15:00:07 RRSAgent has joined #tt 15:00:07 logging to https://www.w3.org/2020/05/14-tt-irc 15:00:09 RRSAgent, make logs Public 15:00:11 Meeting: Timed Text Working Group Teleconference 15:01:46 Present: Pierre, Nigel 15:01:51 scribe: nigel 15:01:54 Agenda: https://github.com/w3c/ttwg/issues/114 15:02:14 Previous meeting: https://www.w3.org/2020/05/07-tt-minutes.html 15:03:08 Present+ Gary, Andreas 15:03:12 Chair: Gary, Nigel 15:03:23 Present+ Atsushi 15:03:41 atai has joined #tt 15:04:35 Topic: This meeting 15:05:19 Present+ Cyril 15:05:30 pal has joined #tt 15:05:37 Gary: Today we have IMSC 1.2 - the APA WG HR comments, and then the ARIB incoming 15:05:42 .. liaison issues that have been opened. 15:05:59 cyril has joined #tt 15:06:10 .. Followed by TTML2 2nd Ed IR which includes one discussion of tests. 15:06:18 Nigel: That one we can strike off, it's done. 15:06:43 Gary: Then just the IR piece. And are there any other out of band items? 15:06:58 group: [none] 15:07:04 Gary: Then no further business. 15:07:20 Topic: IMSC 1.2 APA WG HR comments 15:07:41 Nigel: I've been in touch with APA WG and Philippe and you may have seen there's been 15:07:49 .. some movement on the issues this week. 15:09:11 .. Hopefully they will all be done this week. 15:10:12 Pierre: On issue #519, we ought to follow up directly with Janina and Gottfried after this 15:10:26 .. meeting. My concern is we will be back to another long cycle so you (Nigel) or I should 15:10:33 .. follow up with Janina about this particular issue. 15:10:40 Nigel: Okay I'm happy to do that. 15:12:08 Pierre: Hopefully Gottfried will be satisfied with the pull request, I expect it because it is 15:12:19 .. factual. We should talk about #520 a little bit. 15:12:49 Topic: APA WG comment: Requested Additional WCAG 2.1 References imsc#520 15:12:56 github: https://github.com/w3c/imsc/issues/520 15:13:16 Pierre: The APA suggested that we add a specific reference to the guideline on non-text 15:13:50 .. contrast. We already mention the matching reference on text contrast. 15:14:01 .. What I don't understand is, by definition, all content in IMSC is text so I don't see 15:14:14 .. why this would ever apply. They mention emojis, but where do you draw the line 15:14:29 .. between emoji and kanjis. They say anyway you should reference the section. 15:14:34 .. We could do it anyway and not care. 15:14:42 .. I don't see why it would ever apply in IMSC, generally. 15:14:43 q+ 15:14:50 ack n 15:15:13 Nigel: My view is we should just add the reference as requested, for two reasons. 15:15:23 .. First reason is it doesn't harm. 15:16:27 .. Second reason is that although our intent is for image profile to have images that 15:16:39 .. mainly contain text, it does not have to be used for that, and any image content 15:17:02 .. can be used. Even if the images do contain text, they may contain other visual content 15:17:09 .. for which the guideline does apply. 15:17:25 Pierre: On the first point I think it is actually harmful because for 15:17:34 .. some reason the non-text contrast is different than the text contrast. 15:17:45 .. You wouldn't want kanji and non-kanji to have different contrast in the same sentence. 15:17:56 .. On the second point, of course people can do whatever they want, but IMSC is really 15:18:06 .. intended for timed text. We say that if there is an image profile document there ought 15:18:13 .. to be a text profile equivalent. 15:18:22 .. We don't have to account for all things people may want to do. 15:18:34 .. I don't see why an image should have a different contrast on screen than text. 15:18:45 .. Unless we can point to a specific example within the scope of IMSC for which 15:18:55 .. this success criterion may apply I don't think we should include it. 15:19:33 Nigel: Which guideline requires the higher contrast ratio, text or non-text? 15:19:57 Pierre: Text and images of text, 4.5:1, as opposed to 3:1 for non-text contrast. 15:20:24 Nigel: Then it is a no-op - if you meet the 4.5:1 ratio then the 3:1 guideline is exceeded. 15:20:28 Pierre: Yes, we could note that. 15:21:04 Nigel: So we make it a blanket requirement to meet the contrast requirements of both 15:21:12 .. text and non-text WCAG criteria. 15:21:31 Pierre: Everything that's relevant to IMSC is in 1.4.11, it is for UI and graphical objects. 15:21:43 q+ 15:21:54 .. It is not germaine. The one that is really relevant is 1.4.3. All that people need to care 15:21:58 .. about is that one. 15:22:02 ack a 15:22:20 Andreas: Apologies for my disinformation if I have not got the complete case fully understood. 