15:03:07 RRSAgent has joined #tt 15:03:11 logging to https://www.w3.org/2024/07/04-tt-irc 15:03:11 RRSAgent, make logs Public 15:03:12 Meeting: Timed Text Working Group Teleconference 15:03:12 Agenda: https://github.com/w3c/ttwg/issues/285 15:03:28 scribe+ cpn 15:03:40 nigel has changed the topic to: TTWG Teleconference 2024-07-04 1500 UTC. Agenda: https://github.com/w3c/ttwg/issues/285 calendar and joining info at https://www.w3.org/events/meetings/0ae37799-0b56-4486-bc63-4fe241678675/20240704T150000/ 15:04:36 Present: Atsushi, Chris_Needham, Cyril, Ewan, Nigel 15:04:51 Regrets: Gary 15:04:53 Chair: Nigel 15:04:57 scribe: nigel 15:05:02 Previous meeting: https://www.w3.org/2024/06/20-tt-minutes.html 15:05:07 Topic: This meeting 15:05:11 scribe+ cpn 15:06:20 Nigel: DAPT, ttml:role issues, TPAC. Anything to add? 15:06:27 (nothing) 15:06:53 Topic: DAPT 15:07:33 Subtopic: Add section about mapping from TTML to the DAPT data model w3c/dapt#216 15:07:40 github: https://github.com/w3c/dapt/pull/216 15:08:01 Nigel: I made some changes after discussion last week 15:08:13 ... I'm 90% of the way there, needs a re-review 15:08:37 Cyril: I haven't had a chance to read again 15:08:56 Nigel: This is the biggest thing holding up CR 15:09:35 ... I wanted to defer defining something an explicit signal for when a div represents a script event, and leave it to another PR 15:10:00 Cyril: I want to re-read, but let's assume we can do that 15:11:29 Nigel: I tried to make the wording about content profiles generic, so there's now a content type 15:12:00 ... So it allows us to add other content profiles later, if we want to 15:12:34 ... This needs some review 15:13:00 Cyril: Where do we stand on Pierre's question from last time? 15:13:30 ... He said in his experience, trying to leave extensibility hooks for a future version wasn't necessarily the best approach, 15:13:45 ... as opposed to having a v2 being backwards compatible. 15:14:09 Nigel: I think how it should be read now is that we've allowed ourselves to make that decision in the future 15:14:29 ... We don't make any promises that all future DAPT versions can be read by v1 processors 15:14:57 Cyril: I see that it requires compatibility with the declared content profile 15:15:21 .. So what about using divs in that context? Do we need provision for grouping of divs in v1? 15:15:43 Nigel: We don't prohibit nested divs, we just define rules from when they're there, if you're going from TTML to DAPT data model 15:16:32 Cyril: So if you receive a TTML2 document with DAPT content profiles in it, if the impl wants to go back to a DAPT content model, you scan the document and identify what's there, ignoring the rest? 15:16:34 Nigel: Yes 15:16:54 Cyril: I'll read again with this model in mind 15:17:50 Cyril: Some other questions. We're also clarifying processor behaviour when there's additional vocabulary 15:18:08 ... There's foreign vocabulary and unrecognised vocabulary 15:18:32 ... Unrecognised means the impl knows it doesn't support, whereas foreign is any namespace outside the ones defined in the spec 15:18:43 Nigel: Yes, and specific attribute names for those in the global namespace 15:19:07 Cyril: Can be both foreign and recognised or not recognised? 15:19:20 ... So they're orthogonal concepts? 15:19:43 Nigel: Foreign is a subset of unrecognised, the way I've defined it 15:20:13 Cyril: So you can split unrecognised into two sets: things inside the spec, and things outside 15:20:37 Nigel: Please leave feedback, I've defined a term in relation to something that's undefined. That needs changing 15:20:57 Cyril: About the behaviour, we have 3 classes of processors: presentation, transformation, validation 15:21:21 ... They may or may not behave differently with foreign vocabulary 15:21:39 Nigel: Transformation processors have to prune. Validation is a subset of Transformation 15:22:00 Cyril: Pruning everything except what's in a metadata element or a descendent of metadata element 15:22:02 Nigel: Yes 15:22:25 ... And shouldn't put anything in the metadata element that depends on the semantic of the content 15:22:42 Cyril: And presentation processors? 15:22:55 Nigel: They should recognise elements and attributes they don't support 15:23:09 Cyril: So if you know it's a feature you support but there's no profile declaring the feature... 15:23:34 Nigel: That's in Profile Signalling 15:24:23 Cyril: There was a sentence that talked about this: along the lines of you may do something or fix it? 15:24:48 ... The second paragraph in the new 6.2 15:25:30 Nigel: There's a question about what the last clause there means 15:25:45 Cyril: May need rephrasing depending on the class of processor 15:26:26 Nigel: I'm resistant to that, it might introduce complexity 15:26:47 MattS has joined #tt 15:28:06 ... That is something we should change, in section 6.2, second paragraph isn't about document conformance claims, it's about processor behaviour 15:28:19 ... Also we should check where the content profiles have been made generic, haven't done it for processor profiles. 