15:00:51 RRSAgent has joined #tt 15:00:55 logging to https://www.w3.org/2023/09/28-tt-irc 15:00:55 RRSAgent, make logs Public 15:00:56 Meeting: Timed Text Working Group Teleconference 15:01:21 Agenda: https://github.com/w3c/ttwg/issues/263 15:01:59 Previous meeting: https://www.w3.org/2023/09/12-tt-minutes.html 15:03:01 pal has joined #tt 15:03:05 scribe: nigel 15:03:13 Present: Nigel, Gary, Cyril, Pierre 15:03:20 Regrets: Andreas 15:03:37 Topic: This meeting 15:03:43 Nigel: Today our agenda is: 15:03:55 .. TPAC 2023 reflections 15:04:37 .. IMSC-HRM - do we have anything to cover on this today? 15:04:37 Pierre: We received feedback from one content provider, which was positive. 15:04:46 .. I am working with three others. 15:05:00 .. So far, it's been pretty good. 15:05:06 .. Bugs were found in the reference implementation, which were fixed. 15:05:19 .. There are also bugs in some content providers' libraries. 15:05:25 .. I'm cautiously optimistic that there are no major issues with the spec itself. 15:05:40 .. Now everybody is back from IBC and vacation I'm going to try to get it done by end of October. 15:05:49 Cyril: You said one provider - that's Netflix, right? 15:05:58 Pierre: Yes, the only one who has provided feedback to the group. 15:06:07 .. One of the three others has provided me with some results privately. 15:06:33 Cyril: I don't know what we decided - when we did the test Nigel there were bugs, but that's okay. 15:06:45 .. The Netflix content did not invalidate the IMSC-HRM model, so it is probably good. 15:06:57 .. One thing we found that was interesting, but still does not jeopardise the model, 15:07:21 .. for some content, Netflix produces content with very small cues - I ran about 3000 pieces of content - 15:07:30 .. and we decided the content should have been authored differently. 15:07:41 .. The issue is with 2 speakers speaking almost at the same time, they have cues that overlap, 15:07:47 .. but not completely, in time. 15:08:00 .. If you have 2 speakers, one speaks, then the other starts speaking, then the first stops, 15:08:19 .. Netflix splits that into 3 non-overlapping ISDs. If they are very short, that was creating a 15:08:25 .. content validation error according to the HRM. 15:08:33 .. I suggest we keep that as an issue and keep talking about it. 15:08:38 Pierre: Yes, I think that's worth discussing. 15:09:00 .. The bottom line is that the HRM model does not assume that the renderer can detect identical 15:09:15 .. regions or parts of ISDs. 15:09:25 Nigel: It does assume some level of caching, at least. 15:09:41 Pierre: Yes but it has no notion of identical content, so background redraws are not cached, for example. 15:09:45 .. I'm not sure it's a problem. 15:10:02 .. The Netflix approach, which Cyril will raise as an issue, was introduced to work around some 15:10:07 .. limitations of some clients. 15:10:30 Nigel: I think we just completed that agenda topic! 15:10:55 i/Pierre: We received/Subtopic: IMSC-HRM review feedback 15:11:03 Subtopic: Agenda continued 15:11:16 Nigel: We may also have a few things to discuss on DAPT. 15:11:33 .. In AOB, Andreas sent an email reminder about the DVB liaison, and I have responded 15:11:45 .. on the member-tt list. Not sure if we have anything more to discuss during this call? 15:12:13 group: no request to discuss further today 15:12:26 Nigel: Is there any other business, or points to make sure we cover? 15:13:09 Pierre: What's the plan wrt that liaison? 15:13:22 Nigel: Let's cover in TPAC 2023 reflections 15:13:40 Present+ Atsushi 15:13:47 Topic: TPAC 2023 reflections 15:13:59 Nigel: Just want to open up to any thoughts or observations anyone had? 15:14:18 .. I should comment about the joint meeting with APA WG and MEIG on the Thursday afternoon. 15:14:52 .. We had a good discussion, and it included the liaison from DVB, which APA WG was interested in also. 15:15:11 .. Since the liaison wasn't clearly targeted at any one group, but several might be interested, 15:15:29 .. I asked for a single team contact to bring together the responses and look after sending them. 15:15:54 .. François (tidoust) offered to do this or identify someone else who would. 