15:22:35 .. Did I understand correctly that they asked for, e.g. for an emoji, that this may be 15:22:46 .. considered as image and therefore could have a different contrast than the surrounding 15:22:49 .. text only content? 15:23:07 Pierre: I don't really understand @gzimmermann's answer. 15:23:21 Andreas: We work a lot with emojis in text and we definitely wouldn't have a different 15:23:37 .. contrast for the emoji against the background than the surrounding text. 15:23:44 .. It would be super difficult to arrange and test. 15:24:12 .. It would be distracting if there are multiple emojis with different backgrounds 15:24:16 .. applied. 15:24:42 Nigel: Are they talking about foreground-background contrast only or contrast within 15:24:48 .. the e.g. emoji itself. 15:26:09 .. Answering my own question, in the link to understanding non text content, they show 15:26:22 .. graphical images and explain that the contrast within the symbols is included. 15:26:34 Pierre: I read 1.4.11 as being targeted at UIs not text that humans read. 15:26:57 q+ 15:27:23 Andreas: Yes I fully agree with Pierre because all text needs to comply so 15:27:37 .. you would need to combine this with graphic like objects everywhere they may be 15:27:40 .. combined with text. 15:27:57 ack at 15:32:38 q+ 15:33:02 Nigel: I'm a bit worried that by not taking the suggestion we may be preventing something 15:33:17 .. that we would like to permit, i.e. that it relaxes the contrast requirement within an emoji 15:33:25 .. symbol, so allowing more flexibility. 15:33:43 Pierre: The text contrast requirement is for the border of the glyph compared to the background. 15:33:55 Nigel: Okay but what about within that border? 15:33:58 ack at 15:34:14 Andreas: I have an example where there is a black opaque background and yellow text, 15:34:28 .. and then you add an emoji that is yellow on the outside. The outline of course is black, 15:34:44 .. so the contrast between the border and the background is very low. This is a very 15:34:48 .. typical use case. We do this! 15:34:51 Nigel: Good point! 15:34:59 .. I don't have an answer for that. 15:36:15 .. Just heading back to the comment, as Pierre has noted, the images are images of text, 15:36:24 .. so where that applies the 4.5:1 rule applies. 15:37:50 .. I think for your example Andreas perhaps we need a note to say that there must be 15:38:00 q+ 15:38:05 .. enough contrast between the image on the inside of the border and the background. 15:38:45 Andreas: You need a good automated way to calculate what background colour this applies to. 15:38:57 .. You would not really recommend a different background colour for an emoji compared 15:39:02 .. to the rest of the text. 15:39:07 ack c 15:39:18 Cyril: I wonder how this would apply to the use case you presented some time ago Nigel 15:39:27 .. where you had the Twitter logo inline with the text? 15:39:58 Nigel: So if the Twitter logo didn't have 4.5:1 to the background, what would you do? 15:40:07 Cyril: Yes, I don't know, is it text? 15:41:11 Nigel: I guess you'd use an alternate version of the image to achieve the contrast ratio. 15:41:28 Cyril: In simple fonts you have one colour per glyph, but for an image there are more colours 15:41:47 .. so you have to have different rules. If you store the image in a font stored just like text 15:41:53 .. the same text requirement would work. 15:41:57 .. Is that true? 15:42:13 Nigel: I have a feeling that you can put colours in fonts now. 15:42:20 Cyril: Yes I meant simple fonts. 15:42:37 .. Can we say that the 4.5:1 requirement applies to content inside a font even if it is not 15:42:44 .. text only when that text is single-coloured? 15:43:05 Pierre: I don't claim to have the definitive answer but if you look at success criterion 1.3, 15:43:16 .. there's a hint about why it exists, and an exemption for large text, where the contrast 15:43:21 .. ratio is at least 3:1. 15:43:52 s/1.3/1.4.3 15:44:09 .. One component of the decision about what contrast ratio seems to relate to size. 15:44:19 .. I don't know what "large" is defined as being relative to. 15:44:38 .. Trying to bring this to a point, my basic contention is that 1.4.3 is what literally applies 15:44:44 .. to IMSC, in general. 15:45:02 .. I think we can simply say that IMSC is not intended for generic UI elements and overlays, 15:45:07 .. therefore this is the section that applies. 