- From: Nigel Megitt <nigel.megitt@bbc.co.uk>
- Date: Thu, 1 Dec 2016 16:12:53 +0000
- To: W3C Public TTWG <public-tt@w3.org>
- Message-ID: <D465FC49.31980%nigel.megitt@bbc.co.uk>
Thanks all for attending today's TTWG meeting. Minutes can be found in HTML format at https://www.w3.org/2016/12/01-tt-minutes.html
In text format:
[1]W3C
[1] http://www.w3.org/
Timed Text Working Group Teleconference
01 Dec 2016
See also: [2]IRC log
[2] http://www.w3.org/2016/12/01-tt-irc
Attendees
Present
Andreas, Glenn, Mike, Pierre, Thierry, Nigel
Regrets
None
Chair
Nigel
Scribe
nigel
Contents
* [3]Topics
1. [4]This meeting
2. [5]TTML Profiles Registry
3. [6]IMSC (plus Unicode ticket)
4. [7]TTML2
* [8]Summary of Action Items
* [9]Summary of Resolutions
__________________________________________________________
trackbot, start meeting
<trackbot> Meeting: Timed Text Working Group Teleconference
<trackbot> Date: 01 December 2016
<scribe> scribe: nigel
This meeting
nigel: For today, I'd like to cover the TTML Profiles registry,
maybe the Unicode ticket, and the Security & Privacy section
for TTML2.
... AOB?
mike: I'd like a minute on the IANA registry and the page that
supports that, and also
... the post from Pierre about imscjs.
nigel: Sure, we did actually discuss imscjs a little last week
though it's not well minuted.
TTML Profiles Registry
nigel: This is about the issues and PRs etc, and if we should
update it now.
mike: Is the IANA registration complete?
nigel: Yes it was updated on 2016-09-30
->
[10]http://www.iana.org/assignments/media-types/application/ttm
l+xml
[10] http://www.iana.org/assignments/media-types/application/ttml+xml
nigel: It refers to the profile registry document.
... Now looking at the open issues/PRs:
-> [11]https://github.com/w3c/tt-profile-registry/pulls
[11] https://github.com/w3c/tt-profile-registry/pulls
nigel: This is the moment to say that the open issues/pull
requests are all the work to be done.
mike: I think the passage of time is sufficient here.
nigel: I concur.
group: [no objection]
mike: OK I'll go ahead and push this up towards the top of my
list.
nigel: Thank you!
IMSC (plus Unicode ticket)
action-478?
<trackbot> action-478 -- Nigel Megitt to Draft a liaison to
hbbtv requesting further information and proposing an option
e.g. to extend imsc 1 to allow signalling of background height
on span, and request timelines etc. -- due 2016-09-26 --
PENDINGREVIEW
<trackbot>
[12]http://www.w3.org/AudioVideo/TT/tracker/actions/478
[12] http://www.w3.org/AudioVideo/TT/tracker/actions/478
nigel: This is now sent and I updated the action with the
archive link to the liaison that was sent.
close action-478
<trackbot> Closed action-478.
action-487?
<trackbot> action-487 -- Nigel Megitt to Send generic liaison
to atsc, arib, mpeg, dece, cta, dash-if, dtg, hbbtv, smpte. --
due 2016-11-24 -- PENDINGREVIEW
<trackbot>
[13]http://www.w3.org/AudioVideo/TT/tracker/actions/487
[13] http://www.w3.org/AudioVideo/TT/tracker/actions/487
nigel: Same applies here - the liaisons were sent, thanks to
Pierre and all for helping edit
... the text. Links to the liaisons as archived are in the
action.
close action-487
<trackbot> Closed action-487.
nigel: Apologies to Mike for the confusion about the SMPTE one,
which was my mistake.
action-488?
<trackbot> action-488 -- Nigel Megitt to Send liaison to dvb
replacing first sentence from generic response with
acknowledgement sentence. -- due 2016-11-24 -- PENDINGREVIEW
<trackbot>
[14]http://www.w3.org/AudioVideo/TT/tracker/actions/488
[14] http://www.w3.org/AudioVideo/TT/tracker/actions/488
nigel: I did this, and logged the message archive link in the
action.
close action-488
<trackbot> Closed action-488.
nigel: One thing to note is I bumped the response date from 1
Jan to 8 Jan to accommodate my lateness in sending those
messages. Apologies if that causes any difficulties!
action-485?
