{minutes} TTWG Meeting 2015-10-15

Thanks all for attending today's extended meeting – we achieved our goal of closing off the lingering IMSC Pending Review issues.

Notes in HTML format are at: http://www.w3.org/2015/10/15-tt-minutes.html

In text format:


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

                Timed Text Working Group Teleconference

15 Oct 2015

   See also: [2]IRC log

      [2] http://www.w3.org/2015/10/15-tt-irc


          dakim, mike, nigel, tmichel, dae, pal, plh





     * [3]Topics
         1. [4]This meeting
         2. [5]Action Items
         3. [6]TPAC 2015
         4. [7]Incoming Liaison from ATSC
         5. [8]TPAC 2015
         6. [9]Profiles registry
         7. [10]Issues
     * [11]Summary of Action Items

   <trackbot> Date: 15 October 2015


   nigel: Welcome to dakim, whose first meeting this is as a

   dakim: Thank you

This meeting

   <scribe> scribe: nigel

   nigel: Goes through meeting - plans to discuss ATSC liaison,
   IMSC 1 issues, actions, TPAC agenda and timeslots.
   ... Is there any other business?

   group: No AOB

   <mike> my webex port was just terminated

   <dakim> same

   <tmichel> yes I also lost webex !

   <tmichel> yes it does says meeting canceed !

   <tmichel> no I don't have the credentials to start it or a new

   <dakim> i can try to book an audio bridge for everyone to call

   nigel: hold on for a moment, I also can do that but I think
   Thierry might be on the case...

   <tmichel> Yes I am currently discussing with PlH, maybe he has
   the credentials

   <plh> ok, I can book webex

   <plh> give me a minute

   <tmichel> thanks, MIT does not accept my credential ...

   <plh> 312 343 368

   <plh> password: caption



     [12] https://mit.webex.com/mit/j.php?MTID=m231f833db1e0d4bde2ac19d0260c66f2

   says you need to start it...

   <plh> done


   okay that looks like it's up and running - just waiting for
   everyone to call back in...

   pal: No other business from me either.

   tmichel: Should we use this new webex next week or the usual

   nigel: I don't know - can I bounce that back to you to

Action Items


   <trackbot> action-430 -- Thierry Michel to Look into merging
   the group home page and the wiki home page and propose
   something -- due 2015-10-15 -- OPEN


     [13] http://www.w3.org/AudioVideo/TT/tracker/actions/430

   tmichel: I started to look at this and I think the proposal I
   will send is to keep the current home
   ... page as a landing page because each working group has that
   kind of landing page. Then
   ... I will highlight that most of the information is on the
   wiki and include a link.

   nigel: Other people seem to have a better home page. Are we
   stuck with CVS?

   tmichel: Yes the home page is under CVS. I propose to keep
   links to the charter, participants,
   ... how to join etc that don't move much in time, and then all
   the more volatile information
   ... should be kept in the wiki.

   nigel: That's the status quo but with a clearer home page.

   tmichel: Yes, I plan to simplify the page and make it clear
   that they need to go to the wiki
   ... for more information - currently it's not easy to find that
   wiki link.

   close action-430

   <trackbot> Closed action-430.

   <scribe> ACTION: tmichel Update CVS hosted landing page to
   simplify and highlight link into wiki page [recorded in

   <trackbot> Created ACTION-433 - Update cvs hosted landing page
   to simplify and highlight link into wiki page [on Thierry
   Michel - due 2015-10-22].


   <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


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

   nigel: I need to chase on this.

   Action-421: [meeting 2015-10-15] Nigel to chase up on this

   <trackbot> Notes added to Action-421 Check with ttml player
   manufacturers if they're happy to be listed on our site..

TPAC 2015

   nigel: I've added to the wiki page the request to demo TTML2 on
   the Thursday.