15:16:15 .. In that context I think we should bring him in on the reflector discussions. 15:16:52 .. Does anyone have any comments on the response draft from Andreas and my reply? 15:17:01 Pierre: Yes, sounds like a good idea to refresh our collective memory. 15:17:27 -> https://lists.w3.org/Archives/Member/member-tt/2023Sep/0002.html DVB Liaison (member only reflector link) 15:20:40 Nigel: [iterates through the liaison input] 15:22:03 Pierre: On the point of audio track language, and the interaction between the audio signalled in the 15:22:19 .. content and user preference, I think any metadata document that describes what to signal in the content 15:22:30 .. is not useful unless there's an algorithm indicating how that metadata is used by the client. 15:22:43 .. There are subtle interactions between choice of language on the client, whether or not the client 15:23:01 .. has indicated it would like captions or subtitles, and there have been attempts at doing that. 15:23:07 .. it's a surprisingly really hard problem. 15:23:23 .. It would be great to standardise something, and the algorithm should be standardised to, for the client. 15:23:41 Nigel: I would like to say that too. 15:23:56 Pierre: We should say it plainly: unless there's an algorithm that specifies the interaction between 15:24:04 .. user choices and signalling then it is incomplete work. 15:24:21 .. There was an algorithm created back in the Ultraviolet/DECE days, and it's quite complex. 15:24:29 Nigel: Yes, I tried reading that once! 15:24:33 Pierre: We should really emphasise that point. 15:24:41 .. It's particularly important when forced narrative is available. 15:24:43 Nigel: Yes 15:25:09 .. Any more on that, or on TPAC more generally? 15:25:24 Pierre: On TPAC more generally, I was there for the discussion about Apple's suggestion on an API 15:25:40 .. for improving TextTrackCue. Do you know if this is going to be turned into an effort within this 15:25:44 .. group or another group? 15:26:13 Gary: I think it's on Apple to take the action of updating all the relevant specs like HTML, WebVTT etc 15:26:52 -> https://github.com/whatwg/html/pull/9771 WHATWG pull request on HTML 15:27:06 Nigel: They have opened the above pull request on HTML. 15:27:36 .. There's a lot of HTML spec complexity in there, but in terms of the basic requirements I have 15:27:47 .. added a couple of comments, and recommend others review too. 15:29:32 Nigel: The issue I have with this now is that without full CSS support for fillLineGap and linePadding I don't know how we could use it. 15:29:56 Pierre: In creating imscJS we spent a lot of time working out how to make it match the TTML expectations. 15:30:08 .. I'm not aware of any effort being done to validate this API, is my summary. 15:30:22 Gary: From my understanding, the API doesn't preclude any of that, the only change in IMSC is to add 15:30:41 .. the attribute tags to the output HTML from imscJS, so the styling should just be carried over. 15:30:55 Pierre: I can believe that theoretically, but we need to see a comparison between the rendered output and 15:31:00 .. the test references. 15:31:09 Gary: I guess that's part of getting the pull request approved. 15:31:20 Pierre: The reason I'm raising it is that HTML and CSS and TTML are each complex. 15:31:27 .. I've surprised myself in the past with corner cases. 15:31:44 Gary: They brought up that there can be conflicts between the user setting overrides and the 15:32:09 .. IMSC presentation. That's another issue - they said there's nothing they can do about that. 15:32:29 Nigel: Two things. Firstly, without CSS support for fillLineGap and linePadding, I think it will be impossible 15:32:46 .. to make the tests all render correctly, because the imscJS code that works around those HTML and CSS 15:32:59 .. limitations cannot run without the HTML fragment being homed to some DOM element. 