've basically brought this back into play, to come up with an algorithm to come up with corner cases. 15:41:21 Pierre: It's not an optimisation. 15:41:34 Glenn: It is only an optimisation. For me we should only be talking about elements. 15:41:51 .. This discussion is the same as the one we had for presentation related element content. 15:42:09 .. I don't understand why you're spending so much time on this trivial issue that is an optimisation. I plan to ignore it, 15:42:12 .. it doesn't even matter. 15:42:33 Pierre: It does, we're talking about unicodeBidi applying across elements, so it could lead to different results so it does matter for interop. 15:42:37 .. This is complex stuff. 15:42:57 Glenn: I haven't seen any users bring forward non-interoperable content. Do you have any bug reports? 15:43:15 Pierre: Yes that's exactly what led to the issue in the first place, with respect to underline on a ruby container span. 15:43:26 Glenn: That was a real bug in the spec we have fixed already. 15:43:40 Pierre: This is actually because of a bug report on what applies to a ruby container span. 15:43:50 .. This is opened the door to what does apply to ruby container spans. 15:44:03 Glenn: I don't think we should be going down this road of premature optimisation. 15:44:22 Pierre: It's interoperability. The bug is that the spec was unclear and we are clarifying it for better interop. 15:44:43 Glenn: The only real bug was about white space that was potentially considered significant when xml:space=preserve is used. 15:44:50 Pierre: No that was not the only bug. 15:46:18 Nigel: We're trying to work out if the spec is clear about the layout of ruby with unicodeBidi. 15:46:31 Pierre: Specifically the container : base text example. 15:49:13 Nigel: I'm concerned here about if there is an ambiguity that means that two implementations could both seem to be 15:49:44 .. conformant to the spec but render text in a different order, changing the meaning, in which case we need to clarify it. 15:49:57 Glenn: I'm concerned about overspecifying, I think we may get it wrong. 15:50:53 Nigel: Can we merge what we have and open a new issue about this ruby layout complexity? 15:51:07 Pierre: color is really simple. 15:51:50 .. Coming back on the point of a compromise that I've reopened, I raised the point about the other attributes on the original review. 15:52:21 Glenn: I'm at the take it or leave it stage. 15:52:32 Pierre: I'm happy to take over editing the pull request and come up with one we can vote on. 15:52:52 Glenn: I'm going to object to it so it will be put on hold. I already objected to your pull request. 15:53:10 .. I think you've overstepped your prerogative. 15:53:15 Pierre: I'm a member of this group. 15:53:24 Nigel: I'm seeing no overstepping. 15:53:34 Pierre: I'm raising this for interop reasons. 15:53:51 Glenn: If we go to the CSS WG and ask them for their CSS ruby model and they have a firm answer to it I am willing to 15:54:05 .. look at it again. I'm not prepared to make statements we don't have agreement for. 15:54:43 Pierre: What about color? It's the same as textDecoration. 15:54:49 Glenn: Why didn't you raise it in the first place? 15:55:37 Pierre: I had suggested some elements and you took the liberty not to take some into account and I'm bringing them up again. 15:55:44 .. I'm trying to do this based on technical reason. 15:56:31 Nigel: Does the note apply to tts:color? 15:56:41 Glenn: In the same way as it applies to any empty span. 15:56:44 Nigel: So it does apply. 15:56:58 Glenn: The context means some attributes do not apply. 15:59:51 Nigel: I have a proposal: let's add color to this PR, merge it, and open a new issue for wrapOption, unicodeBidi and direction, and go 16:00:05 .. to CSS WG and i18n as Glenn suggested. 16:00:42 Glenn: Alternative proposal: accept these two PRs as they stand. Open a new issue for color and view that on its own merit, 16:00:56 .. and it there's some technical argumentation for the other three, then open new issues for those separately. 16:01:08 .. So far I've not seen any argument that says what we have right now is unacceptable. 16:03:04 Nigel: Unless you think there's a technical argument against adding the note to color then we should include it. 16:04:06 Pierre: I'm happy to do that editorial work. 16:04:13 Nigel: Ok please go ahead on the same PR 16:04:29 Glenn: I will put an objection on that pull request if you do that 16:09:48 Nigel: Okay if you want to make an objection, make it well formed with a rationale. 16:09:52 Glenn: It's a process objection 16:10:21 Nigel: I don't want to spend another hour discussing this. The unicodeBidi issue needs to be raised separately and 16:10:39 .. warrants further discussion but we've spent long enough on this that I think we're approaching the point where I will 16:10:53 .. need to make a call as Chair and let us move on with our lives. 16:10:56 Topic: Meeting close 16:11:12 rrsagent, please publish minutes 16:11:12 I have made the request to generate https://www.w3.org/2019/07/04-tt-minutes.html atsushi 16:11:19 Nigel: Thanks all for attending, especially those in the US on 4th July. [adjourns meeting] 16:11:23 rrsagent, make minutes 16:11:23 I have made the request to generate https://www.w3.org/2019/07/04-tt-minutes.html nigel 16:13:38 nigel, thank you on that. I try to catch up items shortly 16:29:16 scribeOptions: -final -noEmbedDiagnostics 16:29:20 rrsagent, make minutes v2 16:29:20 I have made the request to generate https://www.w3.org/2019/07/04-tt-minutes.html nigel