15:45:12 +1 15:45:23 .. That's my recommendation. Merge the pull request and proceed. 15:45:31 Nigel: Any other views? 15:45:52 Gary: Note that large scale in WCAG refers to 18pt or 14pt bold or larger and the equivalent 15:45:58 .. CJK fonts. 15:46:08 Nigel: Thank you 15:47:24 SUMMARY: We believe that SC 1.4.3 applies to the IMSC use case and requires a contrast ratio that exceeds that of 1.4.11, so we should note that is the primary WCAG guideline that applies to both text and image profile. 15:48:49 Nigel: I think if @gzimmermann still disagrees then we should arrange a call to understand his viewpoint better. 15:48:55 Pierre: I completely agree. 15:49:48 Topic: Address A11Y comments related to WCAG 2.1 imsc#526 15:49:54 github: https://github.com/w3c/imsc/pull/526 15:50:04 Pierre: Nigel, do you still want to continue the thread on this pull request? 15:50:39 Nigel: Yes, no reflection on John but I don't like this text at all. 15:50:52 Pierre: There were many hours spent on this text so my suggestion is to leave it alone, 15:51:03 .. especially at the 11th hour, and move on. If you want to propose a replacement text, 15:51:23 .. we can deal with it, but my recommendation is not to touch it. 15:51:39 Nigel: I do feel quite strongly, so I may propose an alternative. 15:52:02 SUMMARY: Action with @nigelmegitt to consider alternative wordings and whether or not to propose them. 15:52:22 Pierre: If you are going to do that, please do it immediately so we can close #526 or 15:52:26 .. open a different ticket. 15:52:30 Nigel: OK, fair enough. 15:53:06 .. I think I made the last comments on this PR so I was hoping for a response. 15:53:16 Pierre: My response was I would not change it, personally. 15:53:59 Topic: TTML2 Implementation Report 15:54:11 Cyril: I did a pass on the IR to add more rows but I think I need to do a second pass. 15:54:24 .. I'm not sure the repo is up to date. For example I found files marked for 2nd Ed that 15:54:35 .. are no longer in the test.json file. I wonder if those files should be mentioned there or not. 15:54:41 .. I will check and let you know. 15:54:43 Nigel: Thank you. 15:55:44 .. On the ttml2-tests pull requests, they are now all merged, so all the tests should be present. 15:55:58 .. I see that you raised #238 Cyril to say some tests are in the manifest but not in the repo, 15:56:42 .. and now you're saying there are also the converse! 15:56:45 Cyril: Yes. 15:56:53 .. One other thing is we now have invalid presentation tests. 15:57:05 Nigel: Yes that's right I think, where we've defined fallback presentation requirements 15:57:10 .. in the case of invalid data. 15:57:15 Cyril: So we need to add a 4th section. 15:57:32 Nigel: Yes that makes sense. 15:59:13 Cyril: Once I've made the second pass to the report it will be good if people could add 15:59:23 .. their implementations. I am a little worried that we may not have enough implementations 15:59:27 .. to meet the exit criteria. 15:59:30 Nigel: Yes, agreed. 16:00:03 .. It will be easier to see that state of that until we have the report. 16:00:21 Topic: Meeting close 16:01:46 Nigel: Thanks everyone, we're out of time and have covered what we can for the agenda 16:01:58 .. today. Next week I have added an agenda item already for an issue on the TTML Profile 16:02:23 .. Registry, to add the RTP profile. It'd be good if we could tackle the long-outstanding 16:02:39 .. issue 71 on that too, so I'd appreciate anyone's thoughts on how we can do that. 16:02:47 .. [adjourns meeting] 16:02:53 RRSAgent, make minutes v2 16:02:53 I have made the request to generate https://www.w3.org/2020/05/14-tt-minutes.html nigel 16:08:02 s/and Philippe and you/and Philippe. You 16:11:19 s/I meant simple fonts/I meant simple fonts without colours 16:13:01 RRSAgent, make minutes v2 16:13:01 I have made the request to generate https://www.w3.org/2020/05/14-tt-minutes.html nigel 16:17:04 scribeOptions: -final -noEmbedDiagnostics 16:17:09 zakim, end meeting 16:17:09 As of this point the attendees have been Pierre, Nigel, Gary, Andreas, Atsushi, Cyril 16:17:11 RRSAgent, please draft minutes v2 16:17:11 I have made the request to generate https://www.w3.org/2020/05/14-tt-minutes.html Zakim 16:17:14 I am happy to have been of service, nigel; please remember to excuse RRSAgent. Goodbye 16:17:18 Zakim has left #tt 16:17:35 rrsagent, excuse us 16:17:35 I see no action items