15:59:54 RRSAgent has joined #tt 15:59:58 logging to https://www.w3.org/2026/01/29-tt-irc 15:59:58 RRSAgent, make logs Public 15:59:59 Meeting: Timed Text Working Group Teleconference 16:00:04 scribe: nigel 16:00:16 Agenda: https://github.com/w3c/ttwg/issues/326 16:00:22 Previous meeting: https://www.w3.org/2026/01/15-tt-minutes.html 16:00:27 Topic: This meeting 16:01:26 Chair: Nigel 16:01:36 Present+ Andreas 16:01:38 rrsagent, make minutes 16:01:39 I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel 16:03:09 Present+ Atsushi 16:03:48 Present+ Pierre 16:04:34 Nigel: Agenda for today is: 16:04:42 atai has joined #tt 16:04:48 .. DAPT - Implementation activity 16:04:54 .. How we write about DAPT and IMSC compat 16:05:09 .. and IMSC - we have some items flagged for the agenda 16:05:19 .. AOB? 16:05:32 no AOB 16:05:34 Topic: DAPT 16:05:53 Subtopic: Interoperability session 2026-01-26 16:06:08 Nigel: Cyril and I, and an observer from VRT in Belgium, 16:06:18 .. had an interoperability session on Monday. 16:06:22 .. It went pretty well. 16:06:42 .. Netflix's open source converter generated a set of DAPT files. 16:06:58 .. BBC's (not yet open source) ttml validator validated them. 16:07:09 .. It found one issue, which Cyril was able to address. 16:07:17 .. But otherwise it was really positive. 16:07:29 .. And the action to come out of it is to update the implementation report, 16:07:43 .. which is a bit complex because we're leaning on both the CR exit criteria and 16:07:56 .. the Charter success criteria to make the case for progressing. 16:08:11 .. There are one or two features that still have one implementation, which we're thinking about. 16:08:27 .. Any questions? 16:08:39 Andreas: The BBC validator is just for DAPT or generic TTML validator? 16:09:09 Nigel: At the moment it validates that input documents meet the BBC Subtitles Guidelines for EBU-TT-D, 16:09:23 .. or that they are valid DAPT. It's written in a way that can be extended for other profiles. 16:10:31 Topic: DAPT and IMSC compatibility (editorial) 16:10:46 Nigel: We have two open pull requests, one for DAPT, the other for IMSC 1.3. 16:10:50 cpn has joined #tt 16:11:00 -> https://github.com/w3c/dapt/issues/332 w3c/dapt#332 16:11:01 present+ 16:11:08 scribe+ cpn 16:11:15 -> https://github.com/w3c/imsc/issues/622 w3c/imsc#622 16:12:08 Nigel: There's a lot of commonality between these PR 16:12:28 ... From the review of the IMSC one, the best way to proceed isn't completely obvious 16:12:31 s/PR/PRs/ 16:12:51 ... Pierre mentioned not being happy with duplicating text between the specs 16:13:16 ... There's been discussion on DAPT PR #333 16:13:18 -> https://github.com/w3c/dapt/pull/333 w3c/dapt#333 pull request 16:14:42 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 ... 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 ... IMSC doesn't understand DAPT metadata 16:15:56 ... Otherwise, documents in DAPT workflows are entirely different from documents in IMSC workflows 16:16:21 Nigel: The key point is how one is derived from the other 16:16:42 Pierre: Documenting how to convert one to the other might be good, but that's not about compatibility 16:17:27 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 ... 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 ... Places where it makes sense to start with DAPT and generate IMSC 16:18:32 ... Starting from a DAPT workflow, where it the right place to start that. Might vary between different people's workflows. 16:19:09 ... 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 ... 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 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 ... Those are both DAPT concerns, not IMSC concerns 16:21:15 Nigel: What if the IMSC documents that you distribute include DAPT metadata? 16:21:39 ... 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 ... For example, the names of speakers where you could show non-caption/subtitle metadata 16:22:26 Pierre: An IMSC player would ignore the metadata, so what you're describing wouldn't be an IMSC player 16:23:02 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 Pierre: Don't think this belongs in IMSC, could be some other spec. 16:24:00 ... IMSC from the beginning was attempting to reduce fragmentation in distribution of subtitles and captions using TTML 16:24:34 ... 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 ... Example, EBU-TT-D, you can distribute the same documents to IMSC players 16:25:08 ... The same for SMPTE-TT documents, will play fine in an IMSC player 16:25:35 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 Pierre: Yes 16:26:05 ... 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 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 ... 