{Minutes} TTWG Meeting 2020-05-21

Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2020/05/21-tt-minutes.html


In text format:

   [1]W3C

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


                Timed Text Working Group Teleconference

21 May 2020

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

      [2] https://www.w3.org/2020/05/14-tt-minutes.html

      [3] https://www.w3.org/2020/05/21-tt-irc

      [4] https://www.w3.org/2020/05/21-tt-irc


Attendees

   Present
          Atsushi, Cyril, Gary, Nigel, Pierre

   Regrets
          Andreas

   Chair
          Gary, Nigel

   Scribe
          nigel

Contents

    1. [5]This meeting
    2. [6]IMSC 1.2 Introduction
    3. [7]IMSC 1.2 PR
    4. [8]TTML Profile Registry - addition of RTP profile short
       code
    5. [9]TTML2 2nd Edition Implementation Report
    6. [10]IMSC ARIB issues
    7. [11][WR/ARIB] Character Sets w3c/imsc#544
    8. [12][WR/ARIB] (meta) Compatibility with ARIB-TTML
       w3c/imsc#545
    9. [13]IMSC 1.2 PR (continued)
   10. [14]Meeting close
   11. [15]Summary of resolutions

Meeting minutes

  This meeting

   Nigel: Agenda today: IMSC 1.2 intro, ARIB issues, TTML2 IR,
   TTML Profile Registry.
   … AOB? Or points to make sure we get to?

   group: [no other business]

   Nigel: I propose we cover the ARIB topics last if that's ok

   Pierre: I think the priority should be to close all the issues
   on IMSC. I'm not really
   … ready to talk about the ARIB topics but we can go over them
   if we have time.

  IMSC 1.2 Introduction

   github: [16]https://github.com/w3c/imsc/pull/552


     [16] https://github.com/w3c/imsc/pull/552


   Nigel: It feels like what's there now is probably good enough,
   though I think the main
   … remaining comments are from me.

   Pierre: I want to make sure that Atsushi's comment got
   resolved.

   Nigel: Atushi's comment was about the Unicode text wording.

   Atsushi: I assume this part wants to mention that this
   specification should mention that
   … Unicode code points should be used in the encoding but not
   anything else.

   Pierre: To answer that, Unicode is being used maybe not very
   formally here. To the casual
   … reader Unicode text means something.

   Atsushi: I think I should point to some reference here but
   sorry I haven't. I'm curious about
   … using the word "encoding" here.
   … The actual definition is "code point" in Unicode.

   Nigel: Is there something misleading about the current wording
   "encoded according to the Unicode standard"?

   Atsushi: 3 encodings are defined. Encoding is a transformation
   from code point identifier to byte stream.
   … PUA has no meaning in encoding, it's within a code point of
   Unicode.

   Nigel: PUA is not mentioned, it's something that is understood
   by experts.

   <atsushi> > The Unicode Standard defines codes for characters
   used in all the major languages written today.

   Atsushi: [proposes to say that the document consists of Unicode
   code points]

   Pierre: That's fine by me

   Nigel: Is PUA included in that set?

   Atsushi: Included.
   … PUA is defined by each party, not standardised with a match
   between character and code point.

   Pierre: I would be really happy to see the exact proposal on
   the ticket, because that
   … would also allow @vlevantovski to comment. Could I ask you to
   make a proposal in
   … the pull request for the exact text? That would be great.

   Atsushi: Let me do that now.

   Nigel: While Atsushi is doing that, I think it's safe to
   mention that my comments that
   … are still outstanding (thank you for addressing the others),
   are all about adding an
   … example. I think what we have already is good enough, and a
   clear improvement,
   … and crucially, satisfies the APA WG issue, so the best thing
   seems to me to be to
   … move addition of an example to a new issue, and I should try
   to prepare a pull request

   <atsushi> timed text is expressed exclusively using code for
   characters defined in [[[Unicode]]] (just put into github PR)

   Nigel: for that separately. It would be great to do it before
   IMSC 1.2 PR, but not essential.
   … In other words, it could go to a next version.

