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16:04:53 <nigel> Meeting: Timed Text Working Group
16:05:06 <nigel> Agenda: https://github.com/w3c/ttwg/issues/78
16:05:14 <nigel> Log: https://www.w3.org/2019/11/14-tt-irc
16:05:39 <nigel> Present: Atsushi, Cyril, Glenn, Jeffrey_Yasskin, Pierre, Nigel
16:05:43 <nigel> scribe: nigel
16:05:45 <nigel> Chair: Nigel
16:05:57 <nigel> rrsagent, make minutes
16:05:57 <RRSAgent> I have made the request to generate https://www.w3.org/2019/11/14-tt-minutes.html nigel
16:06:36 <nigel> Topic: This meeting
16:06:55 <nigel> Nigel: Glenn requested an additional agenda topic
16:07:01 <nigel> Glenn: Its a quick follow-up to last week
16:07:28 <nigel> Nigel: We also have the security review for TTML2 to deal with
16:07:35 <nigel> s/security/privacy
16:08:07 <nigel> Topic: Improve anonymous span prose, clarify rule ordering (#1139). ttml2#1179
16:08:13 <nigel> github: https://github.com/w3c/ttml2/pull/1179
16:08:26 <nigel> Glenn: Final tweak awaiting approval from Pierre, when you can take a look at it.
16:08:41 <nigel> Pierre: Thanks
16:08:51 <nigel> Nigel: OK ping to Pierre completed!
16:09:10 <nigel> Topic: This meeting
16:09:14 <nigel> Nigel: Any other business?
16:11:21 <nigel> Regrets: Andreas
16:11:25 <nigel> Group: [no other business]
16:11:41 <nigel> Topic: TTML2 Privacy Review comments
16:11:56 <nigel> Glenn: Quick comment: all those comments from Jeffrey look interesting. I took a quick pass at them.
16:12:11 <nigel> .. My first comment is they don't apply to any of the changes in 2nd Ed. They are potentially applicable to TTML2
16:12:27 <nigel> .. in general but they apply to things that changed between TTML1 and TTML2 and not between TTML2 1st Ed and 2nd Ed
16:12:32 <gkatsev> gkatsev has joined #tt
16:12:37 <nigel> .. and in our HR we asked for review of changes to 2nd Ed.
16:12:43 <nigel> Jeffrey: Sorry for missing that.
16:12:58 <nigel> Glenn: I would propose that we don't deal with those in 2nd Ed changes, but would be happy to take them up in
16:13:07 <nigel> .. 3rd Ed as improvements to Security and Privacy.
16:13:17 <nigel> Jeffrey: I think you don't have privacy considerations in most of these specs.
16:13:23 <nigel> .. It seems useful to write some of this down.
16:14:15 <nigel> Nigel: I think we should entertain the idea of improving the privacy information in 2nd Ed.
16:14:39 <nigel> Glenn: I'm open to making the changes and understand they're useful, but technically they don't apply to the changes
16:14:43 <nigel> .. between 1st and 2nd Ed.
16:14:59 <nigel> Jeffrey: I'm personally happy to have them as open issues to address later.
16:15:03 <nigel> .. Not sure about PING as a whole.
16:15:28 <nigel> -> https://w3c.github.io/ttml2/index.html#security-and-privacy TTML2 Appendix P Security and Privacy Considerations
16:15:50 <nigel> Cyril: Question - I didn't have a chance to review the comments. How many are there?
16:16:03 <nigel> Jeffrey: 2 pages, not very severe, worth mentioning but no substantive changes.
16:16:12 <nigel> Cyril: They would apply to TTML1, TTML2 and all the IMSC profiles?
16:16:25 <nigel> Jeffrey: I looked at 3 or 4 specifications. TTML would probably apply to all of the versions.
16:16:31 <nigel> .. There are also some comments on the TT Live stuff.
16:16:47 <nigel> Glenn: From my brief reading most are the sort that would apply to browser technologies that embed some form of
16:16:51 <nigel> .. support for TTML content.
