IRC log of tt on 2015-04-10

Timestamps are in UTC.

00:00:01 [nigel]
pal: I've not found a technical defect with this condition structure, but I think it's incredibly complex.
00:00:17 [nigel]
... It forces people to build a parser for the condition language. It's additive and people are already having
00:00:36 [nigel]
... trouble just rendering TTML. I think it adds a lot of complexity for what originally were a small set of use
00:00:37 [nigel]
... cases.
00:01:07 [nigel]
glenn: There's a trade-off between expressiveness and complexity. If you look at e.g. media query, which people
00:01:28 [nigel]
... might quite likely want to conditionalise content based on, it often generates situations where you need
00:01:44 [nigel]
... at least logical expressions AND, OR, NOT etc and pretty soon want to compare parameters to others, like
00:02:01 [nigel]
... is width or height < or > some value, then you've got numerical comparisons as well as logical ones. Then
00:02:23 [nigel]
... soon you want arithmetic too! Just adding conditions that have named parameters and combinatorial logic
00:02:37 [nigel]
... for logical expressions doesn't seem very different to me than adding something that satisfies the more
00:02:53 [nigel]
... general case, and from a parsing perspective it's really straightforward. To write a parser for what is there
00:03:17 [nigel]
... now vs a subset is going to have almost the same complexity. The syntax now will require a lot of test content though.
00:04:06 [nigel]
... I didn't want to reinvent media queries. To implement the expression language I'd estimate as a day's work.
00:06:00 [nigel]
nigel: You may want to conditionalise XML attributes on the tt:tt element but I can't see how you'd do that.
00:06:17 [nigel]
... For example you might want the extent to be dependent on whether the media is being viewed fullscreen
00:06:32 [nigel]
... or not fullscreen.
00:07:13 [nigel]
glenn: There are limits to it. The precedent for this is the switch element in SMIL and SVG.
00:07:25 [nigel]
... What that system did was to limit the locations where switch is permitted, e.g. you can't use it to switch
00:07:48 [nigel]
... between definitions based on conditions. In TTML we have a number of definitional mechanisms like the
00:08:08 [nigel]
... region and style elements. So far I've permitted condition to be used on those, but the only one it can't
00:08:31 [nigel]
... apply to is the tt element itself. Is there any way to express the information on tt in a conditional way?
00:08:42 [nigel]
... I haven't thought about that.
00:09:02 [nigel]
... I did put condition on tt:tt but that may be overly aggressive.
00:09:11 [nigel]
nigel: You'd have to duplicate the whole tree.
00:09:41 [nigel]
glenn: I'm not sure condition is going to work at all on the tt element.
00:18:54 [nigel]
nigel: It's also unclear to me when the evaluation time is for conditions - is it any time during the presentation?
00:19:30 [nigel]
glenn: My intention was to evaluate once before presentation and not again, but I guess implementations could
00:19:49 [nigel]
... offer on-the-go reevaluation. That could be implementation dependent.
00:20:12 [nigel]
nigel: In terms of the spec it's not clear when the evaluation time should be.
00:20:24 [nigel]
glenn: Certainly adding a note that needs to be defined would be prudent.
00:21:54 [nigel]
nigel: You could also take an approach of using XML Query or other syntax and re-use existing techniques
00:22:04 [nigel]
... as a single evaluation before presentation.
00:22:35 [nigel]
glenn: If you're suggesting throwing this out and using XML Query instead I think that would be overkill.
00:23:01 [nigel]
... I think what's in scope of our discussion is 'is there a testable implementable use case' that this meets, rather
00:23:24 [nigel]
... than complexity of implementation. Complexity is a profile issue. Let's say you want a profile that uses
00:23:49 [nigel]
... condition and limits the form of the expressions, such as 'the only permitted functions are bound parameters'
00:24:11 [nigel]
tai: I have recently been wondering if there will ever be a complete TTML implementation.
00:25:00 [nigel]
... You always need something like IMSC to be an implementable thing.
00:25:30 [nigel]
tai: One proposal for this conditional mechanism: a complete example and use case in the spec would make it
00:25:33 [nigel]
... easier to understand.
00:25:45 [nigel]
glenn: I agree it needs some examples.
00:27:28 [nigel]
nigel: What's the list of use cases we have for this so far: forced display, ...?
00:27:33 [nigel]
glenn: languages
00:28:20 [nigel]
Courtney: I get asked for functionality to present translated subtitles as a licence requirement in some countries, tied to the audio language.
00:28:58 [nigel]
... e.g. if audio language == spanish then you must display subtitles in language XYZ. This is very similar
00:29:02 [nigel]
... to forced subtitles.
00:29:34 [nigel]
tai: I thought of a use case that may or may not work, where you have a complete style set that is in use or
00:31:54 [nigel]
... out of use depending on the condition, to select predefined style sets.
00:32:00 [nigel]
nigel: That could help meet the MAUR requirements
00:32:08 [nigel]
pal: It wouldn't work for regulation.
00:32:29 [nigel]
Courtney: full customisation at the terminal is a requirement for FCC
00:36:36 [nigel]
pal: We don't need to put that functionality into TTML - it's a receiver thing only.
00:37:55 [nigel]
nigel: Maybe it wouldn't work in the US but based on the feedback I see to BBC I think it would really be
00:38:12 [nigel]
... appreciated if broadcasters could offer different style sets, and not outrageous for broadcasters to provide
00:38:15 [nigel]
... them.
00:38:39 [nigel]
tai: In Germany I can see that a useful option might be to put this in the document. We have discussions
00:39:02 [nigel]
... with TV manufacturers too and they don't see it as their business to provide configuration options.
00:40:03 [nigel]
... It's unclear how customisation works now - it has to be done by content provider apps.
00:46:03 [nigel]
Courtney: Whatever layer is doing the rendering is where the options have to be evaluated.
00:46:34 [nigel]
nigel: You could have some content provider provided transformations to allow for some styling.
00:46:49 [nigel]
... There's a problem with any kind of declarative styling which is that to style specific content you need to
00:47:13 [nigel]
... know how it's identified so that you can target (or select) it. Only the document author knows that, because
00:47:36 [nigel]
... it's document dependent.
00:48:14 [nigel]
... That makes customisation always difficult.
00:48:36 [nigel]
Courtney: It could be interesting to investigate whether pre-defined transformations can meet all the user
00:48:50 [nigel]
... requirements for accessibility but there would be lots of work to do on it.
00:49:33 [nigel]
glenn: We have to leave complexity until we've seen the implementations, unless someone can say what
00:49:37 [nigel]
... doesn't work about it.
00:49:57 [nigel]
... Obviously conditionalisation on the tt element is a limiting factor. Can we mitigate that and should we mitigate that?
00:50:25 [nigel]
... If the solution is very complex to specify and hard to understand then that could count against it.
00:50:54 [nigel]
... My main criteria are: is it specifiable, is it usable, is it implementable? Equally important.
00:51:16 [nigel]
... By the way we need to take out stereoLeft and stereoLeft.
00:51:31 [nigel]
Action: glenn remove stereoLeft and stereoRight from <bound-parameter>
00:51:31 [trackbot]
Created ACTION-385 - Remove stereoleft and stereoright from <bound-parameter> [on Glenn Adams - due 2015-04-17].
00:52:50 [nigel]
glenn: Are there any other bound parameters that folk want?
00:53:02 [nigel]
nigel: You could add full-screen and then we can see how that plays out.
00:57:47 [nigel]
nigel: The difference would be that for full-screen you want extent="contain" but if not then "cover" because
00:57:54 [nigel]
... there's more display to use.
00:58:23 [nigel]
glenn: Let me think about that bigger level question there. I've already got a thought process in train for
00:58:47 [nigel]
... how to handle conditionalised parameters. In TTML2 we also allow all the style attributes to be added onto
00:59:20 [nigel]
... the tt:tt element and have them inherited by the region elements. They would maybe also need to be
00:59:24 [nigel]
... conditonal.
00:59:37 [nigel]
nigel: But what's the difference between that and the initial element?
00:59:52 [nigel]
glenn: I guess if you specified initial differently and did not specify them on a region then region would pick
01:00:04 [nigel]
... them up. Yes, maybe its redundant to put them on tt.
01:00:32 [glenn]
ACTION: glenn to investigate whether region style inheritance from tt is necessary given the ability to redefine initial values
01:00:32 [trackbot]
Created ACTION-386 - Investigate whether region style inheritance from tt is necessary given the ability to redefine initial values [on Glenn Adams - due 2015-04-17].
01:02:20 [nigel]
Topic: Recap
01:02:56 [nigel]
nigel: We've covered a lot today. Tomorrow we'll use the 'spare' time available to go over the remaining
01:03:25 [nigel]
... TTML2 topics as well as everything else we have planned - let's prioritise based on time available and what
01:03:32 [nigel]
... everyone wants to do.
01:03:55 [nigel]
... We're restarting in the morning at 8:30.
01:03:58 [nigel]
rrsagent, generate minutes
01:03:58 [RRSAgent]
I have made the request to generate nigel
01:04:19 [nigel]
nigel: Thanks everynone! [adjourns meeting]
01:04:37 [nigel]
rrsagent, generate minutes
01:04:37 [RRSAgent]
I have made the request to generate nigel
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rrsagent, generate minutes
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I have made the request to generate nigel
01:10:02 [nigel]
rrsagent, this meeting spans midnight
01:10:06 [nigel]
rrsagent, generate minutes
01:10:06 [RRSAgent]
I have made the request to generate nigel
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03:52:07 [glenn]
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logging to
15:25:27 [trackbot]
RRSAgent, make logs public
15:25:27 [Zakim]
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15:25:29 [trackbot]
Zakim, this will be TTML
15:25:29 [Zakim]
I do not see a conference matching that name scheduled within the next hour, trackbot
15:25:30 [trackbot]
Meeting: Timed Text Working Group Teleconference
15:25:30 [trackbot]
Date: 10 April 2015
15:25:46 [nigel]
chair: nigel
15:26:01 [nigel]
Present: glenn, pal, tmichel, nigel, Courtney, tai
15:26:05 [nigel]
scribe: nigel
15:26:14 [nigel]
rrsagent, this meeting spans midnight
15:33:51 [nigel]
Topic: Agenda today
15:35:00 [nigel]
nigel: Yesterday's minutes are visible at
15:36:00 [tmichel]
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15:36:12 [dakim]
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15:39:46 [nigel_]
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15:40:01 [nigel_]
glenn: Yes, I've been thinking about that too. I'll create an issue for it.
15:41:04 [nigel_]
nigel: tts:ipd can apply to div, p and span but tts:textAlign only applies to p and span so maybe its needed there.
