15:53:56 RRSAgent has joined #tt 15:54:00 logging to https://www.w3.org/2024/09/27-tt-irc 15:54:00 RRSAgent, make logs Public 15:54:01 Meeting: Timed Text Working Group Teleconference 15:54:06 rrsagent, this meeting spans midnight 15:54:16 rrsagent, make logs public 15:54:22 present+ Nigel_Megitt 15:54:27 Chair: Nigel, Gary 15:54:39 agenda: https://github.com/w3c/ttwg/issues/291 15:55:09 Previous meeting: https://www.w3.org/2024/09/12-tt-minutes.html 15:55:13 rrsagent, make minutes 15:55:15 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 15:55:55 scribe+ nigel 16:01:41 Present+ Cyril 16:02:34 Present+ Atsushi 16:03:27 Present+ James 16:04:59 Present+ Gary 16:05:54 Present+ Surya 16:05:59 Present+ Pierre 16:08:19 Toic: Introductions 16:08:19 s/Toic: Introductions// 16:08:23 Topic: Introductions 16:09:23 Nigel: Nigel Megitt, BBC, co-chair TTWG 16:09:41 atsushi: Atsushi Shimono, W3C Japan, team contact TTWG 16:09:59 jcraig: James Craig, Apple, accessibility groups like ARIA, crossing over to groups like this when there's an overlap of interest 16:10:10 cyril: Cyril Concolato, Netflix 16:10:14 atsushi has joined #tt 16:10:30 gkatsev: Gary, Invited Expert, NBC Universal/Peacock, co-chair TTWG and WebVTT editor 16:10:46 pal: Pierre-Anthony Lemieux, supported by MovieLabs, editor IMSC 16:11:54 surya: Surya Sunkavelli, working on ... 16:13:00 cyril has joined #tt 16:13:07 RRSAgent, pointer 16:13:07 See https://www.w3.org/2024/09/27-tt-irc#T16-13-07 16:13:20 scribe+ cyril 16:13:42 Surya: Hey everyone, my name is Surya Sunkavelli. I work on the Media Foundations team within Encoding at Netflix so my work usually features studio facing use cases and media inspection related projects. With that being said, lately I’ve been working with Cyril for about a couple months now in tracking the DAPT spec as it develops and gets 16:13:43 updated and mapping it back to TTAL, which is a Netflix internal script file exchange format used to interchange between third party dubbing tools and Netflix internal tools like Scripting tool. 16:15:32 eric_carlson has joined #tt 16:15:38 Topic: Agenda bash 16:15:48 nigel: Iterates through topics 16:16:02 -> https://www.w3.org/wiki/TimedText/tpac2024#Topics Meeting topics 16:16:42 jernoble has joined #tt 16:16:50 +present Jer Noble 16:16:58 present+ 16:20:39 group discussion of agenda topics and timings 16:27:56 -> https://github.com/w3c/ttwg/issues/291#issuecomment-2379654028 Results of agenda bash 16:28:38 Topic: Netflix demo of TTAL <--> DAPT 16:28:53 surya: TTAL is an internal Netflix specification for script file exchange 16:29:05 .. I wanted to demo the status of the converter between TTAL and DAPT 16:29:13 .. and the key DAPT features that are being mapped properly 16:29:21 cyril: Netflix blog post explaining TTAL 16:29:32 jcraig: This is not a programming script, but a script for a piece of media? 16:29:38 cyril: Yes, think of it like a transcript 16:29:56 https://netflixtechblog.com/introducing-netflix-timed-text-authoring-lineage-6fb57b72ad41 16:30:16 .. this explains the history behind TTAL 16:30:25 .. It is already used in production, we have partners all around the world 16:30:34 .. that deliver scripts, dubbing scripts mostly but also audio description scripts 16:30:47 .. using this format, but Netflix wants to migrate to DAPT when it is finalised. 16:30:52 surya: [shares screen] 16:31:11 .. List of example DAPT files generated by the converter. 16:31:55 .. [shows example file] 16:32:00 .. xml:lang showing language of file 16:32:09 .. daptm:langSrc to show origin language 16:32:23 .. daptm:represents - I know this is going to change, but looks like this now 16:32:41 cyril: Mentioned previously - Netflix commissioned production of dubbing scripts for some 16:32:53 .. of its open content, where we share content that can be used to test features like HDR etc. 16:33:05 .. One of the titles we have is Meridian and we have asked for the generation of dubbing scripts 16:33:19 .. in ~8 languages. We intend to release that as open source too so 16:33:27 .. people will be able to see the TTAL and DAPT scripts for this title. 16:33:37 surya: Yes, I can see around 8 languages. 16:33:44 .. Here's an example of one of the Meridian ones. 16:34:01 .. This one is an audio description script. 16:34:48 .. It's mapped to visualNonText and visualText 16:35:10 .. With frame rates, we capture that using ttp:frameRate and ttp:frameRateMultiplier. 16:35:17 q? 16:35:50 Nigel: are you using frame based time expressions? 16:36:04 surya: In TTAL we use frame based time expressions, so we do the same in DAPT 16:36:18 cyril: This is the easiest conversion. We may decide to have a different mode where 16:36:24 .. we go to seconds and forget the frame rate. 16:37:21 surya: Features prefixed with nttm: is for Netflix internal metadata from TTAL. 16:37:37 .. We're just storing them here but we're still talking about how best to organise internal specific metadata. 16:37:55 cyril: There are so many ways to capture metadata, attributes, elements, metadata elements, 16:38:00 .. either one or multiple. 16:38:10 .. Would like to have guidance in DAPT about how people should do metadata. 16:38:29 surya: Events and Characters 16:40:05 cyril: In this example here, there is a `ttm:desc` child of a `ttm:agent` 16:40:10 .. Not sure if that's allowed? 16:40:52 nigel: ttm:agent does not accept ttm:desc children 16:41:08 surya: That's something to keep in mind for agents, where to store the metadata 16:41:16 nigel: One option is to change it in TTML2 16:41:54 surya: Specific elements, div captures ids, begin and end times, style ids 16:42:16 .. so the mapping from the events to the style ids. 16:42:38 .. ttm:agent reference, which we map back to ttm:agent elements 16:42:58 .. One issue we haven't finalised yet, is that TTAL and DAPT think differently about how to 16:43:14 .. map script events or timing events. We haven't ironed out the mapping yet, some issues with TTML. 16:43:28 .. We would like segments to map to span elements with time offsets and styles for dubbing. 16:43:33 .. Have to finalise that still. 16:44:02 .. Earlier mentioned daptm:represents, so with the introduction of that we will change 16:44:07 .. how we use daptm:eventType 16:44:35 Nigel: Reminding myself, we got rid of event type didn't we 16:44:40 cyril: Yes, it's now represents 16:45:04 present+ Eric_Carlson 16:45:33 cyril: To summarise, no problem mapping the core types of TTAL into DAPT 16:45:45 .. The question is about mapping additional metadata that is not in the core DAPT vocabulary 16:45:56 .. How best to use the registries or user defined values for some of the attributes 16:46:00 .. That's what we have to work on now 16:46:32 Nigel: Will you share those more widely to see if there's interest in adding those to the registries? 16:46:38 Cyril: Yes, some of them 16:46:45 eric_carlson has joined #tt 16:46:58 Nigel: That's great, a working implementation of a DAPT generating tool 16:46:58 +present eric_carlson 16:47:12 surya: Yes, and there's a tool to go back the other way that we'll complete 16:47:16 cyril: This tool will be open sourced 16:47:20 q? 16:47:50 nigel: Thank you for that demo 16:47:56 Topic: Streamable Text Tracks 16:48:29 Nigel: In Media WG yesterday I raised a follow-up to a conversation in Media and Entertainment 16:48:34 .. Interest Group from Monday, 16:49:01 .. which was about adding to the Media Source Extensions text tracks; it's currently only audio and video. 16:49:20 .. There was a positive discussion, with consideration of some of the thorny technical issues 16:49:27 .. that would need to be resolved. 