Timed Text Working Group Teleconference

<trackbot> Date: 26 March 2015

<scribe> scribe: nigel

This meeting

nigel: We have an extra agenda item today on tmichel's request, for the WebVTT comments

group: no AOB

Actions

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: I did this and sent it round

<inserted> See later - this comment actually refers to Action-382. Action-378 remains open

close action-378

<trackbot> Closed action-378.

nigel: Let's defer discussion of action-379 to the IMSC test suite agenda item

action-381?

<trackbot> action-381 -- Pierre-Anthony Lemieux to Prepare new list of changes to imsc 1 since cr1. -- due 2015-03-26 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/381

pal: I have a draft here but need to do some more work on it before I send it. I'll do that ASAP - apologies for not getting around to it.

action-383?

<trackbot> action-383 -- Glenn Adams to Missing XML declaration -- due 2015-03-26 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/383

glenn: I added this in but have a problem with the bindings processor, so I need to figure out what's going on.
... when I take it out the jaxb binding parser succeeds. But if I don't generate the bindings then
... there's no problem so I need to do some more work to figure out the resolution. I did update
... the schema document in the repository.

nigel: That didn't appear in the TTML Changelog RSS feed for some reason.

reopen action-378

<trackbot> Re-opened action-378.

action-382

<trackbot> action-382 -- Nigel Megitt to Summarise action-369 end point -- due 2015-03-26 -- PENDINGREVIEW

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/382

nigel: My mistake earlier - it should be this one that I close, as discussed earlier.

close action-382

<trackbot> Closed action-382.

action-380?

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

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/380

pal: I did create those issues, and have also implemented them.

close action-380

<trackbot> Closed action-380.

F2F

nigel: On the Las Vegas F2F, there's not much more to report. Dae Kim of Netflix will be observing.

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

glenn: I'm planning to spend some time from April 1 to prepare some updates to TTML2 and will
... be generating some topics that we will want to discuss.

pal: I don't have any particular outstanding items for IMSC 1 right now, though some may arise.
... I do have some TTML2 issues that I plan to raise, which may generate some discussion also.

nigel: Thanks both. Looking at TPAC 2015 in Sapporo, I sent round a link to a survey, whose results
... I will be using to provide a group response to the organisers.

https://www.w3.org/2002/09/wbs/34314/TTWGTPAC2015/

nigel: Thanks for the responses so far. The survey stays open until 22nd April.
... The early results are enough to say that we will have a f2f meeting in Sapporo.
... Probably on the Monday and Tuesday.

pal: It would be really great if the TTWG meetings don't overlap with the HTML media task force meetings.
... A joint meeting could be a really good idea.

nigel: Thanks that's a really good point.
... There's still time to complete this survey - please do if you haven't already.

IMSC 1 Test Suite and Implementation Report

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 did send round some HTML as a source for creating a PNG. Andreas, you had a concern?

atai: I think we should not use HTML as a reference source especially if it uses advanced features.
... It may not look the same on all clients. Even if we recommend a specific browser version it may
... generate a false understanding. We should maybe only use PNGs.

glenn: I'd emphasise that we absolutely cannot use HTML. The two options are SVG and PNG.

nigel: That's fine - and it wasn't my intention that the HTML be used directly.

glenn: Of course it's useful for us in our working group to use HTML to work on mappings or quick demos
... but for test content or images to go into the spec we should use SVG or PNG.

nigel: I'd second that.

pal: The examples worked okay for me though there were some strange artefacts and line box boundaries
... (Chrome on Win7)

nigel: Chrome on Mac OS X looks fine for me.
... I'm happy to turn those into PNGs then. The only thing is that it might help if we reduce the
... amount of text so that it fits on two lines not three, on a 16:9 window. Or reduce the font size.
... I'd be happy either way. I'll do some fiddling with the example and the HTML equivalent and send
... you the results, Pierre.

pal: That makes sense.

nigel: I have a colleague working on an implementation and that generated a question that's
... unclear from TTML. Is the width of the background area of a tt:p the content area of the parent region
... less the padding or is it as wide as the widest line area of the content of the p?

glenn: It should be the width of the content area which is the width of the parent element's area
... minus any padding, so in TTML1 that's the region's width minus region padding, but in TTML2 body and div can have
... their own padding values.

nigel: In that case the examples in TTML are at best ambiguous and possibly misleading. I may raise an issue on this.
... For example the sample image on tts:backgroundColor, where the text width happens to be
... exactly the same as the padding inset area, so it looks as though the purple background on the
... p is wrapped to the contained content not the padding width.

glenn: You're right, I think this could be made clearer. Perhaps a couple of additional examples
... would be appropriate.

nigel: Okay, I'll raise that then.

