{Minutes} TTWG Meeting 2019-11-14

Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2019/11/14-tt-minutes.html

In text format:


      [1] https://www.w3.org/

                Timed Text Working Group Teleconference

14 November 2019

   [2]Agenda. [3]IRC log.

      [2] https://github.com/w3c/ttwg/issues/78

      [3] https://www.w3.org/2019/11/14-tt-irc


          Atsushi, Cyril, Glenn, Jeffrey_Yasskin, Nigel, Pierre





     * [4]Meeting minutes
         1. [5]This meeting
         2. [6]Improve anonymous span prose, clarify rule ordering
            (#1139). ttml2#1179
         3. [7]This meeting
         4. [8]TTML2 Privacy Review comments
         5. [9]Add non-normative Appendix to cover SDR
            compositing. ttml2#1119
         6. [10]TTML2 status - content freeze?
         7. [11]Meeting close

Meeting minutes

   Log: [12]https://www.w3.org/2019/11/14-tt-irc

     [12] https://www.w3.org/2019/11/14-tt-irc

This meeting

   Nigel: Glenn requested an additional agenda topic

   Glenn: Its a quick follow-up to last week

   Nigel: We also have the privacy review for TTML2 to deal with

Improve anonymous span prose, clarify rule ordering (#1139).

   github: [13]https://github.com/w3c/ttml2/pull/1179

     [13] https://github.com/w3c/ttml2/pull/1179

   Glenn: Final tweak awaiting approval from Pierre, when you can
   take a look at it.

   Pierre: Thanks

   Nigel: OK ping to Pierre completed!

This meeting

   Nigel: Any other business?

   Group: [no other business]

TTML2 Privacy Review comments

   Glenn: Quick comment: all those comments from Jeffrey look
   interesting. I took a quick pass at them.
   … My first comment is they don't apply to any of the changes in
   2nd Ed. They are potentially applicable to TTML2
   … in general but they apply to things that changed between
   TTML1 and TTML2 and not between TTML2 1st Ed and 2nd Ed
   … and in our HR we asked for review of changes to 2nd Ed.

   Jeffrey: Sorry for missing that.

   Glenn: I would propose that we don't deal with those in 2nd Ed
   changes, but would be happy to take them up in
   … 3rd Ed as improvements to Security and Privacy.

   Jeffrey: I think you don't have privacy considerations in most
   of these specs.
   … It seems useful to write some of this down.

   Nigel: I think we should entertain the idea of improving the
   privacy information in 2nd Ed.

   Glenn: I'm open to making the changes and understand they're
   useful, but technically they don't apply to the changes
   … between 1st and 2nd Ed.

   Jeffrey: I'm personally happy to have them as open issues to
   address later.
   … Not sure about PING as a whole.

   [14]TTML2 Appendix P Security and Privacy Considerations

     [14] https://w3c.github.io/ttml2/index.html#security-and-privacy

   Cyril: Question - I didn't have a chance to review the
   comments. How many are there?

   Jeffrey: 2 pages, not very severe, worth mentioning but no
   substantive changes.

   Cyril: They would apply to TTML1, TTML2 and all the IMSC

   Jeffrey: I looked at 3 or 4 specifications. TTML would probably
   apply to all of the versions.
   … There are also some comments on the TT Live stuff.

   Glenn: From my brief reading most are the sort that would apply
   to browser technologies that embed some form of
   … support for TTML content.

   Jeffrey: Right

   Glenn: TTML is defined as a content format, with processing
   semantics, but it doesn't define fetching semantics for example
   … or what the outer environment of a browser does in that
   context. Much of the things that would apply in the context
   … of user preferences or things that would expose potential
   privacy matters are to do with the user agent and
   … technically outside the scope as defined in the TTML
   … We might make statements like "In the context of a UA a TTML
   processor should take into account these potential privacy

   Jeffrey: I think I agree

   Cyril: How much would apply to WebVTT?

