{Minutes} TTWG Teleconference 2024-04-11

Thanks all for attending today’s TTWG call. Minutes can be found in HTML format at https://www.w3.org/2024/04/11-tt-minutes.html


In plain text:

   [1]W3C

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


                Timed Text Working Group Teleconference

11 April 2024

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

      [2] https://www.w3.org/2024/03/28-tt-minutes.html

      [3] https://github.com/w3c/ttwg/issues/279

      [4] https://www.w3.org/2024/04/11-tt-irc


Attendees

   Present
          Atsushi, Cyril, Gary, Matt, Nigel, Pierre

   Regrets
          -

   Chair
          Gary, Nigel

   Scribe
          nigel

Contents

    1. [5]This meeting
    2. [6]IMSC-HRM
    3. [7]DAPT
         1. [8]Replace workflowType with represents w3c/dapt#217
         2. [9]Add informative section about mapping from TTML to
            the DAPT data model w3c/dapt#216
    4. [10]AOB
    5. [11]Meeting close

Meeting minutes

  This meeting

   Nigel: Today we have IMSC-HRM and a couple of pull requests on
   DAPT.
   … Anything else for the agenda, or points to make sure we get
   to?

   Cyril: AOB - NAB is coming and we're organising an event we can
   mention

   Nigel: Thank you

  IMSC-HRM

   Nigel: The AC Review poll closed, no objections.
   … I think we need a pull request to address the proposed
   changes?

   Atsushi: Yes. I believe we are waiting. Once the pull request
   is raised and all comments are satisfied
   … we can go to publication. The changes are just suggestions
   and are all editorial,
   … so it would be possible to go directly to Rec but it would be
   better to deal with the suggestions and comments.

   Nigel: Pierre, are you okay to open a pull request for those?

   [12]A few minor editorial suggestions w3c/imsc-hrm#79

     [12] https://github.com/w3c/imsc-hrm/issues/79


   Pierre: I was just waiting to make sure there were no other
   comments.
   … I will prepare the pull request straight away.

   Nigel: Thank you.
   … Anything else to say about this?

   nothing more

  DAPT

   [13]Issues labelled "agenda"

     [13] https://github.com/w3c/dapt/labels/agenda


   Nigel: We discussed these two last time but there were no
   concrete actions,
   … and we said we would continue the discussion on the pull
   requests, but we didn't actually do that,
   … so I put them back on the agenda. Hope that's ok!

    Replace workflowType with represents [14]w3c/dapt#217

     [14] https://github.com/w3c/dapt/issues/217


   github: [15]w3c/dapt#217

     [15] https://github.com/w3c/dapt/pull/217


   Matt: Apologies, I didn't notice anything coming through to me
   for the review request.

   Nigel: This is about replacing workflowType with represents as
   a list of the content types that
   … the document represents.
   … Last time we talked we agreed to make the
   <content-descriptor> into a Registry Table,
   … and I made that change after the call.
   … We also had it as "alternativeFor" last time and had agreed
   to change that into "represents" which I also did.

   Matt: [recalls the discussion, agrees with the intent]

   Nigel: The question for me now is do I go ahead and merge now
   or wait for a review and
   … take appropriate response on the basis of that.

   Matt: I feel I need to read it.

   Cyril: I don't have any change to my pull request approval.
   … Just wondering about the granularity of the "represents",
   could we use represents on Script Events?

   Nigel: Further down the tree?

   Cyril: Yes, if you want to know which Script Events actually
   correspond to each type, we already have
   … Script Event Description which is human readable, and we have
   Script Event Type that has a Registry,
   … but the values don't align - we have dialogue, spoken text,
   on screen text...

   Nigel: Ooh I hadn't thought of that. Looking at it, I agree, it
   seems like this could be one list.

   Matt: I'm happy with the general approach.

   Cyril: I'm thinking - if you were to replace the values of
   represents by the values of Script Event Type...
   … If you made a set of the Script Event Types in the document,
   would that work?

