IRC log of tt on 2024-07-04

Timestamps are in UTC.

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