IRC log of tt on 2021-03-04

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Meeting: Timed Text Working Group Teleconference
16:02:31 [nigel]
Previous meeting: https://www.w3.org/2021/02/04-tt-minutes.html
16:02:39 [nigel]
Agenda: https://github.com/w3c/ttwg/issues/175
16:02:41 [nigel]
scribe: nigel
16:02:50 [nigel]
Present: Gary, Nigel. Pierre
16:02:55 [nigel]
Chair: Gary, Nigel
16:03:42 [nigel]
Present+ Atsushi
16:03:49 [nigel]
Present+ Cyril
16:03:57 [nigel]
Topic: This meeting
16:04:34 [nigel]
Gary: Today we have TTML2, to discuss the updated CR.
16:04:47 [nigel]
.. Then WebVTT, to discuss the current status, talk about outstanding PRs
16:04:55 [nigel]
.. and a new feature request, and what the next steps are.
16:05:07 [nigel]
.. We have GitHub Pages updates and then AOB.
16:05:23 [nigel]
Nigel: You added DST Gary.
16:05:43 [nigel]
.. I would also, if time allows, give an update on the AD profile of TTML2 and implementation state as AOB.
16:06:16 [nigel]
Atsushi: For info share, I need to work on the config updates for some repos.
16:06:29 [nigel]
Nigel: Any other AOB?
16:06:38 [nigel]
s/AOB/other business
16:06:57 [nigel]
Topic: TTML2 - publication of updated CR
16:07:27 [nigel]
Atsushi: I've updated the transition req with the completed document
16:07:51 [nigel]
.. I hope for approval on Friday East Coast US time, and then plan to republish next Tuesday
16:07:54 [nigel]
.. which is the next slot.
16:08:03 [nigel]
.. For now I've run all checks including pubrules and link validator
16:08:09 [nigel]
.. so we're only waiting for approval.
16:08:16 [nigel]
Nigel: Great, thank you.
16:08:30 [nigel]
Atsushi: Sorry for taking time to fix the XSL.
16:08:33 [nigel]
Nigel: Significant changes?
16:08:45 [nigel]
Atsushi: Yes, pubrules have changed for process 2020 so we had to change some headers
16:08:57 [nigel]
.. and some metadata lines, and all of them are handled by the XSL and the DTD.
16:09:11 [nigel]
.. We may need to think about disseminating those changes to TTML1 and TTML3 for the future.
16:09:17 [nigel]
Nigel: Sounds like a good idea!
16:09:29 [nigel]
.. Would be helpful if you could pull request them in.
16:09:38 [nigel]
Atsushi: Yes, you can raise an action item against me.
16:10:32 [nigel]
-> https://github.com/w3c/ttwg/issues/181 Update XSL and DTD for TTML1 and TTML3 w3c/ttwg#181
16:10:42 [nigel]
Nigel: Thank you!
16:10:59 [nigel]
Topic: WebVTT status
16:11:30 [nigel]
Gary: The current status is: last time WebVTT was updated there was a new CR marking some items as at risk.
16:11:53 [nigel]
.. There are more things to mark as at risk, and those items are being built off snapshots of HTML in the repo
16:12:09 [nigel]
.. and are published on /TR, but that output is slightly different than the gh-pages output.
16:12:22 [nigel]
.. I think to make it easier to work on it we probably need to figure out how to bring those two back in line.
16:12:37 [nigel]
.. I don't really know much about the specifics. Maybe for me and Atsushi offline to figure it out.
16:13:08 [nigel]
.. Basically we need to get the changes in that fix the implementation report inline so that we can start progressing the spec forward.
16:13:16 [nigel]
.. However there are a couple of feature requests as well.
16:13:39 [nigel]
.. On the bright side if I understand correctly with P2020 we can republish CRs as often as we want until we want to move to the
16:13:49 [nigel]
.. next step, and then we need to move to the larger CR review. Is that right?
16:14:21 [nigel]
Atsushi: I suppose we need to go through the CR process.
