IRC log of tt on 2015-10-08

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Zakim, this will be TTML
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I do not see a conference matching that name scheduled within the next hour, trackbot
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Meeting: Timed Text Working Group Teleconference
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Date: 08 October 2015
14:04:43 [nigel]
chair: nigel
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scribe: nigel
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Regrets: Andreas, Frans, Mike
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Present: nigel, pal, tmichel
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I am connected but without any sound.
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I will rejoin webex
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Topic: This Meeting
14:07:19 [nigel]
nigel: Most of this meeting will be dedicated to closing IMSC 1 pending review issues
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nigel: AOB?
14:07:51 [nigel]
nigel: Mike has asked to postpone the incoming liaison from ATSC issue.
14:08:09 [nigel]
pal: There's also the topic of profile designators - it would be good to talk about it.
14:08:15 [nigel]
nigel: Great, that's added.
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Topic: Action Items
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14:09:14 [trackbot]
Action-421 -- Nigel Megitt to Check with ttml player manufacturers if they're happy to be listed on our site. -- due 2015-09-24 -- OPEN
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14:09:49 [nigel]
nigel: I did contact the manufacturer we discussed and they said they'd check but haven't yet confirmed.
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nigel: Do we have an implementations page?
14:10:26 [nigel]
tmichel: I don't think we have one yet but I'd like to start one. I think we should have a page
14:10:36 [nigel]
... per technology - one for TTML, one for WebVTT etc.
14:10:51 [nigel]
pal: We have a page for that - remember the contribution from the Web & TV IG?
14:10:56 [nigel]
nigel: Oh yes, I remember now.
14:11:17 [nigel]
14:11:48 [nigel] is a better URL to use
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It's linked from under Timed Text Efforts and Specifications
14:12:40 [nigel]
nigel: I guess we could add it to the group home page too - we probably should tidy up the
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... group page vs wiki home page discrepancy. Having both isn't especially helpful.
14:13:32 [nigel]
tmichel: In former times we had the CVS hosted home page which was hard to edit. Now
14:13:44 [nigel]
... the wiki is simpler for people to add information to. Everyone should be able to add their
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... own product if they want to.
14:14:27 [nigel]
nigel: Is it worth an action to redirect from the home page to the wiki?
14:14:41 [nigel]
tmichel: I'll look into that. There's some information like how to join on the home page.
14:14:52 [nigel]
nigel: Yes. we'd have to migrate the key information.
14:15:01 [nigel]
tmichel: I'll look into it and propose something.
14:15:19 [nigel]
Action: tmichel Look into merging the group home page and the wiki home page and propose something
14:15:19 [trackbot]
Created ACTION-430 - Look into merging the group home page and the wiki home page and propose something [on Thierry Michel - due 2015-10-15].
14:15:49 [nigel]
Topic: TPAC 2015
14:16:07 [nigel]
nigel: Netflix has just joined the WG and would like to spend some agenda time on the Thursday
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... presenting on their open source TTML2 implementation work.
14:16:47 [nigel]
nigel: I'll add that to the topics/agenda page on the wiki.
14:17:05 [nigel]
tmichel: While we're talking about new participants, SImon from Opera joined today replacing Philip.
14:17:14 [nigel]
... Simon is the new editor of the WebVTT spec.
14:17:30 [nigel]
Topic: IMSC stuff...
14:17:59 [nigel]
14:17:59 [trackbot]
action-425 -- Thierry Michel to Send a prompt/thank you to the potential test result contributors for imsc. -- due 2015-10-01 -- OPEN
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14:18:28 [nigel]
pal: I've not heard back and am still chasing, so that's still open. No update despite best efforts.
14:18:44 [nigel]
Topic: Profiles registry
14:19:35 [nigel]
pal: Related to Cyril's email earlier today, which came out of this topic, I think from an
14:19:50 [nigel]
... implementation standpoint he wants users to be able to signal clearly in a TTML document
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... what profiles a document conforms to. In IMSC 1 right now there's a 'MAY user ttp:profile'
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... statement but that's it. Maybe we can add more to IMSC 1 to encourage people to label
14:20:34 [nigel]
... their documents. The challenge is, as we discussed before, EBU-TT-D forbids ttp:profile.
14:20:56 [nigel]
... And ttp:profile supports only one profile. So if a document conforms to both EBU-TT-D and
14:21:09 [nigel]
... IMSC 1 then you should not use ttp:profile but you should use ebuttm:conformsToStandard
14:21:21 [nigel]
... and list both. If the document is not EBU-TT-D conformant it probably isn't a bad idea to
14:21:40 [nigel]
... use ttp:profile and also include ebuttm:conformsToStandard so I'm thinking of adding
14:22:00 [nigel]
... a recommendation to IMSC 1 along those lines.
14:22:16 [nigel]
nigel: I can see the logic to that, yes. It makes sense I think.
