{minutes} TTWG Meeting 2016-07-28

Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2016/07/28-tt-minutes.html


In text format:


   [1]W3C

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


                Timed Text Working Group Teleconference

28 Jul 2016

   See also: [2]IRC log

      [2] http://www.w3.org/2016/07/28-tt-irc


Attendees

   Present
          Nigel, Pierre, Glenn

   Regrets
          Mike, Andreas

   Chair
          Nigel

   Scribe
          nigel

Contents

     * [3]Topics
         1. [4]This meeting
         2. [5]TPAC 2016
         3. [6]TTML1 & TTML2 issues, actions, PRs, editorial
            actions etc
         4. [7]Profiles registry
     * [8]Summary of Action Items
     * [9]Summary of Resolutions
     __________________________________________________________

This meeting

   nigel: [goes through agenda] Looks like our topics for today
   will be TPAC and TTML. AOB?

   all: no AOB

TPAC 2016

   action-475?

   <trackbot> action-475 -- Nigel Megitt to Contact the chair of
   the web & tv ig to ask about schedule and joint meeting time.
   -- due 2016-07-28 -- OPEN

   <trackbot>
   [10]http://www.w3.org/AudioVideo/TT/tracker/actions/475


     [10] http://www.w3.org/AudioVideo/TT/tracker/actions/475


   nigel: No progress to report on this so far
   ... We're set to meet on Monday and Tuesday.

TTML1 & TTML2 issues, actions, PRs, editorial actions etc

   glenn: No actions to report on for me. I did have a chance to
   do a quick review of the
   ... wiki page on timing. Thanks for doing that. I think it will
   help organise some of our
   ... discussions on this area. I'm going to start augmenting
   that page with some additional
   ... information for example providing some historical context
   on some of the terms to
   ... help us see where things were and how they developed. That
   may help us resolve some
   ... mistaken text or understandings that have been introduced.
   The last part of that had
   ... an example with dur on body and end on an element
   underneath which appears to
   ... be longer than the dur on body. That would be handled by
   the SMIL timing semantics
   ... but as you point out they're difficult and they're not
   expressed anywhere in TTML and
   ... maybe, though I'm almost fearful of doing it, in the TTX
   application of the TTT project
   ... is implemented some timing semantics as we attempted to
   interpret it which may or
   ... may not be right. So at least I have a working example. So
   my thought was to try to
   ... use that as well as that the documented SMIL semantics to
   maybe describe the process
   ... that we implemented and put it into the wiki to use as a
   point of departure for maybe
   ... helping document that more thoroughly.

   nigel: Thanks that will be really helpful.

   glenn: By the way on that example, in SMIL end does not express
   begin+dur.
   ... So dur specifies a simple duration where end specifies the
   end of the active duration
   ... which are different things.

   pal: These subtle issues are missed by 99.999% of implementers
   so I really like the idea
   ... of getting a baseline based on what you've implemented at
   least as a starting point.
   ... That's an excellent idea.

   glenn: I definitely mean it as a starting point because I
   wouldn't stand by a statement that
   ... we have implemented it all correctly either. We can try to
   refine it based on other
   ... implementations and common understandings.

   nigel: I wonder if there are any SMIL folk we can talk to about
   the details?

   glenn: Thierry and I were on the SMIL group but couldn't answer
   for the technical details.
   ... The guy who did the main work was Patrick Schmitz - I think
   he attended some of our
   ... early meetings, but he was probably the only guy who
   understood the spec in my opinion.
   ... There was another guy who wrote a book on SMIL, whose name
   I can't remember right now.
   ... He might be another resource. There's a third person, Eric
   Hodge, who was at Real
   ... Networks. I suspect asking him about any of this now would
   mostly draw a blank.

   nigel: Slightly related to this is the new issue I added:
   [11]https://github.com/w3c/ttml2/issues/169


     [11] https://github.com/w3c/ttml2/issues/169


   glenn: I saw that and thought it was reasonable.
   ... I also think we should add something for timing on break
   elements, which we added
   ... in TTML2 and wasn't in TTML1, so some implementations may
   not support it.

   nigel: Agreed. I also wondered about a feature designator for
   nested timed elements, since
   ... some profiles disallow those for simplicity.

   glenn: I'm generally open to adding new features, since they
   don't cost much. Noting that
   ... one of the uses of features is to drive the tests and
   implementation report. So if we
   ... list a feature there then it's harder to make a case that
   we have two implementations
   ... of it than if we have a broader feature definition.

   nigel: Agreed. In this case since there are already processors
   subject to these restrictions
   ... I think we're fairly safe.
   ... Regarding the Safe Crop Area proposal I mentioned last week
   that I intend to
   ... raise an issue and a PR for the proposal unless there are
   any objections to that.

   glenn: I don't see any problem with that. If there are any
   problems with the PR then you
   ... could always address them in the PR branch.

   nigel: yes, of course. My plan is to put the SCA signalling in
   the ttp parameter namespace.

Profiles registry

   nigel: Mike has told me that although he's begun work on the
   edits for this he hasn't
   ... yet managed to complete it, so there's a bit more work to
   do there.
   ... We're out of agenda topics for today so we'll finish ahead
   of time. Thanks! [adjourns meeting]

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


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