   Nigel: I see 3 options.
   … 1. What you said Cyril, allow the event type values to be
   coalesced into represents at the document level.
   … 2. Add a mapping from event type into a simpler smaller set
   of represents values, e.g. title and OnScreenText in event type
   … both map to visualText in represents.
   … 3. Replace eventType with represents and use the same
   registry table for both.
   … The nuance is that represents allows a list, whereas
   eventType maybe should be a single value.

   Cyril: Sorry I only noticed this now. Also the registry table
   for script event type needs some descriptions.
   … I like the idea of the column for mapping to represents.
   … I was wondering what the point of spokenText is?

   Nigel: We spent no time looking at the registry table values
   for event type, they're just example values.

   Cyril: I agree those are the three options, I don't have a
   strong view.
   … You may not want the same granularity of description at the
   document level as at the script event type.

   Nigel: That's why I was thinking of the mapping idea.
   … I think that if we want to do the mapping, that would be a
   new issue and pull request.

   Cyril: A 4th option is to not have the document level summary
   at all but inspect the document contents
   … to see what it contains.

   Nigel: That's true, but...

   Cyril: In the workflow you want an early indication of the
   potential uses of the document.

   Nigel: So you're arguing against that previous point?!

   Cyril: Yes, I just wanted to note the possibility in case we
   want to come back to this in the future.

   Nigel: What to do?
   … Options:
   … 1. Merge now and open a separate issue and pull request to
   deal with mapping from script event type to represents
   … 2. Go round the loop one more time and try to fix this up
   before merging
   … 3. Merge now and do nothing about script event type for the
   time being.
   … By the way we will need to come back to all the Registry
   Tables at some point to make sure
   … they have the right values. All of the entries are
   Provisional right now.
   … Any preferences?
   … My preference is to merge now and then incrementally improve.

   Cyril: We should have an issue that tracks it then.

   Nigel: Do you want to open that then?

   Cyril: Doing it now.

   Matt: Apologies, got to run to another meeting, please prod me
   if there's any more review needed. Apologies again for not
   noticing this one.

   Matt leaves

   SUMMARY: Merge pull request, deal with script event type and
   represents in a separate issue

    Add informative section about mapping from TTML to the DAPT data
    model [16]w3c/dapt#216

     [16] https://github.com/w3c/dapt/issues/216


   github: [17]w3c/dapt#216

     [17] https://github.com/w3c/dapt/pull/216


   Nigel: From last time, I think the determining factor is if we
   need a class of DAPT implementation
   … that maps from TTML2 into the DAPT data model. If we do, that
   means we need to make these
   … provisions normative.

   Cyril: Taking a step back, we did this pull request to cover
   the case that there is a document that
   … conforms to the profile but does not map directly to the DAPT
   data model.
   … In practice if you have an implementation of DAPT that is
   "just" DAPT, which I think will be the majority case,
   … then this situation should not happen. You shouldn't end up
   with a document that cannot be easily mapped.

   Nigel: Yes, to a point.
   … The exception could be from the compatibility perspective -
   some future version of DAPT adds in a feature
   … that we want older DAPT processors to handle gracefully.
   … It's not just about TTML2 generically.

   Cyril: You're right.
   … Thinking out loud, if we added constraints like feature
   extensions to restrict a DAPT document
   … to correspond only to the DAPT data model, what would be the
   problem? Extensibility?

   Nigel: Yes, that would be the main one.
   … It's really the structural issue of divs containing other
   divs or mixed div and p children.
   … Which we agreed there could be a future use for.
   … If we prohibited that then we wouldn't be able to use that
   capability in the future without making a
   … breaking version change to DAPT.
   … Maybe we could argue that, to make sure that conformant
   implementations can deal with those changes,
   … that's why we need to make the informative provisions
   normative.

   Cyril: What about text content anywhere other than p and span?