16:50:06 Cyril: Would like to go through the issues and understand which groups will deal with them. 16:50:27 jer: Two major areas are streaming of raw formats, WebVTT in hls.js, and feature level compat 16:50:43 .. between MSE and HLS, and how to append WebVTT files 16:50:49 pal has joined #tt 16:50:59 .. The MSE API allows you to append in a blob of binary data with a specific MIME type 16:51:13 .. The concept would be you could init a source buffer with a MIME type of webvtt and append chunks 16:51:15 .. of WebVTT files. 16:51:28 .. The Media WG would need to come up with a description of WebVTT in our media file format 16:51:41 .. registry that describes initialisation and media segments for WebVTT and any other formats we would 16:51:45 .. want to support including TTML. 16:51:54 cyril: Are the registries specific to a media type or a MIME type? 16:52:08 .. The registry deals with ISOBMFF, not audio in ISOBMFF, video in ISOBMFF etc. 16:52:12 eric_carlson: I think that's right 16:52:28 jer: Yes we're jumping ahead to the second use case, 16:52:39 .. which is delivering captions inside a media container, not just as raw payload 16:52:52 .. Not just embedded VTT or TTML, but also 608 and 708 captions, which are more commonly found 16:52:57 .. on the web at the moment. 16:53:27 .. Either exposing the raw samples to the client application, so an MSE app in a browser would get 16:53:45 .. a callback maybe or an event fired when new samples or DataCues (not standardised yet), 16:53:56 .. some packet that describes a thing that happens in the timeline, 16:54:11 .. or alternatively, my preference, when MSE encounters timed text, turn it directly into captions 16:54:22 .. and turn it into Text Track Cues that are displayable natively by the user agent. 16:54:27 q+ 16:54:35 eric_carlson: I agree that's better, but there's always a situation where the UA encounters a format 16:54:50 .. it doesn't know how to parse, so we need an escape hatch where the page can override the behaviour, 16:55:12 .. or can handle a format that the UA just doesn't know how to parse. 16:55:14 ack cyril 16:55:29 cyril: I fully support that, with a Netflix hat 16:55:43 .. We care about how we display our subtitles and the consistency of our subtitles across UAs and devices. 16:55:51 .. I agree sometimes the page wants to let the UA do it, 16:55:58 .. and we have to work with regulation, privacy etc. 16:56:18 jer: We're bleeding into the interop issue for later about not being able to rely on the UA's behaviour 16:56:38 cyril: You want the page to be able to render the TTML 16:56:50 eric_carlson: If the page just wants to override the UA behaviour, a page could do what 16:57:00 .. many do now, taking the parsed output and do the rendering themselves. 16:57:11 .. We have to handle the case where the UA doesn't know how to parse. 16:57:40 Nigel: Is there already an equivalent for audio and video formats that the UA doesn't know how to decode? 16:57:42 eric_carlson: No 16:57:59 Cyril: The UA processing and performance requirements are a different order of magnitude 16:58:42 .. Maybe why there wouldn't be that approach 16:58:51 .. Maybe it could be WebCodecs in the future 16:59:06 eric_carlson: Thinking about it, the problem I was thinking of doesn't make sense, because 16:59:20 .. if the UA doesn't know how to parse the content then it just doesn't know, and its the web app 16:59:32 .. that's going to push the data into the parser... No, I take that back. If it's muxed content... 16:59:48 cyril: If it's TTML in MP4, the application will just push it, then the TTML gets extracted and 16:59:56 .. passed back to the application at the appropriate time 17:00:01 eric_carlson: Yes, that's what we need to figure out 17:00:11 .. There isn't an issue where a raw format would be pushed in and we need to deal with 17:00:16 .. exposing that to the page somehow. 17:00:36 jer: A lot of the issues have to do with the MSE specification itself. 17:00:48 .. One common way to do ad insertion is to reuse the same source buffer and append media from 17:01:01 .. a different source, maybe with a call to changeType() to signal the change of codecs. 17:01:18 .. But the MSE API has a requirement that there are always the same number and type of tracks, 17:01:33 .. with unchanging identifiers, even if the payload (codec) type changes. 17:01:50 .. So if you have a main presentation with two 608 tracks, if you wanted to switch midstream to an 17:02:08 .. ad then that would have to have exactly the same number of text tracks too, according to MSE. 17:02:23 .. I don't know if the reason for that is still relevant to text tracks 17:02:34 .. There may be a need to relax that requirement only for text tracks so that you can continue 17:02:39 .. to play without breaking. 17:03:20 Nigel: I can see UI issues about changes to the user's preferred selection 17:03:33 Jer: Exactly, and how do you present that change to the text track 17:03:47 eric_carlson: We have that in HLS already, it can switch rendition to one that has a different set of tracks 17:03:57 .. Nobody has ever complained about it, it could technically be a problem 17:04:04 q+ 17:04:19 jer: Good to know how many people choose a specific language preference 17:04:22 ack gkatsev 17:04:44 gkatsev: That's also for source buffers - for audio and video you're not supposed to have gaps, 17:04:56 .. and that's more likely for text tracks, where there may not be any for a long time. 17:05:16 .. How does this interact with the Safari experiment with the HTML block for rendering? 17:05:29 .. Would this supersede that, or is it independent? 17:05:38 eric_carlson: In my mind they're separate things. 17:05:50 .. I think this is just an extension of what we already do with inband caption tracks 17:06:03 .. where we turn them into WebVTT cues as long as it's a format that we understand. 17:06:11 .. We just use the existing text track mechanism. 17:06:25 eric_carlson: The other problem we need to solve is how to signal 608 and 708 17:06:35 .. Technically the init segment has to describe the stream. 17:06:42 cyril: That is probably an MPEG question 17:06:55 .. A solution is getting published in a couple of months. 17:07:32 .. There will be an amendment to ISOBMFF part 12 that enables signalling T35 messages in the init, 17:07:45 .. and you can put as many bytes as you need. 17:07:55 .. I got confused though because 608 is SEI messages not T35 messages. 17:08:11 jer: HTML has a side spec called Sourcing Inband Tracks 17:08:52 .. It looks like, to signal 608 or 708 you need to have a trac fragment in your moov header. 17:08:59 jernoble has joined #tt 17:09:02 https://dev.w3.org/html5/html-sourcing-inband-tracks/#mpeg4 17:09:04 cyril: Can we have a forum for this conversation to continue? 17:09:14 .. Is it better in TTWG or MediaWG or somewhere else? 17:09:27 eric_carlson: I think it would be better to start it here and then take it to the MediaWG. 17:09:36 .. Just my quick opinion. 17:09:56 Nigel: My 15s of thought says the opposite. 17:10:03 eric_carlson: I think it helps to make progress in a smaller group and then take that to a bigger group. 17:10:23 Adam_Page has joined #tt 17:10:39 Nigel: I would say the spec is squarely in MediaWG so I'd propose setting up a task force in MediaWG to 17:10:48 .. look at this, and then take the results back up to the wider group. 17:10:56 .. Then if there are interested people from here they can join that TF. 17:11:05 q? 17:11:29 Cyril: Need to get the terminology right, useful to do it in a task force 17:11:54 Nigel: someone needs an action to take this task force proposal to the chair of the MediaWG 17:11:58 jernoble: I will take that action 17:12:21 Topic: IMSC 17:13:35 Nigel: May need to let this topic flow over into a later session if we don't have time now 17:14:32 Pierre: Background: a couple of weeks ago an issue was reported by a user of IMSC, a service 17:14:46 .. provider to a large content platform, that their French subtitling and captioning team had run 17:14:55 .. into an issue where they couldn't get superscript and subscript characters. 