   Jeffrey: I don't know, there may have been more review because
   of browser implementation

   Cyril: Reason for asking is we could make a separate note and
   then refer to it

   Jeffrey: That's plausible.
   … The only stuff in TTML is potential fingerprinting which is
   only a thing if natively implemented so it
   … applies more to WebVTT than TTML in the current world.

   Pierre: I think it would be useful to have a paragraph about
   … Any objections to having a paragraph in 2nd Ed if someone
   writes it?

   Glenn: I would really like to avoid putting new material in
   TTML2 at this point, by preference.
   … Unless its typos my thinking is we shouldn't make a change.

   Pierre: I don't disagree with that.

   Cyril: Do we need to review them one by one now?

   Nigel: Maybe not

   Jeffrey: I'm happy to raise issues for discussion. It's
   possible I've got some of them wrong.
   … The next step for TTML is to file a GitHub issue?

   Nigel: Yes please and thank you very much for doing this.

   Jeffrey: Can we talk about the TTML Live comments. Two things
   in there maybe more important than fingerprinting.

   Nigel: Please go ahead.

   Jeffrey: In the TT Live document in general I was worried that
   a naive implementation might put a subtitler's name
   … in an identifier that would leak. A good implementation
   should not do that.

   Nigel: That's implementation dependent.
   … It certainly would be worth advising distribution encoder
   implementers to sanitise the output.

   Jeffrey: That would make sense.

   Pierre: Question - in the case of accessibility, the specs that
   have checklists for conformance, a lot of accessibility
   … criteria apply across the board. Has there been similar
   thought about privacy?

   Jeffrey: Yes the TAG maintains a privacy and security
   questionnaire. It's not rule based like the accessibility
   … 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
   … be a UA thing.

   Pierre: "Don't distribute personal information to consumers" is
   a general requirement across the board and should not
   … need repeating everywhere.

   Jeffrey: Right, my thought was that TTML might have personal
   information in specific fields if naively implemented
   … so it would be worth calling those out.

   Pierre: Understood - if there's specific data. It would be
   great to include those in a checklist.

   Gary: I wanted to mention about WebVTT, it sounds like it has
   had some of this review. It has a sec and privacy
   … section in the spec that says downloading captions is a user
   preference but it is not a problem of the caption spec
   … itself but how you deliver it. WebVTT right now is fairly
   tied to HTML so the privacy preference is more tied to HTML
   … because you generally, if you just have a caption file
   implementing the WebVTT spec then that doesn't by itself
   … become a privacy information. But on a web page and you
   select to load the Japanese captions that could potentially
   … leak information.
   … Sounds like having a shared document is a good idea because
   I'm certain there's overlap there.

   Nigel: Sounds like a really good thing to work towards.

   Jeffrey: The last thing is in the WebSocket document you use
   ws:// and you should probably use wss:// in most places.

   Nigel: Yes

   Jeffrey: There's an example about how to build the URLs for the
   request and one says to put the sequence id in the
   … domain name which potentially exposes it to the DNS which is
   probably not right if the sequence id might have a
   … personal information in it.

   Nigel: Thanks for raising that, I hadn't considered it. It's
   feasible to put someone's name in a sequence identifier but
   … not something I expect everyone would do.
   … I'm happy to add some text advising people not to do that.

   Glenn: You've done an amazing job in a short time Jeffrey, I
   applaud you! The specs are complex.

   Nigel: To summarise this,
   … Jeffrey will raise some GitHub issues,
   … we will look at creating a single document with privacy
   issues relating to timed text document formats,
   … and may make some TTML2 3rd Edition changes to add pointers
   to that, or make other privacy section changes.
   … And finally thank you again to Jeffrey and PING for this
   … Anything else to cover on the privacy review?