16:14:34 [nigel]
Gary: It sounds like the next update will need to go through the CR process, but updates to that
16:14:41 [nigel]
.. won't need it until we try to go past CR.
16:14:50 [nigel]
Atsushi: I propose to publish as a CR Draft.
16:14:57 [nigel]
Gary: Yes, that's exactly what I was thinking.
16:15:09 [nigel]
Atsushi: Then the CR Draft could be a good pointer for wide review.
16:15:21 [nigel]
Gary: Yes, which I think would be useful because of the feature changes.
16:15:35 [nigel]
Atsushi: Yes, a CRD (not a CRS) can be published by group decision here.
16:15:48 [nigel]
Gary: Perfect, yes. I think probably we'd want to go through several iterations of CRD as we bring
16:15:55 [nigel]
.. in some of these features, until we're ready to proceed.
16:16:19 [nigel]
.. I think that's it for that agenda item.
16:16:28 [nigel]
Topic: WebVTT Outstanding Pull Requests
16:16:47 [nigel]
Gary: I mainly brought them up to remind people they exist, and if anyone has any objection or support, to
16:17:07 [nigel]
.. allow them to voice them. I think they've all been approved, by Silvia.
16:17:25 [nigel]
.. Should I list them here? They're all in the agenda.
16:18:21 [nigel]
-> https://github.com/w3c/webvtt/pull/461 Make VTTRegion lines be a long.
16:18:40 [nigel]
-> https://github.com/w3c/webvtt/pull/470 Update region lines parsing to round to +/- MAX_VALUE
16:18:54 [nigel]
-> https://github.com/w3c/webvtt/pull/460 New snapshot with new at-risk items
16:19:09 [nigel]
-> https://github.com/w3c/webvtt/pull/493 Added unbounded TextTrackCue.endTime
16:19:39 [nigel]
Gary: The end time is the new feature.
16:20:00 [nigel]
.. The items being marked at risk are text-wrap: balance, which I think everyone agrees might be nice but not
16:20:07 [nigel]
.. implementable or verifiable, so just remove it.
16:20:29 [nigel]
.. Then there's text-combine: upright, which might be worth looking at. At the time it was marked at risk because of insufficient
16:20:42 [nigel]
.. browser support, and CSS WG said not to consider vendor prefixes as a good alternative.
16:21:23 [nigel]
.. The snapshot PR adds the new features and adds those at risk items to the existing list.
16:22:17 [nigel]
Nigel: The text-combine: upright - not sure the impact of that?
16:22:36 [nigel]
Gary: Yes, it's not great for Japanese support, and things might have improved, but this may be one where we remove
16:22:52 [nigel]
.. it for the initial release and then add it back in as an "evergreen" feature.
16:23:20 [nigel]
Nigel: I think the term is "candidate feature", i.e. a CR-stage feature that can be marked like that in the Rec.
16:23:39 [nigel]
Gary: Yes, and eventually I think you can do a new snapshot to mark it as a regular feature.
16:23:44 [nigel]
Nigel: Yes, I think there's a process for that.
16:24:30 [nigel]
Topic: [WebVTT] Added unbounded TextTrackCue.endTime w3c/webvtt#493
16:24:39 [nigel]
github: https://github.com/w3c/webvtt/pull/493
16:24:54 [nigel]
Gary: The idea is that a cue can start with a defined time but with an undefined (infinity) end time.
16:25:14 [nigel]
.. The idea is for live streams where a cue, say a chapter, can show up, but then because the end isn't in the live stream yet
16:25:25 [nigel]
.. you want the cue to reflect the end time of the video, which is also infinity for the video.
16:25:42 [nigel]
.. It also aligns it with WebVMT which is a fork of WebVTT which has done that already.
16:25:52 [nigel]
.. I think the change makes sense and is fairly uncontroversial.
16:26:11 [nigel]
Nigel: Is the semantic well defined for updating the end time to a definite value?
