13:59:30 RRSAgent has joined #tt 13:59:30 logging to http://www.w3.org/2016/07/14-tt-irc 13:59:32 RRSAgent, make logs public 13:59:32 Zakim has joined #tt 13:59:34 Zakim, this will be TTML 13:59:34 ok, trackbot 13:59:35 Meeting: Timed Text Working Group Teleconference 13:59:35 Date: 14 July 2016 14:01:09 Present: Glenn, Harold, Nigel 14:01:12 chair: Nigel 14:01:15 scribe: nigel 14:02:18 regrets: Mike, Andreas, Frans, Thierry 14:03:54 Present+ Pierre 14:04:06 Topic: This meeting 14:04:49 nigel: I think we're mainly covering TTML stuff today. Any other business to cover? 14:04:56 group: no other business 14:05:18 Topic: TTML1 & TTML2 issues, actions, PRs, editorial actions etc 14:05:29 action-472? 14:05:30 action-472 -- Nigel Megitt to Make sure there is a ttml2 issue for considering adjustment of inline region semantics -- due 2016-06-16 -- PENDINGREVIEW 14:05:30 http://www.w3.org/AudioVideo/TT/tracker/actions/472 14:06:01 nigel: I did this, by adding https://github.com/w3c/ttml2/issues/168 14:06:14 close action-472 14:06:14 Closed action-472. 14:07:42 action-443? 14:07:42 action-443 -- Glenn Adams to Prepare a document showing mapping arib ruby extension features to ttml2 for use as a liaison document to arib. -- due 2015-11-05 -- OPEN 14:07:42 http://www.w3.org/AudioVideo/TT/tracker/actions/443 14:08:01 glenn: Can we reword this somehow - I think it's low priority. 14:08:18 nigel: Are all the ARIB ruby extension features mapped to something in TTML2? 14:08:40 glenn: I know on the ARIB set they had support for a marquee functionality which I have 14:08:50 ... not had a chance to investigate its semantics. That would be the only one. 14:09:02 ... My hope is that we could map that to set or animate without any additional features. 14:09:10 nigel: I think that's a dependency then. 14:09:30 glenn: That's the only feature in the ARIB extensions that I have not accounted for explicitly. 14:09:56 ... I have also not checked if the ARIB spec has added any new features. Probably a year and a half since I reviewed in Japanese. 14:10:08 nigel: I think they did an English translation too. 14:10:11 glenn: I did not use that. 14:10:32 nigel: In that case the dependency is on https://github.com/w3c/ttml2/issues/119 14:11:04 action-443: [Meeting 2016-07-14] There is a dependency on https://github.com/w3c/ttml2/issues/119 before commencing this. 14:11:05 Notes added to action-443 Prepare a document showing mapping arib ruby extension features to ttml2 for use as a liaison document to arib.. 14:11:56 nigel: I've changed the due date on this action to 26th August. 14:12:59 nigel: Let's move to the recent issues on github 14:13:17 glenn: There's an open PR: https://github.com/w3c/ttml2/pull/167 14:14:24 nigel: I made one comment on this re the use of the term absolute profile designator. 14:14:31 glenn: That's a good point - I'll try to fix this. 14:18:45 glenn: Does the Repository Manager run any other checks than the IPR one? 14:19:00 nigel: I don't believe so - it might be useful to use a Continuous Integration tool to check 14:19:17 ... that each commit results in a successful build of the HTML. Would that be of interest? 14:19:40 glenn: I'd consider it, however I have to go through the generate ED process each time I edit anyway 14:19:46 ... so it's not really needed right now. 14:20:20 nigel: Thanks for that PR. I encourage everyone else to have a look and review it. 14:20:33 glenn: By the way, with the PR I intend only to modify the XML source and not the HTML 14:20:44 ... version, so that means that if anyone wants to review then they need to run the tool 14:20:58 ... to generate the HTML themselves. The reason I don't want to do it in the branch is 14:21:12 ... that then I would have to manually merge the XML only. I don't want to regenerate the HTML 14:21:23 ... each time because it makes a lot of minor modifications in the file that are not visible 14:23:05 ... such as ID generations and timestamps. If we have multiple commits it would likely 14:23:12 ... make automatic merging complicated. 