15:41:47 [nigel_]
glenn: I'll create an issue for that too.
15:43:21 [nigel_]
15:43:21 [trackbot]
issue-384 -- tts:displayAlign may need to apply to content elements -- raised
15:43:21 [trackbot]
15:43:26 [nigel_]
reopen issue-384
15:43:26 [trackbot]
Re-opened issue-384.
15:44:23 [nigel]
15:44:23 [trackbot]
issue-385 -- tts:textAlign may need to apply to div, body -- raised
15:44:23 [trackbot]
15:44:29 [nigel]
reopen issue-385
15:44:29 [trackbot]
Re-opened issue-385.
15:45:23 [nigel]
nigel: My last thought on this one is that the empty spans with ipd and bpd shouldn't be pruned.
15:45:30 [nigel]
... This is related to issue-368
15:45:33 [nigel]
15:45:33 [trackbot]
issue-368 -- The [Construct Intermediate Document] process erroneously prunes empty <br> elements -- open
15:45:33 [trackbot]
15:46:23 [nigel]
issue-368: [Meeting 2015-04-10] Any empty content element that generates an area e.g. by setting ipd or bpd must not be pruned either.
15:46:23 [trackbot]
Notes added to issue-368 The [Construct Intermediate Document] process erroneously prunes empty <br> elements.
15:46:46 [nigel]
nigel: As there are no more thoughts from yesterday, let's crack on with the planned agenda.
15:47:12 [nigel]
Topic: IMSC 1 Test Suite and Implementations
15:48:04 [nigel]
15:48:21 [nigel]
pal: The test suite seems pretty stable. I know we've had some comments back that have been corrected.
15:48:43 [nigel]
... As far as I know its available for people to test. I was recently at an event where a couple of people
15:49:11 [nigel]
... tried to run the test suite for documents wrapped into MXF. I think people are trying it and experimenting.
15:49:11 [courtney]
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15:49:17 [nigel]
tai: Do they run the TTML tests too?
15:49:54 [nigel]
pal: I don't know about that - but the maximum rate tests do exercise a lot of feature areas.
15:50:03 [nigel]
... I'm focusing on the IMSC 1 tests.
15:50:40 [nigel]
... I know that some folk have tried this but getting them to contribute their tests to W3C is a challenge.
15:50:58 [nigel]
... They're not quite sure how the work is going to be used.
15:51:28 [nigel]
nigel: So maybe we need some better comms here to help people understand.
15:51:43 [nigel]
pal: A lot of implementors will not be W3C members because the web isn't their main business.
15:51:48 [nigel]
... So how do we manage this?
15:52:52 [nigel]
nigel: Another data point here is an example I had recently - I was talking to someone whose dev team
15:53:05 [nigel]
... was in another part of the world and they didn't feel they could push that team to do extra work, but
15:53:19 [nigel]
... when they had delivered they would be able to try it. So maybe its lead time too.
15:54:09 [nigel]
glenn: For TTML1 we had a template spreadsheet.
15:54:51 [nigel]
tai: For manufacturers to proceed without guidance can be quite difficult. There may be a win win if
15:55:09 [nigel]
... we can also help them with their implementation work, in providing guidance, advice etc. on the spec.
15:55:29 [nigel]
pal: Another obstacle that's related but different is that some manufacturers have as a policy non-disclosure
15:56:03 [nigel]
... of results until a spec is published, to avoid appearing to have non-compatibility with the spec until it has
15:56:09 [nigel]
... been formally finished.
15:56:56 [nigel]
tmichel: You don't necessarily have to make public the implementor's name - they can be anonymised, as long
15:57:02 [nigel]
... as we know in the group which one is which.
15:57:19 [nigel]
glenn: I heard you use the word "compatibility" which they don't have to claim, for our purposes.
15:57:27 [nigel]
pal: That's a good point.
15:57:45 [nigel]
... W3C has implementation before standardisation - that's different from other groups where they
15:57:53 [nigel]
... standardise, implement and then fix the standard if needed.
15:58:17 [nigel]
tai: We do see that in e.g. XML too where products area available before the spec is a recommendation.
15:58:57 [nigel]
... For commercial vendors if you give clear guidance and offer work together that would help.
15:59:06 [nigel]
... Another possibility is to see if there's an open source implementation.
15:59:12 [nigel]
pal: That would be ideal.
15:59:36 [nigel]
tai: In my experience with open source groups they are quite keen and do want real example content as
15:59:39 [nigel]
... well as test content.
16:00:26 [nigel]
... For presentation, that would be more a player like VLC for example. IRT has been in touch with them as
16:00:44 [nigel]
... part of the HBB4ALL group, and when we discussed with them the EBU-TT-D standard and the other related
16:01:00 [nigel]
... standards the VLC groups were quite interested in implementing when there is test content available.
16:01:15 [nigel]
... They gave me the impression they might implement based on examples rather than the spec.
16:01:24 [nigel]
dakim: Caption vendors always ask for an xsd.
16:01:45 [nigel]
pal: If you give them the maximum rate subtitle stuff, that has some useful coverage of styles, timing etc.
16:02:25 [nigel]
nigel: Have we issued a formal invitation to provide implementations?
16:02:41 [nigel]
tmichel: We did that formally when we published CR.
16:02:45 [nigel]
nigel: Who saw that?
16:02:57 [nigel]
tmichel: W3 groups, members. It was on the W3 home page.
16:03:08 [nigel]
pal: A lot of the implementors won't have seen that.
16:03:24 [nigel]
tmichel: If we know who we want to target I can help send the comms to them.
16:03:31 [nigel]
glenn: It's best not to ask for general input.
16:03:55 [nigel]
pal: I really like the idea of a form.
16:03:58 [dakim_]
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16:04:07 [nigel]
nigel: Like a WBS form that's open to non-members?
16:04:17 [nigel]
pal: Could be, or even a PDF form.
16:05:03 [nigel]
nigel: I think there are two actions here: 1. Create the set of questions; 2. Collate the list of recipients.
16:05:22 [nigel]
pal: I'd be happy to provide the list as I know it. I'd like some help with the form, since something similar
16:05:25 [nigel]
... has already been done.
16:12:58 [nigel]
tai: What does this mean for the schedule?
16:13:19 [nigel]
tmichel: I was proposing to start by contacting potential implementors by email, and then maybe invite
16:13:40 [nigel]
... them to attend a telecon. Another thing is to invite people as invited expert during the implementation
16:13:42 [nigel]
... period.
16:14:00 [nigel]
nigel: I think that sounds a bit heavyweight - we don't need the invited expert bit IMO.
16:14:19 [nigel]
tai: It's important not to make joining as an invited expert a requirement because the process isn't so easy, to join.
16:14:53 [nigel]
pal: Does W3C have a presence at IBC?
16:14:57 [nigel]
tai: EBU does.
16:15:03 [nigel]
glenn: W3C has a presence at NAB.
16:15:10 [nigel]
pal: That's a little soon, being tomorrow!
16:15:32 [nigel]
tai: There may well be presentations at the IBC EBU booth - if you're there we can check with the EBU group and
16:15:52 [nigel]
... Frans if we can mention IMSC too. We get feedback that there's confusion about how all the different standards
16:16:03 [nigel]
... relate to each other.
16:16:11 [nigel]
nigel: Sounds good to me.
16:16:47 [nigel]
s/me./me (wearing my EBU group co-chair hat).
16:17:00 [nigel]
Action: pal Collate list of potential implementors of IMSC 1.
16:17:00 [trackbot]
Created ACTION-387 - Collate list of potential implementors of imsc 1. [on Pierre-Anthony Lemieux - due 2015-04-17].
16:17:24 [nigel]
Action: tmichel Start preparing the IMSC 1 Implementation report form.
16:17:25 [trackbot]
Created ACTION-388 - Start preparing the imsc 1 implementation report form. [on Thierry Michel - due 2015-04-17].
16:18:08 [nigel]
Action: tai Check with EBU group if we can have a combined event at IBC with EBU group and IMSC/W3C
16:18:09 [trackbot]
Created ACTION-389 - Check with ebu group if we can have a combined event at ibc with ebu group and imsc/w3c [on Andreas Tai - due 2015-04-17].
16:22:54 [dakim]
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16:24:13 [nigel]
nigel: I found a couple of issues from a colleague who implemented the linePadding and multiRowAlign tests
16:24:17 [nigel]
... and from Andreas.
16:24:44 [nigel]
... 1. The example PNGs don't honour the displayAlig="center" setting (because I forgot that in the HTML)
16:24:57 [nigel]
... 2. The region doesn't begin 10% down
16:26:16 [nigel]
... 3. The text is so long that in real world implementations it doesn't necessarily fit on a line.
16:26:50 [nigel]
nigel: I think we need to regenerate the PNGs to match the TTML, and also make the text shorter.
16:27:25 [nigel]
Action: nigel Update the multiRowAlign and linePadding TTML files to have shorter lines of text
16:27:25 [trackbot]
Created ACTION-390 - Update the multirowalign and linepadding ttml files to have shorter lines of text [on Nigel Megitt - due 2015-04-17].
16:27:27 [nigel]
Action: nigel Update the multiRowAlign and linePadding PNGs to match the TTML
16:27:28 [trackbot]
Created ACTION-391 - Update the multirowalign and linepadding pngs to match the ttml [on Nigel Megitt - due 2015-04-17].
16:28:24 [nigel]
tai: I also noticed that the document order of the <p> elements is different from the display order of the regions
16:28:43 [nigel]
... So the first subtitle with the green background is rendered at the bottom and the second subtitle with
16:28:59 [nigel]
... the black background is rendered at the top. I think it would confuse people so I'd suggest to change that.
16:29:11 [nigel]
... It may just be a distraction.
16:30:37 [nigel]
pal: I'll be happy to change that.
16:30:52 [nigel]
nigel: This came from pal's original examples. I didn't change it because although it looks surprising it isn't
16:30:58 [nigel]
... wrong. I almost quite like it!
16:32:05 [nigel]
Action-390: Also change the region ordering to be more intuitive.
16:32:05 [trackbot]
Notes added to Action-390 Update the multirowalign and linepadding ttml files to have shorter lines of text.
16:32:22 [nigel]
nigel: Some of the other example have it too, e.g. forcedDisplay1.ttml
16:32:41 [nigel]
Action: pal tweak the examples with multiple regions so that they appear in a more intuitive order.
16:32:41 [trackbot]
Created ACTION-392 - Tweak the examples with multiple regions so that they appear in a more intuitive order. [on Pierre-Anthony Lemieux - due 2015-04-17].
16:33:02 [nigel]
Action-392: (nigel will do the multiRowAlign and linePadding ones as per Action-390)
16:33:02 [trackbot]
Notes added to Action-392 Tweak the examples with multiple regions so that they appear in a more intuitive order..
