15:01:35 RRSAgent has joined #tt 15:01:35 logging to https://www.w3.org/2020/09/03-tt-irc 15:01:37 RRSAgent, make logs Public 15:01:38 Meeting: Timed Text Working Group Teleconference 15:01:57 mike has joined #tt 15:02:00 Agenda: https://github.com/w3c/ttwg/issues/143 15:02:19 Previous meeting: https://www.w3.org/2020/08/27-tt-minutes.html 15:02:36 Present: Andreas, Nigel, Cyril, Atsushi, Pierre 15:02:41 Chair: Nigel 15:02:58 (trying to join... my head is not working already, although, after 6h+ online sessions from evening...) 15:03:24 cyril has joined #tt 15:03:45 Present+ Gary, Mike 15:03:51 s/Chair: Nigel/Chair: Gary, Nigel 15:04:17 scribe: nigel 15:04:22 Topic: This meeting 15:04:46 Nigel: Today I've put TTML2 #1211 back on the agenda in case we want to discuss more. 15:04:57 .. Also Virtual TPAC planning, and TTML Profiles Registry 15:05:07 .. AOB? 15:05:48 group: [no AOB] 15:06:29 Topic: Interaction between tts:writingMode and tts:direction on paragraph element. w3c/ttml2#1211 15:06:42 atai has joined #tt 15:06:43 Pierre: I'd like to discuss how we get to a resolution on this; it is blocking resolution of an 15:06:47 .. issue on imsc.js 15:08:06 .. What about if we pick a time and date and say "we're going to solve this on this time and date" 15:08:19 .. and ask everyone to come in with all the input needed etc. Then at the end we'll pick 15:08:20 .. something. 15:08:56 q+ 15:09:02 Nigel: Would it make sense to gather our best knowledge and then raise it in the joint meeting 15:09:05 .. with the CSS WG? 15:09:37 Pierre: The answer should be yes, I'm hesitating because I am not a specialist in Arabic, Hebrew etc 15:09:52 .. and there's a limitation on CSS; if that would be helpful I'm happy to ask the question on 15:10:08 .. the CSS mailing list: explaining that direction in CSS sets the direction and writing mode, 15:10:19 .. which Elika has already told me it is not a limitation but a feature. 15:10:30 Nigel: Also something we should ask internationalisation? 15:10:44 Pierre: We're unlikely to change CSS on this, there's a lot more international content in 15:10:59 .. CSS than in TTML, so I doubt that we would change their mind without a compelling set 15:11:12 .. of examples, which we don't. Glenn might be the best person to provide that, but he has 15:11:33 .. not. I would tend to saying "do what CSS does" in the absence of the test content and 15:11:43 .. examples to have a definitive opinion. 15:11:56 Andreas: Which specification can we target for a change here? 15:12:01 Pierre: TTML2, ultimately. 15:12:04 ack a 15:12:11 Andreas: OK, there was also the idea to constrain IMSC. 15:12:23 .. The second thing is more a concern, from the current discussion, I think I understand 15:12:33 .. how it was meant and how it should work, which may already help IMSC, and it should 15:12:50 .. be possible to implement, but my concern is about how everything works together and 15:13:01 .. that it is not explained enough in TTML. It is only in the reference implementation of TTPE 15:13:04 .. and not in the spec. 15:13:10 Pierre: To make things worse it is broken in TTPE too. 15:13:19 github: https://github.com/w3c/ttml2/issues/1211 15:13:35 Pierre: So I am not super excited to consult CSS, we should use what's in browsers today 15:13:44 .. and only ask for a change if we find a fatal flaw. 15:14:22 Nigel: Are you making a specific proposal to remove the application of direction to p? 15:14:37 Pierre: Yes, but I think it is not sufficient because setting it on span also changes the 15:14:44 .. definition of start and end as Gary pointed out. 15:14:56 .. I'm suggesting we pick a time, aim to solve within an hour and reach consensus. 15:15:03 .. That gives everybody an opportunity to prepare. 15:15:09 .. After or at TPAC, for example. 15:16:56 https://www.w3.org/wiki/TPAC/2020/GroupMeetings 15:17:27 Nigel: OK, TPAC dates are a little unclear, the obvious date range is 19-24 October. 15:18:34 .. How about making it the main topic of our call on 8th October, the regular weekly call? 15:19:56 Andreas: We may need to extend the call 15:20:02 Nigel: I've created https://github.com/w3c/ttwg/issues/151 for that meeting. 15:20:31 Nigel: Any specific points about this issue to raise while we're here? 15:20:42 Cyril: Small point to clarify. Many times in our discussions we mentioned the semantic 15:20:54 .. derivation and hinted that we could use the direction as a way to interpret the edge 15:21:01 .. for padding and textAlign, and Glenn never responded to that part. 15:21:13 .. My understanding is that they are not normative and that may be why he did not consider 15:21:23 .. them at all. Is that true that they are not normative? 15:21:23 q+ 15:21:31 Nigel: I think so, need to check. 15:21:47 Cyril: Then we should be careful - it may mean the CSS writing mode reference is not normative. 15:22:40 Nigel: Yes, it's in Appendix N which Non-Normative. 15:22:50 Andreas: I think this is really the point. You say that it is semantically derived from those 15:23:03 .. specs, but don't explain a lot in the spec itself, and then make the derivation informative. 