15:33:15 .. And in the proposal, no client code can run on it when that is the case. 15:33:35 .. Secondly, if CSS support were added for those features, then that could work around some of the 15:34:01 .. oddities that could result from user settings being unexpected, in respect of those two styling features. 15:34:22 .. I haven't even thought about ruby and text decoration but I think that ought to work, in principle. 15:34:37 .. So maybe the feedback to Apple is yes, but we need CSS support for those missing features. 15:34:52 Gary: Yes, and I think that was discussed and maybe we need to bring that in more strongly that as 15:34:59 .. part of this the CSS related discussions need to be restarted. 15:35:13 .. To the first point, potentially, and I guess this is the question, the document fragment we give to the API, 15:35:30 .. there's nothing disallowing it from being added to the DOM first to apply the workaround beforehand. 15:35:54 .. Theoretically this could be done, as a workaround. 15:36:22 Nigel: Yes, though if the user makes the text size bigger then it would break. 15:36:43 Pierre: I don't think anyone has implemented imscJS this way and tested it fully. 15:37:00 Gary: I think Eric did implement it this way, but maybe did not cover all the edge cases. 15:37:14 Pierre: This API is definitely a bit different from what I saw 4 or 5 years ago. 15:37:26 Gary: I don't disagree that a lot more testing is needed, especially with more complex inputs. 15:37:59 Nigel: Sounds like an action to land this point somehow, not sure who is best placed to do so. 15:38:28 .. I'm certainly happy to send a message to Eric and James from Apple, as well as Marcos. 15:39:16 Gary: Final point: they link to some tests they wrote for WebKit in their PR, but it does seem to be on the simple side. 15:39:54 Nigel: Any other TPAC discussion points? 15:39:58 group: none 15:40:08 Topic: DAPT 15:40:15 s/DAPT/IMSC-HRM 15:40:22 Cyril: What are the next steps to move forward? 15:40:29 .. One more content provider reporting and that is it? 15:41:00 Nigel: Good question - what are the exit criteria? 15:41:03 .. We have tests 15:41:06 Pierre: Yes. 15:41:13 .. I think we need 2 content providers. We have one. 15:41:24 .. I'm hoping that we can, in a month, decide whether or not we need changes. 15:41:57 Nigel: [reads CR exit criteria] 15:42:07 Cyril: So we already meet the criteria? 15:42:17 Nigel: Apparently so, though in the weakest way we possibly could! 15:42:35 Atsushi: I'm not sure what the first criteria means - do we need a content document 15:42:49 .. produced by a content producing implementation and validated by a content validator, 15:43:22 .. but I am not sure. We have a manual set of test suites and validated by [scribe missed] 15:43:37 .. but if current criteria are that the same document needs to be produced by one implementation 15:44:00 .. and validated separately, then we need some other set of content. 15:44:18 Nigel: We discussed at the top of the meeting, and mentioned that Netflix has an implementation 15:44:40 .. that they have verified by processing about 3,300 documents through the validator. 15:44:45 Atsushi: That's great! 15:45:01 Cyril: I did send an email. There were ~20 languages, some subtitles for deaf and hard of hearing, 15:45:16 .. some forced narratives, some translation subtitles. 15:45:45 Pierre: As another data point: 15:45:59 From another content platform: I ran the tool over the weekend on 25,000 randomly selected samples from our library. I recorded 100 failures and I have attached the output of the tool for those failures. 15:46:11 Pierre: I'm trying to get them to release those results. 15:46:24 .. So far I think all the failures are in the files themselves. That gives a sense of the scale. 15:46:30 .. 25,000 TTML files. 15:46:47 .. So far all the failures were errors in the TTML that probably came from errors in translation from 608, 15:46:53 .. by my guess. 