     [16] https://www.w3.org/wiki/TimedText/tpac2015

   nigel: Are there any requests for specific days to cover
   specific topics?

   dakim: The netflix request is for the Thursday

   nigel: Thanks, that's already noted.
   ... Any other preferences for particular dates, slots etc?
   ... If not then I'll allocate them as is convenient.
   ... The other thing to note is the charter discussion: if
   anyone has any scope changes they
   ... would like to propose then this will be the time to do
   that. Otherwise we'll simply be
   ... proposing an extension in time.

Incoming Liaison from ATSC



     [17] https://lists.w3.org/Archives/Member/member-tt/2015Oct/0000.html

   nigel: This is a request to make a derivative work based on
   part of TTML2

   mike: This is a request to comply with the W3C copyright
   notice. We were planning to put
   ... the new text under a different namespace. Plh advised that
   this is still a derived work and
   ... needs internal approval. He wanted us to come here first
   and get the group's view.

   nigel: The first point is that the current text does not match
   what we agreed as per


   <trackbot> issue-224 -- Support text placement in 3D coordinate
   spaces (not zIndex compositing). -- open


     [18] http://www.w3.org/AudioVideo/TT/tracker/issues/224

   mike: Yes, hence the request to keep tracking developments.

   nigel: Right now I'd be unhappy for ATSC to adopt what we know
   is definitely not what we want.

   pal: The first step is to make the changes.

   nigel: Yes, the Editor hasn't done that yet.

   pal: Maybe someone else could edit that section?

   nigel: Yes, that would be okay.

   mike: I wanted simply to address the legal compliance question,
   but we should follow this through.
   ... I have asked Glenn about making the fixes.

   pal: So ATSC would ideally like to copy and paste from a W3C
   Editor's Draft?

   mike: Right - the previous liaison was that ATSC would like to
   reference the 3D part, and our
   ... reaction was that we couldn't give a timescale, so ATSC has
   asked to derive from and track
   ... the latest state.

   pal: And the challenge is that to copy/paste from a rec track
   doc the WG needs to approve it?

   mike: There's a boilerplate W3C policy on copying, and it's not
   permitted to make a derivative
   ... work. Even though we're not changing the text but we are
   moving it to an ATSC namespace,
   ... plh considered it to be a derivative work.

   pal: Imagine someone were to come across a working draft of a
   W3C spec and love it. Nothing
   ... prevents that person from referencing a paragraph in that
   spec, at their own risk. W3C rules
   ... don't prevent that.

   mike: No, that would be fine. Past experience is that those
   were ethereal. Unless the group
   ... wants to make sure the Working draft URL is persistent.

   nigel: The /TR Working Drafts already have a static link.

   pal: Also the links to changesets in Mercurial can be used.

   nigel: I wouldn't recommend that.

   plh: We don't guarantee the stability of those links.

   pal: Until the WD is updated.

   plh: Why can't we update the WD?

   pal: It would take work! I'm not sure what state it is in.

   nigel: I think the actions are 1) make the edits to
   tts:disparity and 2) publish a new WD.
   ... Would that work Mike?

   mike: Yes as long as the WD link is permanent. The ATSC process
   is ongoing too by the way.

   nigel: Can anyone volunteer to fix up tts:disparity?

   pal: Yes I can do that.

   nigel: Great, thank you.

   mike: The expectation is that it matches CEA 708.1.

   pal: Yes

   nigel: As far as I know there are two ways of doing this, which
   differ only by a factor of 2.

   pal: I can do that.

   mike: Thank you. You should drop Glenn a note because he
   considers it to be his action right now.

   issue-224: [Meeting 2015-10-15] pal volunteers to do the
   editing to implement this

   <trackbot> Notes added to issue-224 Support text placement in
   3D coordinate spaces (not zIndex compositing)..

   pal: In terms of the liaison back, we need to indicate that
   this is a WD of TTML2, and it is a draft
   ... so the group has spent some time on it but please don't
   depend on any of the document.

   mike: That goes without saying. Why don't I draft a liaison
   request, saying Request Denied, but
   ... we have good news!

   nigel: Sounds good to me!