14:22:24 [nigel]
pal: I'd like to be responsive to the request.
14:22:38 [nigel]
nigel: I agree - there's a use case we haven't spent a lot of time considering that is obviously
14:22:56 [nigel]
... important. I'd like Andreas's and Frans's input on this specific proposal too, but on the
14:23:04 [nigel]
... surface I think it makes a lot of sense.
14:23:45 [nigel]
nigel: You can recommend using the URI designators.
14:23:58 [nigel]
pal: That would definitely be the recommendation!
14:24:15 [nigel]
... From a tools perspective it would certainly help tools to determine the document's profile.
14:25:11 [nigel]
nigel: We just need to be careful that ebuttm:conformsToStandard is indicating document
14:25:51 [nigel]
... conformance in other words the equivalent to TTML2's ttp:contentProfiles attribute.
14:26:13 [nigel]
... Whereas ttp:profile indicates a processor profile, so we shouldn't mix the messages there.
14:27:43 [nigel]
pal: I don't know why we hadn't collectively thought about this before. I think it works in exactly the right way.
14:28:26 [nigel]
nigel: I can see how this would work really well - if an IMSC 1 processor is needed then it's on
14:29:19 [nigel]
... the ttp:profile attribute and if not, because an EBU-TT-D processor is okay, then it would be
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... omitted.
14:29:36 [nigel]
pal: I think we can file an issue for this, especially given Glenn's email just now proposing that
14:29:55 [nigel]
... IMSC 1 includes a 'should include ttp:profile attribute' statement, then implement and review
14:29:57 [nigel]
... next week.
14:30:14 [nigel]
pal: [filing issue right now]
14:32:06 [nigel]
14:32:06 [trackbot]
issue-448 -- Add recommendation for ttp:profile and ebuttm:conformsToStandard -- raised
14:32:06 [trackbot]
14:32:11 [nigel]
reopen issue-448
14:32:11 [trackbot]
Re-opened issue-448.
14:32:21 [nigel]
pal: I'm going to reply to the thread too.
14:33:25 [nigel]
nigel: I think it's worth pinging back to EBU to check if they might reopen the discussion on
14:33:34 [nigel]
... whether or not to permit ttp:profile on EBU-TT-D documents.
14:34:53 [nigel]
nigel: Of course if you have a stream of EBU-TT-D documents e.g. in DASH then this is likely
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... to be redundantly repeated data.
14:35:16 [nigel]
pal: Of course the packager could strip it out if it knows the data won't be needed downstream.
14:36:08 [nigel]
nigel: We may be putting packagers in an uncomfortable situation of needing to modify the
14:36:14 [nigel]
... samples they're given to wrap up.
14:36:32 [nigel]
pal: True - we're talking about a few bytes though and it's tiny in comparison with e.g. HTTP headers.
14:36:59 [nigel]
Topic: Issues
14:38:11 [nigel]
nigel: Let's go through Pending Reviews...
14:38:13 [nigel]
14:38:13 [trackbot]
issue-404 -- Where is #image feature defined? -- pending review
14:38:13 [trackbot]
14:38:32 [nigel]
pal: I think this is unambiguous, well specified and can be closed.
14:38:39 [nigel]
nigel: +1
14:38:41 [nigel]
close issue-404
14:38:41 [trackbot]
Closed issue-404.
14:38:51 [nigel]
14:38:51 [trackbot]
issue-405 -- why is #nested-span prohibited on image profile? -- pending review
14:38:51 [trackbot]
14:39:17 [nigel]
nigel: This isn't even a proposal to change the spec. It's a question with an answer.
14:39:32 [nigel]
pal: I think Glenn would have responded if he disagreed.
14:39:38 [nigel]
close issue-405
14:39:38 [trackbot]
Closed issue-405.
14:39:48 [nigel]
14:39:48 [trackbot]
issue-406 -- #lineBreak-uax14 is never 'used' by a document? -- pending review
14:39:48 [trackbot]
14:41:09 [nigel]
pal: uax14 is mandated for processors in the text profile and stated as not applicable to document instances.
14:41:21 [nigel]
... The image profile is silent about it.
14:41:30 [nigel]
nigel: Do we permit the profile features to be listed in the document?
14:41:54 [nigel]
pal: We do. The presence of the profile designator in the document requires that the processor
14:42:14 [nigel]
... implements uax14. What the spec currently says is the document constraints. The uax14
14:42:23 [nigel]
... feature is not applicable to constraints on the document.
14:43:23 [nigel]
nigel: There's a niche issue for the text profile: if the profile features are included then it would
14:43:41 [nigel]
... be an error to state that the #linebreak-uax14 feature is a 'shall not use'.
14:45:02 [nigel]
... That would create a situation where an IMSC 1 text profile conformant processor should
14:45:50 [nigel]
... reject an IMSC 1 text profile conformant document that includes this profile feature as
14:45:54 [nigel]
... 'shall not use'.
