Meeting minutes
This meeting
Nigel: Today we have some IMSC 1.2 FPWD Next steps, IMSC 1.1 Errata.
… AOB includes the rejoining, if there are any questions about that,
… and next meeting on Jan 9th.
… Any other agenda points?
group: [no other agenda points]
IMSC 1.2 FPWD Next Steps
Request WR for IMSC 1.2 ttwg#87
Nigel: I'm behind on this. I had hoped to get it done earlier today, but haven't managed to.
… Practically speaking the difference between sending tomorrow or at beginning of Jan is minor, but I will do it as soon
… as I can make the time. Apologies for the delay.
… Moving towards IMSC 1.2 issues.
… Last week we made some resolutions to issues Glenn raised, in his absence. Any points to raise there?
Glenn: No, no input.
Nigel: Thanks
Potential semantic conflict between ttp:profile and ttp:contentProfiles. imsc#506
github: https://github.com/w3c/imsc/issues/506
Nigel: The proposal from last week was:
… Add a normative SHOULD statement to TTML2: The set of features that may be present in the document should all be in the set of features supported by the processor, or generate a warning.
… This is a proposed requirement for a validator, based on mismatches between the effective content profile and the
… effective processor profile.
… If we agree to this proposal then we will move the issue to the TTML2 repo.
Glenn: It's semantically inconsistent with the definition of processor profiles because only features that the processor
… profile designates to be required elicits an abort... [thinking out loud]
… It might never produce a warning. I need to think about it a little more.
… Offhand that doesn't sound semantically consistent with the current semantics but I'll give it a once-over offline.
Nigel: Thank you
SUMMARY: @skynavga to consider the proposal further
IMSC 1.1 Errata
Nigel: We have 4 errata proposed, to iterate through.
… Has everyone followed that there is a new errata publication process.
Pierre: I've looked into it a little bit.
Nigel: The document describes the process at the top.
… Essentially we label errata issues with Errata on GitHub, and Editorial if it is editorial, and the document version, and
… the errata page will be updated automatically.
Glenn: Will it harvest PR data or issue data?
Nigel: I think it is the text of the issue itself.
Glenn: Sounds like magic!
#extent-root implies support for #extent-auto imsc#489
github: https://github.com/w3c/imsc/issues/489
Pierre: I copied the text from IMSC 1.2 which we had agreed to.
Cyril: I'm trying to understand what it means - is it specifying format if a value is specified or is it requiring a value?
Pierre: "specified value" has a defined meaning in TTML
Cyril: I understand, I'm asking if the attribute is required on the element or not?
Pierre: The only way to have a specified value is if it is specified.
Cyril: Sure, but this text doesn't say what happens if it is not specified.
Pierre: If the author does not specify a value then the specified value is undefined, so it cannot be.
Cyril: It does not exist...
Pierre: Exactly, so it cannot be a length expression, therefore it implies it is required.
… The implication is the only way to satisfy the constraint is to include the attribute.
… We should fix this in IMSC 1.2 and then port it back.
Nigel: We can agree the words here and do it here and in IMSC 1.2.
Pierre: Absolutely. We can hold off making this change now and come back to it next meeting in case there is a better idea.
Nigel: Simple wording change - add "is required to be present"
Pierre: Folk weren't happy with that previously on the thread.
Nigel: I don't see that here - Glenn's comment on 10th Oct included it for example.
Pierre: I'll point to the IMSC 1.2 issue that was closed on this.
… It is #475
… It's a long thread. Suggest Cyril reopens the issue and adds the suggestion.
Cyril: Ok will do.
SUMMARY: Reconsider the wording for this in conjunction with IMSC 1.2 #475 and come up with something all are happy with.
Pierre: Remember we have to be careful about `<set>`, initial value etc.
… Specify does not necessarily mean it is on the element itself, which is why "is present" is not awesome.
Cyril: Being consistent with oneself is difficult!
Pierre: Thankfully we have GitHub to remind ourselves.
Nigel: We've toyed with trying to work "computed" in here in the past too.
Pierre: Yes, and the reason it was open is that style properties can be specified using child style elements, which is
… the equivalent of specifying the style property on the element itself.
… There are many ways for something to be considered specified.
Nigel: I think we're talking about the value of the attribute in the specified style set for the region element, following
… the style resolution process.
Pierre: That term in TTML2 is "specified style"
… What I'm saying is "shall be present" is not right because it excludes the example that Cyril raised in #475.
Nigel: In TTML2 terminology section "specified style set" is defined but not "specified style". It may be elsewhere.
