IRC log of tt on 2026-01-29

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Meeting: Timed Text Working Group Teleconference
16:00:04 [nigel]
scribe: nigel
16:00:16 [nigel]
Agenda: https://github.com/w3c/ttwg/issues/326
16:00:22 [nigel]
Previous meeting: https://www.w3.org/2026/01/15-tt-minutes.html
16:00:27 [nigel]
Topic: This meeting
16:01:26 [nigel]
Chair: Nigel
16:01:36 [nigel]
Present+ Andreas
16:01:38 [nigel]
rrsagent, make minutes
16:01:39 [RRSAgent]
I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel
16:03:09 [nigel]
Present+ Atsushi
16:03:48 [nigel]
Present+ Pierre
16:04:34 [nigel]
Nigel: Agenda for today is:
16:04:42 [atai]
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.. DAPT - Implementation activity
16:04:54 [nigel]
.. How we write about DAPT and IMSC compat
16:05:09 [nigel]
.. and IMSC - we have some items flagged for the agenda
16:05:19 [nigel]
.. AOB?
16:05:32 [nigel]
no AOB
16:05:34 [nigel]
Topic: DAPT
16:05:53 [nigel]
Subtopic: Interoperability session 2026-01-26
16:06:08 [nigel]
Nigel: Cyril and I, and an observer from VRT in Belgium,
16:06:18 [nigel]
.. had an interoperability session on Monday.
16:06:22 [nigel]
.. It went pretty well.
16:06:42 [nigel]
.. Netflix's open source converter generated a set of DAPT files.
16:06:58 [nigel]
.. BBC's (not yet open source) ttml validator validated them.
16:07:09 [nigel]
.. It found one issue, which Cyril was able to address.
16:07:17 [nigel]
.. But otherwise it was really positive.
16:07:29 [nigel]
.. And the action to come out of it is to update the implementation report,
16:07:43 [nigel]
.. which is a bit complex because we're leaning on both the CR exit criteria and
16:07:56 [nigel]
.. the Charter success criteria to make the case for progressing.
16:08:11 [nigel]
.. There are one or two features that still have one implementation, which we're thinking about.
16:08:27 [nigel]
.. Any questions?
16:08:39 [nigel]
Andreas: The BBC validator is just for DAPT or generic TTML validator?
16:09:09 [nigel]
Nigel: At the moment it validates that input documents meet the BBC Subtitles Guidelines for EBU-TT-D,
16:09:23 [nigel]
.. or that they are valid DAPT. It's written in a way that can be extended for other profiles.
16:10:31 [nigel]
Topic: DAPT and IMSC compatibility (editorial)
16:10:46 [nigel]
Nigel: We have two open pull requests, one for DAPT, the other for IMSC 1.3.
16:10:50 [cpn]
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16:11:00 [nigel]
-> https://github.com/w3c/dapt/issues/332 w3c/dapt#332
16:11:01 [cpn]
present+
16:11:08 [cpn]
scribe+ cpn
16:11:15 [nigel]
-> https://github.com/w3c/imsc/issues/622 w3c/imsc#622
16:12:08 [cpn]
Nigel: There's a lot of commonality between these PR
16:12:28 [cpn]
... From the review of the IMSC one, the best way to proceed isn't completely obvious
16:12:31 [cpn]
s/PR/PRs/
16:12:51 [cpn]
... Pierre mentioned not being happy with duplicating text between the specs
16:13:16 [cpn]
... There's been discussion on DAPT PR #333
16:13:18 [nigel]
-> https://github.com/w3c/dapt/pull/333 w3c/dapt#333 pull request
16:14:42 [cpn]
Pierre: The reason for having compatibility sections in either of them, is if there's overlap in the use cases or workflows for DAPT and IMSC
16:15:09 [cpn]
... The only practical overlap I've heard is someone wishing to create DAPT documents that might be played back on an IMSC renderer, for a quick check I guess
16:15:19 [cpn]
... IMSC doesn't understand DAPT metadata
16:15:56 [cpn]
... Otherwise, documents in DAPT workflows are entirely different from documents in IMSC workflows
16:16:21 [cpn]
Nigel: The key point is how one is derived from the other
16:16:42 [cpn]
Pierre: Documenting how to convert one to the other might be good, but that's not about compatibility
16:17:27 [cpn]
Nigel: There's text in DAPT about directing the text presentation of IMSC documents. So a transformation where you take the character data and use that to change the output when you create the IMSC document, to indicate changes of speaker, is appropriate fo the destination
16:17:58 [cpn]
... Or filtering on subsets of the text content, for dialog or captions. Selecting based on the language or text language source to generate subtitles
16:18:13 [cpn]
... Places where it makes sense to start with DAPT and generate IMSC
16:18:32 [cpn]
... Starting from a DAPT workflow, where it the right place to start that. Might vary between different people's workflows.