16:26:38 [nigel]
Gary: I believe it is, but the fun part is that is defined in HTML!
16:26:47 [nigel]
.. I think it does account for updating the times of the cue.
16:27:05 [nigel]
Nigel: So the change was already made in HTML and we are just tracking it here, is that right?
16:27:16 [nigel]
Gary: There's a pull request out for it, so I guess they want to get it all in at once.
16:27:55 [nigel]
Cyril: Just a remark - do you know that there's a related change request on the carriage of WebVTT in MP4 by Dave Singer, to match this?
16:27:59 [nigel]
Gary: I do not
16:28:04 [nigel]
Cyril: I can tell you there is!
16:28:07 [nigel]
Gary: Makes sense.
16:28:25 [nigel]
Cyril: I see that the HTML pull request is not approved - should we wait for that before we do it in case they make a change?
16:28:45 [nigel]
Gary: Given that the change in WebVTT is 3 words, basically, we can wait to merge it until the WebVTT HTML part is approved.
16:29:11 [nigel]
.. It would be good to make sure all the ducks are in a row on WebVTT, which means figuring out the IPR and checking no-one objects to the change.
16:29:33 [nigel]
Nigel: Unless there is a circular reference it must be clear which one has to move first.
16:29:56 [nigel]
Gary: They sound kind of separate. The HTML one updates Text Track Cue constructor and object to allow the end time to be unbounded.
16:30:32 [cyril]
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16:30:44 [nigel]
.. VTTCue is separate. No, I guess you need both.
16:30:44 [cyril]
rrsagent, pointer
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See https://www.w3.org/2021/03/04-tt-irc#T16-30-44-1
16:31:06 [nigel]
Nigel: I can see that the change is to the type of the end time, to be unrestricted double, and defining the interpretation.
16:31:08 [nigel]
Gary: Yes
16:31:31 [nigel]
Cyril: I don't see a change to the serialisation - how would it be shown, as Infinity?
16:31:38 [nigel]
Pierre: JSON can represent infinity
16:31:52 [nigel]
s/can/cannot
16:32:05 [nigel]
Nigel: Right, but this is not JSON
16:32:21 [nigel]
Pierre: Right, but having gone through something similar recently, unbounded/infinity is poorly supported.
16:32:32 [nigel]
.. There's no widely accepted representation - just a data point.
16:33:03 [nigel]
.. For instance as long as you stay within Javascript you can deal with Infinity, assuming the underlying platform supports IEEE floats.
16:33:24 [nigel]
Gary: I think the way WebVMT does it is by omitting the end time after the ->
16:33:37 [nigel]
Cyril: For WebVTT that's a breaking change though.
16:33:58 [nigel]
Gary: Yes, it's possible this is why it is just in the contract for the value, and not in the actual syntax itself.
16:34:18 [nigel]
Cyril: Maybe there should be information about ignoring the end value or having a special value or something?
16:34:37 [nigel]
Gary: Yeah you're right we should figure out whether and how we want to have a syntax for this.
16:35:17 [nigel]
.. Maybe not having the end time, even though it is a change, maybe it can be added on top without breaking things, I'm not sure.
16:36:06 [nigel]
Nigel: Is the requirement only for constructing the VTTCue object in client code, or for providing a serialised fragment of WebVTT?
16:36:31 [nigel]
Gary: Yeah if we only care about the javascript the current change should be enough, and maybe that's a good place to separate it.
16:36:47 [nigel]
.. Do the Javascript contract first and then figure out the syntax.
16:37:25 [nigel]
Nigel: Cyril, does the change you mentioned before about MP4 imply some form of serialisation requirement?
16:37:30 [nigel]
Cyril: I'll have to check.
16:37:47 [nigel]
Gary: Chris Needham's example is Javascript code constructing the cue object.
16:38:20 [gkatsev]
-> https://github.com/whatwg/html/issues/5297 HTML issue for Add TextTrackCue end time representing end of media
16:38:57 [nigel]
Cyril: The text I can see doesn't talk about serialisation - it talks about what to do if a cue with indefinite duration exists.