   <scribe> ACTION: mdolan Draft outgoing liaison to ATSC
   proposing to reference an updated WD of TTML2 [recorded in

   <trackbot> Created ACTION-434 - Draft outgoing liaison to atsc
   proposing to reference an updated wd of ttml2 [on Mike Dolan -
   due 2015-10-22].

   nigel: Can I propose that pal, you don't push the regenerated
   HTML but just the XML and ask
   ... Glenn as Editor to pull it and generate the HTML before
   pushing so he has a chance to review.

TPAC 2015

   pal: I would like to revisit the topic of moving away from
   tracker towards github and other tools.
   ... The lack of notifications on changes with tracker is
   becoming a blocker. Can we take 30 minutes
   ... to revisit that topic and see if now is a good time.

   plh: I'm interested in that conversation.

   pal: I've found with tracker that it's tough to notice comments
   that people have added to issues.

   nigel: Is there wider context?

   plh: You're probably one of the last WGs using Mercurial and
   Tracker - most other groups
   ... have moved to github, which has problems too but many
   advantages. I would favour moving
   ... to github.

   nigel: I have no problem with that, but I'm interested in the
   mechanics. Can issues be migrated?

   plh: There's no way to migrate the issues from tracker. I think
   there's a way to migrate the
   ... Mercurial repo while keeping its history.

   pal: Yes there is.

   plh: I'm happy to show how other groups are using github during
   the TPAC meeting.

   nigel: Great, let's consider that added!

   <scribe> ACTION: nigel add tools to TPAC agenda [recorded in

   <trackbot> Created ACTION-435 - Add tools to tpac agenda [on
   Nigel Megitt - due 2015-10-22].

Profiles registry


   <trackbot> action-429 -- Mike Dolan to Draft a wg note for the
   profile short name registry and ttml media type registration --
   due 2015-10-08 -- OPEN


     [21] http://www.w3.org/AudioVideo/TT/tracker/actions/429

   mike: The learning curve was higher than I expected. Pal is
   lending a hand but it's going to
   ... take a bit of work. I can make Cyril's suggested changes on
   the wiki. I've got other things
   ... to do so it won't happen before TPAC. The publishing
   process is interestingly complex.
   ... I was going to edit the recent other note but it's quite
   contorted to do by hand. The structure is quite complicated.
   ... Then the Mercurial post needs to be sorted out.

   nigel: You might want to start with a fresh Respec doc or
   there's also bikeshed.
   ... Thierry, do you have an empty template you can send?

   tmichel: Yes I'll send Mike an empty template. Do you want to
   make it a Note?

   mike: I think we agreed to do that.

   tmichel: Okay.

   <scribe> ACTION: tmichel Send mdolan an empty respec based Note
   as a starting point for action-429 [recorded in

   <trackbot> Created ACTION-436 - Send mdolan an empty respec
   based note as a starting point for action-429 [on Thierry
   Michel - due 2015-10-22].

   nigel: Let's take a 3 minute break and come back to look at
   IMSC issues for the second half of the meeting...



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


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

   pal: I modified this to mandate lineBreak-uax14 for text
   profile and leave silent for image profile.
   ... nigel raised a separate issue about profiles that we can
   deal with separately.

   close issue-406

   <trackbot> Closed issue-406.


   <trackbot> issue-407 -- Excluding #bidi and #direction on image
   profile is inconsistent -- pending review


     [24] http://www.w3.org/AudioVideo/TT/tracker/issues/407

   pal: To summarise, some features in TTML1 imply other features.
   This was a case where there
   ... was an inconsistency so I tried to correct that
   inconsistency as proposed by the commenter,
   ... by saying #bidi is not applicable in the image profile
   because not all included features are
   ... supported.

   nigel: On image profile, are some of the implied features

   pal: Yes. So bidi cannot be used in its entirety.

   nigel: Okay I see, #writingMode-horizontal is permitted (from
   the common features) but
   ... since #direction and #unicodeBidi are prohibited then it
   does not apply.
   ... I'd suggest removing the "Not applicable" since it's not
   the spec's job to decide that.

   pal: ok

   issue-407: [meeting 2015-10-15] Propose new text: "See implied
   features: some are prohibited, others are permitted"

   <trackbot> Notes added to issue-407 Excluding #bidi and
   #direction on image profile is inconsistent.

   reopen issue-407

   <trackbot> Re-opened issue-407.