16:16:53 <gkatsev> RRSAgent: pointer
16:16:53 <RRSAgent> See https://www.w3.org/2019/11/14-tt-irc#T16-16-53
16:16:54 <nigel> Jeffrey: Right
16:17:11 <nigel> Glenn: TTML is defined as a content format, with processing semantics, but it doesn't define fetching semantics for example
16:17:28 <nigel> .. or what the outer environment of a browser does in that context. Much of the things that would apply in the context
16:17:42 <nigel> .. of user preferences or things that would expose potential privacy matters are to do with the user agent and
16:17:56 <nigel> .. technically outside the scope as defined in the TTML specification.
16:18:17 <nigel> .. We might make statements like "In the context of a UA a TTML processor should take into account these potential privacy concerns"
16:18:21 <nigel> Jeffrey: I think I agree
16:18:26 <nigel> Cyril: How much would apply to WebVTT?
16:18:45 <nigel> Jeffrey: I don't know, there may have been more review because of browser implementation
16:18:57 <nigel> Cyril: Reason for asking is we could make a separate note and then refer to it
16:19:02 <nigel> Jeffrey: That's plausible.
16:19:16 <nigel> .. The only stuff in TTML is potential fingerprinting which is only a thing if natively implemented so it
16:19:24 <nigel> .. applies more to WebVTT than TTML in the current world.
16:19:33 <nigel> Pierre: I think it would be useful to have a paragraph about that.
16:19:44 <nigel> .. Any objections to having a paragraph in 2nd Ed if someone writes it?
16:20:00 <nigel> Glenn: I would really like to avoid putting new material in TTML2 at this point, by preference.
16:20:12 <nigel> .. Unless its typos my thinking is we shouldn't make a change.
16:20:16 <nigel> Pierre: I don't disagree with that.
16:20:35 <nigel> Cyril: Do we need to review them one by one now?
16:20:38 <nigel> Nigel: Maybe not
16:20:53 <nigel> Jeffrey: I'm happy to raise issues for discussion. It's possible I've got some of them wrong.
16:21:18 <nigel> .. The next step for TTML is to file a GitHub issue?
16:21:26 <nigel> Nigel: Yes please and thank you very much for doing this.
16:21:40 <nigel> Jeffrey: Can we talk about the TTML Live comments. Two things in there maybe more important than fingerprinting.
16:21:57 <nigel> Nigel: Please go ahead.
16:22:12 <nigel> Jeffrey: In the TT Live document in general I was worried that a naive implementation might put a subtitler's name
16:22:31 <nigel> .. in an identifier that would leak. A good implementation should not do that.
16:22:53 <nigel> Nigel: That's implementation dependent.
16:24:41 <gkatsev> q+ about webvtt
16:24:50 <nigel> .. It certainly would be worth advising distribution encoder implementers to sanitise the output.
16:24:56 <nigel> Jeffrey: That would make sense.
16:25:21 <nigel> Pierre: Question - in the case of accessibility, the specs that have checklists for conformance, a lot of accessibility
16:25:34 <nigel> .. criteria apply across the board. Has there been similar thought about privacy?
16:25:52 <nigel> Jeffrey: Yes the TAG maintains a privacy and security questionnaire. It's not rule based like the accessibility checklists.
16:26:09 <nigel> .. I'm working on a more formal threat model for privacy stuff. I don't think most of it will apply to TTML, but it would
16:26:15 <nigel> .. be a UA thing.
16:26:33 <nigel> Pierre: "Don't distribute personal information to consumers" is a general requirement across the board and should not
16:26:37 <nigel> .. need repeating everywhere.
16:26:54 <nigel> Jeffrey: Right, my thought was that TTML might have personal information in specific fields if naively implemented
16:27:00 <nigel> .. so it would be worth calling those out.
16:27:20 <nigel> Pierre: Understood - if there's specific data. It would be great to include those in a checklist.
16:27:23 <nigel> ack gkatsev
16:27:45 <nigel> Gary: I wanted to mention about WebVTT, it sounds like it has had some of this review. It has a sec and privacy
16:28:00 <nigel> .. section in the spec that says downloading captions is a user preference but it is not a problem of the caption spec
16:28:27 <nigel> .. itself but how you deliver it. WebVTT right now is fairly tied to HTML so the privacy preference is more tied to HTML
16:28:42 <nigel> .. because you generally, if you just have a caption file implementing the WebVTT spec then that doesn't by itself
16:29:02 <nigel> .. become a privacy information. But on a web page and you select to load the Japanese captions that could potentially
16:29:06 <nigel> .. leak information.