16:35:40 [nigel]
nigel: I'd like to show a prototype implementation that my colleagues at BBC R&D have put together based on
16:36:16 [nigel]
... gstreamer, using MPEG DASH to publish the content. I asked them to put the multiRowAlign and linePadding
16:36:35 [nigel]
... examples through it. They had to make a tweak because they're not actually valid EBU-TT-D as they use
16:37:02 [nigel]
... time expressions like "1s" where EBU-TT-D requires "hh:mm:ss.sss" type format.
16:37:10 [nigel]
pal: Okay let's change that in the examples.
16:38:24 [nigel]
Action-390: Change the time expressions to EBU-TT-D compliant ones too.
16:38:24 [trackbot]
Notes added to Action-390 Update the multirowalign and linepadding ttml files to have shorter lines of text.
16:39:02 [nigel]
nigel: There are some tests that could be EBU-TT-D compatible too with these changes.
16:40:18 [courtney_]
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16:40:21 [nigel]
Action-392: Also change the time expressions to be EBU-TT-D compliant on all that could be compliant
16:40:21 [trackbot]
Notes added to Action-392 Tweak the examples with multiple regions so that they appear in a more intuitive order..
16:43:20 [nigel]
pal: Can we add this to the implementation report?
16:43:47 [nigel]
nigel: Yes, as far as I'm concerned we can do that. Thierry is there any reason why not?
16:44:08 [nigel]
tmichel: No reason why not. It would be good to post the videos too.
16:44:16 [nigel]
nigel: They're large files, but otherwise no problem.
16:44:33 [nigel]
tai: So for the BBC implementation they could just submit that they've passed those two tests?
16:44:53 [nigel]
tmichel: Yes, that's fine. And it's okay to show even one test being passed by any implementation. Each
16:45:07 [nigel]
... test does need to have at least 2 implementations.
16:45:26 [courtney]
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16:45:26 [nigel]
tai: Is there any requirement to double check that the claims of passing the test are true?
16:45:42 [nigel]
tmichel: We've relaxed this. PReviously we would show the implementations working, but now it's based on
16:45:58 [nigel]
... trust. THe only thing we should avoid is a misunderstanding of the output that you're supposed to get. You
16:46:15 [nigel]
... have to compare the output with some proof - it could be a video, a textual description, an image, or an SVG
16:46:20 [nigel]
... file etc.
16:46:44 [nigel]
tai: Or it could be a member verification?
16:46:55 [nigel]
pal: Yes, I was just asking nigel if BBC could submit this.
16:47:21 [nigel]
tmichel: Each company should add their entry on the implementation report, using the form we're going to make.
16:47:48 [nigel]
pal: There's space on the wiki so until we have the form we could just add a table to the results section
16:48:11 [nigel]
... on the implementation report, and then we can update when we have a fancier system.
16:48:36 [nigel]
Action: nigel Send pal details of implementation and tests passed so he can create a table in the implementation report
16:48:36 [trackbot]
Created ACTION-393 - Send pal details of implementation and tests passed so he can create a table in the implementation report [on Nigel Megitt - due 2015-04-17].
16:49:48 [nigel]
nigel: So we have a good news story - at least one implementation of two of the tests.
16:51:02 [nigel]
Topic: IMSC 1 schedule and CR publication
16:51:31 [nigel]
rrsagent, generate minutes
16:51:31 [RRSAgent]
I have made the request to generate nigel
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17:17:58 [nigel]
pal: Let's look at today's schedule.
17:18:40 [nigel]
17:19:02 [nigel]
pal: According to our schedule interop testing would have ended and we'd be publishing a CR2 around now.
17:19:21 [nigel]
... Interop testing is ongoing, and we have made some changes to the spec. Should we have a second CR?
17:20:13 [nigel]
... Should we proceed with that now, or wait for interop testing and feedback. Do we need a second CR at all?
17:20:28 [nigel]
... If we decide on a second CR we should maybe just do it according to our schedule.
17:20:40 [nigel]
tmichel: I think it's better to publish a second CR now because there are no implementations yet and so its
17:20:59 [nigel]
... easier to justify the changes to the director. If you wait until PR then it's a tougher sell.
17:21:07 [nigel]
pal: So maybe that answers that question!
17:21:26 [nigel]
tmichel: The second issue is, if we publish a CR2, we might start thinking about at risk features if there are
17:21:37 [nigel]
... any, that we may want to remove to make going to PR easier.
17:21:51 [nigel]
nigel: We currently have no at risk features marked.
17:22:10 [nigel]
pal: That's right. The three that were in my mind most "at risk" due to implementations were multiRowAlign,
17:22:25 [nigel]
... linePadding and image. We've seen an implementation of multiRowAlign and linePadding this morning so
17:22:50 [nigel]
... they're not at risk, and I've seen plans for doing image already. So I don't believe there should be any at
17:22:52 [nigel]
... risk features.
17:23:50 [nigel]
nigel: You've created the CR diff. Are there any open issues?
17:24:24 [nigel]
pal: The only open issue is the one on begin, that we opened yesterday. Issue-382.
17:24:41 [nigel]
pal: Based on our discussion I think the answer is clear but I want to check on that some more.
17:24:57 [nigel]
... We also have issue-375.
17:24:59 [nigel]
17:24:59 [trackbot]
issue-375 -- Use of the ebutts:linePadding and ebutts:multiRowAlign in IMSC 1 -- pending review
17:24:59 [trackbot]
17:26:01 [nigel]
pal: In the CR it used to say "may be used" and now has "with the following provisions" and there's also the
17:26:04 [nigel]
... note added.
17:26:43 [nigel]
tai: After we filed the first issue we found some additional points. Originally we wanted to allow the extension
17:26:57 [nigel]
... attributes to be permitted on the content elements, in contrast to EBU-TT-D that only allows them on style
17:27:04 [nigel]
... elements.
17:27:26 [nigel]
... There was a minor thing about the wording of the note to make clear that there is a difference between
17:27:43 [nigel]
... IMSC and EBU-TT-D and I proposed some wording that Pierre has added.
17:28:54 [nigel]
tai: I've read the updated text and am happy with it. There may be a small grammar issue - adding a 'the'.
17:28:58 [nigel]
nigel: I've read it too.
17:29:06 [nigel]
pal: I'm going to make that grammar change right now.
17:29:59 [nigel]
dakim: What's the plan for referencing TTML2 from IMSC?
17:30:17 [nigel]
pal: The plan is to make an IMSC 2 that references TTML2. Since both are similarly delayed it makes sense to
17:30:28 [nigel]
... stay with that plan. Let's discuss more after we're done with IMSC 1 here.
17:32:02 [nigel]
pal: I've pushed the grammar change now.
17:32:18 [nigel]
close issue-375
17:32:18 [trackbot]
Closed issue-375.
17:32:29 [nigel]
nigel: Great, now we have only one open issue.
17:32:49 [nigel]
pal: So it sounds like the overhead for a second CR is low based on tmichel's input.
17:33:01 [nigel]
tmichel: Yes, let's not say that these are substantial changes.
17:33:29 [nigel]
pal: Yes. Some of them are normative provisions. Are they extensive or substantially affect the overall scope...
17:33:47 [nigel]
glenn: Historically in this group our criteria has been: does it change the syntax in any way? If yes, it's substantive.
17:34:02 [nigel]
... If it significantly alters the compliance rules then we've also considered it substantive.
17:34:05 [nigel]
nigel: What does that mean?
17:34:24 [nigel]
glenn: There's some subjectivity in the word "significantly", which is a group choice.
17:34:31 [nigel]
pal: So let's review the changes and determine that.
17:35:03 [nigel]
glenn: We've also got some changes under the wire by saying that they fix a mistake, or haven't been implemented etc.
17:37:30 [nigel]
17:38:13 [nigel]
pal: §6.6 Removal of frame rate relationship with related video object. One of the issues here is that you can't
17:38:31 [nigel]
... realistically test this without some video. In other words the impact is nil because we couldn't test this anyway.
17:38:58 [nigel]
... Any implementations that enforce the old language are still compliant. So the practical impact of this
17:39:04 [nigel]
... change is practically nil.
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17:43:59 [nigel]
tmichel: the exact wording in the W3C process defines substantive in
17:45:34 [nigel]
glenn: In the past we have not considered the 3rd bullet in point 3 above to be substantive.
17:45:43 [nigel]
tmichel: This is the new process though.
17:46:11 [nigel]
pal: By the letter here any change that affects a normative provision falls into point 3.
17:46:41 [nigel]
tai: What's the consequence if some changes are substantive?
17:46:48 [nigel]
tmichel: In that case we need to have a director call.
17:47:43 [nigel]
nigel: Even if we have some substantive changes I'm happy to take the Director through them.
17:50:35 [nigel]
nigel: This specific change to §6.6 falls under the third bullet in point 3, so it does affect conformance;
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17:50:48 [nigel]
... therefore under the new process it does count as substantive.
17:51:17 [nigel]
nigel: The next one is in §6.7.1.
17:51:34 [nigel]
pal: Again this is relaxing a constraint that used to bind a value in the TTML with an external object.
17:52:04 [nigel]
pal: The first change in this section is in the same category as the previous one we just discussed.
17:52:12 [nigel]
nigel: Right, so this is classed as substantive.
17:52:31 [nigel]
pal: The next one, removing the conformance regarding aspectRatio and extent is substantive for sure
17:52:41 [nigel]
... because it removes an enforceable check in the document.
17:53:00 [nigel]
nigel: The third change in this section is the removal of a note.
17:53:05 [nigel]
pal: That one is editorial by definition.
17:53:39 [nigel]
nigel: The next change is in §7.4. This changes the initial value of tts:displayAlign.
17:53:48 [nigel]
pal: That would affect presentation, i.e. processor behaviour.
17:54:04 [nigel]
nigel: This is also classed as substantive.
17:54:16 [nigel]
nigel: Next one is the same for textAlign.
17:54:21 [nigel]
nigel: This is also classed as substantive.
17:54:40 [nigel]
nigel: The next one is the set of changes to linePadding and multiRowAlign.
17:55:12 [nigel]
pal: I think they have to be substantive because they clarify the situation relative to the previous version.
17:55:32 [nigel]
nigel: Agreed.
17:55:53 [nigel]
pal: I'd like the group believe that they are extensive enough to warrant doing wide review again for example.
17:56:09 [nigel]
... In my opinion the answer is no, but maybe we can have a group consensus to take to the Director.
17:56:19 [nigel]
nigel: This is also classed as substantive.
17:56:50 [nigel]
nigel: That was the last change.
