{minutes} TTWG Meeting 2015-10-08

Thanks to those who attended today's meeting. Minutes can be found at http://www.w3.org/2015/10/08-tt-minutes.html

There's a proposal to extend next week's meeting to 2 hours to close off the remaining IMSC 1 issues as much as possible in advance of TPAC.

In text format:


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

                Timed Text Working Group Teleconference

08 Oct 2015

   See also: [2]IRC log

      [2] http://www.w3.org/2015/10/08-tt-irc


          nigel, pal, tmichel

          Andreas, Frans, Mike




     * [3]Topics
         1. [4]This Meeting
         2. [5]Action Items
         3. [6]TPAC 2015
         4. [7]IMSC stuff...
         5. [8]Profiles registry
         6. [9]Issues
     * [10]Summary of Action Items

   <trackbot> Date: 08 October 2015

   <scribe> scribe: nigel

This Meeting

   nigel: Most of this meeting will be dedicated to closing IMSC 1
   pending review issues
   ... AOB?
   ... Mike has asked to postpone the incoming liaison from ATSC

   pal: There's also the topic of profile designators - it would
   be good to talk about it.

   nigel: Great, that's added.

Action Items


   <trackbot> Action-421 -- Nigel Megitt to Check with ttml player
   manufacturers if they're happy to be listed on our site. -- due
   2015-09-24 -- OPEN


     [11] http://www.w3.org/AudioVideo/TT/tracker/actions/421

   nigel: I did contact the manufacturer we discussed and they
   said they'd check but haven't yet confirmed.
   ... Do we have an implementations page?

   tmichel: I don't think we have one yet but I'd like to start
   one. I think we should have a page
   ... per technology - one for TTML, one for WebVTT etc.

   pal: We have a page for that - remember the contribution from
   the Web & TV IG?

   nigel: Oh yes, I remember now.


     [12] https://www.w3.org/wiki/TimedText/


   is a better URL to use

     [13] https://www.w3.org/wiki/TimedText/EffortsAndSpecifications

   It's linked from [14]https://www.w3.org/wiki/TimedText under
   Timed Text Efforts and Specifications

     [14] https://www.w3.org/wiki/TimedText

   nigel: I guess we could add it to the group home page too - we
   probably should tidy up the
   ... group page vs wiki home page discrepancy. Having both isn't
   especially helpful.

   tmichel: In former times we had the CVS hosted home page which
   was hard to edit. Now
   ... the wiki is simpler for people to add information to.
   Everyone should be able to add their
   ... own product if they want to.

   nigel: Is it worth an action to redirect from the home page to
   the wiki?

   tmichel: I'll look into that. There's some information like how
   to join on the home page.

   nigel: Yes. we'd have to migrate the key information.

   tmichel: I'll look into it and propose something.

   <scribe> ACTION: tmichel Look into merging the group home page
   and the wiki home page and propose something [recorded in

   <trackbot> Created ACTION-430 - Look into merging the group
   home page and the wiki home page and propose something [on
   Thierry Michel - due 2015-10-15].

TPAC 2015

   nigel: Netflix has just joined the WG and would like to spend
   some agenda time on the Thursday
   ... presenting on their open source TTML2 implementation work.
   ... I'll add that to the topics/agenda page on the wiki.

   tmichel: While we're talking about new participants, SImon from
   Opera joined today replacing Philip.
   ... Simon is the new editor of the WebVTT spec.

IMSC stuff...


   <trackbot> action-425 -- Thierry Michel to Send a prompt/thank
   you to the potential test result contributors for imsc. -- due
   2015-10-01 -- OPEN


     [16] http://www.w3.org/AudioVideo/TT/tracker/actions/425

   pal: I've not heard back and am still chasing, so that's still
   open. No update despite best efforts.

