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{minutes} TTWG Meeting 2016-09-01

From: Nigel Megitt <nigel.megitt@bbc.co.uk>
Date: Thu, 1 Sep 2016 15:21:37 +0000
To: Timed Text Working Group <public-tt@w3.org>
Message-ID: <D3EE04A5.29DCB%nigel.megitt@bbc.co.uk>
Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2016/09/01-tt-minutes.html

If you have not registered for TPAC you have until 2nd September to do so at the advanced rates!

In text format:


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

                Timed Text Working Group Teleconference

01 Sep 2016

   See also: [2]IRC log

      [2] http://www.w3.org/2016/09/01-tt-irc


          dakim, glenn, mike, nigel, pal, Andreas





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

   <scribe> scribe: nigel

This meeting

   nigel: Several topics have been discussed recently: TPAC, IMSC
   Image profile, TTML2 inline region semantics
   ... Any other business or points to prioritise?

   pal: Inline region semantics

TPAC 2016

   nigel: You have 1 day left to register if you have not already,
   and get the advanced rates


   <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


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

   nigel: Still no response from Web & TV IG, I have no idea why.
   Will keep pestering them.


   <trackbot> action-476 -- Nigel Megitt to Put together a tpac
   straw man agenda -- due 2016-08-25 -- PENDINGREVIEW


     [12] http://www.w3.org/AudioVideo/TT/tracker/actions/476


     [13] https://www.w3.org/wiki/TimedText/tpac2016#TTWG_TPAC_2016

   nigel: [runs through draft agenda as it stands]

   glenn: I'm going to post a couple of new issues that we will
   probably need to discuss.
   ... One is support for rounded background, and there are a
   couple of issues regarding
   ... more complete support for the more advanced background
   attributes. There may be a
   ... few missing that I think should be added. I'll post some
   issues on these to drive agenda items.
   ... Also on the support for anonymous region generation I've
   got some material on that as well.
   ... It turns out that we need to add back something we used to
   have in animation, which
   ... is the ability to have animation elements point at content
   elements, but we changed it
   ... around to have content elements point at animation
   elements. To support anonymous
   ... inline region for the current region we need an anonymously
   generated set element point
   ... back up to the region.

   atai: I can show something on HTMLCue/VTTCue and we should
   spend time looking at it.
   ... There's a question regardless of approach if we should talk
   with another WG about this.
   ... I think something will need to change in the HTML spec
   because the spec is format
   ... independent but the implementation is WebVTT specific, so
   to have a format agnostic
   ... spec for cues then some additions or changes to HTML are

   nigel: Do you know which other groups?

   atai: I think we need to know which group is responsible for
   that part of the spec.

   glenn: We could actually draft a spec or some material in this
   group, publish it as a Note and
   ... throw it over the fence to another group to turn it into a
   Rec. That's one option.

   atai: What I found out is firstly that the TextTrackCue should
   be implemented correctly in
   ... the browser. They only have VTTCue specific
   implementations, though as I read it from the
   ... HTML spec there should be a generic TextTrackCue
   implementation. Initially it may be as
   ... simple as following the spec as it is written and then add
   a property as a payload. Then
   ... the rest would be done with javascript as a small addition
   that would help present any other
   ... timed content.

   nigel: Any other requests for agenda items, or for scheduling?

   atai: I think there could be some interest in Web & TV IG in
   better integration between TTML and HTML5.

   nigel: Okay, I'll keep chasing on the joint meeting action.

   close action-476

   <trackbot> Closed action-476.

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

   nigel: I think we wanted to discuss inline anonymous regions...

   glenn: I propose that we adopt a parameter on a per document
   basis that defines the desired
   ... behaviour for anonymous inline regions. We have already
   done half the work, for new
   ... regions, and need to make progress with current. Then later
   if we want to choose only
   ... one of those options we can do that. That's my proposal.
   ... Perhaps we should try to discuss how we develop and
   possibly discard features during the spec development process,
   at TPAC.
   ... My general position is that the process step of dropping
   features without implementation applies.

   nigel: That's certainly the formal position.

   pal: I'm not sure if I'm the only one wanting to discuss this.

   atai: I'm also interested in this.

   pal: This is about how we allocate our limited amount of

   <atai> +q

   nigel: I will add an agenda topic for TPAC to consider our
   deliverable timelines and how
   ... reliable our estimates are for meeting them, and if we need
   to take any action.

   glenn: I have scheduled a lot of time to get a CR candidate
   ready for Nov 1.