17:57:32 [nigel]
nigel: On the point about wide review, some of the changes are relative to SMPTE-TT so arguably we should
17:57:37 [nigel]
... give them the chance to respond.
17:58:08 [nigel]
... Just sending to SMPTE is narrow review though not wide review.
17:58:56 [nigel]
nigel: My view is that this doesn't need wide review. One of the changes was in response to the previous
17:58:58 [nigel]
... wide review.
17:59:14 [nigel]
pal: Yes, that arrived beyond the feedback deadline and we chose to defer knowing that we might have other
17:59:15 [nigel]
... changes.
18:00:12 [nigel]
nigel: When we've completed the one remaining open action I'll raise a proposal in a future meeting to request
18:00:20 [nigel]
... transition to CR for the updated ED.
18:04:55 [nigel]
Topic: Steps for exiting CR for IMSC 1
18:05:16 [nigel]
pal: Thierry, what are the steps for exiting, once we've published CR2?
18:05:24 [nigel]
tmichel: First we have to publish CR2!
18:06:10 [nigel]
tmichel: We have to organise the request and the Director's call because there are substantive changes.
18:06:23 [nigel]
pal: I will come back with a proposal for closing the last remaining issue.
18:07:35 [nigel]
nigel: In the CR we have exit criteria, which are just about implementation. For CR2 we will need a new 'earliest
18:07:38 [nigel]
... date'?
18:07:46 [nigel]
tmichel: Yes, at least 4 weeks beyond CR2 publication.
18:08:17 [nigel]
nigel: So I think the steps are: 1) Complete the implementation report to meet the criteria, 2) request transition to PR.
18:08:26 [nigel]
pal: And we have actions from earlier to help with 1.
18:09:37 [nigel]
pal: On the timeline, we will hopefully do CR2 in April, and probably not make PR in June. While that's going
18:09:47 [nigel]
... on we can start drafting IMSC 2.
18:10:25 [nigel]
pal: The only thing that will be tough is that SMPTE wanted IMSC 1 to reach Rec in July so they can reference it.
18:10:29 [nigel]
nigel: That's still possible.
18:10:45 [nigel]
pal: True.
18:11:00 [nigel]
nigel: If SMPTE has that goal and can encourage implementations then that will help them.
18:12:02 [nigel]
pal: The plan for IMSC 2 is to base it on IMSC 1 and add any TTML 2 features such as Ruby or SMPTE requested
18:12:07 [nigel]
... features that people want.
18:13:01 [nigel]
Present+ loretta
18:13:17 [Loretta]
Loretta has joined #tt
18:13:26 [nigel]
nigel: [5 minute break]
18:22:21 [courtney]
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18:31:03 [nigel]
Topic: WebVTT FPWD Feedback handling
18:33:05 [nigel]
Loretta: How do the CG and the WG work together?
18:33:20 [nigel]
nigel: For Rec track stuff that has to come from the WG and feedback to go back to the WG.
18:33:51 [nigel]
... If there are any technical changes to the spec needed then it would be bad if the CG isn't happy with them.
18:34:13 [nigel]
Courtney: It can be tricky to get consensus from the CG.
18:34:43 [nigel]
tmichel: The WG has done a wide review. We received comments from i18n and CSS WG. We're expecting
18:35:07 [nigel]
... review from accessibility. That will close the debate on the wide review, as it will represent feedback from
18:35:13 [nigel]
... all the groups we have dependencies with.
18:35:26 [nigel]
... The only group missing is HTML and I'm expecting a statement that they're satisfied.
18:36:14 [nigel]
nigel: I want to explore that some more - for IMSC 1 we took the view that wide review goes beyond just
18:36:26 [nigel]
... W3C group dependencies and to the wider world.
18:36:40 [nigel]
tmichel: That's even better if we can demonstrate that review, but it's not essential.
18:39:18 [nigel]
nigel: I was expecting more. For example to include the liaisons with external groups.
18:40:16 [nigel]
tai: David Singer did post on the EBU group asking for wide review. That group hasn't provided any formal feedback.
18:40:36 [nigel]
nigel: As a statement of fact, I don't believe there has been any feedback from any external group. I don't have
18:40:43 [nigel]
... visibility of any other requests David may have made.
18:41:29 [nigel]
18:44:07 [nigel]
nigel: We had a conversation by email about the process for responding and collecting wide review dispositions.
18:44:08 [nigel]
18:44:21 [nigel]
Loretta: who has the action to take that forward?
18:45:36 [nigel]
tai: I think Dave offered to do it, on April 2.
18:45:50 [nigel]
nigel: That email, says he doesn't
18:46:01 [nigel]
... see a problem with doing it, but that's not the same as taking the action, right?
18:46:39 [nigel]
nigel: He offered to do bridging, and my follow-up was attempting to isolate where the bridging is needed.
18:46:52 [nigel]
Courtney: I think what he means is he's asked Silvia to do it.
18:47:31 [nigel]
... There's another email thread about CSS WG feedback, where a more concise version of it.
18:48:38 [nigel]
Courtney: We should have an ETA and know who is writing the dispositions document we discussed last week.
18:48:49 [nigel]
Loretta: presumably the CG is blocking that?
18:49:04 [nigel]
tmichel: The bridging also includes acceptance by this group of any proposals made by the CG.
18:49:20 [nigel]
pal: In the case of IMSC 1 step 1 was to document every comment, which tmichel did. Then a proposed
18:49:35 [nigel]
... response was created and the commenter accepted or not and we discussed it. That's exactly what's
18:49:58 [nigel]
... required by the Director. The first step would be to document every comment received.
18:50:22 [nigel]
tai: The working model between CG and WG is new as tmichel noted last week.
18:50:32 [nigel]
nigel: I agree on both tai's and pal's points and don't think they're exclusive.
18:50:44 [nigel]
pal: So the issues could be in the bug tracker.
18:50:55 [nigel]
Loretta: Can we tag that they're comments so we can formally collate them?
18:51:19 [nigel]
pal: There's also the recurring issue of IP - if the CG creates new IP in the course of responding to the comments,
18:51:40 [nigel]
... how do we ensure that the IP meets the requirements of W3C, in a continuous way?
18:52:18 [nigel]
nigel: If there's a spec change made by a CG member who is not a WG member then the IP needs to be cleared
18:52:23 [nigel]
... on a case by case basis.
18:52:47 [nigel]
Courtney: Is this only what's in the spec?
18:52:48 [nigel]
tmichel: Only the spec changes need to be cleared.
18:53:01 [nigel]
Courtney: If the IP question is based on versions of the spec...
18:53:09 [nigel]
pal: Then you might want to do another clearance call.
18:53:24 [nigel]
tmichel: This is so complicated! I've been tracking people from the CG that have been active contributors and
18:53:37 [nigel]
... some never responded and are listed in the acknowledgement section as active contributors.
18:54:00 [nigel]
Courtney: Part of the problem is that it's taken so long that people may have moved on.
18:54:39 [nigel]
... It sounds like we need to talk to Dave and maybe Silvia and get clarity on what everyone needs to be produced
18:54:52 [nigel]
... and a date for when it will be done and who is doing it. Let's get a schedule and then work to it.
18:55:25 [nigel]
tmichel: Now it's in the tracker the CG should make proposals for the comment, as a first step IMO. The
18:55:39 [nigel]
... second step is for the TTWG to approve them.
18:55:59 [nigel]
Courtney: We don't need to do that piecemeal for every comment.
18:56:17 [nigel]
nigel: Part of the problem is we didn't set a review feedback end date on the FPWD of WebVTT so when do we stop?
18:57:07 [nigel]
Courtney: We can get a specific date for accessibility review.
18:57:09 [nigel]
tmichel: I'll do that.
18:57:27 [nigel]
Courtney: Then we have to make a decision point - do we have wide review?
18:59:41 [nigel]
nigel: We should check the process too on that. I have reservations on this. Let's review the process and charter.
19:00:14 [nigel]
nigel: The process wants the charter's dependencies specifically to have been contacted. I don't think there's
19:00:51 [nigel]
... any archived evidence of Dave emailing them all, just the W3C groups in 3.1 of the charter. 3.2 and 3.3
19:01:06 [nigel]
... seem to be missing. The general public has been told, due to publication on the W3C homepage.
19:01:41 [nigel]
... In terms of appropriate times, the end date for feedback was not clear on the FPWD.
19:02:02 [nigel]
nigel: One way to proceed here is to issue a second WD and a specific call for wide review with an end date
19:02:18 [nigel]
... and process any feedback from that, having solicited from all the dependencies on the charter.
19:02:28 [nigel]
tmichel: That would be a good way to proceed.
19:02:52 [nigel]
Courtney: I think that sounds like a good set of next steps for getting the wide review done. What's next after
19:02:54 [nigel]
... that?
19:03:11 [nigel]
tmichel: Then we move to CR.
19:03:35 [nigel]
nigel: Part of the CR is to specify exit criteria, which must include implementation experience.
19:03:54 [nigel]
tmichel: In the pipe we also have issues regarding styling for example, such as inline or external stylesheets.
19:04:07 [nigel]
... Do we want to have those resolved in the current version or a later version?
19:04:18 [nigel]
Courtney: IMO we should defer to a later version.
19:04:23 [nigel]
Loretta: I would really like it in this version.
19:05:32 [nigel]
Courtney: Then we have to get implementations. I see the value of having it in there but we don't have
19:05:37 [nigel]
... consensus on the design.
19:05:55 [nigel]
Loretta: To my mind the conversation on this happens in the CG, and I think I saw a consensus emerging.
19:06:14 [nigel]
Courtney: It's been quiet in the CG for the last 6 weeks.
19:06:27 [nigel]
tmichel: Even if we went to CR for the current version I don't think there's evidence of implementation for
19:06:34 [nigel]
... the whole spec.
19:06:53 [nigel]
Courtney: I don't agree. We've been supporting this in Apple since last fall in two separate implementations.
19:07:04 [nigel]
... In addition Google has an implementation.
19:07:40 [nigel]
Loretta: It's not complete yet. The parsers and encoders support it, but Chrome does not. It doesn't do regions.
19:07:48 [nigel]
... What counts as an implementation?
19:08:01 [nigel]
nigel: We can choose that in the CR exit criteria. We have some flexibility.
19:08:21 [nigel]
tmichel: We also need test suites. In my experience browser implementations don't implement a lot of features
19:08:23 [nigel]
... completely.
19:08:45 [nigel]
tai: This is the same conversation as we had for IMSC, and we decided that we don't need single implementations
19:09:01 [nigel]
... that pass all the tests, just that every test is passed by at least two implementations.
19:09:14 [nigel]
... Silvia has started on the test suite in git.
19:09:36 [nigel]
Courtney: We've been working on the tests too but don't have anything to share yet.