Profiles registry

   pal: Related to Cyril's email earlier today, which came out of
   this topic, I think from an
   ... implementation standpoint he wants users to be able to
   signal clearly in a TTML document
   ... what profiles a document conforms to. In IMSC 1 right now
   there's a 'MAY user ttp:profile'
   ... statement but that's it. Maybe we can add more to IMSC 1 to
   encourage people to label
   ... their documents. The challenge is, as we discussed before,
   EBU-TT-D forbids ttp:profile.
   ... And ttp:profile supports only one profile. So if a document
   conforms to both EBU-TT-D and
   ... IMSC 1 then you should not use ttp:profile but you should
   use ebuttm:conformsToStandard
   ... and list both. If the document is not EBU-TT-D conformant
   it probably isn't a bad idea to
   ... use ttp:profile and also include ebuttm:conformsToStandard
   so I'm thinking of adding
   ... a recommendation to IMSC 1 along those lines.

   nigel: I can see the logic to that, yes. It makes sense I

   pal: I'd like to be responsive to the request.

   nigel: I agree - there's a use case we haven't spent a lot of
   time considering that is obviously
   ... important. I'd like Andreas's and Frans's input on this
   specific proposal too, but on the
   ... surface I think it makes a lot of sense.
   ... You can recommend using the URI designators.

   pal: That would definitely be the recommendation!
   ... From a tools perspective it would certainly help tools to
   determine the document's profile.

   nigel: We just need to be careful that
   ebuttm:conformsToStandard is indicating document
   ... conformance in other words the equivalent to TTML2's
   ttp:contentProfiles attribute.
   ... Whereas ttp:profile indicates a processor profile, so we
   shouldn't mix the messages there.

   pal: I don't know why we hadn't collectively thought about this
   before. I think it works in exactly the right way.

   nigel: I can see how this would work really well - if an IMSC 1
   processor is needed then it's on
   ... the ttp:profile attribute and if not, because an EBU-TT-D
   processor is okay, then it would be
   ... omitted.

   pal: I think we can file an issue for this, especially given
   Glenn's email just now proposing that
   ... IMSC 1 includes a 'should include ttp:profile attribute'
   statement, then implement and review
   ... next week.
   ... [filing issue right now]


   <trackbot> issue-448 -- Add recommendation for ttp:profile and
   ebuttm:conformsToStandard -- raised


     [17] http://www.w3.org/AudioVideo/TT/tracker/issues/448

   reopen issue-448

   <trackbot> Re-opened issue-448.

   pal: I'm going to reply to the thread too.

   nigel: I think it's worth pinging back to EBU to check if they
   might reopen the discussion on
   ... whether or not to permit ttp:profile on EBU-TT-D documents.
   ... Of course if you have a stream of EBU-TT-D documents e.g.
   in DASH then this is likely
   ... to be redundantly repeated data.

   pal: Of course the packager could strip it out if it knows the
   data won't be needed downstream.

   nigel: We may be putting packagers in an uncomfortable
   situation of needing to modify the
   ... samples they're given to wrap up.

   pal: True - we're talking about a few bytes though and it's
   tiny in comparison with e.g. HTTP headers.


   nigel: Let's go through Pending Reviews...


   <trackbot> issue-404 -- Where is #image feature defined? --
   pending review


     [18] http://www.w3.org/AudioVideo/TT/tracker/issues/404

   pal: I think this is unambiguous, well specified and can be

   nigel: +1

   close issue-404

   <trackbot> Closed issue-404.


   <trackbot> issue-405 -- why is #nested-span prohibited on image
   profile? -- pending review


     [19] http://www.w3.org/AudioVideo/TT/tracker/issues/405

   nigel: This isn't even a proposal to change the spec. It's a
   question with an answer.

   pal: I think Glenn would have responded if he disagreed.

   close issue-405

   <trackbot> Closed issue-405.


   <trackbot> issue-406 -- #lineBreak-uax14 is never 'used' by a
   document? -- pending review


     [20] http://www.w3.org/AudioVideo/TT/tracker/issues/406

   pal: uax14 is mandated for processors in the text profile and
   stated as not applicable to document instances.
   ... The image profile is silent about it.

   nigel: Do we permit the profile features to be listed in the

   pal: We do. The presence of the profile designator in the
   document requires that the processor
   ... implements uax14. What the spec currently says is the
   document constraints. The uax14
   ... feature is not applicable to constraints on the document.

   nigel: There's a niche issue for the text profile: if the
   profile features are included then it would
   ... be an error to state that the #linebreak-uax14 feature is a
   'shall not use'.
   ... That would create a situation where an IMSC 1 text profile
   conformant processor should
   ... reject an IMSC 1 text profile conformant document that
   includes this profile feature as
   ... 'shall not use'.

   pal: This is a strange and theoretical case, that applies only
   to the uax14 feature.

   nigel: We could add a statement that if profile features are
   included within a document then
   ... they shall not conflict with the processor conformance
   rules for IMSC 1.

