{Minutes} TTWG meeting 2020-04-30

Thanks all for attending today's TTWG Meeting. Minutes can be found in HTML format at https://www.w3.org/2020/04/30-tt-minutes.html


In text format:

   [1]W3C

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


                Timed Text Working Group Teleconference

30 April 2020

   [2]Previous meeting. [3]Agenda. [4]IRC log.

      [2] https://www.w3.org/2020/04/23-tt-minutes.html

      [3] https://github.com/w3c/ttwg/issues/109

      [4] https://www.w3.org/2020/04/30-tt-irc


Attendees

   Present
          Atsushi, Cyril, Gary, Nigel

   Regrets
          Andreas, Pierre

   Chair
          Gary, Nigel

   Scribe
          nigel

Contents

    1. [5]This meeting
    2. [6]IMSC 1.2 - ARIB liaison
    3. [7]IMSC /rec
    4. [8]WebVTT: over-specification in Conformance: Unicode
       normalization w3c/webvtt#483
    5. [9]TTML2 2nd Edition Implementation Report
    6. [10]AOB - TPAC 2020 planning
    7. [11]Meeting close

Meeting minutes

  This meeting

   Gary: Today we have a couple of IMSC topics, specifically more
   discussion about the
   … ARIB liaison, something about IMSC /rec.
   … A question for WebVTT around Unicode normalisation.
   … Some TTML2 2nd Ed IR updates, and then more TPAC planning
   maybe.
   … Any other business?

   group: [no other business]

  IMSC 1.2 - ARIB liaison

   Nigel: Not sure if we can cover the IMSC ARIB liaison topic
   today, actually.

   Atsushi: I can write a private email to get more information.

   Nigel: Thank you that would be great, also to remove any
   potential language issues from
   … being a problem. Thank you.

  IMSC /rec

   Atsushi: For information, the in-place republishing has
   finished,
   … so there are updated links in the Rec publications for 1.0.1
   and 1.1.

   Nigel: Thank you for that. I'll remove this from the agenda
   now!

  WebVTT: over-specification in Conformance: Unicode normalization
  w3c/webvtt#483

   github: [12]https://github.com/w3c/webvtt/issues/483


     [12] https://github.com/w3c/webvtt/issues/483


   Gary: This issue came from the i18n working group, about
   Unicode normalisation.
   … WebVTT specifically disallows this, and says to compare the
   bytes directly.
   … The issue raised is that it is not what we want, potentially.
   … I don't have much knowledge personally of why you would want
   or not want to do it.
   … From digging around in the history, it sounds like it was
   mostly to make sure that
   … things that are required in WebVTT are easy to identify like
   the arrow in the time
   … signature so that we aren't matching normalised Unicode and
   can find it more easily.
   … I want to ask if anyone had more knowledge about it, or if
   TTML or IMSC handle
   … Unicode normalisation.

   Nigel: I think in TTML it is delegated to XML so whatever XML
   says, which we assume is
   … the correct thing, is what happens.

   Gary: Yes. It's relevant that WebVTT is not XML but a text
   format with markup.
   … David Singer said that for the text of the cues we could do
   normalisation, but even that
   … might be a bit more complicated because HTML tags are allowed
   to be used.

   Nigel: Also what about metadata payload in the cues?
   … For example if it is JSON, does that specify Unicode
   normalisation? I do not know.

   <atsushi> [13]https://infra.spec.whatwg.org/#json


     [13] https://infra.spec.whatwg.org/#json


   Atsushi: In JSON I believe that it depends on the processor for
   values

   <gkatsev> [14]json specification

     [14] https://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf


   Gary: The spec is quite small and just says it is a sequence of
   Unicode code points.

   Atsushi: I think currently in WebVTT, case sensitive
   non-normalised matching is defined.

   Nigel: The issue is that it is _not_ using that.

   Atsushi: I think the linked document was written after work on
   WebVTT began.
   … The standard operation was written after WebVTT so maybe even
   if the result is the same
   … but some text is over-specified in the current standard.

   Cyril: A different angle: do we have tests for this in WPT?

   Gary: For Unicode normalisation?

   Cyril: Yes, to match the MUST NOT in the spec.

   Gary: I'm not sure

   Nigel: Are you thinking about if we can establish what
   implementations do now via the tests?

   Cyril: Yes

   Gary: From a quick look I'm not seeing anything specific to
   Unicode.

