W3C

Timed Text Working Group Teleconference

19 Mar 2015

See also: IRC log

Attendees

Present
pal, glenn, nigel, tmichel
Regrets
Frans, mike, jdsmith, atai2
Chair
nigel
Scribe
nigel

Contents


<trackbot> Date: 19 March 2015

this meeting

group: no AOB

Action Items

action-364?

<trackbot> action-364 -- Glenn Adams to Add paragraph in intro that summarizes changes from ttml1 (comment from tm) -- due 2015-03-17 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/364

glenn: No progress on this one. This needs to be done for the WD for wide review.
... This can be pushed back more.

nigel: I've added a comment and pushed it back to 17th April to be more in keeping with the updated
... timeline for TTML2.

action-378?

<trackbot> action-378 -- Pierre-Anthony Lemieux to Draft smpte request including dispositions from action-369 and backgroundcolor initial value question -- due 2015-03-05 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/378

nigel: Mike sent an email to the reflector shortly before this meeting suggesting that removing
... the initial value constraints from IMSC 1 would be a reasonable idea, which would mean we
... don't need to make any requests from SMPTE about that part of the action.

pal: I've done some informal polling. There's the initial value issue and also ttp:frameRate and ttp:frameRateMultiplier
... being tied to the related video object, and also rounding rules that were left from CFF.
... Everything I've heard is consistent with Mike's view that CFF's intention was not to reference
... all of SMPTE-TT but just the backgroundImage part.
... On the frame rate issue the trend these days is to make frame rate and resolution independent
... TTML files, and the frame rate constraint isn't consistent with that. I haven't heard a clear reason
... why that's required in IMSC 1.

nigel: On the rounding, we should maybe have one consistent set of rounding rules between IMSC1 and TTML1SE

pal: My proposal is to 1) remove the SMPTE default values, 2) remove the constraint on frame rate
... being the same as the related video object and 3) to remove the rounding constraint difference
... to make it the same in IMSC 1 as in TTML1SE.

glenn: On the frame rate and frame rate multiplier, that was there to facilitate conversion from
... frame values to second values in SMPTE continuous mode, or media mode.

pal: My suggestion is to make those changes, and issue a new CR.

tmichel: It depends how substantial the changes are - if they're just editorial then we can issue
... a new CR. Since we're not on the old process we don't have to go back to LC.

nigel: There's a query here on how substantive the changes are - I support them, but wonder
... what the criteria are.

tmichel: That's not well defined and is in the end down to the Director.

pal: The IMSC timeline allows for another CR. What would the process be for this second CR.

tmichel: We issue a transition request, and if the Director approves then we move to the second CR.
... Then once we have enough implementations to meet the exit criteria then we can do so. We can
... proceed to PR if there are no features that have not been implemented. If there are at risk
... features that have not been implemented they may get removed.

pal: If the changes don't affect the test suite...

tmichel: That's a good definition for 'not substantial' changes.

glenn: I would not consider these changes to be substantial. I view clarification of semantics to
... be editorial - for me the definition is that there is a change to syntax or normative conformance
... requirements.

tmichel: I would agree with that. Or if it impacts implementation.

nigel: My understanding is that we do not need a further wide review to go CR->CR.

pal: Is there a minimum period between CR and PR?

tmichel: To exit CR you do have to put an earliest possible date, but you can also remain in CR for
... years if you'd rather wait for implementations.

pal: I propose to make those changes, and other changes, and prepare a list of the delta since the
... current CR.
... How does that sound?

nigel: Sounds good to me.

tmichel: +1.
... If you do label those changes, mention them as substantive or editorial.

pal: For now I will just list them without labelling them.

<scribe> ACTION: pal Create IMSC 1 issues for removing initial value constraints, rounding definitions different to TTML1 and frame rate relationship to video [recorded in http://www.w3.org/2015/03/19-tt-minutes.html#action01]

<trackbot> Created ACTION-380 - Create imsc 1 issues for removing initial value constraints, rounding definitions different to ttml1 and frame rate relationship to video [on Pierre-Anthony Lemieux - due 2015-03-26].

pal: I think we no longer need a communication to SMPTE on initial value history

<scribe> ACTION: pal Prepare new list of changes to IMSC 1 since CR1. [recorded in http://www.w3.org/2015/03/19-tt-minutes.html#action02]

<trackbot> Created ACTION-381 - Prepare new list of changes to imsc 1 since cr1. [on Pierre-Anthony Lemieux - due 2015-03-26].

pal: I haven't created the draft wording for the SMPTE liaison yet - I need to unfold all the comments

nigel: Probably best if I can pull that all together.

glenn: I don't have any further comments on the Action-369 thread

<scribe> ACTION: nigel Summarise Action-369 end point [recorded in http://www.w3.org/2015/03/19-tt-minutes.html#action03]

<trackbot> Created ACTION-382 - Summarise action-369 end point [on Nigel Megitt - due 2015-03-26].

Action-379?