17:15:10 .. They turn out to be more important in French than in English because France has a 17:15:20 .. governmental organisation that sets standards for the language. 17:15:45 .. Those standards say that the abbreviation of first and second, like 1er, must be in superscript. 17:16:02 .. Everyone in France understands it if they are not superscript, but French standards are to put 17:16:08 .. the ordinal numeral as superscript. 17:16:20 .. So this is a shortcoming of IMSC, evidently. 17:16:35 .. The good news is there's already a TTML2 feature that allows super or sub to be specified. 17:16:50 .. Because we have this significant issue and other backlog issues it seems like a good time to 17:16:54 .. do a minor revision to IMSC 17:16:58 cyril: Is there a list? 17:17:06 pal: Yes, I'll go through it in a few seconds. 17:17:21 .. The intent is a minor revision, and fix this substantial issue. 17:17:36 .. I've gone through, and sent an email to the reflector yesterday, and taken a stab 17:17:49 .. at labelling the backlog issues that we should try to tackle if we are going to embark on this. 17:17:58 .. I labelled this as 1.3 because we're at 1.2 now. 17:18:27 .. There's one big category of backlog issues which are related to the results of a liaison with ARIB, 17:18:40 .. a Japanese organisation that have defined a profile of TTML for the Japanese broadcast market. 17:19:02 .. Where we left off is we alerted ARIB about 1.1 or 1.2 and got suggestions back that require more 17:19:13 .. detailed discussion to make sure we would not do something that would not work for them. 17:19:18 .. We never got that collaboration going. 17:19:30 .. Something we should probably do would be to send a communication to ARIB saying we are about 17:19:40 .. to start on IMSC1.3, now is the time to have this discussion. 17:19:46 .. Otherwise those issues will stay in the backlog. 17:20:15 Nigel: Atsushi, do you have any contacts there? 17:20:33 atsushi: There is NHK, but my main contact in this area has moved company, so I need to. 17:20:49 .. establish new contacts. I'm not sure if we should write a liaison or make a direct contact. 17:20:52 Nigel: We can do both 17:21:11 atsushi: Both would be fine. There stance is not to be too responsive generally. 17:21:24 pal: That's fine, I just don't think we should do anything without active collaboration with ARIB. 17:21:28 atsushi: I understand, yes 17:21:53 .. Let me contact during lunch, if I can, today, some colleagues and give me the chance to feed back 17:21:58 .. during the afternoon session. 17:22:14 pal: If we go ahead we should craft a formal liaison. 17:22:17 atsushi: Yes, of course. 17:22:33 pal: In terms of backlog... 17:22:53 -> https://github.com/w3c/imsc/issues?q=is%3Aissue+is%3Aopen+label%3Aimsc1.3 IMSC 1.3 issues 17:23:36 pal: I suggest running through them, and taking notes if there are any. 17:23:40 .. [go throughs the list] 17:23:46 .. Super/sub support 17:23:49 .. Factor out HRM 17:24:03 .. Namespace name docs are out of date - not a spec issue, a repo issue 17:24:22 .. Editorial bug about the wrong feature being referenced with time offset 17:24:41 .. Improve the introduction 17:24:51 .. Improve para wording for WCAG SC 1.1.1 17:25:07 .. was controversial and text is convoluted, time to clean up. 17:25:24 scribe+ 17:25:43 pal: IMSCvnext is prepared for future version, and the same as backlog 17:25:50 ... also should be fine to be removed 17:26:16 ... one live feedback on character sets of Japanese 17:26:29 s/pal: /Pierre: / 17:26:39 ... some suggestion from APA on description on semantics 17:26:45 ... we should at least ping folks 17:27:11 ... make sure we will pick in next slot 17:27:33 ... folloinwg three items, 493, 492, 490, are not blocker, or even we can close 17:27:46 ... 489 is errata 17:27:55 ... 484 is super long discussion thread 17:28:34 ... forcedDisplay and visibility hidden, neither anything we can do or need to do , but we should again back on this discussion 17:28:49 ... nice to have, but no particular point to have 17:29:08 ... #82, will not touch image profile, unless it is broken 17:29:15 nigel: it exists and broken already 17:29:38 pierre: unless somebody have absolute need... 17:29:51 nigel: serious question, any issue actually impact to image profile? 17:30:09 pierre: three issues pointed above - 493, 492, 490 17:30:24 nigel: ok to keep open unless touching these three, or something need to do? 17:30:31 pierre: fine to keep open 17:30:42 nigel: we only update text profile in 1.3, without image profile 17:31:01 ... people could use image profile from previous ones like 1.2 or even 1.0, it this correct 17:31:38 pierre: not sure, only objection is working or not, would not touch anything more on this unless something happens 17:31:40 nigel: ok 17:31:57 pierre: agree on concept, personally, anyway 17:32:09 nigel: all sound good to me 17:32:54 pierre: my three requests, one to decive what to proceed, create a liaison with ARIB, discussion with APA on 503 17:33:21 https://github.com/w3c/imsc/issues/524#issuecomment-598299006 17:33:40 -> https://github.com/w3c/imsc/issues/524#issuecomment-598299006 Comment regarding APA feedback to resolve 17:34:22 Topic: Next part of the day's meetings 17:34:30 -> https://www.w3.org/events/meetings/5d9bf691-6f90-45b9-9c2a-b89faaedb191/ Joint meeting with APA and MEIG 17:35:04 rrsagent, make minutes 17:35:06 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 17:35:28 Nigel: [temporary adjournement] 17:45:47 nigel has joined #tt 18:01:03 nigel has joined #tt 18:02:50 Adam_Page has joined #tt 18:04:16 nigel has joined #tt 18:09:14 atsushi has joined #tt 18:40:26 Adam_Page has joined #tt 19:30:59 nigel has joined #tt 19:33:01 Zakim has left #tt 20:30:09 nigel has joined #tt 20:33:59 nigel has joined #tt 21:01:23 Zakim has joined #tt 21:01:40 Topic: Afternoon session 21:02:42 Nigel: Welcome everyone to the afternoon session. 21:03:28 Subtopic: IMSC (continued) 21:04:04 Pierre: Proposal is to proceed with a minor revision of IMSC with the primary objective of addressing the lack of support for superscript and subscript 21:04:26 .. and secondarily resolving outstanding editorial and blocking issues in the backlog. 21:04:46 PROPOSAL: Proceed with a minor revision of IMSC as detailed in the minutes 21:04:51 Nigel: Any objections? 21:05:27 Pierre: Then I think the other one, assuming we go ahead, is to get a liaison going to ARIB, 21:05:32 sideshowbarker has joined #tt 21:05:34 Bernd has joined #tt 21:05:34 .. a last shot at getting this done. 21:05:48 Present+ Bernd, sideshowbarker 21:06:05 atsushi has joined #tt 21:06:26 PROPOSAL: Liaise with ARIB about feature improvements in IMSC, specifically the backlog issues 21:06:34 Nigel: Any objections to either of the above? 21:06:42 rrsagent, this meeting spans midnight 21:07:03 RESOLUTION: Proceed with a minor revision of IMSC as detailed in the minutes 21:07:10 RESOLUTION: Liaise with ARIB about feature improvements in IMSC, specifically the backlog issues 21:08:12 Nigel: We should think about whether industry needs us to keep going with multiple 21:08:20 .. active versions of IMSC or if we can deprecate any of them. 21:08:47 .. Similarly, should we mark it as "allows changes" rather than continuing with the version numbering approach. 21:09:02 Pierre: Good question. If we allow changes, what's the approach to removing unused features. 21:09:17 atsushi: Updateable Recs can accept candidate amendments or candidate new features. 21:09:23 .. At any time we can change these candidate changes. 