   Pierre: Atsushi's change is fine with me.

   <atsushi> [17]https://glyphwiki.org/wiki/u3110


     [17] https://glyphwiki.org/wiki/u3110


   Nigel: I might have used "character codes"

   Pierre: Or "code points"

   Atsushi: This U+3110 is a code point defined by Unicode.
   … 3110 is the code point, and this will be transformed into
   several formed, like in UTF
   … it will be 3 bytes.

   Pierre: Understood. How about my proposal "using code points
   defined in Unicode"

   Atsushi: Should be fine also.

   Pierre: I will make the change now.
   … I just want to point out that because the only representation
   is UTF-8 it is true
   … that the only representation is Unicode, right, but you're
   saying that is too specific?
   … In other words it is not wrong to say it is encoded according
   to Unicode.

   Atsushi: I actually wondered if people would think other
   encodings would be valid
   … like UTF-16, which is a Unicode encoding.

   Pierre: Right, and it's forbidden in IMSC.

   Atsushi: I just wanted to be clear about that.

   Pierre: [makes the change]
   … Nigel, you will resolve your review comment and open a new
   issue?

   Nigel: Yes.

   Pierre: Then we can close this after our usual 2 week period.

   Nigel: Yes.
   … Any other comments on the introduction text before we move
   on?

   SUMMARY: @nigelmegitt to open new issue for example, normal PR
   review to continue.

  IMSC 1.2 PR

   Pierre: What's our target for seeking transition to PR?

   <atsushi> [18]https://www.w3.org/AudioVideo/TT/wip/

   TTWG-2019-spec-timeline.html

     [18] https://www.w3.org/AudioVideo/TT/wip/TTWG-2019-spec-timeline.html


   Nigel: I think we deal with all the review comments and then
   CfC transition to PR.
   … I'm not aware of any other dependencies.

   Pierre: So we could start the CfC based on pull #552?
   … I would encourage that.

   Atsushi: The Implementation Report is finished I think?

   Nigel: Yes

   Atsushi: Then it might be okay to begin the call for consensus
   within this working group.
   … If there are no other remaining issues for this spec.

   Nigel: The only way this is going to work is if we decide to
   make no changes based on
   … the ARIB comments.

   Pierre: We can wait until the end of the meeting.

  TTML Profile Registry - addition of RTP profile short code

   github: [19]https://github.com/w3c/tt-profile-registry/issues/

   72

     [19] https://github.com/w3c/tt-profile-registry/issues/72


   Nigel: I prepared a pull request for this, #73
   … Just wanted to check if anyone has any comments or might have
   an objection.
   … Otherwise we can do the 2 week review as normal.
   … If anyone can have a look at the pull request and approve it,
   that would be very
   … helpful for merging.
   … Any objections?

   group: no objections

   Resolution: Proceed with this pull request under normal 2 week
   TTWG procedure

  TTML2 2nd Edition Implementation Report

   Cyril: I did a verification.
   … I compared the number of files in the repo vs the number in
   the JSON file.
   … Just focusing on the 2nd Ed the numbers are the same so we
   should be good.
   … They're different for non-2nd Ed but I don't think it's a
   concern.
   … For more details, we have 57 files for validation and 14 for
   presentation.
   … The total is 71 and that's the number in the IR. I will check
   that they're the right ones too.
   … I added the 4th section for invalid presentation tests.

   Nigel: Great, this is good enough for me to add the
   implementation that I'm aware of.
   … I will do that.
   … We should assume this is now the correct set and obviously if
   anyone finds any errors
   … please fix them.
   … Now we need to register implementations and verify that we
   have enough to pass
   … CR exit criteria.
   … Any other actions/comments/questions on this?

   group: [no]

  IMSC ARIB issues

   Nigel: I went through these and I think Pierre did too.
   … The only one that might result in a change I think is the
   character sets for "ja" language code.

   Pierre: Yes, that's an easy one. Whether or not we do it now,
   at this 11th hour, I'd rather
   … not but it's an easy and a good addition.