19:10:25 [nigel]
... So first we get evidence of wide review then we define the exit criteria, which could be passing tests in a
19:10:28 [nigel]
... test suite?
19:10:29 [nigel]
nigel: Yes.
19:12:53 [nigel]
Courtney: Going back to the inline styling question, because I'm interested in getting to a published version
19:12:56 [nigel]
... as soon as possible.
19:13:13 [nigel]
nigel: Thinking about the existing CSSWG response, and other potential responses, in my opinion it's quite
19:13:29 [nigel]
... high risk to omit inline styling and require styling from a host HTML page.
19:13:57 [nigel]
Loretta: I support the desire to get to Rec quickly.
19:14:21 [nigel]
... Previously the issue with inline styling was about syntax - the CG didn't agree it.
19:14:35 [nigel]
Courtney: I think the action there is to contact David and Silvia and get a status on that.
19:15:32 [nigel]
pal: Whatever decision they make, if there's a formal comment made then this group has to approve the response
19:16:36 [nigel]
... and the commenter's response to that may be positive or negative.
19:17:41 [nigel]
tai: So the WG has to approve the edit and that the comment has been addressed. Do we have the expertise
19:17:49 [nigel]
... on the spec to state that?
19:19:04 [nigel]
nigel: My understanding is that we can't proceed without the expertise but that we have enough members
19:19:22 [nigel]
... from the CG like Silvia, Dave, Courtney, Loretta and Philip that we do have enough expertise.
19:19:49 [nigel]
Courtney: So we have a 4 step process:
19:20:04 [nigel]
... 1. Get feedback.
19:20:12 [nigel]
... 2. Someone from the CG writes a proposed response.
19:20:22 [nigel]
... 3. The WG reviews the response and maybe edits.
19:20:29 [nigel]
... 4. Get the response form the original commenter.
19:22:06 [nigel]
nigel: Step 2 is interesting - ideally I'd prefer for an individual who is a member of both the CG and WG and
19:22:45 [nigel]
... can be representative of the CG, so that at least we have some WG backing for the responses immediately.
19:23:06 [nigel]
Courtney: I agree with that. I'm happy to talk to Dave about that - he may already have someone in mind to do that.
19:24:20 [nigel]
nigel: I want to record the actions - can I just check it makes sense to put them in the WG tracker? They're
19:24:22 [nigel]
... WG actions.
19:25:04 [nigel]
tai: Makes sense.
19:25:13 [nigel]
Courtney: We're at a hand-over point between CG and WG.
19:25:51 [nigel]
tmichel: Does it make sense to use the dispositions tracker for this?
19:25:59 [nigel]
nigel: I would defer that until we know who is doing it.
19:26:13 [nigel]
Loretta: have other groups used different tools?
19:26:30 [nigel]
tmichel: You can do whatever you want. You can produce an Excel document or an HTML page that describes it
19:26:54 [nigel]
... You do need links to the archive for reference. The dispositions tool tracks the process steps.
19:27:03 [nigel]
Loretta: In practice does everyone use it?
19:27:06 [nigel]
tmichel: no.
19:27:19 [nigel]
glenn: people use github and a variety of tools.
19:27:41 [nigel]
nigel: Let's record the actions.
19:28:31 [nigel]
Action: Courtney Determine who is responsible for putting together the dispositions of comments document and get a schedule from them.
19:28:31 [trackbot]
Created ACTION-394 - Determine who is responsible for putting together the dispositions of comments document and get a schedule from them. [on Courtney Kennedy - due 2015-04-17].
19:29:06 [nigel]
Action: tmichel Chase the accessibility WG for a date for getting WebVTT feedback
19:29:06 [trackbot]
Created ACTION-395 - Chase the accessibility wg for a date for getting webvtt feedback [on Thierry Michel - due 2015-04-17].
19:31:20 [nigel]
Courtney: if our response to comments is to change the spec do we have to redo the request for wide review?
19:31:31 [nigel]
tmichel: If you publish a new WD then you only need to ask for comments on the delta.
19:32:12 [nigel]
tmichel: If we publish a new WD for wide review we should send an email to the groups on the charter and
19:32:25 [nigel]
... make sure it's archived. If Dave did that before then the emails are not on the archive.
19:34:02 [nigel]
nigel: For IMSC 1 we sent to all the charter dependency groups and the W3C external liaisons filtered by
19:34:12 [nigel]
... interest area, BCCing the member-tt list so they were archived.
19:35:29 [nigel]
Action: dsinger produce evidence of request for wide review for WebVTT, for the archive
19:35:29 [trackbot]
Created ACTION-396 - Produce evidence of request for wide review for webvtt, for the archive [on David Singer - due 2015-04-17].
19:37:15 [nigel]
nigel: So we're deferring the decision on a second WD dependent on the disposition of comments.
19:38:00 [nigel]
nigel: Are the region semantics in WebVTT stable?
19:38:17 [nigel]
Loretta: I think that's at risk. Philip doesn't like the way it's specced currently. AFAIK it's only implemented in
19:38:46 [nigel]
... Apple's players. It's not in Chrome, IE, Firefox or Opera.
19:38:53 [nigel]
Courtney: Why is it at risk?
19:39:59 [nigel]
nigel: I'm asking because I couldn't identify a resolution or consensus in the CG about the syntax and semantics.
19:40:14 [nigel]
tmichel: The WG has published it so it is a consensus in that sense.
19:40:29 [nigel]
Loretta: If it's not implemented widely then that won't do us any favours.
19:41:37 [nigel]
tmichel: What about the ::past and ::future pseudo-classes? I couldn't see support for that on any browser.
19:42:09 [nigel]
tai: From reading the spec I'm unsure in general how much CSS feature support is required.
19:43:23 [nigel]
nigel: While we're listing things we're curious about, what about the red box in §6.1 of the FPWD, which
19:43:33 [nigel]
... looks incomplete? We can't go to CR with that there, right?
19:44:47 [nigel]
Courtney: It's not like that in the latest ED.
19:44:56 [nigel]
nigel: In that case there have been changes.
19:45:37 [nigel]
Loretta: There will be an action if we want to take a new snapshot. Someone needs to do a diff.
19:45:42 [nigel]
nigel: That's an Editor's job.
19:47:24 [nigel]
Loretta: Someone needs to understand what has changed in the ED to establish the diffs. The changes may
19:47:27 [nigel]
... be unrelated to comments.
19:48:57 [nigel]
nigel: I've filed bug #28464 for §6.1
19:49:07 [nigel]
tmichel: Does WebVTT do ruby support?
19:49:20 [nigel]
Courtney: Yes it supports ruby but not to the extent that's in TTML2.
19:50:47 [nigel]
nigel: One of my key points is to make sure that there's alignment between new features in TTML and WebVTT.
19:51:05 [nigel]
... If the WebVTT Ruby implementation blocks future extension to get to the support level of TTML2 then
19:51:08 [nigel]
... we should file a bug.
19:51:13 [nigel]
tmichel: Who decides?
19:51:17 [nigel]
nigel: THat's a WG decision.
19:51:44 [nigel]
Courtney: We can use that as a criterion for evaluating new feature proposals.
19:51:47 [nigel]
nigel: +1
19:52:28 [nigel]
tmichel: Another thing that has been discussed is if the CSS feature list should be a whitelist or a blacklist.
19:52:43 [nigel]
... Dave, Nigel and I had different views of what the current wording means, and ought to mean.
19:52:50 [nigel]
Courtney: Can CSS support profiles?
19:53:07 [nigel]
glenn: No it does not, and there's no standard way to tell if a feature is implemented. There are some heuristics
19:53:27 [nigel]
... and javascript libraries like modernizr that can be used to mitigate those issues.
19:53:43 [nigel]
... One of the things I do is to set a value to something other than its initial value and then read its computed
19:54:01 [nigel]
... value. It's not a guarantee that the feature is implemented, but it's a good hint if you can't even get that far.
19:55:24 [nigel]
nigel: Let's adjourn for lunch!
19:55:29 [nigel]
group: Strong agreement!
19:55:33 [nigel]
rrsagent, generate minutes
19:55:33 [RRSAgent]
I have made the request to generate nigel
21:38:42 [dakim]
dakim has joined #tt
21:41:01 [glenn]
glenn has joined #tt
21:41:48 [courtney]
courtney has joined #tt
21:44:44 [nigel]
Topic: WebVTT <--> TTML Mapping
21:46:07 [nigel]
Courtney: We don't have too much to discuss with the group yet, but want to let you know about our plan.
21:46:22 [nigel]
... We discussed this in Geneva and I've been unable to make much progress since then. We want more
21:46:38 [nigel]
... structure around this so we can get it done. Andreas and I are working on a timeline and an outline for
21:46:55 [nigel]
... a document. We welcome help from anyone who wants to contribute text. Andreas and I will divide it up
21:47:04 [nigel]
... otherwise but if anyone else wants to help that would be great.
21:47:17 [nigel]
nigel: What will that look like?
21:47:34 [nigel]
Courtney: We haven't finalised anything. But let's think about the approach. Glenn brought this up in
21:47:56 [nigel]
... Geneva, that mapping from TTML to WebVTT directly isn't the way to go, instead to go from ISD to WebVTT.
21:48:08 [nigel]
... What we thought we could do is to map from IMSC to WebVTT.
21:48:27 [nigel]
glenn: There is a spec for the ISD format in TTML2, but the mapping semantics need to be inferred from the
21:48:48 [nigel]
... rest of the spec but it's not perfect yet. A tool I've been working on, open source, based on TTX (TT transformer)
21:49:10 [nigel]
... will take an arbitrary TTML document and spit out a sequence of ISDs. So that's an examplar of what the
21:49:22 [nigel]
... semantics should be, but they're not written in detail in the spec.
21:49:45 [nigel]
Courtney: If our goal was to write sample code we could use that but our task is to write a document.
21:50:02 [nigel]
glenn: What that tool does is to flatten out the timeline and create a document for each interval during which
21:50:22 [nigel]
... no changes occur, and also flattens out the styles into the ISD documents. So a lot of the complexity in TTML
21:50:40 [nigel]
... disappears in that domain, and then it's easier to do a translation into some target format. If you don't do that
21:51:06 [nigel]
... but focus on IMSC you still have to deal with the complexity of the styling system.
21:51:21 [nigel]
Courtney: Does IMSC require sequential timelines?
21:51:37 [nigel]
pal: No, not unless you have progressivelyDecodable set.
21:51:51 [nigel]
Courtney: My feeling is that its easier to start with a subset of TTML and then extend it later.