16:39:15 [nigel]
.. I don't understand it - it will need review. I don't think it answers your question Nigel, and it raises more.
16:39:46 [nigel]
Nigel: Perhaps it's just explaining how to handle the case, without saying how it might happen, so it's future-proof in that case!
16:41:06 [nigel]
Nigel: Interesting to know how a syntax change would be handled by existing parsers.
16:41:15 [nigel]
Pierre: Have any tests been provided? That might help answer the question.
16:41:28 [nigel]
Gary: The requested change is only to the Javascript contract.
16:41:38 [nigel]
Pierre: So there are no tests?.
16:41:44 [nigel]
s/?//
16:42:06 [nigel]
Gary: No, [checks wpt] there are no tests.
16:42:11 [nigel]
Nigel: Is it testable?
16:42:42 [nigel]
Gary: Yes, it's just create a new VTTCue with an infinite end time and verify that one was created with infinity for end time.
16:43:06 [nigel]
.. For the syntax it is possible that if we add the syntax of no end time the error correction might just ignore that cue. I need to check.
16:44:03 [nigel]
Nigel: Good shout about tests - our working model changed a couple of years ago to try to write tests alongside substantive
16:44:20 [nigel]
.. changes at the time of the PR, so we're not rushing to back-fill the IR at the end when we've forgotten the context.
16:44:25 [nigel]
Gary: Yes
16:45:27 [nigel]
SUMMARY: 1. Make sure we have tests for the change; 2. Enquire whether a syntax change is needed, and if so, investigate if it can be added in a non-breaking way.
16:45:35 [nigel]
Topic: WebVTT next steps
16:45:58 [nigel]
Gary: Some potential steps for moving forward - merge all the outstanding PRs,
16:46:12 [nigel]
.. update the snapshot, go through the CfC process for a new CRS.
16:46:15 [nigel]
Nigel: CRS not CRD?
16:46:32 [nigel]
Gary: I think once everything is in we'd want to go to a CRS before PR.
16:46:43 [nigel]
.. The one thing I'm unsure about is the stuff we want to remove as at risk.
16:46:51 [nigel]
.. Would that be before or after we make the CR.
16:47:18 [nigel]
Nigel: Need to decide whether to remove those features altogether or just mark them as a candidate feature.
16:47:42 [nigel]
Gary: Yeah I think remove text-wrap:balance but mark the text-combine: upright as a candidate feature.
16:47:53 [nigel]
.. That would make it easier than adding it back in later.
16:48:11 [nigel]
Nigel: Would be worth making explicit proposals for each one of these at risk features.
16:48:32 [nigel]
Gary: Yes, I'm describing my view of what I think makes sense to progress WebVTT.
16:48:51 [nigel]
.. Another thing we need to consider is the WebVTT headers - that's another feature I think we should bring in,
16:49:07 [nigel]
.. so that e.g. HLS doesn't need to define its own WebVTT header and can just reference our spec.
16:49:37 [nigel]
Topic: GitHub Pages after switching master to main branch names
16:50:10 [nigel]
Nigel: I noticed a couple of repos using gh-pages were returning 404s on their published URLs, ADPT and IMSC.
16:50:26 [nigel]
.. I haven't checked the others. I managed to kick GitHub Pages into reprocessing them and then they were fine.
16:50:43 [nigel]
Atsushi: 2 things:
16:51:05 [nigel]
.. 1. I found discontinuities in the GitHub Pages API's log. There might be some issue on the GitHub side.
16:51:31 [nigel]
.. 2. I listed 4-5 repos in the agenda+ that refer 404s for GitHub Pages but have a setting. So we need to do a similar operation for them.
16:51:50 [nigel]
.. I somehow doubt that the current configuration for some of these repos is right - that they are pointing to the wrong branch names.
16:52:05 [nigel]
.. Let me check offline with you Nigel for what is the correct config for these repos.
