14:01:37 RRSAgent has joined #tt 14:01:37 logging to http://www.w3.org/2017/05/25-tt-irc 14:01:39 RRSAgent, make logs public 14:01:39 Zakim has joined #tt 14:01:41 Zakim, this will be TTML 14:01:41 ok, trackbot 14:01:42 Meeting: Timed Text Working Group Teleconference 14:01:42 Date: 25 May 2017 14:02:40 scribe: nigel 14:02:50 Chair: Nigel 14:03:26 Present: Nigel, Dae, Pierre, Nigel 14:03:34 Regrets: Andreas, Thierry 14:04:35 Present+ Glenn 14:05:00 glenn has joined #tt 14:07:04 Topic: This Meeting 14:07:24 Nigel: I don't think we have anything to discuss on TPAC today; 14:07:37 .. on TTML2 there's a request to discuss Audio Description (AD) at the head of the meeting 14:08:16 .. and we have a bunch of TTML issues and pull requests plus some activity on IMSC. 14:08:30 Pierre: We have a blocker for pull request #230 so we can not close that until we have 14:08:37 .. resolved the bigger question in TTML1. 14:09:05 Nigel: The HDR in PNG is currently paused awaiting feedback so we should cover that 14:09:07 .. briefly. 14:09:18 pal has joined #tt 14:09:25 .. Any other business or points that anyone wants to make sure we cover today? 14:09:34 group: [silence] 14:09:51 Nigel: OK that's our agenda. 14:10:38 Pierre: I'm not opposed to AD today but without Mike and Andreas being present it might 14:10:45 .. need to be repeated later. 14:11:54 Dae: I see that Mike has views on this too. 14:12:12 Nigel: I've had private conversations with Mike about AD and I think he has reservations 14:12:18 .. but is willing to accept it, probably. 14:12:28 Topic: TTML2 - Audio Description 14:12:44 Nigel: In terms of a walk-through, the first thing is the Requirements: 14:12:57 -> https://github.com/w3c/ttml2/wiki/Audio-Description-Requirements Audio Description Requirements 14:13:14 Nigel: These were circulated in September and revised following feedback in October to 14:13:28 .. establish the alignment with the MAUR requirements covering the same space. 14:15:02 .. It is envisaged that, workflow-wise, small additions to TTML2 would satisfy any subset 14:15:08 .. of the workflow described. 14:22:19 Pierre: [concerns about the ability for TTWG to influence distribution formats] 14:22:35 Nigel: [commitment from BBC to produce an open source implementation showing how 14:22:55 .. client side mixing could work in a browser] No intention to require or request that 14:23:06 .. TTML2 is used as a distribution format for AD. 14:23:49 Glenn: Doing integration work to add audio into TTML2 it became clear that the semantics 14:24:07 .. for audio were incomplete. TTML has requirements for text to speech. 14:24:38 .. Adding further functionality that completes the audio semantics and also happens to 14:25:11 .. satisfy the ability to provide the audio description service requirements is something 14:25:32 .. we should do to make audio work in TTML. This is the wrong time to be making a 14:25:44 .. decision about whether to include these new features - if it goes into the spec then 14:25:59 .. we have a process for figuring out if it stays in beyond CR, based on implementations. 14:26:33 Nigel: Thanks both. So that's a quick summary of the requirements, then in the issue: 14:26:39 -> https://github.com/w3c/ttml2/issues/195 Add support for Audio Description requirements 14:26:51 Nigel: I describe some specific semantic requirements for TTML2. 14:31:28 .. [describes the audio processing model being proposed] 14:31:42 .. Map from a TTML2 element structure into a Web Audio graph 14:32:00 .. Additionally I see that text to speech semantics were added by Glenn subsequently, 14:32:02 .. which is fine. 14:32:14 Glenn: My audio model for TTML is quite simple. Right now TTML produces a series of 14:32:31 .. raster images typically on visual presentation medium. It does not yet have an audio output, 14:32:47 .. but it certainly can. All of the equipment that I'm looking at in terms of supporting the 14:33:00 .. audio feature set basically ends up producing a single audio output stream similarly 14:33:17 .. to how the visual rendering part of TTML produces a single motion picture output. 