   Nigel: I'm a bit confused about where the line is drawn between
   parsing the WebVTT
   … document e.g. during processing, cue matching etc. and text
   presentation.
   … If some payload text is passed onto a text renderer and
   there's a step that does
   … normalise the text, is that broken, according to the spec
   text in §2.2?

   Gary: The example is about cue matching, which is very
   specific.

   Nigel: Is "processing" a defined term?

   Gary: It could refer to the "processing model" part of the
   spec.
   … That would make sense because that's when you would be
   applying styling and whatnot.

   Atsushi: I am not sure that there is any case that is not
   covered by "case sensitive non-normalising"
   … if there is no such case then I suppose it may be possible to
   write it into the standard
   … in a simpler way.

   Gary: You mean to link to the charmod-norm spec to the section
   that matches what
   … we want to do in WebVTT?

   Atsushi: Actually the character model normalisation is not a
   Rec track doc but a WG note
   … so it cannot be normative. You would need to copy and paste
   the spec text.
   … Recently there are several standards that say this kind of
   thing so having this kind of
   … spec may be easier for readers and may not have some strange
   cases.
   … The last point of the issue comment is for character
   encoding, but I'm not sure if we need
   … to have this strong restriction for later processing by
   scripts or web browser.

   [not sure I got that very well]

   Gary: You mean from cue text?

   Atsushi: Yes

   Nigel: Does the requirement that WebVTT is always UTF-8 make
   some of the concern
   … disappear here?

   Atsushi: I need to think about that more.
   … At this moment I don't see any difference between the
   suggestion and the current
   … spec text and description.

   Nigel: Not sure how we move to a resolution on this. Gary?

   Gary: I think I need to read up on the charmod-norm first and
   it would be good to get
   … clarification on how WebVTT being specified as UTF-8
   affects/does not affect things.
   … It does sound like it might be okay to change how we handle
   the cue text normalisation
   … but we likely don't want to do that for other parts of
   WebVTT.

   SUMMARY: Investigation of impact to continue.

  TTML2 2nd Edition Implementation Report

   Nigel: For the IR I think, unless there's an update, we still
   need to update the IR page
   … to reflect the full set of TTML2 2nd Edition tests.

   Cyril: yes, still need to do that.
   … Did we merge all the test PRs?

   Nigel: I see 2 open pull requests to add tests.

   Cyril: #252 is not approved yet. Nigel and I commented on it.
   … #235 is not approved, only a comment from Nigel.

   Nigel: Aargh I forgot to review Glenn's commit on #252 that he
   says addressed my comments.
   … On #235 there's an outstanding comment that hasn't been
   addressed.

   <nigel> s/253/235

   Nigel: Looks like we need to do those first.

   Cyril: What's the outcome. Should we wait until we merge those
   pull requests?

   Nigel: They're likely to be fixed and merged.

   Cyril: I can consider them merged for the purpose of mentioning
   them in the IR

   Nigel: I think that's pretty safe.

   Cyril: Then I'll do that.
   … Then is this the end, can we give implementations a prompt to
   start filling their parts.

   Nigel: I believe so.

   Cyril: I will try to update the Netflix column.
   … As I said last time I don't expect that we will pass many of
   the tests because most of
   … them are features that we're not interested in.

   Nigel: On the topic of implementations I just updated our
   Adhere audio description
   … implementation, which is at [15]https://bbc.github.io/Adhere/

   so you can try it out if you like.
   … It includes the TTML2 audio-in-body test which I believe
   passes.

     [15] https://bbc.github.io/Adhere/


  AOB - TPAC 2020 planning

   github: [16]https://github.com/w3c/ttwg/issues/112


     [16] https://github.com/w3c/ttwg/issues/112


   Nigel: On the time-per-session question, we sometimes go to 2
   hours here, but I always
   … force a break in the middle.

   Gary: Yeah, longer than 2 hours is too much.

   Nigel: We discussed hallway conversations, any more progress on
   that?

   Gary: A comment from last time is to have a "hallway track"
   session open all the time,
   … not tied to a working group.

   Nigel: That's a good idea. I've seen breakout rooms used on
   Zoom, but only where there
   … is a central person creating them and sending people to them.
   … I don't know if they can be used in an ad hoc way.

   Gary: Yes it's easier on zoom, I don't know if anyone can do it
   if the permissions can be setup that way.

  Meeting close

   Nigel: Let's adjourn for today. Thanks everyone. [adjourns
   meeting]

   <nigel> s|s/253/235||


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