16:52:27 [nigel]
Nigel: Ok - and the difference is whether to publish the main branch or a separate gh-pages branch?
16:52:39 [nigel]
Atsushi: Yes, some are pointing at gh-pages but there's no branch, only a main.
16:52:44 [nigel]
.. I think we need to check one by one.
16:52:59 [nigel]
.. Detailed list is in my email to you - please check.
16:53:08 [nigel]
Nigel: I just had a hard time parsing it! I will have another look.
16:53:17 [nigel]
Atsushi: I have no idea what happened yet.
16:54:18 [nigel]
Nigel: I think there's no point in having a separate gh-pages branch unless there's a build script that makes a separate web page.
16:54:30 [nigel]
.. If it's just respec then we can publish the main branch directly.
16:55:05 [nigel]
Atsushi: I checked the branches and the config, and there were discontinuities.
16:55:20 [nigel]
.. When a change is made GitHub takes the commit and builds something to be provided to the GitHub Pages web server.
16:55:35 [nigel]
s/s./s, from 2017 to Feb 2020.
16:56:17 [nigel]
.. If we use some build script like for TTML, once the CI commits the build result to gh-pages GitHub takes that commit into web server storage.
16:56:22 [nigel]
.. I will check the history of that.
16:57:16 [nigel]
Nigel: All I'm saying is that for respec or markdown documents we can publish main directly.
16:57:28 [nigel]
Atsushi: Yes exactly, I need to check for each repo.
16:57:31 [nigel]
Nigel: Thanks.
16:57:44 [nigel]
Topic: AOB - DST
16:58:11 [nigel]
Gary: DST changes in the US on March 14th, between this meeting and our next scheduled meeting.
16:58:24 [nigel]
Nigel: And it will change in Europe on a later date.
16:58:48 [nigel]
.. Probably Sunday 28th March.
16:59:59 [nigel]
Nigel: Need to confirm offline - I think we will most likely adjust our time to track DST, the only question is when.
17:00:15 [nigel]
Atsushi: I am fine to open a PR to update the calendar files.
17:02:18 [nigel]
Nigel: The only difference between previous DST switches is that we have Atsushi active in Japan. If we adjust to keep local time the same
17:02:30 [nigel]
.. in US and Europe then it will be 1 hour earlier in places like Japan without DST.
17:02:41 [nigel]
.. Will that cause a problem for you Atsushi?
17:02:52 [nigel]
Atsushi: I'm not sure - I will check.
17:03:26 [nigel]
Gary: The EU passed ending DST, but I don't know when that change will happen. The UK is doing something independently.
17:04:03 [nigel]
Nigel: I like to deal with each change as it comes and not worry about it too much in advance!
17:07:03 [nigel]
.. Gary, if you can get round to sending an email today, great, otherwise I will try to get around to it tomorrow.
17:07:13 [nigel]
Topic: Meeting close
17:07:22 [nigel]
Nigel: Thanks everyone! [adjourns meeting]
17:07:26 [nigel]
rrsagent, make minutes v2
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I have made the request to generate https://www.w3.org/2021/03/04-tt-minutes.html nigel
17:23:52 [nigel]
s/Nigel. Pierre/Nigel, Pierre
17:23:53 [nigel]
rrsagent, make minutes v2
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I have made the request to generate https://www.w3.org/2021/03/04-tt-minutes.html nigel
17:24:21 [nigel]
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17:24:25 [nigel]
zakim, end meeting
17:24:25 [Zakim]
As of this point the attendees have been Gary, Nigel., Pierre, Atsushi, Cyril
17:24:27 [Zakim]
RRSAgent, please draft minutes v2
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I have made the request to generate https://www.w3.org/2021/03/04-tt-minutes.html Zakim
17:24:30 [Zakim]
I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye
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Zakim has left #tt
17:27:07 [nigel]
rrsagent, excuse us
17:27:07 [RRSAgent]
I see no action items