Andreas: Can we discuss issue-375?

issue-375?

<trackbot> issue-375 -- Use of the ebutts:linePadding and ebutts:multiRowAlign in IMSC 1 -- open

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/375

Andreas: I can confirm that ebutts:multiRowAlign does apply only to tt:p and is inheritable. We should
... update EBU-TT-D, and in the meantime we should update IMSC 1 accordingly.

pal: Just to confirm, the proposed resolution is to add some text to IMSC 1?

Andreas: I'll just check...
... ... I think the issue we raised is that it could be used for inline styling, but then you brought up

<glenn_> hmm, i just lost audio, calling back

Andreas: the other issue. Yes, I think it's not right because it only applies to tt:p. If you apply it to region,
... body or div it would give a completely different result. If it applied to a div then the reference would
... be the longest line in the container. It should only apply to tt:p and be inheritable.

pal: How do you want to proceed?

Andreas: I can propose some text. It's just a matter of reproducing the information that's on the
... style attributes in TTML. I'll put the proposed text in the issue for review.

issue-375: [meeting 2015-003-26] Andreas to propose some wording to make clear that ebutts:multiRowAlign applies only to tt:p and is inheritable.

<trackbot> Notes added to issue-375 Use of the ebutts:linePadding and ebutts:multiRowAlign in IMSC 1.

pal: Andreas, could I ask you to do this by the end of the week? That will allow me to complete my
... report on the changes since the CR.

Andreas: Yes, I will do that.

pal: Thanks

WebVTT

nigel: Since Thierry is not on the call, and he requested this topic, I'll defer it.

Issues

issue-376?

<trackbot> issue-376 -- Missing XML declaration -- raised

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/376

reopen issue-376

<trackbot> Re-opened issue-376.

nigel: This is the schema issue we discussed earlier - work has already begun.

issue-379?

<trackbot> issue-379 -- ruby text should used special inheritance algorithm -- raised

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

glenn: As we were implementing Ruby support we realised that inheriting the font size and line height
... by default it would collide with an automatic sizing algorithm for fonts because one could not
... distinguish between the author's genuine intent vs having no default or initial value, in which
... case automatic sizing would apply. What we've implemented is that for textContainer it does not
... inherit any fontSize or lineHeight unless it's explicitly specified on the textContainer and on the
... text Ruby that could be a child of a textContainer (or not). It can inherit from a parent textContainer
... but no further. In other words if the textContainer specified a fontSize or lineHeight the contained
... text would also get that, otherwise it would not.

nigel: It's tempting to suggest the keyword auto for fontSize, to make the same distinction.

glenn: There's somewhere else where that could be useful, for content fitting, but I don't want to
... go there quite yet. For example, find a font size that will fit the content into the region.
... The tradition of the keyword auto in CSS is: let the UA figure out what's best. So it's impossible
... to define interoperability when it comes to the use of auto.

reopen issue-379

<trackbot> Re-opened issue-379.

issue-367?

<trackbot> issue-367 -- Clarify initial value override for tts:textAlign -- pending review

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/issues/367

pal: This has been implemented.

nigel: This and issue-377 and issue-378 have been implemented this week and nobody on the call
... has had a chance to review yet, so let's leave those for another week.

pal: There's nothing to call out particularly - these implementations follow what we came to a
... consensus on during the last call.

nigel: I think you can proceed with the changes relative to CR document based on assumed acceptance of these issue implementations.

pal: That's what I'll do.

nigel: We've hit time for today, so thanks very much everyone. We'll meet again same time next
... week, which for folk in Europe is back to the traditional time because DST comes in this week here.
... [adjourns meeting]