21:09:36 .. Once the candidate changes pass the same procedure as normal Rec, including 21:09:54 .. HR, WR, AC Review, everything will be merged into the Rec as normative parts of the specification. 21:10:14 .. In theory everything that is similar to CR even if the spec is published with a Rec URL. 21:10:20 .. Anything can be done. 21:10:44 Nigel: So any candidate change can be made, even deprecation or removal of features? 21:10:47 atsushi: Yes 21:10:58 Pierre: Even those changed versions of the Rec are dated, is that right? 21:11:40 atsushi: Yes the publication date changes, even with candidate amendments 21:12:41 Pierre: Hard to see any reason not to do it 21:13:02 Nigel: @sideshowbarker and I have been discussing this, there are significant markup requirements 21:13:14 .. for the candidate changes, but there is tooling on the way to help with that. 21:13:22 atsushi: I never want to have to do this for TTML! 21:13:36 Nigel: We can decide about the allows-changes status before we go to CR. 21:13:50 .. Any other points on IMSC for us to think about? 21:14:02 no other points 21:14:17 Present+ Dana 21:14:23 zakim, who is on the call? 21:14:24 Present: Bernd, sideshowbarker, Dana 21:14:30 eric_carlson has joined #tt 21:14:39 dana has joined #tt 21:15:04 Subtopic: WebVTT Interop and issues 21:15:15 gkatsev: Thanks for coming, I'd love to hear about the WebVTT interop stuff 21:18:00 present+ Jean-Yves_Avenard 21:18:47 dana: [Presents slides] Hi, I'm Dana, first TPAC, I work on the WebKit team at Apple 21:19:06 .. For some time I've been researching WebVTT and learning about the problems with it, 21:19:11 .. why it's not widely used. 21:19:18 .. I'm hear to present what I've learned through my research, 21:19:27 .. and some ideas for making it more attractive for websites to use. 21:19:39 .. [slide: Recap of previous years' efforts] 21:19:52 .. Will talk about where we are in the discussion, usage of WebVTT in the wild, 21:20:05 .. Web Platform Test interop test results and what they mean, 21:20:17 .. bugs and missing features in WebKit and the WPT infrastructure, 21:20:21 .. and then ideas for fixing things. 21:20:31 .. [slide: Recap of previous years' efforts] 21:20:43 .. In previous years we discussed adding a generic text track cue class. 21:20:55 .. But important to make sure we're building on something that works, i.e. WebVTT. 21:21:10 .. Clear to everyone that WebVTT is not in the state it needs to be given it's not widely used. 21:21:22 .. WebVTT rendering is rarely used on high-traffic websites 21:21:35 .. Some sites use WebVTT format, but render cues themselves, e.g. Hulu. 21:21:47 .. Suggests rendering is the reason it's unattractive. 21:21:56 .. Problem that sites render it themselves because they don't have access to the 21:22:05 .. accessibility features that are only possible through using WebVTT. 21:22:19 .. Without using WebVTT, cannot get subtitles in PiP or full screen on the iPhone. 21:22:35 .. Users lose out on acccessibility and other features when sites use don't use WebVTT. 21:22:45 .. Anecdata: Interop is a problem. 21:22:54 .. WebVTT appears differently on different browsers, so it's not reliable. 21:23:00 .. [slide] WPT results 21:23:12 .. Websites tell us they don't like interop of WebVTT between browsers. 21:23:16 .. Backed up by results of the test. 21:23:25 .. Rendering scores are critically low. 21:23:32 .. No browser passes >30% of rendering tests. 21:23:41 .. Chrome, Edge and Safari pass <6% of the rendering tests. 21:23:52 .. For the past month I've been going through WebKit's rendering test failures, 21:23:58 .. and categorising the bugs. 21:24:03 .. Most are implementation issues, 21:24:13 .. 6 are likely bugs in the tests or the test infrastructure. 21:24:18 .. I'm also new to WebVTT so I could be wrong. 21:24:34 .. This is approximately how it is. 21:24:42 .. I'm planning on filing these issues. 21:24:52 .. We already have them in the WebKit bug database for our own tracking purposes. 21:25:01 .. Also planning on posting the 6 test bugs into the WPT repo. 21:25:14 .. [slide] Stand-out bug is accessibility preferences 21:25:32 .. Someone already opened web-platform-tests/wpt#46453 21:25:44 .. Problem is on Mac and iPhone user can set accessibility preferences for captions, 21:25:54 .. but the WPT tests don't take those into account, so we fail almost all the tests. 21:26:07 .. The default style we apply via our system settings and the test infrastructure doesn't know about that. 21:26:16 .. Similar issue in Chrome I beleive. 21:26:21 .. Couple of solutions: 21:26:33 .. 1. Turn off accessibility styling before running tests, in the test env. 21:26:49 .. We don't prefer this because we also want to test the interaction between user styling and rendering. 21:26:59 .. 2. Add the concept of a cue window to the WebVTT spec. 21:27:04 .. There's discussion about this under the issue. 21:27:15 .. Exposing this concept of a cue window would allow the websites to override the system 21:27:26 .. styling of the cue window, which we can then incorporate into the tests. 21:27:43 .. We prefer the second solution, to ensure the accessibility. 21:27:53 .. [slide] I also found other issues with the tests. 21:28:05 .. We fail ~80 of them for non-obvious reasons, when it looks to me as though the two images 21:28:20 .. are identical or almost identical, maybe differing by blurriness, and I'd like to get some help 21:28:24 .. to look into why this is the case. 21:28:38 .. More obvious bugs: inconsistencies between the expected and the actual, like border around the video. 21:28:43 .. Those are about 6. 21:28:56 .. The other 35 are webkit bugs we are tracking and dedicating time to fixin. 21:29:14 .. [slide] We think the solution to WebVTT interop is first filing and testing the bugs in the 21:29:30 .. test infrastructure. We also support proposing a WebVTT focus area at Interop 2025, 21:29:39 .. deadline is Oct 9 2024. 21:29:50 .. Would like feedback and suggestions on what a good proposal would look like. 21:30:04 .. Even if we are not successful at getting WebVTT into Interop 2025, we are still committed to fixing 21:30:12 .. out bugs to match WebKit's WebVTT implementation to the spec. 21:30:25 .. We think it's important to the health of the web that pages can rely on native subtitle presentation. 21:30:34 .. This would allow for more accessibility features to be accessible by users. 21:30:40 .. That's it, thank you! 21:30:41 q? 21:30:53 gkatsev: Thank you very much, that was awesome! 21:31:08 dana: If it's interesting I have the spreadsheet of bugs and what it impacts. 21:31:26 Pierre: Going back to your first slides, these are great numbers. 21:31:33 cyril has joined #tt 21:31:33 .. Have you also collected numbers on IMSC in the process? 21:31:38 dana: No, just WebVTT 21:31:47 pal: Any sense of what the numbers might be for IMSC and TTML? 21:31:48 RRSAgent, pointer 21:31:48 See https://www.w3.org/2024/09/27-tt-irc#T21-31-48 21:31:51 dana: No I haven't. 21:32:05 pal: I think many of the same results exist for IMSC and TTML where rendering is done 21:32:14 .. by page code, and the same accessibility challenges exist for TTML 21:32:25 jcraig: Are there WPT tests for TTML? 21:32:33 gkatsev: No, because it's not natively supported 21:32:42 jcraig: That would be the first step before doing this 21:32:52 pal: The same exact issues that you've noted exist for TTML and there are some platforms 21:33:05 .. that only use TTML and are forced to use a polyfill or burn in after rendering server-side. 21:33:24 dana: It would be preferable to use WebVTT rather than IMSC to make the accessibility features work 21:33:26 q+ 21:33:33 pal: Many of the same considerations apply to both 21:33:34 q+ to mention FCC requirements for captions 21:33:49 gkatsev: Making this a baseline for the future, for HTML fragment cues are both methods of getting 21:34:03 .. IMSC support natively, so having really good WebVTT interop will allow those to work better also. 21:34:20 dana: It could sound a little far-fetched imagining a future where WebVTT is the most used format. 