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


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


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


     [26] http://www.w3.org/AudioVideo/TT/tracker/actions/432

   nigel: I started a thread on this but haven't had the answer
   yet. My view is to go ahead with this
   ... and if there's a problem then come back to it.

   pal: Can you propose some specific text?

   Action-432: [meeting 2015-10-15] nigel to check on details and
   propose specific wording

   <trackbot> Notes added to Action-432 Nigel, pal, andreas and
   frans to hook up re changing imsc 1 ebu-tt feature references
   to point to tech3350 v1.1.

   issue-410: [meeting 2015-10-15] see Action-432 update.

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


   <trackbot> issue-411 -- "shall be inherited" on #multiRowAlign
   -- pending review


     [27] http://www.w3.org/AudioVideo/TT/tracker/issues/411

   nigel: The same edit for issue-410 should apply to issue-411

   reopen issue-411

   <trackbot> Re-opened issue-411.

   reopen issue-410

   <trackbot> Re-opened issue-410.

   issue-411: [meeting 2015-10-15] see Action-432 update.

   <trackbot> Notes added to issue-411 "shall be inherited" on

   action-432: [meeting 2015-10-15] also applies to issue-411

   <trackbot> Notes added to action-432 Nigel, pal, andreas and
   frans to hook up re changing imsc 1 ebu-tt feature references
   to point to tech3350 v1.1.


   <trackbot> issue-412 -- The term 'SHALL' should not be used in
   the definition of Related Video Object -- pending review


     [28] http://www.w3.org/AudioVideo/TT/tracker/issues/412

   pal: I think the document is better and implements what the
   commenter suggested.

   close issue-412

   <trackbot> Closed issue-412.


   <trackbot> issue-413 -- What does "reproducible without error"
   mean? -- pending review


     [29] http://www.w3.org/AudioVideo/TT/tracker/issues/413

   nigel: So you've applied the change that Glenn okayed?

   pal: Yes I think so!

   close issue-413

   <trackbot> Closed issue-413.


   <trackbot> issue-417 -- #writingMode constraint inconsistent in
   image profile -- pending review


     [30] http://www.w3.org/AudioVideo/TT/tracker/issues/417

   pal: I've just posted an update that changes this one as well
   as the one nigel just suggested.
   ... #writingMode now says "See implied features: some are
   prohibited, others are permitted."
   ... And I've added the change set to the issue.

   nigel: Are there any other partial ones?

   pal: I searched and couldn't find any other.
   ... Issue-407 and issue-417 are addressed with the same text
   nigel proposed on issue-407

   <mike> dropping for another meeting

   nigel: Since I know there are other bigger issues with profiles
   I don't want to spend any more time on these

   pal: Also they don't have any conformance implications.

   close issue-407

   <trackbot> Closed issue-407.

   close issue-417

   <trackbot> Closed issue-417.


   <trackbot> issue-418 -- semantics of ttp:aspectRatio is
   ambiguous -- pending review


     [31] http://www.w3.org/AudioVideo/TT/tracker/issues/418

   nigel: After the last change I made a proposal.

   pal: So you wanted to add a note to Example 2 saying how it
   would look on a 4:3 display also?

   nigel: Yes.

   pal: Okay I can do that. I think that's an excellent

   nigel: My aside was just because the numbers seemed like magic
   - which maths sometimes does!

   pal: I'm going to implement that change right now...