16:29:27 <nigel> .. Sounds like having a shared document is a good idea because I'm certain there's overlap there.
16:29:39 <nigel> Nigel: Sounds like a really good thing to work towards.
16:29:41 <gkatsev> ack about
16:29:43 <gkatsev> ack webvtt
16:30:08 <nigel> Jeffrey: The last thing is in the WebSocket document you use ws:// and you should probably use wss:// in most places.
16:30:10 <nigel> Nigel: Yes
16:30:26 <nigel> Jeffrey: There's an example about how to build the URLs for the request and one says to put the sequence id in the
16:31:38 <nigel> .. domain name which potentially exposes it to the DNS which is probably not right if the sequence id might have a
16:31:44 <nigel> .. personal information in it.
16:32:08 <nigel> Nigel: Thanks for raising that, I hadn't considered it. It's feasible to put someone's name in a sequence identifier but
16:32:14 <nigel> .. not something I expect everyone did.
16:32:36 <nigel> s/did/would do
16:32:49 <nigel> .. I'm happy to add some text advising people not to do that.
16:33:03 <nigel> Glenn: You've done an amazing job in a short time Jeffrey, I applaud you! The specs are complex.
16:34:37 <nigel> Nigel: To summarise this,
16:34:44 <nigel> .. Jeffrey will raise some GitHub issues,
16:35:06 <nigel> .. we will look at creating a single document with privacy issues relating to timed text document formats,
16:35:24 <nigel> .. and may make some TTML2 3rd Edition changes to add pointers to that, or make other privacy section changes.
16:35:34 <nigel> .. And finally thank you again to Jeffrey and PING for this feedback.
16:35:59 <nigel> .. Anything else to cover on the privacy review?
16:36:19 <nigel> Jeffrey: Thank you for your time. [leaves]
16:37:04 <nigel> Topic: Add non-normative Appendix to cover SDR compositing. ttml2#1119
16:37:11 <nigel> github: https://github.com/w3c/ttml2/issues/1119
16:40:01 <nigel> Nigel: Do we need to agree that the EOTF linearization uses gamma 2.2 and the inverse 709 EOTF uses 2.4 and there's
16:40:29 <nigel> .. no change to the primaries? Do we need to worry about number ranges?
16:40:48 <nigel> Pierre: I don't think we need to worry about number ranges, because both 709 and sRGB are relative luminance systems
16:41:37 <nigel> .. so I think we can use the full range. Both 709 quantisation schemes are in use. We don't need to cover narrow range
16:41:43 <nigel> .. 709 - this example covers full range 709.
16:41:50 <nigel> .. Full range 709 is used in practice.
16:41:53 <nigel> Nigel: Thanks for that.
16:42:01 <nigel> Pierre: It depends on the application.
16:42:17 <nigel> Nigel: Great, so as long as it's clear that we're talking about full range 709 we're ok
16:42:26 <nigel> Pierre: Yes, we should change the title to avoid people getting confused.
16:42:42 <nigel> Nigel: And those gammas are uncontroversial?
16:42:55 <nigel> Pierre: As far as I know, yes. If you don't apply this conversion then colours won't match in practice.
16:43:37 <nigel> Nigel: OK so the change essentially looks good, then the question moves to when we should implement it, should we
16:43:58 <nigel> .. attempt to shoehorn it into TTML2 2nd Ed or wait until 3rd Ed?
16:44:05 <nigel> .. I note that this is an informative section.
16:44:19 <nigel> Glenn: There's a bigger question that Pierre asked which is have we stopped making changes to 2nd Ed other than
16:44:32 <nigel> .. typos basically, which is more general than this particular issue. I think we should ask the group to make a decision
16:44:34 <nigel> .. on this.
16:45:29 <nigel> SUMMARY: TTWG Thanks @dkneeland for this contribution, and is considering when it can be added to the specification, within TTWG publication timelines.