21:34:26 .. We think this is the first step, to improve interop 21:34:41 .. Makes that future more of a possibility than it is now. 21:34:41 q+ to mention WPT, okay to write WPT tests for any spec, even if not implemented; allows test-driven development 21:34:44 scribe+ 21:35:13 nigel: I think it's a really good idea to do what you're suggesting here to look at higher problem spaces 21:35:34 .. we need to figure out how to make subtitles accessible and see how things go from there 21:35:50 .. webvtt interop is a good baseline but there's missing features 21:36:03 .. there's things in ttml that can't be done in webvtt 21:36:25 .. there's also format issues like server-side transforms 21:36:54 .. isn't necessarily a good fit for a lot of reasons, speaking for the BBC 21:37:35 .. I've definitely seen problems for mapping from ttml into webvtt 21:37:37 q+ to mention overriding the user styles in the LayoutTest or ideally WPT test 21:37:43 ack me 21:37:43 jcraig, you wanted to mention FCC requirements for captions and to mention WPT, okay to write WPT tests for any spec, even if not implemented; allows test-driven development and to 21:37:47 ... mention overriding the user styles in the LayoutTest or ideally WPT test 21:37:51 ack nigel 21:38:10 qq+ 21:38:35 nigel: my vision of an accessible way would be something that make it more agnostic from webvtt 21:39:10 jcraig: Thank you for the presentation, a few points back. 21:39:25 jcraig: It's ok to write WPT tests for things that have a spec 21:39:29 .. for example include .tentative in the test name 21:39:39 .. It's common to do that for test driven development on the web platform. 21:39:47 qq+ to mention IMSC and TTML test suites 21:39:51 ack jcraig 21:39:52 jcraig, you wanted to react to nigel 21:40:00 .. We already have a CI environment that can run those. 21:40:11 .. Additionally, one of the reasons that this test is important is that there are FCC 21:40:23 .. requirements, and have been for almost a decade, about caption styles, 21:40:43 .. that we support on our platforms, and even games platforms support, 21:41:00 .. but I do agree that we should not bypass the accessibility settings. 21:41:23 .. There may be some intermediary settings, like Dean Jackson had a way to make OS level settings 21:41:36 .. before the test run, and write different tests for different OS level settings. 21:41:47 .. Then you can test the rendering part and the customisation settings. 21:41:52 eric_carlson: I think that's an excellent idea. 21:42:02 .. In WebKit's own internal tests we ignore the system styling completely. 21:42:09 .. It's a way to have consistent tests. 21:42:20 .. Your idea makes a lot more sense. 21:42:27 jcraig: Dean's tests were something like reduced motion. 21:42:32 eric_carlson: I have lots of ideas about how to do it. 21:43:07 nigel: TTML has large set of test suite, which is not on wpt 21:43:20 ack me 21:43:21 nigel, you wanted to react to nigel to mention IMSC and TTML test suites 21:43:32 jcraig: other tests have been ported to WPT... 21:43:39 pal: On this issue of WPT tests, how do you create tests that there is no way to expose on a web platform? 21:43:50 .. Are you deliberately showing that they're all failing? Is that useful? 21:44:30 jcraig: TTML you want to render in the browser, right? 21:44:36 .. If not then no point in adding to WPT. 21:44:52 .. Not sure how familiar you are, it's a massive CI platform that tests every feature on every web platform. 21:44:57 q+ 21:45:06 .. It's become the expectation of the place to write the tests if they're platform independent. 21:45:22 pal: I'm a big fan, just not sure if it's useful to write TTML tests because they would fail by design. 21:45:32 jcraig: I wouldn't write a lot of them, just write a base level of coverage. 21:45:33 q+ to comment 21:45:46 pal: Not trying to convince anyone, just pointing out that we have both in the ecosystem. 21:45:58 .. Until and unless one gets 100% of the market we are going to have these issues that were 21:46:02 .. highlighted at the beginning. 21:46:06 .. Two options are: 21:46:22 .. 1. Try to get to agreement to use only one. not worked over 12 years. 21:46:30 .. 2. Support both, just like there are lots of image codecs etc. 21:46:46 .. Until we resolve this issue (note zero objection from me for fixing webvtt), 21:47:01 .. we are going to keep having the same issue that you found at the beginning. 21:47:14 .. We need to solve the fundamental issue before we get a great developer and user experience. 21:47:19 .. Maybe now is not the right time. 21:47:21 q+ 21:47:22 TTML2 test suite (large set of TTML XML files) -> https://github.com/w3c/ttml2-tests 21:47:41 q- 21:47:50 jcraig: Sounds like no objection to more VTT testing or to proposing interop area for Interop 2025, 21:48:07 .. or for fixing the main issues of WebVTT even if it doesn't solve the wider long term timed text issues. 21:48:10 dana: It can't hurt 21:48:22 gkatsev: I think Interop 2025 would be awesome because it would feed back into the spec, 21:48:27 .. and allow us to get to Rec. 21:48:30 ack gkatsev 21:48:40 q+ 21:48:46 .. ON the TTML / IMSC side I think it might be a bit early for WPT tests, but with the work 21:49:02 .. on streaming text tracks and html fragment, when that's further along, we could write WPT tests 21:49:12 .. for them, especially if part of the use case for that is native IMSC support. 21:49:27 jcraig: Dana, from my experience, I wrote several hundred tests last year, you're probably right 21:49:30 .. that there are bugs. 21:49:43 gkatsev: Definitely bugs, I've seen maybe 10% of tests are invalid. 21:49:51 jcraig: First implementer finds the bugs! 21:50:04 dana: That would be a goal before interop, that we have a functioning test suite. 21:50:06 q? 21:50:13 scribe+ 21:50:29 nigel: one of the point in testing difficult, approach is by design by design 21:50:41 ... use of preference setting is pain 21:51:05 ... last year we discussed and got some responce on this, web principle document from TAG 21:51:44 ... observation made by me, use of caption is so wide, these days use cases are widely spread 21:51:51 ... not like 20 years ago 21:52:15 ... broder and too many use cases and users exist now, incl. disabilities 21:52:17 The TAG's Design Principles issue Nigel mentioned: https://w3ctag.github.io/design-principles/#do-not-expose-use-of-assistive-tech 21:52:26 ... we need to revisit to these for principle design 21:52:47 ... other side, totally different display than native captions 21:52:56 ... we would not get usage data 21:53:08 ... will not get source of data for improovement of us 21:53:30 ... your horming users allows to gather statistics of use, it helps 21:53:50 ... you can only observe on or off for WebVTT 21:53:59 ... not site customizations 21:54:24 ???: if in specific site, data could be collected 21:55:00 nigel: talking about is that player page and what is key focus 21:55:21 ???2: definitely agree that captions are widely used now 21:55:27 s/???/Jean-Yves Avenard/ 21:55:35 ... problem with exposing user preferatnce exists 21:55:39 s/???2/eric_carlson/ 21:55:51 ... anybody customize styles are uniquely identifiable 21:56:06 ... inject large fingerprinting vector 21:56:17 ... absoletely no way to expose 21:56:22 q? 21:56:33 ack nigel 21:56:44 nigel: if the world changes and allows access to these preferences, it cause another side 21:57:19 cyril: try to give TTML and WebVTT information 21:57:40 .. Netflix produces both styles of captions, the vast majority that is consumed is TTML. 21:57:50 .. A small amount WebVTT and a small amount image. 