14:46:12 [nigel]
pal: This is a strange and theoretical case, that applies only to the uax14 feature.
14:47:05 [nigel]
nigel: We could add a statement that if profile features are included within a document then
14:47:30 [nigel]
... they shall not conflict with the processor conformance rules for IMSC 1.
14:47:48 [nigel]
Action: nigel File issue re profile feature inclusion in IMSC 1 documents
14:47:48 [trackbot]
Created ACTION-431 - File issue re profile feature inclusion in imsc 1 documents [on Nigel Megitt - due 2015-10-15].
14:48:03 [nigel]
pal: We could add that to the profile section for document conformance.
14:48:52 [nigel]
pal: Going back to issue-406, Glenn suggested to require the feature. Shall we start the 2 week review clock on this today?
14:48:56 [nigel]
nigel: yes, let's do that.
14:49:10 [nigel]
14:49:10 [trackbot]
issue-408 -- Initial value of color -- pending review
14:49:10 [trackbot]
14:51:11 [nigel]
close issue-408
14:51:11 [trackbot]
Closed issue-408.
14:51:41 [nigel]
14:51:41 [trackbot]
issue-409 -- Font family of default means monospaceSerif -- pending review
14:51:41 [trackbot]
14:52:22 [nigel]
pal: IMSC 1 defines what it means for "default" fontFamily, i.e. what a processor shall do when
14:52:38 [nigel]
... the fontFamily is set to "default". Glenn points out that this isn't always the right thing to do.
14:53:01 [nigel]
... My response to that is that authors should not rely on default. TTML1 doesn't prohibit
14:53:14 [nigel]
... implementations from mapping the default font to a known one.
14:55:56 [nigel]
nigel: I'm a bit nervous here - Glenn hasn't proposed a solution, and I don't know why.
14:56:13 [nigel]
... For example we could include a table mapping language to default font map or reference
14:56:17 [nigel]
... one in e.g. CLDR.
14:57:20 [nigel]
pal: Document authors can make their choice though if default won't work for them.
14:57:40 [nigel]
nigel: My nervousness here is that we're making a language market-specific value for default,
14:57:48 [nigel]
... which could make use of default less useful.
14:58:08 [nigel]
nigel: However Glenn knows most about this from those here and he hasn't picked it up.
14:58:32 [nigel]
pal: We should close this on the basis of no response in over 1 month. It can be reopened if someone is unhappy.
14:58:40 [nigel]
close issue-409
14:58:40 [trackbot]
Closed issue-409.
14:58:50 [nigel]
14:58:50 [trackbot]
issue-410 -- Constraints on #linePadding and #multiRowAlign -- pending review
14:58:50 [trackbot]
15:01:59 [nigel]
nigel: The problem with SHALL NOT here suggests a syntactic conformance requirement whereas
15:02:32 [nigel]
... what you mean is that if the attributes are present then they shall be ignored by implementations.
15:03:33 [nigel]
pal: We don't have Glenn's view on this so it would be uncool if he doesn't agree.
15:05:51 [nigel]
... Don't forget the problem arose in EBU-TT-D.
15:06:06 [nigel]
nigel: The new EBU-TT Part 1 v1.1 might get us out of that problem - it defines the features
15:07:11 [nigel]
... and states that they may be used in EBU-TT-D, and fixes the gaps from the original definition.
15:07:52 [nigel]
Action: nigel Nigel, pal, andreas and frans to hook up re changing IMSC 1 EBU-TT feature references to point to tech3350 v1.1
15:07:52 [trackbot]
Created ACTION-432 - Nigel, pal, andreas and frans to hook up re changing imsc 1 ebu-tt feature references to point to tech3350 v1.1 [on Nigel Megitt - due 2015-10-15].
15:09:27 [nigel]
issue-410: [meeting 2015-10-08] See also Action-432 - it may be possible to avoid the problem by referencing tech3350 v1.1.
15:09:27 [trackbot]
Notes added to issue-410 Constraints on #linePadding and #multiRowAlign.
15:09:59 [nigel]
nigel: We're out of time so I'll adjourn now.
15:10:14 [nigel]
pal: Maybe we could do 2 hours next week to get through the remaining issues ahead of TPAC?
15:10:35 [nigel]
nigel: That's fine for me.
15:10:57 [nigel]
pal: I'd like to have gone through all of them - there's one that may need TPAC discussion.
15:11:10 [nigel]
... Glenn brought up an excellent question about the HRM, in relation to Arabic, where the
15:11:25 [nigel]
... mapping between code point and glyph is in the majority of cases is not 1:1 and the shape
15:11:39 [nigel]
... depends on the context. That really messes up the glyph buffer. I'm researching it.
15:12:10 [nigel]
... The glyph buffer was put in to support e.g. 608, 708 and Teletext. Hopefully we'll have closed all the others.
15:14:15 [nigel]
nigel: Thanks both. [meeting adjourned]
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