13:59:15 RRSAgent has joined #tt 13:59:15 logging to http://www.w3.org/2016/04/21-tt-irc 13:59:17 RRSAgent, make logs public 13:59:17 Zakim has joined #tt 13:59:19 Zakim, this will be TTML 13:59:19 ok, trackbot 13:59:20 Meeting: Timed Text Working Group Teleconference 13:59:20 Date: 21 April 2016 13:59:57 Present: Glenn, Nigel 14:01:55 Present+ Plh 14:02:25 Present+ Pierre 14:03:01 plh: I can't stay for long but want to note that the IMSC 1 Rec was published today 14:03:11 plh: https://www.w3.org/TR/ttml-imsc1/ is REC 14:03:19 plh: https://lists.w3.org/Archives/Member/w3c-ac-members/2016AprJun/0012.html 14:03:30 plh: Karen told me this morning she still wants to do the press release but unfortunately 14:03:37 ... it won't happen this morning due to other events. 14:03:43 atai has joined #tt 14:04:06 plh: I did not put last week's stuff in, because I received it from Pierre too late yesterday, 14:04:13 ... so it got published as is today. 14:04:25 nigel: Fantastic, well done everyone, great news! 14:04:41 glenn: An announcement message did go out shortly before the meeting. 14:05:04 plh: Congratulations again, apologies I cannot stay for the rest of the meeting. 14:05:23 Present+ Andreas 14:05:49 Topic: This meeting 14:07:01 nigel: I don't think there's much to discuss on Charter, but there's stuff to discuss re TTML1 and TTML2 14:07:06 scribe: nigel 14:07:09 nigel: AOB? 14:07:29 group: no AOB 14:07:40 Topic: Action Items 14:08:18 tmichel has joined #tt 14:09:00 Present+ tmichel 14:09:16 glenn: I need to write up some of these - some have been taken care of one way or another. 14:09:29 ... No specific progress to report on them this week. 14:10:40 action-459? 14:10:40 action-459 -- Thierry Michel to Process the PR at https://github.com/w3c/tt-profile-registry/pull/3 and post for review to the reflector -- due 2016-04-21 -- OPEN 14:10:40 http://www.w3.org/AudioVideo/TT/tracker/actions/459 14:11:09 tmichel: Thanks to plh the pull request has been merged while I was away. 14:11:18 ... The follow up is for the group to review the draft. 14:11:56 mike has joined #tt 14:11:59 tmichel: Plh told me you want to split the table? 14:12:17 nigel: Yes, I don't mind who does it but the table is a bit unwieldy now so I think it should be split. 14:12:27 tmichel: Shall I do that? 14:12:40 nigel: I'm happy for you to do that. 14:13:14 tmichel: Okay I'll do that after the call and send around a call for review probably tomorrow. 14:14:12 action-459: [TTWG meeting 2016-04-21] agreed to split the table prior to sending for review. 14:14:12 Notes added to action-459 Process the PR at https://github.com/w3c/tt-profile-registry/pull/3 and post for review to the reflector. 14:14:36 Present+ Mike 14:14:48 mike: There's still an action to replicate the media type information from Annex C of 14:15:11 ... TTML1 and add the codecs parameter and update the IANA registration. Is that still 14:15:13 ... needed? 14:15:15 nigel: Yes please. 14:16:51 mike: So the process is to make a Pull Request and then request review? 14:17:04 glenn: Which document? 14:17:05 nigel: https://w3c.github.io/tt-profile-registry/index.html 14:17:25 nigel: Yes, we can be flexible about this, but for example making a pull request and discussing 14:17:31 ... it in a meeting prior to merging would be fine. 14:18:01 glenn has joined #tt 14:18:56 mike: Okay I'll do a pull request against the profile registry and then we can all look at it. 14:19:02 nigel: Fantastic, thank you Mike. 14:20:01 nigel: I also propose to merge Cyril's TTML versions document into this too, as a separate exercise. 14:20:06 ... That material is more descriptive. 14:20:21 ... https://dvcs.w3.org/hg/ttml/raw-file/5ee90ec0d897/ttml-status/index.html 14:20:49 nigel: Looking at that, there's so little content in there that we maybe just add new 14:20:56 ... descriptive sections and leave Cyril's where it is. 14:21:33 Topic: IMSC 14:21:45 nigel: Following on from the Rec publication noted at the top, are there any other points? 