W3C

Timed Text Working Group Teleconference

23 Feb 2017

See also: IRC log

Attendees

Present
Nigel, Andreas, Glenn, Mike, Pierre, Thierry
Regrets
Chair
Nigel
Scribe
nigel

Contents


<scribe> scribe: nigel

This meeting

Nigel: Today, we have IMSC version naming and liaison draft, and next WD publication.
... And there are lots of TTML2 things, which we should try to cover some of at least.
... Any other points to cover today or other business?

group: No AOB

IMSC

nigel: We have a proposal to use 1.1 instead of 1.0.1.
... Glenn earlier sent a formula for version numbering but did not cite any reference.

Glenn: That's correct, it is from my experience.

Nigel: Is there anyone who cannot live with the proposal to use IMSC 1.1?

Pierre: On the form of the name, 1.1 in my mind goes too far in terms of industry perception;
... I was happy with an alternative like "Second edition".
... From a function perspective it also raises the profile feature designators.
... I would also be happy with something else like "IMSC 1 Amendment 1" or "imsc1.0-am1" for example.
... For other SDOs that would convey the magnitude of the change.

Glenn: That terminology has not been used in W3C before.

Thierry: We do not have a clear policy in W3C - as long as plh agrees then it is quite open.
... It is up to the group.

Andreas: I think I wrote already on the reflector what Pierre mentioned - I am unhappy with 1.1
... because that would imply a change that does not reflect the difference. It would be viewed
... as a major revision, which it is not. I would also favour 1.0.1 but something else like
... amendment would work for me.

Glenn: I would be okay with calling it "amendment 1". I don't really like it but since there
... is no tradition I don't think will object to it.

Nigel: I am not sure about the objection to 1.0.1 since there is no prescribed rule that it breaks.
... I am also not sure about how "Amendment 1" would be considered since it sounds like
... an Edition.

Glenn: This certainly isn't an Edition in the traditional sense of W3C.

Nigel: I'm actually concerned about the nature of the objection itself since there is no documentary
... rule set that we are breaking.
... And I am also not happy with the impression that Amendment gives.

Thierry: There is no policy for this. We brought this name to Philippe a few weeks ago
... and, knowing the changes that go into the document, he agreed to it. That does not
... mean we cannot change it, but for W3C that's perfectly reasonable.

Glenn: An objection does not have to be based on a policy document.

Andreas: I think we have really good reasons for breaking tradition here and also we are
... showing we are flexible and fast in dealing with changes to requirements which is a good thing.
... So there is a good reason to do something different from what we did before.

Thierry: Right now we have 1.0.1 - could I suggest we publish the WDs using the same
... short name and take this to the Director on the transition to CR?

Pierre: I think what Thierry mentioned would be a path forwards - proceed as we are today
... and have the "Amendment 1" in our back pocket and deal with the objection at CR, knowing
... that we have this fallback.

Andreas: I don't have a big problem with Amendment 1, but I have seen it in MPEG specs -
... maybe we could understand how they use it?

Mike: There's no real versioning in ISO, it's only done by amendments, corrigenda and new
... editions, where new editions are a roll-up of everything that has happened in corrigenda
... and amendments, and versioning is only by year. It's a different model fundamentally.
... The numbers are designators for the standard.
... And they are informal anyway, they're not formally part of the title of the document.

Glenn: I have no problem with the holding pattern that Thierry presented.

Nigel: Okay let's do that then.
... Moving on to the liaison text I sent, were there any problems?

Glenn: You'd incorporated my comments about the version being possibly subject to change, so I was happy.

Nigel: Thanks for the reminder, yes there was some email back and forth which ended, so
... unless there are any other comments then I'm going to take the last version as being okay.
... Now for publishing a WD for WR, there's nothing more to be done is there?

Pierre: Correct there are no issues open and all the changes are merged.

-> https://github.com/w3c/imsc/issues/213

Pierre: Will this issue generate any significant changes?
... Do we just need to add a paragraph on the consequences for XML schema explaining that
... content from other namespaces are pruned before validation?