15:29:34 Cyril: Is there anything else that this PR addresses? 15:30:05 Nigel: The dark mode change due to ReSpec and W3C stylesheet change 15:30:45 Apols - I need to head to another meeting... 15:31:14 https://lists.w3.org/Archives/Public/spec-prod/2024AprJun/0000.html 15:31:44 Nigel: Worth checking if it works, including the diagrams 15:39:05 SUMMARY: Review to continue 15:39:21 Topic: Permit ttm:role attribute in ttm:desc elements w3c/ttml2#1247 15:39:28 github: https://github.com/w3c/ttml2/issues/1247 15:40:39 Nigel: We last discussed in May. As DAPT defines desc type, so I suggest closing this with no changes, so not at ttm:role on metadata descendents 15:40:51 Cyrill: Agree 15:41:02 SUMMARY: Close with no change 15:41:24 Topic: TPAC 2024 15:43:08 Nigel: We have joint meeting with APA and MEIG on Monday. Joint meeting Friday with Audio CG and TTWG meetings 15:43:52 -> TPAC schedule https://www.w3.org/2024/09/TPAC/schedule.html 15:44:02 Chris: Is there overlap with MEIG in first session Monday? 15:44:29 Nigel: Yes, It's not supposed to be 15:46:24 Chris: Maybe we can combine APA/TTWG and APA/MEIG into one session 15:46:44 ... Also Media WG overlaps with MEIG/APA 15:46:45 Nigel: Yes, that worked well last time 15:47:26 Nigel: Chris, let's follow up with the team 15:48:21 Chris: Should we talk about the MSE and substitles issue you raised in the MEIG repo? 15:48:55 Nigel: Currently subtitles are all out of band with MSE. Not clear why that is. In the past Mark Watson thought it was a good idea 15:49:20 ... Could be worth revisiting, now we have more experience, would it solve problems? 15:50:52 Chris: To summarise this would be TTML or IMSC in MP4 , processed through MSE and surfaced into the TextTrack API 15:51:23 Nigel: Yes. Also WebVTT. CMAF defines IMSC in MP4 15:52:26 Chris: Include in the MEIG/TTWG joint meeting? 15:52:35 Nigel: For that meeting, we also want to cover DAPT 15:54:46 Nigel: Another use case, is where you're streaming DAPT with audio resources and you want to do client side mixing. Instead of including as base64, include as subsamples in the MP4 and have a way to reference them from the TTML. They could then be more efficiently encoded 15:55:04 Cyril: Another way is to have an audio track, and refer the TTML document to sections of the audio track 15:55:15 Nigel: Sounds plausible as an alternative 15:57:45 ... Adaptation sets currently let you have audio main mix and audio with AD, but there isn't away to have both and have the client side mix them 15:57:49 Topic: Future meetings 15:58:23 -> New TTWG Project page https://github.com/orgs/w3c/projects/96 15:58:54 Nigel: Chairs and editors aren't available for the August 1 meeting 15:59:24 ... Propose cancelling that one 16:00:02 ...Cyril: I may not make the July 18 meeting 16:00:22 s/...Cyril/Cyril/ 16:01:21 in DST, meeting starts from midnight, but non DST it's from 1am.. ;) 16:02:28 s/Cyrill/Cyril/g 16:02:35 Topic Meeting close 16:02:49 Nigel: Thanks everyone, we're slightly over time, let's adjourn for today. [adjourns meeting] 16:02:52 rrsagent, make minutes 16:02:53 I have made the request to generate https://www.w3.org/2024/07/04-tt-minutes.html nigel 16:05:13 s/resistant to that/resistant to introducing processor classes 16:06:19 s/CMAF defines IMSC in MP4/The CMAF profile requires IMSC in MP4 16:06:55 s/there isn't away/there isn't a way in DASH 16:07:25 s/Topic Meeting close/Topic: Meeting close 16:07:27 rrsagent, make minutes 16:07:28 I have made the request to generate https://www.w3.org/2024/07/04-tt-minutes.html nigel 16:08:23 rrsagent, make minutes 16:08:24 I have made the request to generate https://www.w3.org/2024/07/04-tt-minutes.html nigel 16:09:21 i/Topic: Permit/Topic: TTML 16:09:26 s/Topic: Permit/Subtopic: Permit 16:09:28 rrsagent, make minutes 16:09:29 I have made the request to generate https://www.w3.org/2024/07/04-tt-minutes.html nigel 16:10:31 rrsagent, make minutes 16:10:32 I have made the request to generate https://www.w3.org/2024/07/04-tt-minutes.html nigel 16:13:28 scribeOptions: -final -noEmbedDiagnostics 16:13:51 zakim, end meeting 16:13:51 As of this point the attendees have been Atsushi, Chris_Needham, Cyril, Ewan, Nigel 16:13:53 RRSAgent, please draft minutes v2 16:13:54 I have made the request to generate https://www.w3.org/2024/07/04-tt-minutes.html Zakim 16:14:00 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 16:14:01 Zakim has left #tt 16:15:31 rrsagent, excuse us 16:15:32 I see no action items