15:47:01 Nigel: Syntactical errors, or something like that? 15:47:23 Pierre: Not sure what you'd call them - for example, timestamps in hh:mm:ss:ff and the frame counter 15:47:37 .. goes beyond the frame rate, e.g. if 30fps, and a frame count of 30! 15:47:55 cyril has joined #tt 15:48:05 RRSAgent, pointer 15:48:05 See https://www.w3.org/2023/09/28-tt-irc#T15-48-05 15:48:37 Nigel: Occasionally we see errors like that too, which we do catch. 15:48:57 Pierre: We are trying to complete the CR exit criteria report by the end of October. 15:49:35 Nigel: Yes, good idea, let's try to get this completed soon - does that timescale work for everyone? 15:50:02 .. I'm going to record assent by silence here! 15:50:19 .. That's great, gives us about a month to verify that we have met the exit criteria. 15:51:02 Topic: DAPT 15:52:34 Nigel: I have one question - anything from you Cyril? 15:52:40 Cyril: Wide review inputs 15:53:04 Nigel: Yes, I have been making the point generally, on email and to people at IBC, that now is the time 15:53:19 .. to review the spec and provide comments, while we're in WD and more easily can make changes. 15:53:56 .. I did talk to 3 or 4 organisations about DAPT specifically and some were very positive, and said they 15:54:03 .. would either be implementing or reviewing or both. 15:54:10 .. It was extremely positive. 15:54:42 Cyril: I did open the TAG review and the i18n review, since we last talked. 15:54:51 .. I haven't received any feedback yet, though it has not been long. 15:55:04 Atsushi: For i18n we just reviewed it and resolved it as completed, for information. 15:55:13 .. We will mark it as completed shortly. 15:55:15 Cyril: Great! 15:55:26 Atsushi: The action on GitHub might take a little time. 15:55:42 Cyril: I can see that aphilips moved it from in-review to completed an hour ago. 15:56:35 Nigel: One question from me: I thought we had resolved to make langSrc be absent or a language code, 15:56:40 .. but couldn't find it documented. 15:56:42 Cyril: Yes we did 15:56:47 Atsushi: It's in our minutes 15:56:54 Gary: You're not misremembering. 15:57:09 Nigel: Thank you! I think the action is on me to implement that, so I will go ahead with that. 15:57:39 .. The other thing I wanted to note was that I just opened an editorial pull request in response to an 15:57:59 .. issue raised by Andreas, about the definitions of script and transcript, so if anyone can review that, 15:58:06 .. it's only small, and that'd be helpful! 15:58:08 https://www.w3.org/2023/09/12-tt-minutes.html#x959 ? 15:58:29 -> https://github.com/w3c/dapt/pull/183 Redraft opening section of §2.1 w3c/dapt#183 15:59:24 Cyril: Did you have any feedback from privacy and security reviews? 15:59:27 Nigel: No not yet 15:59:33 Cyril: We discussed removing styles too? 16:00:28 Nigel: Yes we agreed to do that, in w3c/dapt#124 16:01:04 Cyril: The language one was w3c/dapt#148 16:01:09 Nigel: Ah, thank you, I will do that. 16:01:14 Topic: Meeting close 16:01:30 Nigel: Thank you everyone, we're at time, and just completed the agenda. Let's adjourn. Be free! 16:01:37 .. [adjourns meeting] 16:01:38 rrsagent, make minutes 16:01:40 I have made the request to generate https://www.w3.org/2023/09/28-tt-minutes.html nigel 16:02:10 Chair: Gary, Nigel 16:11:12 s|reads CR exit criteria|reads CR exit criteria at https://www.w3.org/TR/imsc-hrm/#sotd 16:12:09 s/Occasionally we see errors like that too/Occasionally we see errors like that too in our tooling in the BBC 16:13:08 rrsagent, make minutes 16:13:09 I have made the request to generate https://www.w3.org/2023/09/28-tt-minutes.html nigel 16:21:43 scribeOptions: -final -noEmbedDiagnostics 16:21:47 zakim, end meeting 16:21:47 As of this point the attendees have been Nigel, Gary, Cyril, Pierre, Atsushi 16:21:49 RRSAgent, please draft minutes v2 16:21:51 I have made the request to generate https://www.w3.org/2023/09/28-tt-minutes.html Zakim 16:21:58 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 16:21:58 Zakim has left #tt 16:22:06 rrsagent, excuse us 16:22:06 I see no action items