   Jeffrey: Thank you for your time. [leaves]

Add non-normative Appendix to cover SDR compositing. ttml2#1119

   github: [15]https://github.com/w3c/ttml2/issues/1119

     [15] https://github.com/w3c/ttml2/issues/1119

   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
   … no change to the primaries? Do we need to worry about number

   Pierre: I don't think we need to worry about number ranges,
   because both 709 and sRGB are relative luminance systems
   … so I think we can use the full range. Both 709 quantisation
   schemes are in use. We don't need to cover narrow range
   … 709 - this example covers full range 709.
   … Full range 709 is used in practice.

   Nigel: Thanks for that.

   Pierre: It depends on the application.

   Nigel: Great, so as long as it's clear that we're talking about
   full range 709 we're ok

   Pierre: Yes, we should change the title to avoid people getting

   Nigel: And those gammas are uncontroversial?

   Pierre: As far as I know, yes. If you don't apply this
   conversion then colours won't match in practice.

   Nigel: OK so the change essentially looks good, then the
   question moves to when we should implement it, should we
   … attempt to shoehorn it into TTML2 2nd Ed or wait until 3rd
   … I note that this is an informative section.

   Glenn: There's a bigger question that Pierre asked which is
   have we stopped making changes to 2nd Ed other than
   … typos basically, which is more general than this particular
   issue. I think we should ask the group to make a decision
   … on this.

   SUMMARY: TTWG Thanks @dkneeland for this contribution, and is
   considering when it can be added to the specification, within
   TTWG publication timelines.

TTML2 status - content freeze?

   Nigel: I thought we agreed at TPAC that we would proceed
   towards TTML2 2nd Ed publication as quickly as possible
   … and make minimal changes.
   … The only thing that perhaps could lead me to reconsider that
   would be if the Charter delay and Process issue
   … raised by Thierry means we are in an enforced hiatus, in
   which case we may as well allow further improvements.

   Atushi: Philippe has been out of action this week.

   Glenn: My opinion is not to make any changes other than fixing
   typos. I would not even make editorial changes
   … like adding an informative annex. That would go a lot further
   than a typo change.
   … It involves thinking about content a lot more.
   … I would prefer to limit our changes to fixing links, typos
   and that sort of thing.
   … Putting in even an informative annex does require us to think
   about whether it is correct or not.
   … Sorry I have to leave now. [leaves]

   Pierre: I had not realised that we are still pending, because
   2nd Ed has not been published and neither has IMSC.
   … My reaction is that, looking at the commit log, there are
   commits well after TPAC. Some of them are really substantial.
   … It seems arbitrary to reject this change but accept
   everything else. We really have to have a plan. We can't just
   … arbitrarily say we won't accept a substantial change now but
   we accepted a bunch of other stuff after TPAC.

   Nigel: All the open issues on TTML2 have a 3ED milestone

   Pierre: On 1119 it was given that milestone on 21st Sep
   … I think it would make sense to make no further changes for
   now but we may need to make changes in response to
   … review comments.
   … We need a plan.

   Nigel: There was an action on Atsushi to make a publication
   plan but I don't think I've seen that.

   Pierre: Thierry put something on the reflector.

   Nigel: Did he? I have not caught up with that.

   Pierre: We should come up with a plan - right now we can't say
   anything to Dave Kneeland.

   Nigel: That's true.

   Nigel: I agree we seem to have some kind of impasse at the
   moment and need to be able to make progress.

Meeting close

   Nigel: Thanks everyone, meet again same time next week. I will
   be joining from an unusual location so hopefully I will
   … not have any connectivity issues. [adjourns meeting]

    Minutes manually created (not a transcript), formatted by
    Bert Bos's [16]scribe.perl version Mon Apr 15 13:11:59 2019
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     [16] https://w3c.github.io/scribe2/scribedoc.html

     [17] https://dev.w3.org/2002/scribe/scribedoc.htm

     [18] https://github.com/w3c/scribe2/commits/master/scribe.perl

Received on Thursday, 14 November 2019 17:14:08 UTC