{Minutes} TTWG Meeting 2020-05-14

Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2020/05/14-tt-minutes.html


In text format:

   [1]W3C

      [1] https://www.w3.org/


                Timed Text Working Group Teleconference

14 May 2020

   [2]Previous meeting. [3]Agenda. [4]IRC log.

      [2] https://www.w3.org/2020/05/07-tt-minutes.html

      [3] https://github.com/w3c/ttwg/issues/114

      [4] https://www.w3.org/2020/05/14-tt-irc


Attendees

   Present
          Andreas, Atsushi, Cyril, Gary, Nigel, Pierre

   Regrets
          -

   Chair
          Gary, Nigel

   Scribe
          nigel

Contents

    1. [5]This meeting
    2. [6]IMSC 1.2 APA WG HR comments
    3. [7]APA WG comment: Requested Additional WCAG 2.1 References
       imsc#520
    4. [8]Address A11Y comments related to WCAG 2.1 imsc#526
    5. [9]TTML2 Implementation Report
    6. [10]Meeting close

Meeting minutes

  This meeting

   Gary: Today we have IMSC 1.2 - the APA WG HR comments, and then
   the ARIB incoming
   … liaison issues that have been opened.
   … Followed by TTML2 2nd Ed IR which includes one discussion of
   tests.

   Nigel: That one we can strike off, it's done.

   Gary: Then just the IR piece. And are there any other out of
   band items?

   group: [none]

   Gary: Then no further business.

  IMSC 1.2 APA WG HR comments

   Nigel: I've been in touch with APA WG and Philippe. You may
   have seen there's been
   … some movement on the issues this week.
   … Hopefully they will all be done this week.

   Pierre: On issue #519, we ought to follow up directly with
   Janina and Gottfried after this
   … meeting. My concern is we will be back to another long cycle
   so you (Nigel) or I should
   … follow up with Janina about this particular issue.

   Nigel: Okay I'm happy to do that.

   Pierre: Hopefully Gottfried will be satisfied with the pull
   request, I expect it because it is
   … factual. We should talk about #520 a little bit.

  APA WG comment: Requested Additional WCAG 2.1 References imsc#520

   github: [11]https://github.com/w3c/imsc/issues/520


     [11] https://github.com/w3c/imsc/issues/520


   Pierre: The APA suggested that we add a specific reference to
   the guideline on non-text
   … contrast. We already mention the matching reference on text
   contrast.
   … What I don't understand is, by definition, all content in
   IMSC is text so I don't see
   … why this would ever apply. They mention emojis, but where do
   you draw the line
   … between emoji and kanjis. They say anyway you should
   reference the section.
   … We could do it anyway and not care.
   … I don't see why it would ever apply in IMSC, generally.

   Nigel: My view is we should just add the reference as
   requested, for two reasons.
   … First reason is it doesn't harm.
   … Second reason is that although our intent is for image
   profile to have images that
   … mainly contain text, it does not have to be used for that,
   and any image content
   … can be used. Even if the images do contain text, they may
   contain other visual content
   … for which the guideline does apply.

   Pierre: On the first point I think it is actually harmful
   because for
   … some reason the non-text contrast is different than the text
   contrast.
   … You wouldn't want kanji and non-kanji to have different
   contrast in the same sentence.
   … On the second point, of course people can do whatever they
   want, but IMSC is really
   … intended for timed text. We say that if there is an image
   profile document there ought
   … to be a text profile equivalent.
   … We don't have to account for all things people may want to
   do.
   … I don't see why an image should have a different contrast on
   screen than text.
   … Unless we can point to a specific example within the scope of
   IMSC for which
   … this success criterion may apply I don't think we should
   include it.

   Nigel: Which guideline requires the higher contrast ratio, text
   or non-text?

   Pierre: Text and images of text, 4.5:1, as opposed to 3:1 for
   non-text contrast.

   Nigel: Then it is a no-op - if you meet the 4.5:1 ratio then
   the 3:1 guideline is exceeded.

   Pierre: Yes, we could note that.

   Nigel: So we make it a blanket requirement to meet the contrast
   requirements of both
   … text and non-text WCAG criteria.

   Pierre: Everything that's relevant to IMSC is in 1.4.11, it is
   for UI and graphical objects.
   … It is not germaine. The one that is really relevant is 1.4.3.
   All that people need to care
   … about is that one.

   Andreas: Apologies for my disinformation if I have not got the
   complete case fully understood.
   … Did I understand correctly that they asked for, e.g. for an
   emoji, that this may be
   … considered as image and therefore could have a different
   contrast than the surrounding
   … text only content?

   Pierre: I don't really understand @gzimmermann's answer.

   Andreas: We work a lot with emojis in text and we definitely
   wouldn't have a different
   … contrast for the emoji against the background than the
   surrounding text.
   … It would be super difficult to arrange and test.
   … It would be distracting if there are multiple emojis with
   different backgrounds
   … applied.

   Nigel: Are they talking about foreground-background contrast
   only or contrast within
   … the e.g. emoji itself.
   … Answering my own question, in the link to understanding non
   text content, they show
   … graphical images and explain that the contrast within the
   symbols is included.

   Pierre: I read 1.4.11 as being targeted at UIs not text that
   humans read.

   Andreas: Yes I fully agree with Pierre because all text needs
   to comply so
   … you would need to combine this with graphic like objects
   everywhere they may be
   … combined with text.