21:52:13 [nigel]
tai: It makes sense to start with IMSC because it simplifies things, has a similar target usage, to WebVTT, and
21:52:36 [nigel]
... we might even start with a first draft based on something even more restricted to support the most
21:52:55 [nigel]
... commonly used features. Then we can add more as it is needed. From a formal perspective for an algorithm
21:53:14 [nigel]
... I think it may be the way to go to use ISDs, but it makes sense in the document to tackle certain features
21:53:40 [nigel]
... like position, timing, style, explain how it works in each spec, and then at least readers will understand the
21:54:01 [nigel]
... context and how it works. Even if any algorithm specified isn't used at least readers will be able to make
21:54:27 [nigel]
... their own. I think we made a good start in Geneva that is well minuted.
21:54:43 [nigel]
... Another thing we started is to work on the test files that we have that need to be built up for WebVTT. All
21:54:59 [nigel]
... these features can best be described using examples. The missing test files for WebVTT could also be
21:55:01 [nigel]
... generated.
21:55:20 [nigel]
Courtney: I think we're going to do some more work on this next week (me and Andreas). In our conference
21:55:44 [nigel]
... call in 2 weeks we should have an outline and a schedule that we can share and discuss. We could circulate
21:56:18 [nigel]
... it on email too.
21:57:12 [nigel]
nigel: It might make sense to use Mercurial to store it and allow it to be shared, or some other versioning tool.
21:57:18 [tmichel]
rrsagent, draft minutes
21:57:18 [RRSAgent]
I have made the request to generate tmichel
21:57:25 [nigel]
tai: That's publicly visible right?
21:57:28 [nigel]
nigel: yes.
21:57:36 [nigel]
Courtney: It would be good to have versioning.
21:57:48 [nigel]
tai: I think it's important to do a first draft and then take it step by step.
21:58:12 [nigel]
Courtney: I wanted to know if anyone wanted to contribute additionally.
21:58:22 [nigel]
Loretta: Speak to me about this - I'll see what I can do.
21:58:52 [nigel]
Courtney: It will also be good for developing the test suite.
21:59:13 [nigel]
Loretta, tai, Courtney: discusses actual plans for getting together to work on this.
22:00:04 [nigel]
nigel: Are there any particular inputs that you need e.g. in terms of expertise, understanding etc.
22:00:26 [nigel]
Courtney: I think we may need to call on Glenn for TTML expertise and Silvia for WebVTT!
22:00:45 [nigel]
glenn: One of these days someone will ask me to output WebVTT from my tool, and then I'll have to learn it!
22:00:53 [nigel]
Courtney: Are you available to do that?
22:01:02 [nigel]
glenn: Yes. The tool is all Java and is open source.
22:01:18 [nigel]
... There's another project called the TTV TImed Text Validator. TTX is the transformer layer on top of that.
22:01:33 [nigel]
... So this new timed text presentation engine is a layer on top of TTX, so it validates the TTML input,
22:01:41 [nigel]
... translates it into ISDs and then formats them.
22:02:26 [nigel]
tai: Is there a place where we collate implementations?
22:02:35 [nigel]
glenn: It would be a good idea to add that to the wiki.
22:02:41 [nigel]
nigel: Sounds good to me.
22:02:55 [nigel]
... though we wouldn't necessarily endorse them.
22:03:09 [courtney]
courtney has joined #tt
22:04:18 [nigel]
tai: It's good to let people know about this activity on the mappings in case people are also working on it.
22:04:35 [nigel]
Loretta: Probably good to make some progress before raising expectations that we then discover we can't meet.
22:05:37 [nigel]
nigel: Have you looked at the idea of picking the features that are easiest to match, even if they're from TTML2
22:05:44 [nigel]
... like the tts:position attribute?
22:05:53 [nigel]
tai: I think we should start with TTML1 because it's more useful.
22:06:02 [nigel]
Courtney: We can certainly look at some low hanging fruit.
22:07:01 [nigel]
nigel: An outcome of this work might be to identify subsets of the two specs that easily map to each other,
22:07:21 [nigel]
... and also any small additions to one spec or the other that would make the mapping much easier. We should
22:08:08 [nigel]
... capture those as outputs of the work if possible.
22:08:37 [nigel]
tai: That would help with a more general desire to align the specs.
22:08:47 [nigel]
nigel: Knowing where the semantic overlap lies would be useful.
22:09:29 [nigel]
glenn: Sure, where there are things like ruby, let's make sure they align semantically.
22:10:45 [nigel]
nigel: I'm just saying if observations like that are made then we should capture them.
22:11:19 [nigel]
tai: If there are possibilities of making mapping easier, like in TTML2 to map the semantics to CSS then in
22:11:25 [nigel]
... the long run that will make it easier.
22:12:04 [Loretta]
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22:14:00 [nigel]
nigel: Looking at our charter, there are other documents that we could be working on, like the Note on live,
22:14:13 [nigel]
... and the mapping of 608/708 to WebVTT. Where's that last one up to?
22:14:20 [nigel]
Courtney: Silvia wrote a second draft of that.
22:14:54 [nigel]
nigel: Has Silvia done that in the CG - if it's in our charter I'd hope to publish it from here.
22:15:05 [nigel]
Courtney: It's on the CG at the moment.
22:15:24 [nigel]
22:16:04 [nigel]
nigel: I see there's quite a lot of work there - great!
22:16:13 [nigel]
Courtney: Yes, and it's been updated recently.
22:16:25 [nigel]
tai: She also proposed a mechanism for putting inline styles into VTT.
22:16:42 [nigel]
Loretta: I don't think that's in the WebVTT spec yet. Certainly the original syntax for inline styles was never
22:16:48 [nigel]
... adopted into the VTT spec.
22:16:59 [nigel]
tai: So a new proposal might overwrite this?
22:17:15 [nigel]
Loretta: Sure if a new syntax is adopted then that document should be updated to include it.
22:17:56 [nigel]
nigel: Thanks for making progress on the WebVTT TTML mapping document - it'll be good to make some
22:17:59 [nigel]
... progress there.
22:18:41 [nigel]
... Do you have a longer term schedule in mind?
22:19:00 [nigel]
Courtney: We're hoping for something in time for the Sapporo face to face but it's too early to commit to a
22:19:09 [nigel]
... schedule until we've started working on it.
22:19:27 [nigel]
tai: Also we might size the task to fit a particular timescale, at least for a first iteration.
22:19:59 [nigel]
... One last comment: is there an idea to have a common telephone conference where the WebVTT and TTML
22:20:11 [nigel]
... communities can come together? Would that be of use?
22:20:32 [nigel]
Courtney: I think, speaking for myself, in the past it's been tough for Silvia because she's in Australia. So
22:20:47 [nigel]
... finding a good time could be difficult. A standing meeting might not have much support but we can
22:20:52 [nigel]
... schedule specific reviews as we need them.
22:21:03 [nigel]
tai: That would be good to have.
22:21:28 [nigel]
Loretta: We're ideally located to make finding meeting times maximally difficult!
22:21:39 [nigel]
Courtney: Some working groups rotate it.
22:21:55 [nigel]
pal: My suggestion is make sure there's a really clear agenda if you want people to get up in the middle of the night.
22:23:10 [nigel]
nigel: Here in a meeting of 7 members and 1 observer, approximately half the members here today have an
22:23:17 [nigel]
... interest in WebVTT, so we're already doing it.
22:23:25 [nigel]
Loretta: Of course not all the skills are here though!
22:24:17 [nigel]
Topic: Actions
22:24:20 [nigel]
22:24:20 [trackbot]
action-379 -- Nigel Megitt to Obtain png images for #linepadding and #multirowalign test cases. -- due 2015-03-19 -- PENDINGREVIEW
22:24:20 [trackbot]
22:24:36 [nigel]
nigel: I did those PNGs but now they need fixing.
22:25:04 [nigel]
... But that's captured in Action-391, so I'll close this one.
22:25:08 [nigel]
close action-379
22:25:08 [trackbot]
Closed action-379.
22:25:19 [nigel]
22:25:19 [trackbot]
action-381 -- Pierre-Anthony Lemieux to Prepare new list of changes to imsc 1 since cr1. -- due 2015-03-26 -- PENDINGREVIEW
22:25:19 [trackbot]
22:25:39 [nigel]
pal: The next step is to close the outstanding issue and then prepare CR2.
22:25:46 [nigel]
close action-381
22:25:46 [trackbot]
Closed action-381.
22:26:39 [nigel]
nigel: I think we need a new date for the SOTD and a summary of differences since CR1.
22:27:23 [nigel]
Action: pal Prepare CR2 transition version (after closing one remaining issue on IMSC 1)
22:27:23 [trackbot]
Created ACTION-397 - Prepare cr2 transition version (after closing one remaining issue on imsc 1) [on Pierre-Anthony Lemieux - due 2015-04-17].
22:27:40 [atai2]
atai2 has joined #tt
22:28:05 [nigel]
nigel: We also have two overdue actions, action-365 and action-378 which we can't complete either of yet.
22:28:50 [nigel]
pal: That's right. Do we want to make the request to SMPTE as part of the wide review request on the next WD
22:28:53 [nigel]
... of TTML2?
22:29:11 [nigel]
nigel: We could, I'm not sure. No particular reason to wait that I know of.
22:29:18 [nigel]
pal: Okay, well that's ongoing.
22:29:53 [nigel]
Topic: Issues
22:30:03 [nigel]
nigel: I don't believe we have any pending review issues - no we don't.
22:30:34 [nigel]
22:30:34 [trackbot]
issue-382 -- Require a computed non-indefinite begin time -- open
22:30:34 [trackbot]
22:30:50 [nigel]
pal: So just to confirm, if I list the TTML1 features, there's a #timing feature.
22:30:59 [nigel]
glenn: That's a very generic feature.
22:31:12 [nigel]
pal: Okay, so there's no granularity to build on.
22:31:32 [nigel]
glenn: By the way the process for coming up with the features was subjective, and we used it to drive our
22:31:54 [nigel]
... tests. You're supposed to test features, but very few specs list features. So we took the approach of creating
22:32:02 [nigel]
... more fine grained features.
22:32:27 [nigel]
Topic: Sapporo TPAC F2F
22:34:34 [nigel]
nigel: Looking at the survey results there's already enough backing for a meeting to say there's consensus
22:34:40 [nigel]
... to hold a meeting in Sapporo.
22:35:22 [nigel]
... There's a clear preference for the Monday and Tuesday and no objections to that, so it's clear that we
22:35:26 [nigel]
... should prefer those days.
22:38:47 [nigel]
nigel: In terms of joint meetings, someone has suggested CSS-WG, and another suggestion is HTML WG.
22:39:16 [nigel]
glenn: This is going to be difficult unless we make it short and extremely focused, like a single specific question
22:39:23 [nigel]
... to answer. Otherwise it will be a waste of time.