14:23:28 nigel: This suggests an elegant solution that we may not have time or inclination to pursue right now 14:23:36 ... would be to generate the HTML only in the gh-pages branch. 14:24:05 nigel: For this kind of change I think most folk could review just the XML change. I was 14:24:17 ... able to check out the branch, run ant to make the HTML, and review that locally. 14:25:37 glenn: https://github.com/w3c/ttml2/issues/164 14:25:59 glenn: In TTML1 (not SE) we did not use Root Temporal Extent, but External Time Interval 14:26:12 ... and it was defined by the external processing context. I'm reviewing notes to understand 14:26:23 ... why we changed it. That review will have an impact on what we recommend. 14:26:40 ... There are some problems with circular definitions in the current text, in how the body 14:26:52 ... element references the root temporal interval, and the root temporal interval references 14:27:06 ... the body definition. Maybe the suggestion to redo some of the terminology will be appropriate. 14:27:16 nigel: Yes, it certainly is complex! 14:27:32 glenn: Maybe the reason for differences in interpretation is because we have different 14:27:47 ... understandings of what is meant by the term. For example in my mental model the 14:28:02 ... idea of a media offset seemed to make sense, and in Nigel's it made less sense. 14:28:13 nigel: Indeed, it is extremely problemati! 14:28:18 c/i!/ic! 14:28:23 glenn: We need to resolve that pretty soon. 14:28:49 pal: Nigel, can you summarise what you mean by media offset and what the problems are? 14:30:48 nigel: It's a value that is used to add or subtract from media time expressions in the 14:31:10 ... documents to arrive at some other timeline. My problem with it is that it creates an 14:32:23 ... ambiguity with other ways of solving this problem that exist, such as ISOBMFF. 14:33:21 glenn: It's similar to the referenceBegin that's in N.2 https://www.w3.org/TR/ttml1/#time-expression-semantics-media 14:35:04 pal: I don't understand why we need this. If you want to offset why not just modify all the times in the document? 14:35:36 nigel: By the way, you could just modify the effective value of referenceBegin just by 14:35:41 ... adding a begin attribute to the body element. 14:35:56 glenn: You can also put times on style and region elements, which are not descendants 14:36:03 ... of body, so that wouldn't be complete. 14:36:44 nigel: I'd like to mention the Safe Crop Area proposal. https://lists.w3.org/Archives/Public/public-tt/2016Jun/0003.html 14:42:19 nigel: [describes the problem statement and proposed solution from the PDF document] 14:42:50 glenn: I wonder if we could achieve this using a convention on the region, such as an 14:43:06 ... attribute that designates a region as specifying a safe crop area. It would be a little 14:44:07 ... simpler because there are already a lot of tools and parsers that already process regions. 14:44:25 nigel: That could be made to work: this is not about where to position relative to the 14:44:38 ... root container region though, but about which parts of the root container region must 14:44:51 ... be shown. Also you would have to go a long way down parsing the document to find 14:45:11 ... this information if present, which would not be ideal. 14:45:19 glenn: I see, yes, you're probably right about that. 14:45:35 glenn: In terms of which namespace to put this in, my rule of thumb is that if a piece 14:45:45 ... of information is used formally by the processor in some way then it should be in the 14:45:52 ... parameter namespace rather than in metadata. 14:45:57 nigel: I agree. 14:46:24 nigel: This proposal defines some processor behaviour so I would put it into the parameter namespace. 