14:33:29 .. That would be the more generalised output. As for the model for processing audio, I'm 14:33:39 .. currently assuming that it's possible to do it all in software but that implementations 14:33:53 .. could optionally use hardware features to optimise and improve efficiency. For example 14:34:08 .. mixing, panning, text to speech synthesis, I'm assuming it is possible to do all these in 14:34:17 .. software in a presentation engine. 14:34:22 Nigel: There's good evidence for that by the way. 14:34:39 Glenn: On some devices that may be impractical, just as it may be impractical to do 14:34:48 .. visual compositing and HDR color on some devices. 14:35:25 Nigel: Thanks Glenn, that's the summary. Any other questions? 14:36:22 Dae: It seems like it won't be in IMSC2. If AD is threatening the timescale of WR, are we 14:37:25 .. agreed to remove it? 14:38:26 Nigel: I agree that it would not be in IMSC 2. I'm not happy to agree with removal from WR at this stage. 14:41:07 Dae: [question about handling of WR comments and if they are prioritised for audio 14:41:11 .. relative to other features] 14:41:24 Nigel: No specific priority given for or against any feature set including audio. 14:41:39 Glenn: I think we should not talk about this in terms of AD but just in terms of audio 14:42:38 .. features. We should just be focusing on generic audio. 14:44:07 Nigel: +1 to that - in terms of profiles, we may later want an AD in TTML2 profile based on 14:44:18 .. the audio semantics in TTML2, so that is the point when we should discuss AD more 14:44:20 .. specifically. 14:44:45 Dae: [question about removing features, and when in the process to do this] 14:50:39 Nigel: Typically we would not remove features unless they are at risk in CR and they 14:50:50 .. prevent us meeting the CR exit criteria, in which case we would remove them to move 14:50:56 .. to PR. 14:51:18 .. Conversely during WR we need to agree a disposition of all received comments, and if 14:52:17 .. in extremis we get feedback explaining that we have a big technical problem with a 14:52:31 .. feature then we could agree to remove that feature prior to CR. 14:55:01 Dae: [does not want to extend the publication period for WR] 14:57:21 Nigel: I have committed to put effort into getting the audio features in within the agreed 14:57:27 .. timescales for WR. 14:57:47 Pierre: [queries expertise in group for dealing with audio and DA 14:57:52 s/DA/AD 14:58:07 Pierre: and ability to specify this and influence industry] 14:59:05 Nigel: [does not consider there to be a specific requirement for vendors to be members 14:59:16 .. of the group] 15:03:34 Dae: [concerns that a large number of audio-related comments during WR could delay 15:03:38 .. onward progress] 15:03:52 Nigel: We've discussed this for about an hour now, let's take a break and reconvene in 5 15:04:04 .. minutes and begin with the TTML issue that's also blocking IMSC. 15:04:09 rrsagent, make minutes 15:04:09 I have made the request to generate http://www.w3.org/2017/05/25-tt-minutes.html nigel 15:08:54 Topic: LWSP between non-terminal components of style and parameter attributes 15:09:12 -> https://github.com/w3c/imsc/pull/230 Required spaces between non-terminal components of styling and parameter attributes (issue #221) 15:09:34 -> https://github.com/w3c/ttml2/issues/315 LWSP in rgba expressions? 15:09:50 Nigel: Interesting there's no TTML1 issue. 15:10:01 Pierre: It looks like we have to solve this in TTML1 to make progress in IMSC. 15:10:40 Glenn: I think there's a fair consensus at this point (to verify) that white space around 15:10:56 .. COMMA in tts:fontFamily is probably justified in TTML1, but not in RGB expressions. 15:11:15 .. The justification is based on actual usage; we have plenty of fontFamily examples where 15:11:30 .. there is white space but I cannot find any in RGB expressions in TTML, though there are 15:11:43 .. plenty in CSS. My suggestion is we add a note to TTML1 clarifying that LWSP is permitted 15:11:56 .. around commas in fontFamily and another emphasising if necessary that it is not 15:12:08 .. permitted in RGB expressions. I have a different answer for TTML2 however. 15:12:16 Nigel: Would that work in TTML1 Pierre? 