22:39:48 [nigel]
nigel: My question is, what do people want to do there?
22:40:24 [nigel]
glenn: Bert Bos has made comments on WebVTT. He might be interested in the line balancing algorithms.
22:40:34 [nigel]
pal: I mistakenly hit the button for HTML WG and am going to unclick it.
22:40:50 [nigel]
tai: We mentioned over lunch that working with HTML to understand how TTML TextTrackCues can work.
22:41:08 [nigel]
glenn: We have a spec I wrote called the TTML API Level 1 and Level 2 (two specs) that try to define some
22:41:25 [nigel]
... things on top of the TextTrackCue interface that somewhat mirror the WebVTTCue. But there are lots of
22:41:46 [nigel]
... issues getting browser vendors to implement them. Microsoft and Opera might have an interest but
22:42:11 [nigel]
... Google, Apple and Mozilla don't seem to be interested. But my position is that it would be a pretty good
22:42:44 [nigel]
... way to go to use Javascript to populate a set of HTMLCues. Then you could transform into HTML on the
22:43:08 [nigel]
... server and feed it using Ajax and HXR to populate it, or have client side javascript that translates the TTML
22:43:23 [nigel]
... file locally, though that would probably be more complicated and less efficient than doing it on the server.
22:43:40 [nigel]
... That approach would allow either browser based HTML rendering or create a fragment containing SVG with
22:44:01 [nigel]
... a pre-rendered version of the cue. It turns out that inside the implementation in Webkit and Blink the
22:44:26 [nigel]
... same approach is used, to convert WebVTT to HTML and use that.
22:44:47 [nigel]
pal: If this group has a consensus view that would be a good reason to meet with the HTML WG.
22:45:11 [nigel]
glenn: The most likely answers are either 1) no or 2) write that as an extension spec and bring it to the HTML WG.
22:45:46 [nigel]
... There are various reasons for doing that - it's easier not to touch the HTML5 spec. Creating extensions is
22:46:02 [nigel]
... easier, so that's how I would approach it. If that's the likely response then we could organise our inputs to
22:46:07 [nigel]
... feed their expectations.
22:46:37 [nigel]
pal: There'd be value in saying how to do it, though we don't have a volunteer for how to do that yet.
22:47:20 [nigel]
glenn: The whole area of text cues in HTML5 is problematic in terms of testing and interoperability because
22:48:14 [nigel]
... they used a subjective process for getting to Rec. Those areas were marked as at risk during the CR process.
22:48:31 [nigel]
... Instead of addressing that they just published anyway.
22:48:36 [nigel]
tai: But it's in the Rec?
22:48:52 [nigel]
glenn: It is, so its final. The question is what comes next. The formal way that the HTML WG has decreed is that
22:49:14 [nigel]
... if you want to do something that doesn't fix 5.0 or add features for 6 then bring it as an extension.
22:50:06 [nigel]
nigel: How does that approach interact with the WebVTT TTML mapping work?
22:50:12 [nigel]
Loretta: It's orthogonal.
22:50:17 [nigel]
glenn: +1
22:50:39 [nigel]
... You can say that the lack of a TTMLCue is a motivator for the mapping work, because you could use the
22:50:54 [nigel]
... mapping as a playback mechanism. I think its worth proposing a more generic cue proposal to the group
22:51:11 [nigel]
... at some point.
22:52:11 [nigel]
nigel: That sounds like a great idea; so far we have nobody wanting to volunteer to work on that.
22:52:26 [nigel]
... Just to test the view of the group, do we have consensus that an HTMLCue would be a good way to do it?
22:52:29 [nigel]
tai: +1
22:52:31 [nigel]
pal: +1
22:53:00 [nigel]
glenn: The good thing is that with a generic cue type then you can use any input format as long as you have
22:53:54 [nigel]
... javascript to create it. I already have a fairly complete proposal from Opera proposing a way to do this in
22:54:00 [nigel]
... blink.
22:54:07 [nigel]
tai: But that's not public.
22:54:22 [nigel]
glenn: Eric Lindstrom who was at our meeting in Geneva wrote it.
22:54:34 [nigel]
pal: Could we bring that document to the group for review and take it to HTML WG?
22:54:47 [nigel]
glenn: It's blink specific so it would need to be made more generic.
22:55:02 [nigel]
... Maybe we could ask Eric if he wants to take this forward.
22:56:40 [nigel]
tai: I can contact Eric if you give me an action.
22:56:56 [nigel]
Action: atai2 Contact Erik Lindstrom re HTMLCue
22:56:56 [trackbot]
Created ACTION-398 - Contact erik lindstrom re htmlcue [on Andreas Tai - due 2015-04-17].
22:57:10 [courtney]
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22:57:25 [nigel]
glenn: Opera has membership of this group via Philip Jägenstedt.
22:58:50 [nigel]
nigel: We do have consensus here that this is a good way to go, i.e. to propose to HTML WG HTMLCue as an extension
23:04:48 [nigel]
nigel: That's everything from the survey results that I need for my response to the organisers. That doesn't
23:04:59 [nigel]
... close the survey - any new or amended responses will still be taken into account.
23:05:36 [nigel]
... But it does mean we will go ahead with a Monday and Tuesday meeting.
23:05:48 [nigel]
... Is there anything that we want to cover in that meeting?
23:06:05 [nigel]
tai: We should reserve some time for the mapping, regardless of what state we're in.
23:06:30 [nigel]
pal: Hopefully we'll be done with IMSC 1 but if not we should address any blockers. We should also work on
23:06:49 [nigel]
... a 1st draft of IMSC 2, that should exist at that time. The hope is that IMSC 2 is simpler as a document
23:06:59 [nigel]
... than IMSC 1 because all the features will be a subset of TTML2.
23:07:15 [nigel]
glenn: You will probably want an informative section mapping IMSC 1 features into IMSC 2 if they're no longer
23:07:29 [nigel]
... present in IMSC 2. I imagine you might want to say something about migration, continuing use of old content etc.
23:08:11 [nigel]
nigel: For TTML2 maybe we should be targeting implementation reports.
23:08:24 [nigel]
glenn: I definitely hope we'll be in CR by then.
23:08:46 [nigel]
pal: When will you be able to show implementations of your tool?
23:09:13 [nigel]
glenn: The TTPE presentation tool I've been writing should be available at end of June. Probably end of August
23:09:22 [nigel]
... to finalise the arabic, hebrew and bidi additions to it.
23:09:31 [nigel]
pal: That will remove a huge risk to TTML2.
23:09:48 [nigel]
glenn: I'm hoping to be able to get a lot of the new features into it as well. So we can have at least one
23:10:06 [nigel]
... system to pass tests. I'm also adding support to the TTML Validator to validate the new constructs.
23:10:23 [nigel]
... So in a sense we could point to the Validator as one implementation and the presentation engine as the
23:10:53 [nigel]
... other implementation even though one is built on the other.
23:12:01 [nigel]
nigel: There is a question the Director will ask about who wrote the implementations. In this case we could have
23:12:19 [nigel]
... an answer which is that the spec and both implementations were written by the same individual. I don't think
23:12:26 [nigel]
... that he'd be that happy with that!
23:13:05 [nigel]
tai: A quick question about what TTPE does: from the documentation I'm not clear what the outputs are?
23:13:39 [nigel]
glenn: [draws on the whiteboard] There are 3 layers: TTV, TTX and TTPE. Generic TTML files can feed into
23:13:59 [nigel]
... TTV - TTML1 or TTML2. It validates every feature of TTML1 and i'm enhancing it as I go to support TTML2
23:14:38 [nigel]
... features. TTX converts into ISDs in a sequence which consists of multiple instances of an ISD.
23:15:16 [nigel]
... TTPE then does two things: layout and then rendering. It takes the ISDs and creates an area tree which
23:15:44 [nigel]
... is very similar to what's in XSL-FO, or a box tree in CSS terms. It has things like block areas, line areas,
23:16:01 [nigel]
... glyph areas, space areas that fill the lines up. The rendering process then turns that into the chosen output
23:16:35 [nigel]
... format (specified on the command line) - one of XML for debug, SVG or PNG. I've also specced out renderers
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23:16:58 [nigel]
... for html and vtt that I and the other engineers working on this haven't built yet. They just take the area
23:17:16 [nigel]
... tree as the input and then write out whatever is needed to create the same visual output as is specified.
23:18:02 [nigel]
... It's very easy for SVG. TTV and TTX are both in the TTV project in github. TTPE is a separate project.
23:20:10 [nigel]
pal: When that implementation is available, that removes a huge risk for TTML2 because there's at least one
23:20:31 [nigel]
... baselins implementation for features. So it's hard for me to imagine not being able to enter CR in August.
23:20:39 [nigel]
23:21:15 [nigel]
Loretta: It looks like there's a lot of input for the TTML to WebVTT mapping there.
23:21:39 [nigel]
glenn: The question is how to map from the area tree to WebVTT. It's hard to work out how to do the positioning in WebVTT.
23:22:00 [nigel]
... Since WebVTT doesn't have pixel positioning I may have to use the regions feature to do the layout.
23:22:17 [nigel]
... One of the things about the mapping is that you can lose information without losing everything. At the basic
23:22:44 [nigel]
... level I could pull the text out of the area tree and blast it into a WebVTT cue. That would lose a lot of information!
23:23:08 [nigel]
... It's a question how to include positioning properly.
23:23:30 [nigel]
Courtney: Another item for the F2F in Sapporo should be the WebVTT progress.
23:23:48 [nigel]
dakim: Do you think the ruby stuff is important for WebVTT v1?
23:24:04 [nigel]
Courtney: I think it's less important than inline styling, and also we need to figure out how to do it in terms
23:24:19 [nigel]
... of the design. A lot of what we need is already in CSS so maybe if you do inline styling in CSS maybe you
23:24:34 [nigel]
... get all the ruby functionality you need.
23:24:52 [nigel]
dakim: I've got a bug open with Philip that you can't annotate the rt tag.
23:25:13 [nigel]
Courtney: If that's a minor change to the spec then we could consider adding that. I want to balance the features
23:25:21 [nigel]
... against getting to a spec as quickly as possible.
23:25:51 [nigel]
nigel: Obviously that's a consensus issue for the group.
23:25:59 [nigel]
Loretta: the call is when it's needed not whether it's needed.
23:26:10 [nigel]
rrsagent, generate minutes
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I have made the request to generate nigel
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Topic: TTML2 topics continued
23:39:30 [nigel]
q+ pal to ask about ttp:contentProfiles "any"
23:40:30 [nigel]
pal: I'd like to walk through the positioning of images in TTML2 also
23:40:40 [nigel]
s/q+ pal to/pal: I'd like to
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23:42:37 [nigel]
dakim: I'm wondering why people would use extent and origin on content elements to define inline regions instead of just ipd and bpd
23:44:43 [nigel]
nigel: For ttp:contentProfiles what sense does "any" make?