<trackbot> Action-379 -- Nigel Megitt to Obtain png images for #linepadding and #multirowalign test cases. -- due 2015-03-19 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/379

nigel: I've been in touch with Andreas about this, and also verified that we do need separate images
... for this because the test cases aren't in the referenced EBU document. This is ongoing.

F2F

nigel: I think more people have joined now.

https://www.w3.org/wiki/TimedText/F2F-april-2015

nigel: We now have 7 attendees.
... I suspect the first item on the agenda will be to work out the agenda scheduling!
... We have the opportunity to discuss both TTML and also WebVTT issues over the 2 days,
... and Dave Singer has invited the CG to attend in person or maybe by dialling in.

IMSC Test Suite and Implementation Report

pal: I have received some feedback and committed some minor changes.
... Glenn, apparently one of the TTML XSDs is missing the XML declaration line at the beginning.

glenn: That's possible - let me take a quick look.

pal: This is the ttm1-styling.xsd file

glenn: Yes, it's missing, but it's still valid XML.

pal: Apparently Xerces complains about it.

glenn: since the other files all have it then it should probably have it.
... Looks like an editorial oversight.

pal: I will file an issue for this.

glenn: That will also prompt me to check the TTML2 schema too.

<inserted> Issue-376 captures this.

Issues

issue-289?

<trackbot> issue-289 -- For TTML created for overlay on top of video, signal the aspect ratio of the video the TTML was created for -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/289

nigel: This was implemented in ยง14.3.2 <named-item> targetAspectRatio

glenn: Yes, all of the EBU proposed metadata are defined there. They're still subject to
... refinement and syntax. There's an editorial note to format the syntax rather than making it
... an open string. That's a tbd for me to go back to the source.
... We may want to cover document aspect ratio separately because there will be extra verbiage.
... Including parameters.

nigel: I want to verify that the EBU is happy with this general approach as well.
... In the meantime it's hard to complete the review without the syntax being complete by
... definition or reference.

glenn: We did close off a load of SMPTE issues that had a similar objection on the basis that we
... can review the editorial fixes later and raise any issues.

nigel: This applies to issue-289, issue-290, issue-291 and issue-292 which are all implemented
... the same way.

close issue-289

<trackbot> Closed issue-289.

issue-290?

<trackbot> issue-290 -- For TTML created for overlaying on video, add ebuttm:documentTargetActiveFormatDescriptor -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/290

close issue-290

<trackbot> Closed issue-290.

issue-291

<trackbot> issue-291 -- Document Intended Target Bar Data -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/291

close issue-291

<trackbot> Closed issue-291.

issue-292

<trackbot> issue-292 -- Specify target formats for which the TTML has been authored for easy conversion -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/292

close issue-292

<trackbot> Closed issue-292.

issue-353?

<trackbot> issue-353 -- Normatively define short code processorProfiles parameter -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/353

glenn: I marked this as a duplicate of issue-351

nigel: I don't agree - it's a pre-requisite for issue-351

reopen issue-353

<trackbot> Re-opened issue-353.

issue-353: This is not a duplicate of issue-351 but is a pre-requisite for it.

<trackbot> Notes added to issue-353 Normatively define short code processorProfiles parameter.

issue-359?

<trackbot> issue-359 -- Add support for font kerning enable/disable -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/359

glenn: This is similar to other properties that are on p and span like fontStyle. It comes from a
... usage in the LambdaCap system in Japan that allows kerning to be switched on or off. I have no
... data on how often it is used. Kerning is the other side of the coin from letter spacing so they go together.
... In Japan it would only be used for roman characters (romaji).
... There is a CSS property in the fonts module of the same name, with the same semantics.

close issue-359

<trackbot> Closed issue-359.

issue-364?

<trackbot> issue-364 -- Relax constraint between the extents of the root container and the dimensions of the related video object frame -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/364

pal: This has been done for a while - it was done after the CR but is already in the test suite.
... It was the response to Simon Hailes' comment.
... The general idea is to make it possible for authors to be able to create resolution independent files.

close issue-364

<trackbot> Closed issue-364.

pal: This is one of the changes I'll be listing prior to publishing a new CR.

nigel: We've just closed all the pending review issues! And we're out of time, this is a good point to end on.
... Thanks everyone, see you at the same time next week. [adjourns meeting]

Summary of Action Items

[NEW] ACTION: nigel Summarise Action-369 end point [recorded in http://www.w3.org/2015/03/19-tt-minutes.html#action03]
[NEW] ACTION: pal Create IMSC 1 issues for removing initial value constraints, rounding definitions different to TTML1 and frame rate relationship to video [recorded in http://www.w3.org/2015/03/19-tt-minutes.html#action01]
[NEW] ACTION: pal Prepare new list of changes to IMSC 1 since CR1. [recorded in http://www.w3.org/2015/03/19-tt-minutes.html#action02]
 
[End of minutes]

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$Date: 2015/03/19 15:08:21 $