16:19:09 [cpn]
... An option might be to capture, position-wise, in the DAPT stage, in a way that's conformant to IMSC, and you can flag that it's conformant to both DAPT and IMSC
16:19:38 [cpn]
... That could be useful before leaving the DAPT stage. So it's more than using IMSC in a preview environment (which is also a use case)
16:20:38 [cpn]
Pierre: Sounds like how turn DAPT docs into IMSC is already in the PR. That's different than, when you transform to IMSC it's no longer a DAPT document. So are there scenarios in DAPT workflows where you want to create a document that's both a DAPT and an IMSC document?
16:20:48 [cpn]
... Those are both DAPT concerns, not IMSC concerns
16:21:15 [cpn]
Nigel: What if the IMSC documents that you distribute include DAPT metadata?
16:21:39 [cpn]
... If you want the player to do some thing with that metadata, having it signalled as both a DAPT and IMSC document might be useful for that player
16:22:02 [cpn]
... For example, the names of speakers where you could show non-caption/subtitle metadata
16:22:26 [cpn]
Pierre: An IMSC player would ignore the metadata, so what you're describing wouldn't be an IMSC player
16:23:02 [cpn]
Nigel: During normal playback it could show the IMSC, but inclusion of other data doesn't make it not an IMSC player. Maybe don't do down this rabbit-hole...
16:23:29 [cpn]
Pierre: Don't think this belongs in IMSC, could be some other spec.
16:24:00 [cpn]
... IMSC from the beginning was attempting to reduce fragmentation in distribution of subtitles and captions using TTML
16:24:34 [cpn]
... Those sections on interop with other specs, are there to show that documents will play with high fidelity in an IMSC player
16:24:53 [cpn]
... Example, EBU-TT-D, you can distribute the same documents to IMSC players
16:25:08 [cpn]
... The same for SMPTE-TT documents, will play fine in an IMSC player
16:25:35 [cpn]
Nigel: So, what to do? I sense you're not uncomforable with the DAPT PR, but you are uncomfortable with the IMSC PR
16:25:37 [cpn]
Pierre: Yes
16:26:05 [cpn]
... I don't think, from an IMSC player or author perspective that it's relevant information. The more text there is, the more effort it takes to maintain
16:26:42 [cpn]
Nigel: Makes sense. I think I'm getting to just merge the DAPT PR and not the IMSC PR. Anything useful we can say in IMSC on DAPT?
16:27:22 [cpn]
... It felt useful to me to point readers to DAPT, to at least say that you could make IMSC documents from a DAPT workflow, and refer to DAPT for details
16:27:40 [cpn]
Pierre: Could find a logical place to do that, e.g., in the Introduction on where IMSC documents come from
16:28:05 [cpn]
... A question that has come up in previous years is where IMSC documents come from, so that could be a place
16:28:21 [cpn]
Nigel: I was thinking of Appendix I, on compatibliity with other formats
16:28:50 [cpn]
Pierre: I'd prefer having text on where IMSC documents come from, moreso than having example. The question comes up multiple times
16:29:17 [cpn]
... MDN doesn't say where IMSC documents come from
16:29:43 [cpn]
Nigel: There are different views, e.g, for some people they come from CEA-608 documents
16:30:12 [cpn]
... It's timely now as people are thinking of automated subtitle workflows
16:31:08 [cpn]
... BBC converts teletext to EBU-TT-D...
16:31:19 [cpn]
Nigel: Any other views on this?
16:31:23 [nigel]
q?
16:31:34 [cpn]
Andreas: What you've both said makes sense
16:32:26 [cpn]
Nigel: Two actions to take. One is to close the IMSC PR and the associated issue. Then open a new issue in IMSC to add an editorial section to talk about the authoring workflows for IMSC, e.g., in the Introduction
16:32:52 [nigel]
Present+ Gary
16:32:58 [nigel]
Chair: Nigel, Gary
16:33:07 [cpn]
Nigel: I thought this would be a useful addition to IMSC, but I'm deferring to the editor
16:34:55 [cpn]
Nigel: I think all review comments in the DAPT PR have been done, so can merge it
16:35:01 [cpn]
Pierre: Yes
16:35:45 [cpn]
... There's no other discussion in the IMSC PR, so can close it
16:37:35 [nigel]
Topic: IMSC 1.3
16:38:23 [nigel]
Subtopic: Fixed github link metadata w3c/imsc#631
16:38:30 [nigel]
github: https://github.com/w3c/imsc/pull/631
16:38:55 [cpn]
Pierre: That's simple, question is who should merge it
16:38:57 [nigel]
SUMMARY: @palemieux to merge
16:39:27 [nigel]
Subtopic: Add Examples section to Introduction and add some renderings w3c/imsc#632
16:39:33 [nigel]
github: https://github.com/w3c/imsc/pull/632
16:40:00 [cpn]
Nigel: It's a draft PR for now, to add examples to the Introduction, and add some renderings
16:41:08 [cpn]
.. I want to check in before I do more on this
16:41:36 [cpn]
.. It adds some orientation information for people unfamiliar with the spec. But want to pause to discuss
16:42:17 [cpn]
Pierre: On the rendered examples, it's not a bad idea. But I'd rather we use actual examples. Those examples demonstrate the syntax but they're artificial
16:42:41 [cpn]
... Would it be possible to use a real example, and actual document or fragment?