   <trackbot> issue-419 -- Overflow recommendations + #overflow
   feature -- pending review


     [32] http://www.w3.org/AudioVideo/TT/tracker/issues/419

   nigel: In this case there seems to be no action to take.
   Glenn's point seems to miss that there
   ... is no mandated behaviour for either hidden or visible value
   of tts:overflow in TTML1.

   close issue-419

   <trackbot> Closed issue-419.


   <trackbot> issue-420 -- The TTML timing vocabulary does not
   have elements -- pending review


     [33] http://www.w3.org/AudioVideo/TT/tracker/issues/420

   nigel: The easy path here is to remove "or element" isn't it?
   That would strictly be correct.

   pal: I don't think so. TTML1 §10 is "Timing Element Vocabulary"
   ... By the way this came out of me trying to match TTML1 as
   closely as possible.

   close issue-420

   <trackbot> Closed issue-420.


   <trackbot> issue-421 -- Term "earlier" is ambiguous -- pending


     [34] http://www.w3.org/AudioVideo/TT/tracker/issues/421

   pal: I've satisfied Glenn and Nigel on this one, so it can be

   close issue-421

   <trackbot> Closed issue-421.


   <trackbot> issue-422 -- Presented region + itts:forcedDisplay
   -- pending review


     [35] http://www.w3.org/AudioVideo/TT/tracker/issues/422

   nigel: I added a comment to this.

   pal: Actually itts:forcedDisplay does not modify the computed
   value of tts:visibility. And more
   ... importantly the document conformance should be independent
   of displayForcedOnlyMode.

   nigel: I see - itts:forcedDisplay does not modify the computed
   value of tts:visibility.

   pal: It used to be like that but based on Glenn's earlier
   feedback it was changed to be independent.

   nigel: I don't think there's any change needed here. Maybe the
   phrasing "allows the processor to override the computed value"
   isn't helpful.

   pal: To me that's a different issue, but I agree. If you want
   to propose new wording to the
   ... introductory sentence then please go ahead.

   <scribe> ACTION: nigel [imsc1] propose new wording for intro
   sentence to itts:forcedDisplay [recorded in

   <trackbot> Created ACTION-437 - [imsc1] propose new wording for
   intro sentence to itts:forceddisplay [on Nigel Megitt - due

   close issue-422

   <trackbot> Closed issue-422.


   <trackbot> issue-425 -- Awkward prose re: smpte:backgroundImage
   and ittm:altText -- pending review


     [37] http://www.w3.org/AudioVideo/TT/tracker/issues/425

   pal: I've done what was proposed.

   close issue-425

   <trackbot> Closed issue-425.


   <trackbot> issue-426 -- MHP vs W3C reference for PNG -- pending


     [38] http://www.w3.org/AudioVideo/TT/tracker/issues/426

   pal: I couldn't find a meaningful difference and I take Glenn's
   point. Even if we did say MHP most
   ... people would ignore it anyway!

   close issue-426

   <trackbot> Closed issue-426.


   <trackbot> issue-427 -- Misc prose tweaks -- pending review


     [39] http://www.w3.org/AudioVideo/TT/tracker/issues/427

   close issue-427

   <trackbot> Closed issue-427.


   <trackbot> issue-430 -- independent variables in the HRM --
   pending review


     [40] http://www.w3.org/AudioVideo/TT/tracker/issues/430

   pal: This was a question rather than a proposal. I think I've
   answered it and not heard back.

   nigel: And you told Glenn about this comment on the issue?

   pal: Yes, I reminded him of all the issues I'd addressed, on
   the day (Sep 21)
   ... Regardless, this may be taken up by bigger things due to
   Glenn's other comments on the HRM.

   close issue-430

   <trackbot> Closed issue-430.


   <trackbot> issue-432 -- Multiple layers of background color in
   HRM -- pending review


     [41] http://www.w3.org/AudioVideo/TT/tracker/issues/432

   pal: I asked Glenn if he wanted clarification and he didn't
   respond, so I assume he's not unhappy.

   close issue-432

   <trackbot> Closed issue-432.

   pal: There are a couple of open issues that are linked, that
   I'd like to cover.