21:58:02 .. There's no way for Netflix to migrate to WebVTT short or long term that I can see. 21:58:16 .. I'm curious, one of the problems we have with WebVTT, which we don't use on the web, 21:58:35 .. even on Safari, is the discrepancy between the Safari support vs iOS. 21:58:51 .. If you use Safari you don't get the same results with Core Media native playback. 21:59:10 .. Do you have a sense - WPT doesn't test native support, right - do you do internal testing? 21:59:26 jy: They do their testing, we do ours 21:59:32 eric_carlson: That's something we need to address 21:59:37 .. They don't support CSS etc. 21:59:49 cyril: The way we use WebVTT in Netflix is lots of p-list hooks. 21:59:55 .. Don't even know how to hook those into CSS 22:00:07 eric_carlson: They do now support CSS in WebVTT files, but they don't have a full-blown CSS engine. 22:00:17 .. We can certainly take files that they support and make sure that the rendering is the same in 22:00:21 .. WebKit and in Core Media. 22:00:37 cyril: As a content provider, the choice of WebVTT is not obvious because the differences mean we would 22:00:41 .. have to provide 2 versions. 22:00:46 eric_carlson: I agree that is a problem for us to fix 22:00:58 jy: Does it matter that there are small differences as long as the content is there? 22:01:15 Cyril: We don't care about pixel accuracy, but for Japanese you care about Rubys, vertical text being 22:01:18 .. rendered correctly. 22:01:35 .. Obviously we have positioning requirements to make sure captions don't clash with content in the image. 22:01:41 .. If the position is off it's a problem. 22:01:49 gkatsev: It's about feature support 22:02:06 pal: I think this is actually the core issue, anecdotal evidence I've heard is when a platform goes ahead 22:02:16 q? 22:02:17 .. and tries to use native, and there is native support for TTML in a bunch of players, they realise 22:02:19 ack cyril 22:02:22 q+ 22:02:23 .. that no two players are the same. 22:02:33 .. Some diffs subtle, then they decide to render themselves. 22:02:40 .. Trying to get to interop is a really good idea. 22:02:46 .. Otherwise folks will continue doing it themselves. 22:02:48 q? 22:02:54 rrsagent, make minutes 22:02:55 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 22:03:01 ack gk 22:03:14 gkatsev: A couple of years ago a guy (Dan?) at Demuxed talked about how and why they decided 22:03:30 .. to render everything themselves. Needing to be FCC compliant made them have to render 22:03:40 .. themselves, particularly on set top boxes. 22:03:46 .. Interop2025 would be awesome. 22:03:53 .. My question: do you need anything from us for that? 22:04:03 .. We'd be happy to help, as much as I can, for that. 22:04:10 dana: No I think... 22:04:23 eric_carlson: Signals of support, making it clear, I don't know how, that if you think it's a good idea 22:04:29 .. that you think it's a good idea with the WPT committee. 22:04:36 .. Coming from the WG would be extremely helpful. 22:04:45 gkatsev: Is there an existing mechanism for that? 22:04:53 eric_carlson: I don't know but we'll figure it out and let you know. 22:05:03 jcraig: Typically there are proposals for new focus areas. 22:05:14 .. If the WG agrees, one of the Chairs could just comment in that issue. 22:05:22 .. e.g. to say Timed Text supports this. 22:05:40 dana: When you submit proposals to interop they're on GitHub and you can add discussion comments. 22:05:46 .. Once the proposal exists I will share it. 22:05:53 gkatsev: Can you post it to the timed text mailing list? 22:05:55 dana:: ok 22:05:58 s/::/: 22:05:59 Current Interop Proposals https://github.com/web-platform-tests/interop/issues 22:06:36 https://github.com/web-platform-tests/interop/issues?q=is%3Aissue+is%3Aopen+label%3Afocus-area-proposal 22:06:37 gkatsev: I think we're out of time for this topic, technically out of time for our scheduled session. 22:07:28 gkatsev: On the ATTRIBUTES PR, Nigel and I had the question about the lang and label and kind 22:07:32 .. interact with the track element. 22:07:40 .. That would be really good to disambiguate. 22:08:15 -> https://github.com/w3c/webvtt/pull/523 new ATTRIBUTES block 22:08:15 Subtopic: New ATTRIBUTES block w3c/webvtt#523 22:08:26 github: https://github.com/w3c/webvtt/pull/523 22:08:44 jcraig: Need to assess, if there's a mismatch, which one wins. 22:08:49 .. I don't have a strong opinion. 22:09:00 .. Main reason we want it in the VTT is sometimes there's no HTML as an intermediary, 22:09:05 .. so the track information is missing. 22:09:19 gkatsev: That makes sense, my question would be would this also allow a change in HTML 22:09:26 .. if we're adding precedence to those attributes. 22:09:45 jcraig: I would expect that whatever we land on, we could have the same thing reflected on the track element 22:09:58 eric_carlson: We also would want to add some text to the spec describing the rules of precedence, 22:10:01 .. whichever way we go. 22:10:12 Nigel: How are you going to work out which way to go? 22:10:19 eric_carlson: We'll put a stick in the ground and we'll be right. 22:10:27 gkatsev: My assumption is the track element takes precedence 22:10:36 eric_carlson: That would be right, it would override what's in the file. 22:10:51 gkatsev: Can still have the precedence rules in the VTT spec but would also need them in HTML 22:11:01 eric_carlson: HTML doesn't say anything about how to process the contents of the VTT file, 22:11:05 .. so maybe no change needed. 22:11:14 jcraig: The other editorial suggestions seem fine to me. 22:11:29 .. There was a section question, was just my unfamiliarity with bikeshed. 22:11:46 gkatsev: Should we open an HTML issue now around this to get the conversation going. 22:11:56 jcraig: I'll take that as an action and write it into PR 523 so I don't forget it. 22:12:18 pal: On that last point, if you run into any issues, I can help, please don't hesitate to ask. 22:12:28 jcraig: You mean pushback on HTML? 22:12:38 pal: Sure, ultimately the question is who writes those tests. 22:12:50 .. As Nigel pointed out there's a large body of tests to port to WPT. 22:13:11 .. With reference renderers once we've overcome the issue of should we have that at all in WPT, 22:13:19 .. I'm confident that we'll have the resources to make that happen. 22:14:00 group confusion caused because Pierre misheard! 22:14:15 gkatsev: With that we can, unless there's anything specific to WebVTT right now we can end 22:14:42 SUMMARY: @cookiecrook to raise issue on HTML about track attribute precedence 22:14:58 Subtopic: Break 22:15:56 s/Break/DAPT 22:17:22 nigel: my goal is to get agreement or a plan to get dapt into CR 22:17:46 .. we have these 5 open issues 22:18:00 [shares screen to show dapt issues] 22:18:20 .. lots of activity lately 22:18:27 .. 4 of these have PRs open for them 22:18:43 .. What I would like to do is go over these PRs and see if there's any actions 22:19:02 .. and merge these PRs and do a CfC to request transition to CR 22:19:17 .. which would be subject to group policy, which would be 2 weeks 22:19:31 .. which would give a change to review the spec as a whole 22:19:52 .. editorial things can be fixed, the substantive things are the important bit 22:20:00 cyril: what if there in a big change? 