16:43:00 [cpn]
Nigel: I already have something like that in the BBC Subtitle Guidelines, so that's easy to do, but it takes up a lot of space
16:43:02 [nigel]
-> https://www.bbc.co.uk/accessibility/forproducts/guides/subtitles/#Example-EBU-TT-D-document
16:44:24 [cpn]
Pierre: Have a frame from a BBC show with the EBU-TT-D fragment, showing how it's used in practice?
16:44:35 [cpn]
Nigel: Would that be useful?
16:45:11 [cpn]
Pierre: I'm trying to think of something that's not been don elsewhere. MDN has examples. The IMSC test suite has exhaustive examples
16:45:32 [cpn]
... What's missing is how it shows up in practice
16:45:49 [cpn]
Nigel: The BBC Subtitle Guidelines is a real world example
16:46:18 [cpn]
... [Shows the BBC example]
16:48:31 [cpn]
Pierre: I think that's awesome. I'd just include this. The region stuff is helpful
16:48:48 [cpn]
... It could go in an Annex if it's too long
16:50:16 [cpn]
... Add an acknowledgement too
16:50:33 [cpn]
Nigel: OK, yes
16:50:57 [cpn]
Chris: Move it to an Annex?
16:51:55 [cpn]
Nigel: For people reading from the top, and want orientation, I think it should go in the Introduction. Much easier than reading through the spec detail
16:52:34 [cpn]
Pierre: I'm fine with putting it in the Introduction.
16:52:54 [cpn]
Nigel: And leave the rendering examples in place in the PR?
16:53:54 [cpn]
Pierre: That's fine, no strong opinion. Could link to them if in they're in the test suite
16:54:52 [nigel]
SUMMARY: @nigelmegitt to add example, remove pointers in 2.1 to other examples, leave renders in place.
16:56:51 [cpn]
Topic: AOB
16:56:58 [cpn]
Nigel: Anything else to cover today?
17:00:48 [cpn]
... Welcome back Pierre as IE!
17:00:55 [cpn]
(adjourned)
17:01:07 [cpn]
rrsagent, draft minutes
17:01:08 [RRSAgent]
I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html cpn
17:01:20 [nigel]
i/(ad/Topic: Meeting close
17:02:01 [nigel]
i/(ad/Thanks everyone, next meeting is in 2 weeks on 2026-02-12, w3c/ttwg#327
17:02:09 [nigel]
rrsagent, make minutes
17:02:10 [RRSAgent]
I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel
17:02:33 [nigel]
present+ Chris
17:02:36 [nigel]
present- cpn
17:02:45 [nigel]
Present+ Nigel
17:02:47 [nigel]
rrsagent, make minutes
17:02:48 [RRSAgent]
I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel
17:04:57 [nigel]
s/where it the right place/where is the right place
17:05:16 [nigel]
s/is appropriate fo the destination/is appropriate for the destination
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s/Maybe don't do down this rabbit-hole/Maybe we don't need to go down this rabbit-hole
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s/moreso/more so
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s/been don e/been done e
17:08:34 [nigel]
rrsagent, make minutes
17:08:35 [RRSAgent]
I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel
17:09:05 [nigel]
scribeOptions: -final -noEmbedDiagnostics
17:09:09 [nigel]
zakim, end meeting
17:09:09 [Zakim]
As of this point the attendees have been Andreas, Atsushi, Pierre, cpn, Gary, Chris, Nigel
17:09:12 [Zakim]
RRSAgent, please draft minutes v2
17:09:13 [RRSAgent]
I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html Zakim
17:09:19 [Zakim]
I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye
17:09:27 [Zakim]
Zakim has left #tt
17:09:28 [nigel]
rrsagent, excuse us
17:09:28 [RRSAgent]
I see no action items