15:12:27 Pierre: I'm not sure I'm there yet. There's evidence for spaces in fontFamily so we have to 15:12:42 .. deal with this. What's not clear in my mind is if the revised TTML1 text should say that 15:12:55 .. spaces shall not be there but by the way there's evidence of documents with spaces, 15:13:08 .. therefore processors should be tolerant. Or option 2 is to say spaces are permitted but 15:13:32 .. some processors may reject them. I'm not sure it's clear to everyone. We need an issue 15:13:36 .. in TTML1 and reference it. 15:15:44 .. [creates issue] 15:19:39 -> https://github.com/w3c/ttml1/issues/248 Handling of LWSP in tts:fontFamily #248 15:20:21 Nigel: The next step is to solicit feedback? 15:20:29 Pierre: Yes, or to make a call if no feedback is received. 15:21:01 Nigel: As a strawman I would propose to adopt the second option as a default, i.e. to 15:21:08 .. permit LWSP in document instances. 15:21:18 Pierre: I don't have a strong opinion - I need to discuss it with others. 15:21:33 Glenn: I do have a strong opinion, which is the second option, to permit LWSP in document instances. 15:22:06 Nigel: I will add each option as a separate comment in the issue so people can add a +1 15:22:11 .. reaction to the option they prefer. 15:23:17 .. They're now added on #248. 15:23:33 Nigel: Is there anything else we can do to unblock that issue now? 15:23:46 Pierre: No, if you know vendors or users I would encourage them to weigh in on that issue. 15:24:14 Glenn: Skynav will be able to point to 4 independent implementations that the second 15:24:21 .. option is the better one, going back to 2004 timeframe. 15:25:25 Topic: IMSC Pull Request 229 15:25:36 -> https://github.com/w3c/imsc/pull/229 Remove tabs from examples (issue #225) #229 15:25:42 Pierre: I'm waiting for your input Nigel. 15:25:49 Nigel: Apologies, thank you for the reminder. 15:27:16 Glenn: I think you should remove the white space at the ends of the lines. 15:27:49 Nigel: Is this example supposed to test functionality in the presence of white spaces at 15:27:52 .. the ends of lines? 15:27:55 Pierre: No. 15:28:05 Nigel: In that case we should make them as simple as possible so we should remove the 15:28:15 .. whitespace at the ends of the lines. I will update the PR. 15:28:58 Glenn: I agree that extraneous content should be removed from examples, more generally. 15:29:06 Nigel: I've added a comment to the pull request. 15:29:25 Topic: PQ HDR in PNG 15:29:56 Nigel: I raise this topic just to note that there is a strong objection to the current approach 15:30:06 -> https://github.com/w3c/png-hdr-pq/issues/3 ICC profile contents are ignored, magic string used for labelling #3 15:30:29 .. Please look at the issue and the linked thread in the Color on the Web CG reflector. 15:30:32 s/../Nigel 15:30:39 s/Nigel P/Nigel: P 15:30:52 Pierre: I've tried to get to the bottom of what was concerning Chris because it was not 15:31:24 .. clear and it sounds like the main concern was the implication in the proposed Note that 15:32:06 .. prohibits use of the embedded ICC profile, which is not what it was meant to mean. 15:32:20 .. I have offered to clarify it so that it does not imply that at all. 15:32:47 .. As far as I can tell that is the concern. It is possible that an ICCMax profile might be 15:33:00 .. better, and that could be added later. My main blocker is getting an ICC profile that 15:33:19 .. does not have an Adobe copyright, so that's what I'm working on right now. 15:33:46 .. When I get that updated profile I will commit it, and I've encouraged Chris to revise his 15:33:59 .. issue to be more specific. In the absence of that I will create a pull request that hopefully 15:34:02 .. will satisfy Chris. 15:34:45 Nigel: I think it would be reasonable for me to ping Chris with a reminder tomorrow, given 15:34:52 .. that I proposed a week's review 6 days ago. 15:35:18 Pierre: If he can't agree to that review period then we can say that when we have resolved 15:35:34 .. the copyright issue we plan to move forward, which sets a new effective deadline for 15:35:39 .. expressing his concerns. 15:36:38 Topic: Logical vs Physical pixels 15:36:46 Pierre: Have we got anything more to discuss on this? 15:36:59 Glenn: Last night I did a subsequent edit, and I believe it is all resolved now. 15:37:10 .. I took out unreferenced terminology for example everything with Viewport. 