   atai: I think we should discuss the balance between adding new
   features and the challenge
   ... of implementation when the spec is bigger, from a market
   perspective. It is important for
   ... us to have our specs implemented correctly. We should
   discuss our current experiences
   ... and if this means anything for our spec efforts in general.

   nigel: Summarising, I'll add an agenda topic for TPAC, and on
   the subject of anonymous
   ... regions, Glenn will go ahead with speccing the anonymous
   set approach as he proposed.

   glenn: Just to note that I finally merged those PRs.
   ... One point: when you do propose a PR please don't expand the
   RCS keywords otherwise
   ... I have to manually remove them.

   nigel: It could be that there's a problem with the check-in
   hook then.

   glenn: It did not unexpand them when you checked it in. No
   problem though, I fixed it.
   ... Regarding the other PR that I merged I'll post another
   issue for clearing up the defined term
   ... references.

   nigel: Thanks, that was for my suggestion prior to merging the
   PR, that's fine.

   glenn: I'm going to try to post a number of new PRs between now
   and Lisbon so there may
   ... be some things for people to start reviewing.

   nigel: That would be helpful, thank you.


   nigel: The main topic discussed recently is embedded images.

   pal: It would be good to have a way to generate the ISOBMFF
   files with embedded images,
   ... which gpac doesn't do today.

   glenn: You mean embedded in the BMF not the TTML, right?

   pal: Correct. The fact that gpac doesn't support it is not

   mike: It's not just an image issue. There's currently no tool
   I've found that can BMF wrap
   ... any TTML.

   nigel: I thought gpac can do that - it certainly can do
   EBU-TT-D though I'm not sure about
   ... other profiles of TTML.
   ... Is there any spec implication for IMSC from that

   pal: I didn't see any.

   mike: I have a question: there are lots of provisions in IMSC 1
   that say the content shall not
   ... contain X. I'm wondering whether strategically that is a
   good thing to do in other profiles.
   ... Architecturally it's interesting that there are a handful
   of forbidden things but nothing
   ... is forbidden in other namespaces.

   glenn: I think it's consistent with what EBU-TT-D did which
   seems to be extremely restrictive
   ... on what content can be present, presumably to simplify
   clients. It's an interesting point.
   ... When we added support for IMSC 1 to the TTV tool mostly
   what we added was checks for
   ... restrictions, so as far as I'm aware IMSC 1's restrictions
   are fully checked by TTV right now.

   mike: There's no question that a validator should check the
   spec. I'm not trying to revisit IMSC1.
   ... Some people want implementations that support things not in
   the spec, so that's fine.
   ... But you can add another namespace and that's fine.

   glenn: Because IMSC 1 also says that any error handling is
   implementation dependent then
   ... the normative requirement to prohibit things is very weak.
   An implementation may choose
   ... to ignore them or not. It's useful to note that the core
   conformance in TTML says "ignore
   ... everything you don't understand" basically.

   atai: It's an interesting design approach discussion for
   profiles. The idea for EBU-TT-D is
   ... only things that can be decoded should go in the document.
   Other things added may
   ... change the complete behaviour. That's one approach and that
   gives the decoder a guarantee
   ... that if it's a conformant file then there's only
   understandable content that can be decoded.

   mike: It's consistent at least in EBU-TT-D but I'm throwing it
   out there that there's an
   ... inconsistency in general in TTML profiles.

   atai: There's a question what an IMSC decoder should do when
   unexpected vocabulary is found.
   ... As Glenn says one option is to say "ignore" and "don't use"
   foreign content.

   glenn: I said "vocabulary that the implementation doesn't
   understand" not "that the spec does not permit".
   ... So some implementations can have specific additions.

   atai: This is also important to get some experience back from
   implementations on which
   ... design decisions work and which don't work.


   mike: What's the status of the media registration now that the
   note has been updated?

   nigel: I don't know. I've not heard anything. I'm happy to
   prompt Philippe to remind that we
   ... consider the document ready for the next stage of
   ... It doesn't look like anything has changed at IANA since Feb
   ... I'll remind Philippe. Thanks for merging those PRs.

   mike: There are a couple of non-media-registration related
   issues, which I think were yours Nigel, which we should discuss
   at some point.

   nigel: I'll revisit those and see if I can make any proposals.
   ... OK we're out of time, thanks everyone. [adjourns meeting]

Summary of Action Items

Summary of Resolutions

   [End of minutes]

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Received on Thursday, 1 September 2016 15:22:16 UTC

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