22:20:10 nigel: we can do a new CR snapshot 22:20:20 cyril: the signal is that people can start implementing 22:20:31 nigel: it triggers a couple of things like starting to do a changelog 22:20:59 .. when we met with the APA earlier in the day, it would've been helpful to see a changelog 22:21:14 .. and we can share with other HR groups 22:21:24 .. also makes a need for an IR 22:21:43 atsushi: we need to test but not requirement for CR 22:21:50 nigel: yes, but needed to leave CR 22:22:06 .. I suggest we have a dapt-tests repo and start putting stuff there 22:22:34 .. we already have a repo 22:22:52 atsushi: you need a link to the IR to pass pub rules 22:22:55 .. can be a stub 22:23:03 .. can be a wiki page 22:23:17 nigel: we can have a page on the TT wiki 22:23:29 nigel: start from the oldest 22:24:00 nigel: we need to request delta reviews for HR 22:24:16 nigel: the first one dapt#44 22:24:40 .. cyril proposed adding a paragraph note 22:24:46 .. and there's a PR for that addition 22:24:55 there's an approval from me 22:25:07 .. which we can merge unless there are issues 22:25:24 nigel: next one, dapt#75 define restrictions per script type 22:25:30 .. we have a PR for this 22:25:36 .. which has been approved 22:25:45 .. I think there's some changes 22:25:49 .. but they're small 22:26:09 .. if you're in a prerecording script you shouldn't have audio recordings 22:26:40 .. and either synthesized or audio recoding 22:26:45 .. I can merge during the break 22:26:59 nigel: the next one dapt#227, quite a big one 22:27:07 .. also a PR, which is approved 22:27:32 .. the idea is to capture metadata for script text to know what it represents 22:27:55 .. and we have a top level scriptRepresents and a represents on every event tag, which is inherited 22:28:30 .. the exciting bit is the content-descriptor 22:28:41 .. we have a registry of content descriptors 22:29:19 .. hierarchical scheme, like audio, audio:dialogue 22:29:46 cyril: think of it as you have a time text part and you're annotating whether the text corresponds to dialog or text on screen 22:29:54 .. can be used for translation 22:30:11 .. and produce subtitles files or dubbing script 22:30:22 .. the origin for the info to produce all types of content 22:30:53 nigel: there's a constrait; if you say a script event has a descriptor, but at the document level doesn't include it 22:30:53 .. it's an error 22:31:08 cyril: document level helps do an early error so there's no surprises 22:31:35 nigel: you can be more specific in script event but if you can't use something that wasn't given 22:31:49 .. delimiter is . not ;, so the PR needs a smal update 22:32:51 nigel: dapt#232, responding to implementation issue where people have non dapt impl files but have smpte times and there's not enough info to synchronize 22:33:19 .. we have a PR which introduces some metadata is section D, which describes the problem and adds some optional metadata 22:33:39 .. origin timecode, and start of programme timecode 22:33:58 .. if those two are the same they can synchronize 22:34:19 .. if they're different, you can synchronize, but would need some work for this 22:34:29 .. and they're completely optional 22:35:07 .. one of the key points is metadata only not intended to be used to perform direct synchronization offsets during presentations 22:35:11 q? 22:35:25 nigel: last one is dapt#233 22:35:33 .. no proposed change here 22:35:43 cyril: break discussion? 22:35:49 nigel: can we close with no action? 22:35:56 cyril: ok, let's do that 22:36:03 .. still discuss it during the break 22:36:43 nigel: proposal is to merge PR and then go through the admin needed to get a working group decision to request transition to CR 22:36:46 cyril: I support that 22:37:06 atsushi: I also support it 22:37:12 PROPOSAL: Merge the open Pull Requests and then go through the admin needed to get a WG decision to request transition to CR 22:37:25 RESOLUTION: Merge the open Pull Requests and then go through the admin needed to get a WG decision to request transition to CR 22:37:37 Subtopic: Break 22:37:49 rrsagent, make minutes 22:37:50 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 22:39:15 nigel has joined #tt 23:02:04 nigel has joined #tt 23:03:03 Topic: TTML2 23:04:52 atsushi has joined #tt 23:05:03 cyril has joined #tt 23:05:09 scribe: cyril 23:05:35 nigel: first thing with TTML2, we've been in CR, the last snapshot is 3 years ago 23:05:42 ... we should finish that off 23:05:46 .. what do we need for that? 23:05:53 ... the implementation report 23:06:11 ... shows that the test related to new things we have at least 1 implementation for most things 23:06:40 ... that means we need a second implementation in order to proceed to REC 23:06:54 ... we also have validation tests 23:07:12 .. I'm not sure the best way to have the second passing implementation? 23:07:20 ... there are validators out there 23:07:45 ... I don't think we've got any particular spec changes to make 23:08:18 ... one option is to back out some changes 23:09:19 ... we also have some open issues on TTML2 but we have not triaged them 23:09:53 ... the easy path is just to do implementations 23:10:05 ... it's more complicated if we want to make new changes 23:10:11 ... because we don't have an active editor 23:10:26 ... does anybody have resource availability? 23:10:37 pal: what's absolutely blocking and essential? 23:10:43 nigel: of what? 23:10:53 pal: all the syntax changes require new tests or not? 23:11:02 nigel: all of the tests are done 23:11:07 pal: what's missing? 23:11:11 cyril: implementations 23:11:29 nigel: there is one passing implementation 23:12:13 nigel: there are 2 separate issues 23:12:26 ... as the spec stands right now to take to REC we just need a 2nd implementation 23:12:46 ... the second problem is if we want to make further changes to the spec, we need an editor 23:13:11 pal: assuming we have the 2nd implementation, do we know of changes that are needed? 23:13:14 nigel: no 23:13:29 ... but I need to do a serious runtrough of the open issues 23:14:14 ... it's not zero work 23:14:36 pal: my inclination if I would be editor would be ignore everything that is not marked as blocking 23:14:50 nigel: that's fair 23:15:24 cyril: Reverse question to Pierre's: if we don't get the 2nd implementation how can we move the spec forward, 23:15:30 .. if we need to make a new change to TTML2? 23:15:45 nigel: if we edit a new change in that is substantive 23:15:55 .. we need to write tests and implementations that pass that 23:16:11 ... as it stands we cannot move from CR to REC without second implementations 23:18:06 atsushi: once we have REC, if we need new changes we need WD, CR ... 23:18:47 ... we can do another CR with just the changes that have 2 passing implementations 23:19:03 ... and defer the non-passing tests to a future version 23:19:29 nigel: most of the ones not passing are validation test 23:19:43 .. for presentation there are audio and body features 23:20:03 ... font embdedding family 23:20:15 ... font selection strategy 23:20:31 ... font shear 23:20:52 ... image in body, including png 23:20:58 ... region no default 23:21:12 ... line shear 23:21:19 ... image opacity 23:21:42 pal: we said we need 2 presentation engines? 23:21:44 nigel: yes 23:22:05 pal: for validation, there is a validation tool that can be checked and modified 23:22:12 ... the presentation tests are more challenging 23:23:16 .. what was the second implementation for the 1st edition tests? 23:23:42 nigel: TTPE, IMSC.js or Adhere 23:24:11 ... but at the time we considered validation and presentation as 2 implementations 23:25:42 ... it was and still is adequate 23:25:49 ... the requirements haven't changed 23:25:57 pal: ttval is relative easy to update 23:26:56 ... so if ttval was added for both presentation and validation, would that be sufficient? 23:27:03 cyril: not for presentation 23:27:28 nigel: the audio descriptions would pass 23:28:30 nigel: the action is to rearrange the table so that for each feature you could see if it had a presentation and a validation test 23:28:40 pal: if all we need is a validator implementation, that can be done 23:30:14 .. in my mind, this is really about getting it done so we don't have to think about it anymore 23:30:32 cyril: The world has moved on without the 2nd implementation, and probably without the features at all. 23:30:38 pal: It's more about standards hygiene 23:30:41 Nigel: +1 23:33:33 Cyril: Are there any features in TTML2 required by DAPT? 23:33:38 Nigel: Good question I need to check. 