14:46:46 glenn: We already have one parameter, pixel aspect ratio, which has never really been used, 14:46:58 ... and one might ask if there are any semantics for what a processor should do with that. 14:47:25 ... Up until now people have wondered if it is metadata. 14:47:38 nigel: I think it is a parameter since extent and pixel aspect ratio tell you the shape of the 14:47:47 ... root container region, i.e. the display aspect ratio. 14:48:21 glenn: That's true, but now we have display aspect ratio there's over-constraint, so we 14:48:30 ... need to define what gives if they don't agree. 14:48:42 nigel: Agreed - I thought we had some text on order of precedence. 14:49:08 glenn: We may do. The text needs to be changed to say Display Aspect Ratio in place of Storage Aspect Ratio. 14:49:31 nigel: There's an issue I believe. https://github.com/w3c/ttml2/issues/30 14:50:07 nigel: Any other comments on SCA? 14:50:48 glenn: We should also factor in Mike's comments with the SMPTE documents. 14:50:59 nigel: Thanks for the reminder. My reading of those is that the documents Mike referenced 14:51:12 ... explain the background for how this problem situation can occur but are orthogonal 14:51:31 ... to the SCA proposal - the SCA proposal does not duplicate the active format descriptor 14:51:49 ... semantics but provides for dealing with some of the scenarios it can result in. 14:53:39 nigel: Returning to https://github.com/w3c/ttml2/issues/166 (duplicate designators) 14:53:47 ... is there any semantic ambiguity introduced by having duplicates? 14:54:05 glenn: Interesting. If you have any(X Y X), and on the first attempt to resolve X you get 14:54:20 ... an access error, and proceed to Y and get "not available" too then you would proceed 14:54:33 ... to "X" again which now may be available. Because there's a sequential access operation 14:54:47 ... there you might end up with different semantics. From a cleanliness perspective, we 14:55:01 ... also don't allow attributes on XML elements with duplicated information even though 14:55:17 ... you could argue that they're semantically equivalent. I prefer not to allow duplicates 14:55:33 ... unless I can think of some kind of rational interpretation of it. That was my conclusion. 14:55:57 ... Further, we've already implemented that semantic in TTV (not yet checked in). 14:57:34 nigel: Well you may want to respond to my comment asking this on the github issue. 14:57:37 glenn: Ok 14:58:42 nigel: Thanks all, we're out of issues to discuss for today, so I'll adjourn. [adourns meeting] 14:58:45 rrsagent, generate minutes 14:58:45 I have made the request to generate http://www.w3.org/2016/07/14-tt-minutes.html nigel 15:01:44 s/run ant/run ant (see https://github.com/w3c/ttml2/blob/gh-pages/spec/README.md) 15:01:47 rrsagent, generate minutes 15:01:47 I have made the request to generate http://www.w3.org/2016/07/14-tt-minutes.html nigel 15:02:31 s|c/i!/ic!| 15:02:49 s|i!|ic! 15:03:18 s/as ISOBMFF/as in ISOBMFF 15:03:47 s/PDF/attached PDF 15:05:16 rrsagent, generate minutes 15:05:16 I have made the request to generate http://www.w3.org/2016/07/14-tt-minutes.html nigel 15:11:32 s|/run ant/run ant (see https://github.com/w3c/ttml2/blob/gh-pages/spec/README.md)|| 15:11:58 s|run ant|run ant (see https://github.com/w3c/ttml2/blob/gh-pages/spec/README.md)| 15:12:00 rrsagent, generate minutes 15:12:00 I have made the request to generate http://www.w3.org/2016/07/14-tt-minutes.html nigel 15:12:28 s/s// 15:12:29 rrsagent, generate minutes 15:12:29 I have made the request to generate http://www.w3.org/2016/07/14-tt-minutes.html nigel 15:13:10 ScribeOptions: -final -noEmbedDiagnostics 15:13:11 rrsagent, generate minutes 15:13:11 I have made the request to generate http://www.w3.org/2016/07/14-tt-minutes.html nigel 16:26:50 Zakim has left #tt