   <trackbot> issue-434 -- Behavior in case of multiple images in
   a region -- open


     [42] http://www.w3.org/AudioVideo/TT/tracker/issues/434


   <trackbot> issue-433 -- Presented image definition -- open


     [43] http://www.w3.org/AudioVideo/TT/tracker/issues/433


   <trackbot> issue-424 -- Awkward text re: smpte:backgroundImage
   dimensions -- open

   <trackbot> [44]http://www.w3.org/AudioVideo/TT/tracker/issue424

     [44] http://www.w3.org/AudioVideo/TT/tracker/issue424

   pal: These issues are questions about document non-conformance.
   IMSC 1 specifically does
   ... not specify behaviour in this case. Glenn suggested
   guidance would be helpful. I've tried
   ... drafting generic advice on dealing with non-conformant
   documents. The problem is that
   ... fundamentally this is dependent on the application and the
   user preference. Two extreme
   ... examples:
   ... 1. During authoring I would expect an authoring tool never
   to emit a non-conforming document.
   ... 2. A player - I would hope that a player should do its best
   to do something with a non-conformant document.
   ... Because the circumstances are so broad I don't think it's
   possible to come up with a generic
   ... definition with conformance text for behaviour in case of a
   non-conformant document. We
   ... could go down the path of exploring all the scenarios. I'm
   not sure if we could ever do that
   ... in a useful way. I've not been able to find anything that
   makes sense and is helpful and
   ... non-harmful.

   dakim: With non-conformance, you just have to handle it. A spec
   document isn't the place for
   ... that. Just don't address it. It's your problem!

   nigel: I think that's fair.

   pal: In that case I'm happy to close those issues, maybe with a
   note, until someone has a better idea.

   tmichel: Did Glenn raise a specific request?

   pal: No.

   tmichel: Then it's an implementation issue.

   pal: Yes, I think so too.

   issue-424: [Meeting 2015-10-15] Agreed to close since no
   wording for non-conformance handling has been proposed, by

   <trackbot> Notes added to issue-424 Awkward text re:
   smpte:backgroundImage dimensions.

   issue-434: [Meeting 2015-10-15] Agreed to close since no
   wording for non-conformance handling has been proposed, by

   <trackbot> Notes added to issue-434 Behavior in case of
   multiple images in a region.

   issue-433: [Meeting 2015-10-15] Agreed to close since no
   wording for non-conformance handling has been proposed, by

   <trackbot> Notes added to issue-433 Presented image definition.

   close issue-424

   <trackbot> Closed issue-424.

   close issue-433

   <trackbot> Closed issue-433.

   close issue-434

   <trackbot> Closed issue-434.


   <trackbot> action-431 -- Nigel Megitt to File issue re profile
   feature inclusion in imsc 1 documents -- due 2015-10-15 --


     [45] http://www.w3.org/AudioVideo/TT/tracker/action431

   close action-431

   <trackbot> Closed action-431.

   nigel: We're out of time so I'll adjourn. Thanks everyone for
   your time - we got through loads!
   ... [adjourns meeting]

Summary of Action Items

   [NEW] ACTION: mdolan Draft outgoing liaison to ATSC proposing
   to reference an updated WD of TTML2 [recorded in
   [NEW] ACTION: nigel [imsc1] propose new wording for intro
   sentence to itts:forcedDisplay [recorded in
   [NEW] ACTION: nigel add tools to TPAC agenda [recorded in
   [NEW] ACTION: tmichel Send mdolan an empty respec based Note as
   a starting point for action-429 [recorded in
   [NEW] ACTION: tmichel Update CVS hosted landing page to
   simplify and highlight link into wiki page [recorded in

   [End of minutes]

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Received on Thursday, 15 October 2015 16:21:49 UTC