   <scribe> ACTION: nigel File issue re profile feature inclusion
   in IMSC 1 documents [recorded in

   <trackbot> Created ACTION-431 - File issue re profile feature
   inclusion in imsc 1 documents [on Nigel Megitt - due

   pal: We could add that to the profile section for document
   ... Going back to issue-406, Glenn suggested to require the
   feature. Shall we start the 2 week review clock on this today?

   nigel: yes, let's do that.


   <trackbot> issue-408 -- Initial value of color -- pending


     [22] http://www.w3.org/AudioVideo/TT/tracker/issues/408

   close issue-408

   <trackbot> Closed issue-408.


   <trackbot> issue-409 -- Font family of default means
   monospaceSerif -- pending review


     [23] http://www.w3.org/AudioVideo/TT/tracker/issues/409

   pal: IMSC 1 defines what it means for "default" fontFamily,
   i.e. what a processor shall do when
   ... the fontFamily is set to "default". Glenn points out that
   this isn't always the right thing to do.
   ... My response to that is that authors should not rely on
   default. TTML1 doesn't prohibit
   ... implementations from mapping the default font to a known

   nigel: I'm a bit nervous here - Glenn hasn't proposed a
   solution, and I don't know why.
   ... For example we could include a table mapping language to
   default font map or reference
   ... one in e.g. CLDR.

   pal: Document authors can make their choice though if default
   won't work for them.

   nigel: My nervousness here is that we're making a language
   market-specific value for default,
   ... which could make use of default less useful.
   ... However Glenn knows most about this from those here and he
   hasn't picked it up.

   pal: We should close this on the basis of no response in over 1
   month. It can be reopened if someone is unhappy.

   close issue-409

   <trackbot> Closed issue-409.


   <trackbot> issue-410 -- Constraints on #linePadding and
   #multiRowAlign -- pending review


     [24] http://www.w3.org/AudioVideo/TT/tracker/issues/410

   nigel: The problem with SHALL NOT here suggests a syntactic
   conformance requirement whereas
   ... what you mean is that if the attributes are present then
   they shall be ignored by implementations.

   pal: We don't have Glenn's view on this so it would be uncool
   if he doesn't agree.
   ... Don't forget the problem arose in EBU-TT-D.

   nigel: The new EBU-TT Part 1 v1.1 might get us out of that
   problem - it defines the features
   ... and states that they may be used in EBU-TT-D, and fixes the
   gaps from the original definition.

   <scribe> ACTION: nigel Nigel, pal, andreas and frans to hook up
   re changing IMSC 1 EBU-TT feature references to point to
   tech3350 v1.1 [recorded in

   <trackbot> Created ACTION-432 - Nigel, pal, andreas and frans
   to hook up re changing imsc 1 ebu-tt feature references to
   point to tech3350 v1.1 [on Nigel Megitt - due 2015-10-15].

   issue-410: [meeting 2015-10-08] See also Action-432 - it may be
   possible to avoid the problem by referencing tech3350 v1.1.

   <trackbot> Notes added to issue-410 Constraints on #linePadding
   and #multiRowAlign.

   nigel: We're out of time so I'll adjourn now.

   pal: Maybe we could do 2 hours next week to get through the
   remaining issues ahead of TPAC?

   nigel: That's fine for me.

   pal: I'd like to have gone through all of them - there's one
   that may need TPAC discussion.
   ... Glenn brought up an excellent question about the HRM, in
   relation to Arabic, where the
   ... mapping between code point and glyph is in the majority of
   cases is not 1:1 and the shape
   ... depends on the context. That really messes up the glyph
   buffer. I'm researching it.
   ... The glyph buffer was put in to support e.g. 608, 708 and
   Teletext. Hopefully we'll have closed all the others.

   nigel: Thanks both. [meeting adjourned]

Summary of Action Items

   [NEW] ACTION: nigel File issue re profile feature inclusion in
   IMSC 1 documents [recorded in
   [NEW] ACTION: nigel Nigel, pal, andreas and frans to hook up re
   changing IMSC 1 EBU-TT feature references to point to tech3350
   v1.1 [recorded in
   [NEW] ACTION: tmichel Look into merging the group home page and
   the wiki home page and propose something [recorded in

   [End of minutes]

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Received on Thursday, 8 October 2015 15:23:52 UTC