16:45:41 <nigel> Topic: TTML2 status - content freeze?
16:47:01 <nigel> Nigel: I thought we agreed at TPAC that we would proceed towards TTML2 2nd Ed publication as quickly as possible
16:47:05 <nigel> .. and make minimal changes.
16:47:24 <nigel> .. The only thing that perhaps could lead me to reconsider that would be if the Charter delay and Process issue
16:47:43 <nigel> .. raised by Thierry means we are in an enforced hiatus, in which case we may as well allow further improvements.
16:48:57 <nigel> Atushi: Philippe has been out of action this week.
16:49:16 <nigel> Glenn: My opinion is not to make any changes other than fixing typos. I would not even make editorial changes
16:49:29 <nigel> .. like adding an informative annex. That would go a lot further than a typo change.
16:49:35 <nigel> .. It involves thinking about content a lot more.
16:49:49 <nigel> .. I would prefer to limit our changes to fixing links, typos and that sort of thing.
16:50:04 <nigel> .. Putting in even an informative annex does require us to think about whether it is correct or not.
16:50:13 <nigel> .. Sorry I have to leave now. [leaves]
16:51:11 <nigel> Pierre: I had not realised that we are still pending, because 2nd Ed has not been published and neither has IMSC.
16:51:26 <nigel> .. My reaction is that, looking at the commit log, there are commits well after TPAC. Some of them are really substantive.
16:51:34 <nigel> s/ve/al
16:51:54 <nigel> .. It seems arbitrary to reject this change but accept everything else. We really have to have a plan. We can't just
16:52:10 <nigel> .. arbitrarily say we won't accept a substantial change now but we accepted a bunch of other stuff after TPAC.
16:54:29 <nigel> Nigel: All the open issues on TTML2 have a 3ED milestone
16:55:11 <nigel> Pierre: On 1119 it was given that milestone on 21st Sep
16:56:01 <nigel> .. I think it would make sense to make no further changes for now but we may need to make changes in response to
16:56:04 <nigel> .. review comments.
16:56:29 <nigel> .. We need a plan.
16:56:41 <nigel> Nigel: There was an action on Atsushi to make a publication plan but I don't think I've seen that.
16:56:51 <nigel> Pierre: Thierry put something on the reflector.
16:57:01 <nigel> Nigel: Did he? I have not caught up with that.
16:57:26 <nigel> Pierre: We should come up with a plan - right now we can't say anything to Dave Kneeland.
16:57:28 <nigel> Nigel: That's true.
17:01:24 <nigel> Nigel: I agree we seem to have some kind of impasse at the moment and need to be able to make progress.
17:01:41 <nigel> Topic: Meeting close
17:02:02 <nigel> Nigel: Thanks everyone, meet again same time next week. I will be joining from an unusual location so hopefully I will
17:02:14 <nigel> .. not have any connectivity issues. [adjourns meeting]
17:02:31 <nigel> rrsagent, make log public
17:02:35 <nigel> rrsagent, make minutes
17:02:35 <RRSAgent> I have made the request to generate https://www.w3.org/2019/11/14-tt-minutes.html nigel
17:04:01 <nigel> s/RRSAgent: pointer//
17:04:33 <nigel> Meeting: Timed Text Working Group Teleconference
17:04:36 <nigel> rrsagent, make minutes
17:04:36 <RRSAgent> I have made the request to generate https://www.w3.org/2019/11/14-tt-minutes.html nigel
17:05:36 <nigel> scribeOption: -final -noEmbedDiagnostics
17:05:39 <nigel> rrsagent, make minutes v2
17:05:39 <RRSAgent> I have made the request to generate https://www.w3.org/2019/11/14-tt-minutes.html nigel
17:12:27 <nigel> s|scribeOption: -final -noEmbedDiagnostics||
17:12:33 <nigel> scribeOptions: -final -noEmbedDiagnostics
17:12:44 <nigel> rrsagent, make minutes v2
17:12:44 <RRSAgent> I have made the request to generate https://www.w3.org/2019/11/14-tt-minutes.html nigel
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