14:22:03 tmichel: I noticed yesterday that we don't have an acknowledgments section. It's nice 14:22:13 ... to have so maybe we should put a placeholder for the next version of IMSC. 14:22:25 glenn: I suggest we create an errata document to start with and add an ack section to 14:22:36 ... that as a placeholder. I think this was probably an editorial oversight. 14:23:54 Action: tmichel Add an acknowledgment section to the IMSC 1 errata section. 14:23:55 Created ACTION-461 - Add an acknowledgment section to the imsc 1 errata section. [on Thierry Michel - due 2016-04-28]. 14:24:10 pal: Philippe put the github copy of the errata in the wrong place on github, so I need to 14:24:13 ... move it. 14:24:23 wrong place? 14:24:39 tmichel: Okay, move it and then I'll make a pull request. 14:25:15 pal: Can we put an issue on github to add the acknowledgments? 14:26:00 tmichel: Who should be acknowledged - just group members? 14:26:11 glenn: Only people who have made some kind of contribution to the spec should be 14:26:14 ... acknowledged. 14:26:24 nigel: I've created https://github.com/w3c/imsc/issues/177 14:26:42 glenn: You could also list group participants, but not random people who are not 14:26:50 ... engaged or have not contributed something. 14:27:48 tmichel: If we want other people, e.g. from the community group, let me know. We 14:28:01 ... could also help people for filing implementation reports, again, not mandatory. 14:28:13 s/help/acknowledge 14:28:28 glenn: If people have contributed in some way to the process or the spec then I think 14:28:33 ... they should be acknowledged. 14:28:35 nigel: +1 14:28:46 pal: This work began from a DECE contribution. 14:29:05 glenn: I'd acknowledge the group, unless you choose to pick named individuals. That would be fine too. 14:29:15 ... Take a look at what we did in TTML1 - I think it's instructive. 14:29:26 ... I made special mention to a few people who contributed more than the average share. 14:30:03 nigel: Who's going to start work on this? 14:30:06 tmichel: I will. 14:30:07 nigel: Thanks. 14:30:30 pal: Based on our discussion last week I sent plh too late yesterday a document that's 14:30:44 ... a roadmap to the IMSC family of specifications, addressing what we discussed last week, 14:31:12 ... that "latest version" might point to one of several possibilities. I created that document 14:31:25 ... and a pull request. It did not make it to this release of IMSC 1, but my suggestion is 14:31:37 ... still to accept the pull request and leave that document there. It's useful, and if we 14:31:46 ... ever do a 2nd edition then it will be there ready to go. 14:32:05 ... It's a really short document, that lists the current IMSC documents. Right now there's 14:32:24 ... only one. 14:32:37 glenn: Looking at TTML1, the Latest version points to TTML1, but it could be updated 14:34:23 nigel: We discussed this last week and decided to use a separate document to dereference 14:34:41 ... all the different possible branches that a spec can take, from 1st ed to 2nd ed, or v2 etc. 14:36:08 Topic: TTML 14:36:34 nigel: We have a number of things to cover: background image, time expressions and audio description. 14:36:48 nigel: Let's begin with background image 14:37:10 https://github.com/w3c/ttml2/issues/157 14:37:53 glenn: I was in the process of implementing the semantics for the IMSC background image 14:38:08 ... mechanism, based on SMPTE ST2052, and I realised that there was a discrepancy 14:38:21 ... between what we ended up with in IMSC and the normal CSS/XSL-FO semantics. 14:38:36 ... Here's the scenario: In CSS if you put a background image on a div element, let's say, 14:38:48 ... and there's no content in that div, then you will not see any background image, as 14:38:57 ... I demonstrated in the sample that I attached. 14:39:11 ... If you manually size the content rectangle of the div or insert some content that causes 14:39:26 ... it to be sufficiently big then the background image will become visible (possibly clipped). 