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: 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> 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> 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: 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: 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.
Process 6.2.5 Classes of Changes
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: 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]