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 Pierre: Could find a logical place to do that, e.g., in the Introduction on where IMSC documents come from 16:28:05 ... A question that has come up in previous years is where IMSC documents come from, so that could be a place 16:28:21 Nigel: I was thinking of Appendix I, on compatibliity with other formats 16:28:50 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 ... MDN doesn't say where IMSC documents come from 16:29:43 Nigel: There are different views, e.g, for some people they come from CEA-608 documents 16:30:12 ... It's timely now as people are thinking of automated subtitle workflows 16:31:08 ... BBC converts teletext to EBU-TT-D... 16:31:19 Nigel: Any other views on this? 16:31:23 q? 16:31:34 Andreas: What you've both said makes sense 16:32:26 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 Present+ Gary 16:32:58 Chair: Nigel, Gary 16:33:07 Nigel: I thought this would be a useful addition to IMSC, but I'm deferring to the editor 16:34:55 Nigel: I think all review comments in the DAPT PR have been done, so can merge it 16:35:01 Pierre: Yes 16:35:45 ... There's no other discussion in the IMSC PR, so can close it 16:37:35 Topic: IMSC 1.3 16:38:23 Subtopic: Fixed github link metadata w3c/imsc#631 16:38:30 github: https://github.com/w3c/imsc/pull/631 16:38:55 Pierre: That's simple, question is who should merge it 16:38:57 SUMMARY: @palemieux to merge 16:39:27 Subtopic: Add Examples section to Introduction and add some renderings w3c/imsc#632 16:39:33 github: https://github.com/w3c/imsc/pull/632 16:40:00 Nigel: It's a draft PR for now, to add examples to the Introduction, and add some renderings 16:41:08 .. I want to check in before I do more on this 16:41:36 .. It adds some orientation information for people unfamiliar with the spec. But want to pause to discuss 16:42:17 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 ... Would it be possible to use a real example, and actual document or fragment? 16:43:00 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 -> https://www.bbc.co.uk/accessibility/forproducts/guides/subtitles/#Example-EBU-TT-D-document 16:44:24 Pierre: Have a frame from a BBC show with the EBU-TT-D fragment, showing how it's used in practice? 16:44:35 Nigel: Would that be useful? 16:45:11 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 ... What's missing is how it shows up in practice 16:45:49 Nigel: The BBC Subtitle Guidelines is a real world example 16:46:18 ... [Shows the BBC example] 16:48:31 Pierre: I think that's awesome. I'd just include this. The region stuff is helpful 16:48:48 ... It could go in an Annex if it's too long 16:50:16 ... Add an acknowledgement too 16:50:33 Nigel: OK, yes 16:50:57 Chris: Move it to an Annex? 16:51:55 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 Pierre: I'm fine with putting it in the Introduction. 16:52:54 Nigel: And leave the rendering examples in place in the PR? 16:53:54 Pierre: That's fine, no strong opinion. Could link to them if in they're in the test suite 16:54:52 SUMMARY: @nigelmegitt to add example, remove pointers in 2.1 to other examples, leave renders in place. 16:56:51 Topic: AOB 16:56:58 Nigel: Anything else to cover today? 17:00:48 ... Welcome back Pierre as IE! 17:00:55 (adjourned) 17:01:07 rrsagent, draft minutes 17:01:08 I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html cpn 17:01:20 i/(ad/Topic: Meeting close 17:02:01 i/(ad/Thanks everyone, next meeting is in 2 weeks on 2026-02-12, w3c/ttwg#327 17:02:09 rrsagent, make minutes 17:02:10 I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel 17:02:33 present+ Chris 17:02:36 present- cpn 17:02:45 Present+ Nigel 17:02:47 rrsagent, make minutes 17:02:48 I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel 17:04:57 s/where it the right place/where is the right place 17:05:16 s/is appropriate fo the destination/is appropriate for the destination 17:06:14 s/Maybe don't do down this rabbit-hole/Maybe we don't need to go down this rabbit-hole 17:07:03 s/moreso/more so 17:08:01 s/been don e/been done e 17:08:34 rrsagent, make minutes 17:08:35 I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html nigel 17:09:05 scribeOptions: -final -noEmbedDiagnostics 17:09:09 zakim, end meeting 17:09:09 As of this point the attendees have been Andreas, Atsushi, Pierre, cpn, Gary, Chris, Nigel 17:09:12 RRSAgent, please draft minutes v2 17:09:13 I have made the request to generate https://www.w3.org/2026/01/29-tt-minutes.html Zakim 17:09:19 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 17:09:27 Zakim has left #tt 17:09:28 rrsagent, excuse us 17:09:28 I see no action items