  [WR/ARIB] Character Sets w3c/imsc#544

   github: [20]https://github.com/w3c/imsc/issues/544


     [20] https://github.com/w3c/imsc/issues/544


   Nigel: I think the first question to ask is if this is
   normative/substantive.

   Pierre: We should try to avoid making substantial changes this
   far into the process, but
   … we could formally because it is only informative.

   Pierre: That section, regardless of the normative language
   around it, is meant to inform

   <cyril> " this section defines common character sets that
   authors are encouraged to use."

   Pierre: implementations. You could conclude that it affects
   implementations.

   Cyril: "encouraged to use"

   Pierre: And the W3C Process definition.

   [21]Process 6.2.5 Classes of Changes

     [21] https://www.w3.org/2019/Process-20190301/#correction-classes


   Pierre: Section 8.2 says a document "SHOULD be authored using
   characters from" the common character sets.

   Cyril: There's a relationship between the reference fonts and
   the common character sets, right?

   Pierre: Also
   … I think we should deal with these ARIB comments in the next
   version of IMSC otherwise
   … we may make mistakes.

   Nigel: Back to Cyril's point, there does seem to be a
   substantive relationship between
   … reference fonts and the common character sets and the §9.3
   text on rendering rules.
   … So it looks as though changing the common characters changes
   the code points in the
   … reference fonts and therefore the rendering rules.
   … (sorry that 9.3 is assuming the introduction is added,
   otherwise it's 8.3)

   Nigel: My conclusion is we cannot make this change now but
   should add it to vNext
   … with appropriate care about reference fonts, and checking
   that the code points are
   … indeed all available.
   … Any other points to add before I summarise?

   Pierre: I think that the idea of converging ARIB-TTML and IMSC
   is really a great goal,
   … and we should take the time to do it in collaboration with
   ARIB. I see that as a pretty
   … extensive but worthwhile effort.

   SUMMARY: TTWG would like to adopt this change in a future
   version of IMSC.

  [WR/ARIB] (meta) Compatibility with ARIB-TTML w3c/imsc#545

   github: [22]https://github.com/w3c/imsc/issues/545


     [22] https://github.com/w3c/imsc/issues/545


   Nigel: These 5 issues mainly don't need change right now but
   they do need discussion.
   … I don't think we can make any changes to IMSC 1.2 for them
   but we can consider
   … and discuss changes for future versions, if needed.
   … It's also worth noting that some of the ARIB-TTML features
   look like they are coincident
   … with either existing IMSC 1.2 features or TTML2 features.
   That is why further
   … discussion with ARIB would be very useful, to understand the
   best path forward for
   … all parties.

   Pierre: I think the devil is in the detail and we have to study
   each issue. I agree with Nigel's summary.

   Nigel: Any other comments?

   Cyril: To make sure I understand, you say we will defer to the
   next version but when
   … practically will we start talking about them?

   Pierre: I suggest agenda+ these for the next meeting, to start
   discussing it.

   Nigel: That works for me.

   Cyril: Fine for me also. I would suggest that at least for the
   PUA/Gaiji discussion we invite

   <atsushi> +1 for agree with Nigel's summary.

   Cyril: Vladimir.

   Pierre: Yes. At least on that one it is an intersection of many
   things - what is possible
   … with fonts, what ARIB thinks and what we think! A complex
   discussion.

   SUMMARY: TTWG raised this for discussion today, and would like
   to discuss the sub-issues in further detail in future meetings.

  IMSC 1.2 PR (continued)

   Nigel: We need a version with a PR SOTD.
   … Please could I ask you to prepare one on a separate branch,
   Pierre, based on the pull
   … request branch where we add an introduction.

   Pierre: Yes I will do.

   Nigel: Then I will issue the CfC based on that.

  Meeting close

   Nigel: Thank you everyone, we're out of time and agenda! See
   you next week. [adjourns meeting]

Summary of resolutions

    1. [23]Proceed with this pull request under normal 2 week TTWG
       procedure


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Received on Thursday, 21 May 2020 16:32:36 UTC