   Nigel: It's allowed in p and span but TTML doesn't allow it
   anywhere else.
   … Except for metadata elements etc, of course.

   Cyril: Ok, thank you.

   Nigel: Does that argument about future compat seem correct?

   Cyril: Yes. In general I prefer something normative otherwise
   there won't be interoperability.
   … Does this mean we need a DAPT processor type?

   Nigel: No I don't think it does.

   Cyril: In §7.2 it defines a DAPT Processor in terms of
   conformance to the profile provisions and to the document.
   … How would we do that?

   Nigel: I'd make extension features referencing the new
   normative provisions, so it all ties together.

   Cyril: I would like to take a stab at re-writing §5 or
   proposing changes.

   Nigel: OK, that's fine, otherwise I'd have done it.

   Cyril: Not sure when I'll do it.

   Nigel: Why don't I do a first pass, and then you can review it?

   Cyril: That's fine.
   … I think we should move the new section 5 to after the
   Constraints section. We're only concerned
   … with valid documents, which are defined in the Constraints
   section.
   … I would start by saying that the processing behaviour for a
   processor processing a valid document that
   … contains additional content not in the DAPT model is the
   following...
   … Say there may be conformant DAPT docs that contain more, e.g.
   for a new version, or a round trip through
   … a generic TTML tool.
   … That's how I'd start, by explaining that.
   … Once the context is clear I think it's easier to understand.

   Nigel: I think it'll be important to say that the graceful
   handling feature requirements may be replaced
   … in future versions by something that defines some other
   behaviour.

   Cyril: Did you mention parsing, or just mapping?

   Nigel: Just mapping. I think parsing is defined by XML, we're
   talking about building a data model from the parsed entities.

   Cyril: OK

   Pierre: Are you going to take the TTML approach of pruning?

   Nigel: I don't think so, not quite

   Cyril: For validation purposes, yes.
   … But a read/write processor should try to retain unrecognised
   vocab

   Pierre: The reason for mentioning: if the processor sees
   elements or attributes it does not understand then
   … there's no hope it can understand how to deal with those
   unknown elements.
   … If you merely preserve them, that doesn't take into account
   the semantics of the unknown elements.
   … Generally it's not possible unless you specify extension
   rules such as vocabulary in a particular part of the
   … model does not affect e.g. timing etc.
   … Some things can be preserved with minimal risk, but
   everything else, it's hopeless.

   Cyril: You can have multiple values of profiles in the
   contentProfiles attribute, but if you write back
   … a file then you shouldn't write back values of
   contentProfiles that you don't understand.
   … You could end up with semantically incorrect content.

   Nigel: Example is an attribute for number of words, doc says 3,
   editor adds 2, saves the value as 3 because it
   … doesn't understand it.

   Pierre: There's a danger of getting rules that are so complex
   that nobody understands them.

   Pierre: The TTML model is blunt but straightforward. Just get
   rid of everything you don't understand.
   … Maybe some stuff could have been kept, but at least it is
   predictable.
   … When the author wants the document to be compatible with an
   older version,
   … do it so that when you strip the newer stuff it's still valid
   for the older version.

   SUMMARY: @nigelmegitt to make edits as discussed, @cconcolato
   to review, discussion to continue.

  AOB

   Cyril: there's an event happening where we're gauging appetite
   to talk about live captioning,
   … wondering if there's a TTWG view on it. It's on Monday.

   Nigel: I don't think I can say anything about this as a Chair
   because we've not really discussed it in TTWG.
   … But I may be able to say something in my BBC role.
   … Can we take this offline please?

   Cyril: Can we add this as an AOB for after the meeting so we
   can summarise the outcomes?

   Nigel: Sounds like a good idea.

  Meeting close

   Nigel: We're 3 minutes over, thanks everyone! [adjourns
   meeting]


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Received on Thursday, 11 April 2024 16:11:28 UTC