<trackbot> action-485 -- Thierry Michel to Ask richard ishida
for assistance in unblocking the unicode ticket 8915. -- due
2016-11-10 -- PENDINGREVIEW
<trackbot>
[15]http://www.w3.org/AudioVideo/TT/tracker/actions/485
[15] http://www.w3.org/AudioVideo/TT/tracker/actions/485
nigel: There has been an update on the Unicode ticket
-> [16]http://unicode.org/cldr/trac/ticket/8915#comment:8
[16] http://unicode.org/cldr/trac/ticket/8915#comment:8
pierre: I think we have the scripts to produce one of the
things they are asking for, the delta.
... Maybe we should go through the questions now?
nigel: I think that would be useful, quickly.
pierre: Question 1...
nigel: Does anyone here know the difference between
supplemental and exemplar sets in Unicode?
pierre: I'm not sure, we maybe need to dig deeper or ask for
clarification. This may not be a question for us to answer.
nigel: Agreed.
... It's good they're considering _how_ to do it rather than
_if_.
pierre: Exactly, that is encouraging.
... Question 2: I think the answer is "yes" to both questions.
... I think the Unicode tables try to be statements of fact
rather than mandatory. And that's all we need, a description of
the characters that are used for captions in a particular
language.
glenn: [speculates that supplemental sets are additional
characters but examplar sets are lists of existing characters
for a particular context]
... So I think the answer for question 2 is yes to a and yes to
b.
nigel: +1
pierre: Question 3: We definitely have created that delta set
and can point to it.
<scribe> ACTION: pal Update the Unicode ticket 8915 with a link
to the deltas between what we recommend and what is already in
main and aux sets. [recorded in
[17]http://www.w3.org/2016/12/01-tt-minutes.html#action01]
[17] http://www.w3.org/2016/12/01-tt-minutes.html#action01]
<trackbot> Created ACTION-489 - Update the unicode ticket 8915
with a link to the deltas between what we recommend and what is
already in main and aux sets. [on Pierre-Anthony Lemieux - due
2016-12-08].
pierre: Maybe they are saying that if characters are in use for
captioning in a language then
... it should be added to aux for that language. That would be
fine by me.
nigel: Q 3a may be that they have found a mistake?
pierre: There are two parts to 3a. We can provide the
background behind the selection, which
... is indeed an empirical examination of real data. The other
part, about Hebrew and other
... latin scripts, I will follow up with someone who knows
about this.
glenn: I agree with the question, it does look extremely odd.
Also it may cause trouble having characters with different
directions.
pierre: The basic latin set is included all the time even with
Hebrew, so the question is why
... is a special case made for U+0178 : LATIN CAPITAL LETTER Y
WITH DIAERESIS?
nigel: Looking at the list, Hebrew includes Latin Extended-A
which has other characters
... as well as U+0178.
pierre: It sounds like either there is a mistake - I will check
- but also explain that all the
... Latin Extended A characters are included (plus other Latin
characters) in all the locales.
glenn: I don't believe it includes all Latin characters defined
in Unicode.
pierre: I should have said the "base set" (whatever it's
correct name is).
glenn: Yes, Vietnamese latin characters are not included for
example.
pierre: Should I pass draft text to the group before updating
the ticket?
nigel: I think you can go ahead and update the ticket directly.
pierre: Thanks for keeping tabs on the ticket by the way.
nigel: No worries. Thanks to Richard for prompting them - that
really helped.
action-485?
<trackbot> action-485 -- Thierry Michel to Ask richard ishida
for assistance in unblocking the unicode ticket 8915. -- due
2016-11-10 -- PENDINGREVIEW
<trackbot>
[18]http://www.w3.org/AudioVideo/TT/tracker/actions/485
[18] http://www.w3.org/AudioVideo/TT/tracker/actions/485
nigel: Since this is unblocked, I'll close this.
action-485: [Meeting 2016-12-01] This seems to be unblocked -
thank you Richard! Closing.
<trackbot> Notes added to action-485 Ask richard ishida for
assistance in unblocking the unicode ticket 8915..
close action-485
<trackbot> Closed action-485.
nigel: Do you want a minute on imscjs?
glenn: I would like to hear more about it.
pierre: This is a javascript library intended for rendering
IMSC 1 documents into HTML5
... as faithfully as possible to the spec.
-> [19]https://github.com/sandflow/imscjs
[19] https://github.com/sandflow/imscjs
pierre: There are three main parts, parsing, turning into ISDs
and then mapping the ISDs into HTML5.
... That last part could be replaced by other renderings.
... There are also links to test sample renderings from TTML1
and IRT tests.
... This work is sponsored by MovieLabs.