<cyril> https://developer.mozilla.org/en-US/docs/Web/CSS/specified_value
Cyril: It's an XML term?
Glenn: I would avoid using CSS terminology.
Pierre: 10.4.3.1 in TTML2
TTML2 10.4.3.1 Specified Values
Cyril: Ok can we link to that?
… I will change my comment.
Pierre: It is actually already there in IMSC 1.2 - specified value already says that under #extent-region.
… Your wish has already come through.
Cyril: Apologies, I'll delete my comment and close the issue.
Pierre: Going back to IMSC 1.1 do we have to add this link?
Nigel: I think we should
Pierre: I will modify that then.
… [adds extra text to signify the meaning of "specified value"]
… done
Nigel: I see that "specified value" is now a link.
Pierre: Shall we approve this erratum?
Nigel: Any objections to approving this erratum?
group: [no objections]
Resolution: Approve this erratum as summarised at https://github.com/w3c/imsc/issues/489#issuecomment-562895235
Pierre: The text will be taken from the summary, I understand.
Errata to correct disposition of #bidi in IMSC 1.1 imsc#498
github: https://github.com/w3c/imsc/issues/498
Nigel: This is one where we're simply applying the disposition already agreed in #491 for IMSC 1.2
… Any objections to publishing this erratum?
group: [no objections]
Resolution: Publish this erratum as at https://github.com/w3c/imsc/issues/498#issuecomment-562895537
Errata on non-prohibition of partially supported features imsc#500
github: https://github.com/w3c/imsc/issues/500
Nigel: This is one we already added to IMSC 1.2, defining partial support for a feature.
… Any objections to proceeding with this erratum?
group: [no objections]
Resolution: Publish this erratum as at https://github.com/w3c/imsc/issues/500#issuecomment-562895784
Glenn: I would not say this helps readers but it does somewhat resolve the ambiguity.
Incompatible SMPTE ST 2052-1:2013 extension namespace name imsc#512
github: https://github.com/w3c/imsc/issues/512
Nigel: I did try to ping Mike Dolan about this but he did not respond (on this issue).
… I think this is super tricky to know what to do without input from SMPTE.
Pierre: The long term decision is tricky. IMSC has used the 2010 version from the beginning. In the short term the
… right thing to do for internal consistency in IMSC is to update the reference to 2010.
… For dealing with this in the longer term we need input from SMPTE.
Glenn: TTV did implement it as specified so we would have to go back and retrofit this change.
Pierre: I looked at TTV. For IMSC I think it still uses 2010. It does have a profile for SMPTE-TT 2013 but my reading of
… the code...
Glenn: Okay I did not go back to verify if the IMSC part uses the SMPTE-TT 2013 part for that namespace.
… You may be right.
Pierre: I didn't spend hours but my take is TTV supports 2010 and 2013 but IMSC uses 2010.
Glenn: I support the suggested change.
… I don't remember if this group ever consciously made the decision to use the 2013 namespace. Do you?
Pierre: We never discussed it. When we started IMSC SMPTE-TT was at 2010 so we used it.
… When we moved to IMSC 1.1 we tried to date all references but in our excitement we didn't check if 2013 was
… backward compatible with 2010, and it looks like it is not.
… We need SMPTE to tell us if that was intended or an error within SMPTE.
Glenn: I suspect it was something that wasn't checked.
Pierre: That's why I suggest we revert the reference to the dated 2010 version.
Glenn: I agree.
Resolution: Publish this erratum as at https://github.com/w3c/imsc/issues/512#issuecomment-562895873
Nigel: Just double checking there are no objections before closing this agenda topic?
group: [no objections]
Errata publishing
Nigel: We have 4 recorded errata showing up but none of them is actually listed.
Pierre: I will follow this up with Atsushi and Philippe.
Atsushi: Thank you, let me follow up on this.
Nigel: Thank you.
AOB: (Re-)join to timed text WG after charter renewal
Nigel: I've seen several members rejoining, so that seems to be working okay.
… Any other issues?
group: [none for now, amongst those present]
Nigel: If you have any difficulties please contact Atsushi or Philippe.
<atsushi> let me write one email to Glenn
Nigel: Also make sure your AC rep has nominated you to TTWG.
Next meeting 2020-01-09
Nigel: We will not have our regular call next week or the following week after that, so our next call
… will be on 9th January 2020.
… I want to take this moment to say thank you to everyone for all the work you've put in over the year,
… a lot has happened this year. For those having a break, enjoy it, and for those for whom it is new year, happy new year.
… See you all in January. [adjourns meeting]