15:37:15 Pierre: Ok great. 15:37:44 Glenn: I also took others out like dot pitch, storage units, sample units and substituted 15:37:57 .. logical pixels. I took out the word "physical" and used the word "display" pixels and 15:38:15 .. referred to hypothetical output devices as opposed to actual output devices. 15:38:45 Nigel: Is this in a pull request? 15:38:50 Glenn: It has been merged already. 15:39:04 -> https://github.com/w3c/ttml2/pull/321 Apply improvements to aspect ratio and pixel semantics. #321 15:39:23 .. There is one open issue on the definition of "contain" . 15:39:28 .. Issue 30 has now been closed. 15:39:59 s/Issue 30/#30 15:40:19 Pierre: It sounds like we ended up in a place where the root container coordinate system 15:40:25 .. is all logical, right? 15:40:42 Glenn: Right. We ended up with logical pixels and display pixels and logical pixels have 15:41:07 .. no aspect ratio, but that there's a logical transformation via PAR that creates display 15:41:11 .. pixels from logical pixels. 15:41:16 Pierre: Why have two terms? 15:41:31 Glenn: In my mind you author into logical pixels and there's a transformation process that 15:41:48 .. turns them into dimensioned pixels, and I feel that's an important concept to retain. 15:43:14 .. I am also trying to converge with the SVG model. 15:43:52 Pierre: I think we're very close to having logical coordinates. 15:45:54 Glenn: Please review the changes and raise issues. 15:46:21 Nigel: I've just found a broken link in 10.2.33 to presentation context coordinate space. 15:46:30 Glenn: That's a link I removed so thanks, I'll resolve that today. 15:46:54 Nigel: Ok that's an action on all to review. 15:47:36 -> https://github.com/w3c/ttml2/issues/330 deprecate use of pixel units unless tts:extent on root element is in pixels #330 15:47:45 Glenn: Is there anyone who disagrees with this issue? 15:47:50 group: [silent] 15:48:04 Glenn: I'll take that as tentative support. 15:48:05 David_ has joined #tt 15:48:10 Topic: TTML issues 15:48:25 -> https://github.com/w3c/ttml2/issues/331 revert deprecation of ttp:profile on root element #331 15:48:31 Nigel: I've commented on that. 15:49:52 Glenn: Okay I'll look. 15:50:06 Nigel: I think there's evidence that people are trying deliberately to target multiple 15:50:18 .. processor profiles. 15:50:54 .. Is there any possibility of extending the value space to allow the short codes? 15:51:34 Glenn: I doubt that, due to the use of URI. 15:52:45 .. Right now it is deprecated, we are just talking about undeprecating it. 15:53:11 Nigel: To me undeprecating it could be improved maybe by extending it too. I'm not hugely 15:53:13 .. concerned. 15:53:29 Topic: TTML progress tracking 15:53:43 Glenn: We are getting near the end of May. We plan to have everything at least in pull 15:54:01 .. request form, so I will work this week to knock off the 24 items on my list. I have been 15:57:19 .. taking things off my list that have no pull request. 15:58:06 Nigel: Please do not close issues just because you do not intend to work on them. We will 15:58:20 .. leave issues open so that people who want can pick them up until we decide to 15:58:37 .. assess the open issues and choose to close or defer those we do not have work for. 15:58:51 .. The reason for leaving issues open is to signal that work is needed. 15:59:04 Dae: There are 18 features that need image example - I may need help with those. 15:59:35 Nigel: Okay, feel free to send a message to the group reflector listing those or send the 15:59:43 .. list to me and I can include it in the agenda that I will send on Tuesday. 16:00:16 Nigel: Do you also need the example documents from which to generate the images? 16:00:23 Dae: That would help. 16:02:16 Nigel: We're out of time for today. Thanks all. [Adjourns meeting] 16:02:20 rrsagent, make minutes 16:02:20 I have made the request to generate http://www.w3.org/2017/05/25-tt-minutes.html nigel 16:11:11 ScribeOptions: -final -noEmbedDiagnostics 16:11:12 rrsagent, make minutes 16:11:12 I have made the request to generate http://www.w3.org/2017/05/25-tt-minutes.html nigel 16:30:33 Zakim has left #tt