14:39:41 ... In SMPTE-TT it appears to have been dealt with by stating that the minimum width and 14:39:54 ... height of the area of the div should be at least as large as the size of the background 14:40:10 ... image. I didn't notice this difference to CSS before. The problem we have today is that 14:40:21 ... now we're adding image support to TTML2 and we have IMSC 1 published we have 14:40:33 ... to deal with the effects of that variation somehow and come up with something that 14:40:41 ... makes sense in TTML2. That's the basis of the problem. 14:40:51 pal: In TTML2 images are an element, right? 14:41:04 glenn: There are 2 ways to use images. One is a content image using the image element, 14:41:17 ... which definitely has a size that's equal to its intrinsic image size unless it's otherwise 14:41:29 ... manually sized. If you were to use the image element to map the SMPTE backgroundImage 14:41:36 ... attribute into TTML2 then this won't be an issue. 14:41:50 ... In TTML2 we also added the backgroundImage style property, intending it to work like 14:42:03 ... CSS/XSL-FO. We could solve this by putting some language somewhere saying that 14:42:14 ... mapping from IMSC 1 image should be via the image element. 14:42:18 pal: Yes, why not? 14:42:32 ... We have 2 choices. We could use exactly the same semantics in TTML2 as in SMPTE-TT; 14:42:37 ... the other option is to map to the image element. 14:42:59 glenn: The other option is to use different semantics in TTML2 than in IMSC and adopt 14:43:13 ... the CSS semantics, and require that the element is sized explicitly using ipd and bpd. 14:43:16 ... That would work. 14:43:30 pal: Ideally using TTML2 it looks like the "right" way to do image as content is to use 14:43:32 ... the image element? 14:43:42 glenn: Right, the backgroundImage isn't intended as being used for content. 14:43:55 pal: I'm thinking that we indicate that it should be mapped to the image element in TTML2. 14:44:07 glenn: I agree. We probably need to create a placeholder document to deal with such 14:44:08 ... mappings. 14:44:21 pal: I'm happy to start work on that, and have that as the first item in it. 14:44:32 glenn: It could be maintained as a separate document or we could merge some of it 14:44:39 ... into IMSC 2. We can make that choice later. 14:44:40 pal: Yes. 14:44:53 glenn: What I ended up deciding to do is to map smpte:backgroundImage to the image 14:45:00 ... element because it wants to behave like that. 14:45:02 pal: Ok. 14:45:15 glenn: I'm tentatively using the same semantics as CSS for backgroundImage in TTML2. 14:45:24 pal: In CSS the name is background-image, right? 14:45:28 glenn: Correct. 14:45:33 pal: I guess we'll have to teach people! 14:45:44 glenn: Yes, it could be a source of confusion for authors. 14:45:49 pal: What's the name in XSL-FO? 14:46:13 glenn: backgroundImage. There's also an externalGraphic that works a bit like in SVG as 14:46:28 ... an image. In SVG you can also apply a pattern as a fill, using an image, which works 14:46:34 ... more like background-image. 14:47:03 glenn: We'll continue to have both kinds of concept, a content image and a stylistic 14:47:08 ... background image. 14:47:22 mike: The discussion came as a bit of a surprise to me because noone has looked at this 14:47:35 ... for a while. I think we need to sort this out. The overloading on the name is unfortunate 14:47:59 ... but it really was intended for content. I'm not really happy with any of the options but 14:48:03 ... this is the least bad. 14:48:19 glenn: IMSC doesn't say anything about this right now, but the reference to SMPTE suggests 14:48:25 ... that the normative language in SMPTE-TT applies. 14:48:30 pal: Yes. 14:48:40 glenn: You might want an errata for IMSC 1 that notes that applicability. 14:48:53 pal: Also note that it's not just the backgroundImage attribute but also the semantics 14:48:55 ... that surround it. 14:49:13 glenn: Absolutely. One has to assume that that's true otherwise there's insufficient text to describe it. 14:49:21 pal: Do you want to file a quick issue? 