15:23:24 .. TTML has not sufficient text to explain the layout in general. It leans on XSL-FO but a lot 15:23:35 .. of it is informative not normative so it is really hard to understand how this works together. 15:23:48 .. For an implementer what should they do? Where should they check how it should work? 15:24:09 .. Even if it is not normative, but there is a semantic derivation, there is some kind of dependency. 15:25:09 Nigel: N.2.1 says that it can be used for mapping to CSS or XSL, or to other things like SVG. 15:25:21 .. I think the informative nature of these derivations is supposed to be a strength in that way, 15:25:28 .. but sometimes it appears to be a weakness as well. 15:25:54 Cyril: I just wanted to alert the group about that. 15:25:57 Nigel: Thank you. 15:26:46 Topic: Virtual TPAC 2020 Planning. 15:27:10 Nigel: I think Gary, we haven't done our action, so let's slap our wrists and get on with it! 15:27:17 Gary: I haven't done it, no 15:27:36 Nigel: But Gary, you added the viewport issue to the list of CSS issues. 15:27:38 Gary: Yes 15:28:33 Nigel: There is a proposal from APA to meet with synchronised media groups on 15:28:35 .. Tuesday, Oct. 13 from 14:00–15:00pm UTC (10:00 - 11:00pm EDT) 15:29:49 .. I will respond to say yes, assuming no objections? 15:31:19 Topic: Add syntax of codecs parameter w3c/tt-profile-registry#78 15:31:27 github: https://github.com/w3c/tt-profile-registry/pull/78 15:31:53 Mike: 4 points, a couple are editorial. 15:33:53 Nigel: My plan for the concrete example was to have a separate pull request. 15:34:09 Mike: Sure, we should add it though, as we agreed last week. 15:34:12 Nigel: Yes, no problem. 15:34:22 Mike: Going through my comments. 15:34:43 .. I thought it would be good to note that the element in RFC6381 prohibits "." 15:35:26 .. It's not clear in RFC6381 but you can't add a "." 15:36:57 Nigel: I wanted only to add a constraint statement and not duplicate what's in 6381. 15:37:10 .. We could describe 6381 but not redefine it. 15:37:27 Mike: I think 99% of readers won't go to 6381 so the prohibition of "." is worth calling out in a note. 15:37:36 .. 2nd one is a bit of rewording. 15:37:39 Nigel: Good for me. 15:37:56 Mike: The concrete example using IMSC 1.0.1 and EBU-TT-D 1.0.1 would be valuable. 15:38:08 .. And the 4th one is something about the formatting. 15:38:13 Nigel: The formatting looks good to me. 15:38:16 Cyril: It looks good to me too. 15:39:24 Nigel: That's weird, I stole the formatting from IMSC to make it look the same. 15:39:32 Cyril: There's a typo - I'll put a note on the line. 15:39:53 Nigel: OK sounds like there's a bit of work, but straightforward, thanks for the reviews. 15:40:36 SUMMARY: @nigelmegitt to do 2nd editorial pass 15:40:54 Topic: MIME parameters ("codecs") for bucket ISO BMFF-wrapped TTML versus "application/ttml+xml" w3c/tt-profile-registry#76 15:41:01 github: https://github.com/w3c/tt-profile-registry/issues/76 15:42:38 Nigel: Looks like there's proposed wording and an amendment that Mike is happy with. 15:42:48 Mike: I'll open a pull request. 15:44:29 Nigel: I'm a little confused about what grants the ISOBMFF codecs value the right to use 15:44:37 .. our codecs parameter value as the third component. 15:45:15 Cyril: It's in the RFC, which points to 14496-12 and 14496-30 says the first term (sample entry) 15:45:29 .. is stpp, the second is "ttml" and the third points to the profiles registry. 15:45:40 Nigel: That's clear, thank you. And it says specifically the "codecs" value? 15:45:56 Mike: Yes. The practical purpose is to signal indirectly via the parts in the MP4 file, which 15:46:06 .. might be extracted into the DASH manifest to identify the media types. 15:46:34 Nigel: Thank you that really clarifies it in my mind. 15:46:51 Mike: Yes, it's the same parameter name, perhaps in hindsight we could have picked a different name, but it will work out. 15:47:12 SUMMARY: @mikedo to raise a pull request 15:47:21 Topic: Meeting Close 15:47:35 Nigel: Thanks everyone, we're out of agenda, let's have 13 minutes of our lives back! [adjourns meeting] 15:47:47 rrsagent, make minutes v2 15:47:47 I have made the request to generate https://www.w3.org/2020/09/03-tt-minutes.html nigel 15:48:27 atai has left #tt 15:51:51 s/(trying to join... my head is not working already, although, after 6h+ online sessions from evening...)// 15:53:16 s/But Gary/And Gary 15:55:04 rrsagent, make minutes v2 15:55:04 I have made the request to generate https://www.w3.org/2020/09/03-tt-minutes.html nigel 15:55:28 scribeOptions: -final -noEmbedDiagnostics 15:55:33 zakim, end meeting 15:55:33 As of this point the attendees have been Andreas, Nigel, Cyril, Atsushi, Pierre, Gary, Mike 15:55:35 RRSAgent, please draft minutes v2 15:55:35 I have made the request to generate https://www.w3.org/2020/09/03-tt-minutes.html Zakim 15:55:38 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 15:55:42 Zakim has left #tt 15:55:44 rrsagent, excuse us 15:55:44 I see no action items