23:33:59 Nigel: I will happily nominate Pierre as an editor of TTML2 23:34:39 Atsushi: Issue about the out of date banner on TTML2 old CR snapshot 23:34:52 -> https://www.w3.org/TR/2020/CR-ttml2-20200128/ TTML2 CR 2020-01-28 with banner 23:35:04 .. banner points to latest public recommendation but after that we have CR 23:35:13 .. The question is what do we want from the Outdated banner? 23:35:45 .. Do we want to point to the latest Rec from /TR/ttml2 or the latest publication? 23:35:55 .. or some link to current history. 23:36:12 .. There could be a possibility that everything before the latest Rec points to the Rec, and 23:36:22 .. after the published Rec everything points to the latest publicatino. 23:36:26 s/ino/ion 23:37:28 Nigel: I think that makes sense, before a Rec point to the Rec that follows, 23:37:35 .. and after Rec point to the latest publication. 23:37:52 atsushi: I will raise this and talk to the systems team about it, if that's okay for everyone? 23:38:57 Cyril: OK sure 23:39:08 atsushi: I will draft the text and then ask for review on the TTWG mailing list. 23:39:49 pal: Conclusion on TTML2 2nd Edition? 23:39:59 Nigel: My conclusion was that: 23:40:05 .. 1. Add Pierre as an Editor 23:40:06 cpn has joined #tt 23:40:14 present+ Chris_Needham 23:40:16 scribe+ cpn 23:40:37 .. 2. Encourage folk to work on a 2nd implementation of the features that have 1 passing implementation in the IR 23:41:11 Pierre: We have a blocker on implementation. Doing more work on the spec makes that worse 23:41:33 Nigel: Agree, we shouldn't be addressing issues with feature changes unless there's a path to implementation 23:41:49 ... I expect this to be a small editing job, but the focus should be on implementation 23:42:03 Pierre: Happy to edit, but contingent on their being focus on implementation 23:43:11 ... We need to have resources, people committing to implementation work 23:43:41 Nigel: I agree, otherwise it's a waste of time 23:44:33 ... We all need to consider whether we have resource to commit. Let's come back to it in a month's time 23:45:01 ... I won't do anything about adding you as editor, for the time being 23:45:26 Subtopic: TTML Media Type Definition and Profile 23:46:05 Nigel: This document is good. It's a Note, but since we published it, the Process now has a Registry document type 23:46:17 ... Should we leave this as is, or formally make it a Registry? 23:46:29 ... In general, I want to do as little as possible with it 23:47:03 ... And, given we've done work to create a boilerplate for Registries, it might make sense to move this to the Registry track 23:47:23 ... Atsushi, can we turn a Note into a Registry and keep the same shortname? 23:48:15 Atsushi: Some Registries are still published as draft Notes, It should be possible 23:48:29 ... Need to check the procedure for publishing as a first draft 23:49:18 ... Reusing the same shortname should be fine 23:49:44 Nigel: So I propose to do the work needed to turn this into a Registry Track document. No commitment to how soon, though 23:50:23 Cyril: We need an identifier for DAPT, so we'll need to update it. That could be a good incentive to do it, if we'd be blocked 23:50:37 Nigel: I don't think we would, it's more a hygeine issue 23:51:29 cpn: We've done this in Media WG, we have standalone Registries and Francois has done 23:51:34 .. the work to set up the auto publication 23:51:42 atsushi: Coding systems? 23:52:04 cpn: Yes, they were Notes and we moved them over - WebCodecs and MSE Bytestream Formats 23:52:51 Nigel: Anything else on the Profile Registry? 23:52:53 (nothing) 23:52:59 Subtopic: Joint meeting follow-ups 23:53:05 Nigel: We had 3 joint meetings this week 23:54:05 ... Monday was MEIG, talked about DAPT, and there was interest in that. Wolfgang expressed interest in writing implementation to convert DAPT to next-generation audio 23:54:34 ... We talked about adding text tracks to MSE. MSE supports audio and video, not subtitles and captions 23:55:02 ... There was no negative reaction, some support. We then took it to Media WG on Thursday, and it was more positive 23:55:28 ... I filed an issue to add it. There were technical questions raised, to be answered. 23:55:39 ... Things like switching the number of tracks available when you go to an advert 23:56:04 ... There's currently a requirement to have the same number of tracks, but a different set of text tracks might be available 23:56:21 ... Today we had joint meeting with APA WG. That was generally positive as well 23:57:08 Gary: Something mentioned in APA was symbolics, could result in text track additions 23:57:45 Nigel: Relates to not being able to have markup in text content in TTML 23:58:23 ... Media Session only supports a plain text chapter title, no markup. So no way to embed left-to-right. It's a more general problem 23:59:06 Gary: WIth Media Session, would we want it to start using the chapters kind? 23:59:25 ... We'd want to make sure the caption formats can add the symbolics information 23:59:42 q+ 00:00:37 Chris: Does getting symbolics into Unicode become a requirement? 00:01:05 Nigel: There may not be agreement that it belongs in Unicode 00:01:06 ack c 00:01:35 Subtopic: Conclusion 00:01:51 s/Subtopic/Topic/ 00:02:11 Nigel: Thank you all for your contributions. We covered all the agenda, success! 00:02:38 ... We meet next on Thursday 10 Otober 00:02:43 [adjourned] 00:02:51 rrsagent, make minutes 00:02:52 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 00:03:04 s/Otober/October 00:24:25 scribe+ nigel 00:24:54 i/pal: if all we need/scribe+ nigel 00:24:57 rrsagent, make minutes 00:24:59 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 00:32:18 present+ Nigel, Gary, Cyril, Pierre, Atsushi 00:32:51 present+ James_Craig, Dana, Surya_Sunkavelli, Jer_Noble 00:33:40 present+ Eric_Carlson 00:35:20 s/folloinwg/following/g 00:35:46 s/to decive what to/to decide what to 00:39:03 s/there's things in ttml that can't be done in webvtt/there's things used in practice in ttml that can't be done in webvtt 00:41:15 s/preferatnce/preference/g 00:43:07 s/get dapt into CR/get DAPT into CR 00:43:28 s/ dapt / DAPT /g 00:44:03 s/constrait/constraint 00:44:47 i/cyril: Reverse question/scribe+ nigel 00:45:00 s/embdedding/embedding 00:45:23 s/in my mind, this is really/.. in my mind, this is really 00:46:02 i/Atsushi: Issue about the out of date/Subtopic: TTML2 CR snapshot outdated banner 00:46:32 s/hygeine/hygiene/g 00:46:47 rrsagent, make minutes 00:46:48 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 00:48:53 s/not like 20 years ago/not like 20 years ago so can no longer claim that use of captions implies disability or vulnerability 00:49:13 s/improovement/improvement 00:49:17 s/horming/harming 00:49:26 s/your harming/you're harming 00:49:47 s/not site customizations/not user customisations 00:50:06 rrsagent, make minutes 00:50:07 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html nigel 00:51:42 scribeOptions: -final -noEmbedDiagnostics 00:51:46 zakim, end meeting 00:51:46 As of this point the attendees have been Bernd, sideshowbarker, Dana, Jean-Yves_Avenard, Chris_Needham, Nigel, Gary, Cyril, Pierre, Atsushi, James_Craig, Surya_Sunkavelli, 00:51:49 ... Jer_Noble, Eric_Carlson 00:51:49 RRSAgent, please draft minutes v2 00:51:50 I have made the request to generate https://www.w3.org/2024/09/27-tt-minutes.html Zakim 00:51:56 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 00:51:56 Zakim has left #tt 00:52:39 rrsagent, excuse us 00:52:39 I see no action items