... This is an initial beta release, intended to be
substantially complete in API and in
... functionality, and the goal is to walk towards a 1.0
release in the next couple of months.
andreas: I also tested it and found it helpful. I did not find
any error yet, and everyone I
... told about it said it is really helping for TTML
implementation. Another thing that could
... be relevant is that very easily you can produce images for
all of the TTML samples that
... are in the test suite, so therefore it could be helpful for
this group, and you could think
... about providing images together with the test suite.
pierre: It works only in Chrome and Firefox because of security
issues, but from Firefox
... you can actually export the sequence of images associated
with each ISD.
andreas: It is also helpful for TTML to HTML mapping, so we
also benefit from that.
glenn: I agree with Andreas, it's very nice to have this
available.
... Did you create any new test content or did you use the
former TTML test suite?
... Also have you had a chance to document any rough spots in
terms of trouble mapping
... to HTML or CSS that required giving up formatting semantics
or other things like that?
pierre: I've been using for test the TTML1 test vectors that
are compatible with IMSC1,
... especially for timing semantics that has been extremely
helpful. Also the IRT test vectors
... because they come with nice expected renders, so that's
been nice for finding bugs.
... Ultimately I would like to come up with really good IMSC 1
specific test vectors. I have a
... question for W3C about copyright etc and how they would
feel about turning TTML1 tests
... into IMSC 1 tests.
... On the second question so far I think in the case of IMSC1
there's nothing that cannot
... be mapped to HTML, but time will tell! I've seen some
interesting things with unicode bidi
... and embed, and need to see if there's a spec or a browser
issue - that will take more time.
... One of the IRT test vectors has a discrepancy.
... Another one is xml:space="preserve" which is also something
where we might find surprises.
... Overall, the two features that required the most work were
linePadding and multiRowAlign
... because both of those features require determining line
breaks when there are no specific
... line breaks.
nigel: What about box-decoration-break: clone for linePadding?
pierre: The issue here is multiple nested spans with different
background colours. The clone
... works great if there is only a single background colour for
the entire background of the
... p or the span.
glenn: On multiRowAlign did you end up using display:
inline-block ?
pierre: Yes I think so, after finding line breaks and inserting
br elements where needed.
glenn: I'll have to take a look at it with some examples -
these are tricky areas for sure.
pierre: The strategy is to do a first pass putting every
character in its own span, then check
... the vertical position of each, and when it changes then
insert a hard break.
mike: Comment: I had the opportunity to throw some DECE film
content at it that was
... coded to DECE specs, and it looked like it was doing the
right thing, without looking
... in extreme detail. That was encouraging, with 300-400kb of
XML.
... Question: There's a partial implementation of
IMSC-1/EBU-TT-D in dash.js and I wondered
... if you had some thoughts about integrating into that?
pierre: Yes, in fact I have been touch with one of the main
developers of dash.js TTML code,
... and his comments were 1. How are images supported? and 2.
Why are IE and Edge not supported?
... In fact images are supported, using an image resolver.
... I have not had time to test with IE and Edge, and I was
pleasantly surprised how
... far IE11 has come, and there's a pull request to make 2
changes that will make the
... library compatible with both. The goal was always to make
it compatible with Edge.
... I expect to merge that very soon, and then update the
README. It should be compatible
... with the latest version of Edge, Safari. Chrome, Firefox
and IE11.
... It turns out there is only one CSS feature not supported by
Edge and it was really
... easy to get around it.
TTML2
nigel: I just want to mention Security and Privacy. We
currently don't have a section on this,
... and I've discussed with David Singer and Glenn and this has
led to issue 224 being raised.
-> [20]https://github.com/w3c/ttml2/issues/224
[20] https://github.com/w3c/ttml2/issues/224
nigel: We have three examples now, but any others would be
welcome - please contribute to the issue.
glenn: I thought of another, the use of xlink to cause browsing
away to other content.
nigel: I've added that to the issue.
... We're out of time for today (slightly over) and we've
covered the main agenda topics. Thanks everyone! [adjourns
meeting]
Summary of Action Items
[NEW] ACTION: pal Update the Unicode ticket 8915 with a link to
the deltas between what we recommend and what is already in
main and aux sets. [recorded in
[21]http://www.w3.org/2016/12/01-tt-minutes.html#action01]
[21] http://www.w3.org/2016/12/01-tt-minutes.html#action01
Summary of Resolutions
[End of minutes]
__________________________________________________________
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Received on Thursday, 1 December 2016 16:13:32 UTC