   Nigel: I'm a bit worried that by not taking the suggestion we
   may be preventing something
   … that we would like to permit, i.e. that it relaxes the
   contrast requirement within an emoji
   … symbol, so allowing more flexibility.

   Pierre: The text contrast requirement is for the border of the
   glyph compared to the background.

   Nigel: Okay but what about within that border?

   Andreas: I have an example where there is a black opaque
   background and yellow text,
   … and then you add an emoji that is yellow on the outside. The
   outline of course is black,
   … so the contrast between the border and the background is very
   low. This is a very
   … typical use case. We do this!

   Nigel: Good point!
   … I don't have an answer for that.
   … Just heading back to the comment, as Pierre has noted, the
   images are images of text,
   … so where that applies the 4.5:1 rule applies.
   … I think for your example Andreas perhaps we need a note to
   say that there must be
   … enough contrast between the image on the inside of the border
   and the background.

   Andreas: You need a good automated way to calculate what
   background colour this applies to.
   … You would not really recommend a different background colour
   for an emoji compared
   … to the rest of the text.

   Cyril: I wonder how this would apply to the use case you
   presented some time ago Nigel
   … where you had the Twitter logo inline with the text?

   Nigel: So if the Twitter logo didn't have 4.5:1 to the
   background, what would you do?

   Cyril: Yes, I don't know, is it text?

   Nigel: I guess you'd use an alternate version of the image to
   achieve the contrast ratio.

   Cyril: In simple fonts you have one colour per glyph, but for
   an image there are more colours
   … so you have to have different rules. If you store the image
   in a font stored just like text
   … the same text requirement would work.
   … Is that true?

   Nigel: I have a feeling that you can put colours in fonts now.

   Cyril: Yes I meant simple fonts without colours.
   … Can we say that the 4.5:1 requirement applies to content
   inside a font even if it is not
   … text only when that text is single-coloured?

   Pierre: I don't claim to have the definitive answer but if you
   look at success criterion 1.4.3,
   … there's a hint about why it exists, and an exemption for
   large text, where the contrast
   … ratio is at least 3:1.
   … One component of the decision about what contrast ratio seems
   to relate to size.
   … I don't know what "large" is defined as being relative to.
   … Trying to bring this to a point, my basic contention is that
   1.4.3 is what literally applies
   … to IMSC, in general.
   … I think we can simply say that IMSC is not intended for
   generic UI elements and overlays,
   … therefore this is the section that applies.

   <cyril> +1

   Pierre: That's my recommendation. Merge the pull request and
   proceed.

   Nigel: Any other views?

   Gary: Note that large scale in WCAG refers to 18pt or 14pt bold
   or larger and the equivalent
   … CJK fonts.

   Nigel: Thank you

   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.

   Nigel: I think if @gzimmermann still disagrees then we should
   arrange a call to understand his viewpoint better.

   Pierre: I completely agree.

  Address A11Y comments related to WCAG 2.1 imsc#526

   github: [12]https://github.com/w3c/imsc/pull/526


     [12] https://github.com/w3c/imsc/pull/526


   Pierre: Nigel, do you still want to continue the thread on this
   pull request?

   Nigel: Yes, no reflection on John but I don't like this text at
   all.

   Pierre: There were many hours spent on this text so my
   suggestion is to leave it alone,
   … especially at the 11th hour, and move on. If you want to
   propose a replacement text,
   … we can deal with it, but my recommendation is not to touch
   it.

   Nigel: I do feel quite strongly, so I may propose an
   alternative.

   SUMMARY: Action with @nigelmegitt to consider alternative
   wordings and whether or not to propose them.

   Pierre: If you are going to do that, please do it immediately
   so we can close #526 or
   … open a different ticket.

   Nigel: OK, fair enough.
   … I think I made the last comments on this PR so I was hoping
   for a response.

   Pierre: My response was I would not change it, personally.

  TTML2 Implementation Report

   Cyril: I did a pass on the IR to add more rows but I think I
   need to do a second pass.
   … I'm not sure the repo is up to date. For example I found
   files marked for 2nd Ed that
   … are no longer in the test.json file. I wonder if those files
   should be mentioned there or not.
   … I will check and let you know.

   Nigel: Thank you.
   … On the ttml2-tests pull requests, they are now all merged, so
   all the tests should be present.
   … I see that you raised #238 Cyril to say some tests are in the
   manifest but not in the repo,
   … and now you're saying there are also the converse!

   Cyril: Yes.
   … One other thing is we now have invalid presentation tests.

   Nigel: Yes that's right I think, where we've defined fallback
   presentation requirements
   … in the case of invalid data.

   Cyril: So we need to add a 4th section.

   Nigel: Yes that makes sense.

   Cyril: Once I've made the second pass to the report it will be
   good if people could add
   … their implementations. I am a little worried that we may not
   have enough implementations
   … to meet the exit criteria.

   Nigel: Yes, agreed.
   … It will be easier to see that state of that until we have the
   report.

  Meeting close

   Nigel: Thanks everyone, we're out of time and have covered what
   we can for the agenda
   … today. Next week I have added an agenda item already for an
   issue on the TTML Profile
   … Registry, to add the RTP profile. It'd be good if we could
   tackle the long-outstanding
   … issue 71 on that too, so I'd appreciate anyone's thoughts on
   how we can do that.
   … [adjourns meeting]


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Received on Thursday, 14 May 2020 16:19:26 UTC