14:49:24 glenn: Okay I'll do that. 14:49:42 pal: I think we're going to have to deal with this in the next version of IMSC. We have 14:49:57 ... two possibilities. We can create a document where we track these - that's probably best. 14:50:16 ... I'll refactor the repo to include an IMSC 2 draft, and note this in there. 14:50:24 glenn: Or do what we did in TTML and add a new repo. 14:50:35 pal: Then you can't easily move bugs from one to another. I'm thinking of having 14:50:43 ... multiple subdirectories, one per big version. 14:50:47 glenn: You're the Editor! 14:50:53 nigel: Yes, that's fine. 14:51:07 pal: What about also adding a note to TTML2 for users of backgroundImage, warning 14:51:14 ... about the mapping from smpte:backgroundImage? 14:51:24 ... That might be helpful for IMSC and everyone else to reference. 14:51:40 glenn: Okay, it doesn't hurt to add that as a comment. Or add an informative mapping 14:51:43 ... section. 14:51:49 pal: That would be great. 14:51:58 glenn: For mapping from other versions or profiles of TTML. 14:52:38 action: glenn to create issue on TTML2 to add "Mapping from other Versions and Profiles of TTML" 14:52:38 'glenn' is an ambiguous username. Please try a different identifier, such as family name or username (e.g., gadams, ggoldste). 14:53:03 Action: gadams create issue on TTML2 to add "Mapping from other Versions and Profiles of TTML" 14:53:04 Created ACTION-462 - Create issue on ttml2 to add "mapping from other versions and profiles of ttml" [on Glenn Adams - due 2016-04-28]. 14:53:17 s/action: glenn to create issue on TTML2 to add "Mapping from other Versions and Profiles of TTML"// 14:53:51 nigel: I'd also like to raise https://github.com/w3c/ttml1/issues/210 14:55:40 nigel: This came about from implementation work where it appears that leap second 14:55:49 ... syntax is permitted even when it has no meaning. 14:56:14 glenn: I propose in TTML1 to add a section to ยง10.3.1 matching Nigel's proposal, and 14:56:23 ... in TTML2 then we can strengthen that. 14:56:27 nigel: That sounds good. 14:56:37 glenn: When I process it on TTML1 I'll do it on TTML2. 14:56:53 nigel: I'll add an issue on TTML2 pointing to the TTML1 issue then. 14:57:22 Action: nigel Add an issue on TTML2 regarding 60 second minutes to point to the TTML1 one. 14:57:22 Created ACTION-463 - Add an issue on ttml2 regarding 60 second minutes to point to the ttml1 one. [on Nigel Megitt - due 2016-04-28]. 15:01:19 nigel: I'd also like to signal my intent to specify and implement audio description in TTML2. 15:01:42 nigel: The idea is to add some audio style attributes that could be subject to animation 15:02:00 nigel: and use included or referenced audio files to generate an audio description 15:02:07 https://www.w3.org/TR/REC-CSS2/aural.html 15:02:13 nigel: presentation experience that aligns with current practice. We also intend to 15:02:22 ... implement a prototype of this using web audio. 15:03:11 nigel: Thanks for that link Glenn, I'll check if that includes useful semantics I'll reference them. 15:03:20 glenn: That spec probably covers a lot of what you want to do already. 15:03:37 nigel: I may need to cross-check that with Web Audio as well. 15:04:39 nigel: Apologies I've taken us 4 minutes over. Thanks all [adjourns meeting] 15:04:57 rrsagent, draft minutes 15:04:57 I have made the request to generate http://www.w3.org/2016/04/21-tt-minutes.html nigel 15:06:54 chair: nigel 15:07:00 Regrets: Frans 15:13:11 s/'glenn' is an ambiguous username. Please try a different identifier, such as family name or username (e.g., gadams, ggoldste)./ 15:14:11 rrsagent, draft minutes 15:14:11 I have made the request to generate http://www.w3.org/2016/04/21-tt-minutes.html nigel 15:15:21 ScribeOptions: -final -noEmbedDiagnostics 15:15:23 rrsagent, draft minutes 15:15:23 I have made the request to generate http://www.w3.org/2016/04/21-tt-minutes.html nigel 15:17:48 zcorpan has joined #tt 16:18:33 zcorpan has joined #tt 16:27:31 Zakim has left #tt