23:44:59 [nigel]
glenn: I see what you mean - I can't see why an author would claim conformance with at least one of but not
23:45:06 [nigel]
... all of a set of content profiles.
23:46:42 [nigel]
23:46:42 [trackbot]
issue-386 -- There's no apparent use case for the "any" term in ttp:contentProfiles -- raised
23:46:42 [trackbot]
23:46:45 [nigel]
reopen issue-386
23:46:46 [trackbot]
Re-opened issue-386.
23:47:08 [nigel]
nigel: The next point was also raised by pal: the positioning of images in TTML2
23:47:27 [nigel]
pal: How do you position images?
23:47:43 [nigel]
glenn: If it's a background image then use the background position properties. If it's a non-background image
23:48:10 [nigel]
... then you can treat it like a block or inline area so the rules apply, like ipd and bpd. Extent and origin do
23:48:17 [nigel]
... not apply to content elements - they create regions.
23:48:32 [nigel]
... There are two ways to do it - you can put a background image on a region. That's intended to support
23:48:50 [nigel]
... non-content images. For content images e.g. with rasterised text in them one should not use the
23:49:10 [nigel]
... backgroundImage mechanism but instead use image like in html. Put it in a block context e.g. as a child
23:49:33 [nigel]
... of a div or in a p. So if you put a span with an ipd and bpd then it's now an inline block with an image in it.
23:49:48 [nigel]
... If you want to do fine positioning you have to use spans with ipd and bpd.
23:50:16 [nigel]
pal: So if I wanted an image 80% from the top and 20% from the left of the viewport.
23:50:32 [nigel]
glenn: I'd create a region and define its position using the position attribute or origin. Then I'd put a div in it
23:50:50 [nigel]
... with a single image inside that div. That would be the easiest way to position it.
23:51:23 [nigel]
... If that's the only content in the region it would position it. You can also use ipd and bpd.
23:51:33 [nigel]
nigel: Have we got scaling semantics for images if we use ipd and bpd?
23:52:06 [nigel]
glenn: I thought so - I don't believe there's an issue.
23:53:11 [nigel]
23:53:11 [trackbot]
issue-387 -- Consider applying ipd or bpd to content images -- raised
23:53:11 [trackbot]
23:53:17 [nigel]
reopen issue-387
23:53:17 [trackbot]
Re-opened issue-387.
23:54:24 [nigel]
pal: When I read the document the simple option wasn't obvious.
23:55:00 [nigel]
glenn: By the way displayAlign and textAlign would apply to it.
23:55:14 [nigel]
... I think you may also be permitted to put an image in a body without a div.
23:55:40 [nigel]
... No, body has to have div in it, div can have embedded class like image or other divs or ps.
23:57:38 [nigel]
nigel: The last point to raise is that content elements can have style attributes extent, position, origin, ipd and bpd all applied
23:57:53 [nigel]
... simultaneously. I think the semantics are clear but some readers of the documents will find it hard to
23:58:34 [nigel]
... understand. It may be useful to add non-normative examples or text to explain this scenario.
23:58:57 [nigel]
glenn: That's a feature of languages as they get bigger. I have an issue already to add recommendation text
00:00:34 [nigel]
... to say that style attributes should not be put on content elements where they do not apply and can not be
00:00:37 [nigel]
... inherited from.
00:01:20 [nigel]
nigel: It might also be useful to include an example document or non-normative text somewhere to remove
00:01:28 [nigel]
... or reduce the likelihood of confusion there.
00:03:43 [nigel]
nigel: The last question I have is where we're up to on the CSS semantics mappings?
00:04:01 [nigel]
glenn: I have a proposal out for mapping to html that will generate that, but I don't have the resource to do that
00:04:06 [nigel]
... at the moment.
00:04:13 [nigel]
tai: Didn't you have some draft material for that?
00:05:41 [nigel]
glenn: jdsmith picked up some work from Sean re change proposal 5 but that needs further attention.
00:05:48 [nigel]
00:06:18 [nigel]
glenn: When we started this work there was an idea that someone could create a Javascript shim that would
00:06:32 [nigel]
... generate HTML/CSS.
00:06:52 [nigel]
... CP5 needs to be carefully reviewed because the time evaluation algorithm wouldn't work. It also attempts
00:07:14 [nigel]
... to specify some algorithms on how to resolve styles. We already have some normative language on
00:07:27 [nigel]
... style resolution in the spec. My plan was to take that information and also timing rules and wrote them
00:07:40 [nigel]
... into the spec in a readable fashion in the context of an ISD sequence then it would eliminate talking about
00:07:51 [nigel]
... style and timing resolution in the context of an HTML mapping.
00:09:24 [nigel]
nigel: I was expecting equivalence notes under the style attributes to say what the equivalent CSS semantics
00:10:10 [nigel]
... are to the already stated XSL semantics. I think CP5 is something different and much more complex.
00:10:38 [nigel]
glenn: I'm not sure how useful that would be.
00:10:45 [nigel]
nigel: I think it would be extremely useful.
00:11:24 [nigel]
glenn: In § and §, when we originally talked about a CSS mapping the intent was to define
00:11:42 [nigel]
... two subsections of § one based on XSL-FO and the other on CSS. That means taking part of the
00:13:08 [nigel]
... material from CP5 and formally doing it in a way that is congruous with the XSL-FO.
00:13:59 [nigel]
tai: I understood this activity to be as Glenn described, but even just additional notes as nigel described would
00:14:16 [nigel]
... have a big impact on readability, especially if the CSS semantic is first.
00:14:29 [nigel]
glenn: I'd be happy to put the CSS equivalents first.
00:14:44 [nigel]
tai: People don't know how close the features already are to CSS so it would make the document much more
00:14:48 [nigel]
... accessible.
00:15:22 [nigel]
glenn: It would be insufficient just to create an equivalence table for each style attribute. We'd also have to do an equivalent
00:15:31 [nigel]
... algorithm in §
00:15:34 [nigel]
nigel: I agree with that.
00:15:47 [nigel]
glenn: Nobody has been pushing me to do this much!
00:16:55 [nigel]
glenn: I won't be confident about the algorithm until I've seen it in code though. I'd be happy to use CP5
00:16:59 [nigel]
... as a starting point at least though.
00:18:05 [nigel]
nigel: I think that's all on this and everything I had on the queue to deal with. In terms of your spreadsheet
00:18:14 [nigel]
... glenn did you have any remaining technical questions?
00:19:26 [nigel]
glenn: I don't think so - I have a pretty good idea on most of the remaining things and I will come to the group
00:20:02 [nigel]
... if there are any other questions. For example on disparity if there's anything unclear in the issue.
00:20:21 [nigel]
glenn: I'd like a response from SMPTE to know that they'll be satisfied with what we've proposed.
00:21:07 [nigel]
nigel: pal has the action to draft that. Good to know that there's a pressing need for that.
00:21:18 [nigel]
glenn: I'd like to draft some of the members to do some work particularly on the examples and images of
00:22:10 [nigel]
... examples.
00:22:47 [nigel]
... I have about 25 entries that have to do with creating example source content or images or both. I could do
00:23:06 [nigel]
... it but my time would be better spent creating technical solutions. There's also an annex Q about a CEA708
00:23:13 [nigel]
... mapping that it would be useful to have someone look at.
00:23:37 [nigel]
pal: Just point to RP2052-11 which already does it.
00:23:45 [nigel]
glenn: Does that point to SMPTE additions to TTML?
00:23:58 [nigel]
pal: I doubt it - it doesn't use image. I'm just offering an easy way to do that.
00:24:08 [nigel]
glenn: I don't know if that's going to be sufficient - it needs to be reviewed.
00:24:22 [nigel]
pal: I don't think we need that section - if nobody volunteers to write it we can remove it.
00:25:31 [nigel]
glenn: We've added 6 metadata items preceded with cea708 and others preceded cea608. I have a note to
00:25:49 [nigel]
... elaborate those with reference to 608 and 708. If someone could sign up for doing some of the related
00:25:52 [nigel]
... work items that would be useful.
00:27:03 [nigel]
glenn: In the end with TTML1 where we did this everyone had a role bringing some spec text in.
00:28:14 [nigel]
nigel: Okay, I appreciate the request and think that's a really good idea. It's not necessarily a good moment
00:28:28 [nigel]
... to start assigning tasks now, but let's think about that and how to take it forward.
00:28:41 [nigel]
glenn: I reserve the right to ensure consistency of language and edit contributions.
00:29:33 [nigel]
nigel: Okay, we have the spreadsheet available (see yesterday's minutes) - everyone have a look at that and if
00:29:44 [nigel]
... you want to contribute something contact me or glenn and let's share out those tasks.
00:31:21 [nigel]
glenn: nigel you raised issues on appendix L.
00:31:40 [nigel]
nigel: I've done the work to guess the new values for the conformance column against requirements - it's in the issue.
00:32:39 [nigel]
glenn: In Appendix M the element derivation needs to be updated for the new properties.
00:33:05 [nigel]
... It would be useful to have a list of elements and attributes to add or change on the tables in M.
00:34:15 [nigel]
... By the way you could edit the source document itself if you're set up to run ant, and I could help you set
00:34:36 [nigel]
... up your build environment so you can run the authoring tools. We have an old process for generating the
00:34:54 [nigel]
... spec using an XSLT-based translation process with a DTD. The language we write the spec in is governed by
00:35:20 [nigel]
... XMLSpec that came out of the XML WG.
00:35:28 [nigel]
... There's a stylesheet too.
00:36:27 [nigel]
nigel: Okay, that's interesting - let me know if you're interested in setting that up.
00:37:02 [nigel]
Topic: Meeting ending!
00:37:13 [nigel]
nigel: Thanks to netflix for sponsoring this meeting, and to Glenn for buying lunch.
00:37:21 [nigel]
glenn: And thanks to Netflix for sponsoring that lunch.
00:38:17 [nigel]
nigel: I think we've had a really productive two days, so thanks everyone for attending and contributing.
00:38:26 [nigel]
tai: And thanks for chairing and scribing too!
00:38:28 [nigel]
nigel: Thanks!
00:40:07 [nigel]
nigel: We've done all our goals for this meeting and also handled issues or at least come up with action plans.
00:40:11 [nigel]
... So well done everyone!
00:40:16 [nigel]
... [adjourns meeting]
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I have made the request to generate nigel
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nigel has changed the topic to: TTWG: next meeting 2015-04-16 1400 UTC
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