Mike: I raised this issue. I think it is clear that the intent is to allow foreign attributes and
... What's less clear to me is if foreign namespace elements are permitted and ยง12.1.1 is
... strongly suggestive that they are not permitted on any elements other than tt:metadata. However I think the world was of the view that elements are
... intended to be allowed anywhere. I think rather than going back and trying to enforce
... what may have been an intent 10 years ago it is probably better to clarify what we believe
... today. At least in IMSC 1 it would be helpful to clarify our collective understanding, that
... both attributes and elements in foreign namespace elements are allowed everywhere.
... Does anyone disagree with that understanding?

Glenn: I think it is vague in TTMl1 regarding whether the foreign namespace elements are
... pruned for other processing than validation processing. For validation it is clear they
... are to be ignored/pruned. However given the text on the tt:metadata element it is clear
... that for other kinds of processing they are to be retained. This is an ambiguity that needs
... to be addressed in TTML1 via an errata and in TTML2.

Mike: I don't disagree with that but from an expediency point of view I am inclined to let
... this lie in TTML1, and I would rather leave that alone and clarify it in IMSC 1 and fix it in TTML2.

Glenn: I think we could certainly craft an informative note under the section that describes the pruning
... process that says the pruning is for the purpose of validity assessment for the TTML1 spec
... only and does not necessarily apply to other kinds of processing or validity checking. That
... would not be a technical change.
... That would be in TTML1.

Mike: I don't have a problem with that but it is not sufficient to avoid the ambiguity in IMSC1.

Glenn: I would also put that into TTML2.

Nigel: Isn't the correct place to put this fix into TTML1?
... Regardless of whether or not we add a statement to IMSC 1 informatively, we should fix it in TTML1.

Mike: The specific technical issue is that only the metadata element explicitly permits
... foreign namespace elements.

Nigel: So explicitly permitting them in other elements would be a substantive technical change?

Mike: Right.

Pierre: The implementors of IMSC 1 are unlikely to reach the same conclusion without the
... full background. The question is can we do something in IMSC 1 that is helpful for
... implementors and that is consistent with our direction in TTML2 and hopefully in TTML1.

Andreas: What would the suggestion be Mike?

Mike: An informative note that says foreign namespace elements are permitted anywhere.

Nigel: And all tt namespace children of foreign namespace elements would be pruned for
... TTML presentation too?

Mike: Yes, if an element is pruned for validation it has to be pruned for presentation as well.

Glenn: +1

Mike: For something like smpte:image there is some confusion about if that is even permitted.

Glenn: Mike seems to be suggesting that we should be explicitly adding foreign namespace
... elements to the content model of each element in TTML1, but I do not think that is necessary.
... If it is not prohibited then it is permitted.
... There is a sticky issue that we tried to divorce validity from XML concrete syntax by
... referring to an abstract document instance, but then we define the permitted attributes
... and elements by using XML syntax in our documents. We tried to have our cake and eat
... it too and we're having heartburn now.

Mike: I'll put my proposal in writing somewhere on the issue for IMSC 1 and we can pull request
... it and put it to bed. I look forward to any proposals to address it in TTML1 also.

Nigel: That seems like a good way forward.
... I will add a note to the issue now.

Pierre: I just want to point out that making an XSD that reflects this will be exciting.

Mike: A proper one would require xs:any everywhere.

Andreas: The question is if a schema needs to contain the wildcard element because possibly
... we should validate the pruned document against the schema not the one with the foreign namespace elements in.

Nigel: I've added a note to the issue.

TTML

Nigel: The above topic also was relevant to the TTML agenda item by the way.
... I did want to discuss the placement of TTML.next issues but that is not urgent for today.
... We have a bunch of horizontal review comments from r12a. Glenn are you able to deal with those?

Glenn: I have too many other issues to cover before I get to those so I am going to respond
... later.

Dae: The request for new features on TTML2 passed on Feb 15. So if the review comments
... ask for new features we would say no, right?

Nigel: So far none of them do ask for new features, but yes.
... We're out of time so thanks everyone. [adjourns meeting]

Summary of Action Items

Summary of Resolutions

[End of minutes]

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