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<scribe> scribe: nigel
Philippe: I will have to leave before the bottom of the hour.
Nigel: For today we have TPAC
planning, TTML, IMSC and a new agenda item for HDR in
PNG.
... I have one extra issue for TTML, which is the inline boxes
one, as discussed on the reflector.
Mike: I'd like to spend a minute
or two on how the normative references are interpreted
... when there is no assigned version.
Andreas: I have an additional
proposal, to look at the timeline we made in London
... regarding TTML2 and IMSC 2 work and see where we are. I
think that also affects TPAC.
Nigel: Thanks, any more points to raise?
group: no more
Nigel: Does anyone currently have a preference for meeting on any of the days particularly?
Andreas: I have no preferences but would like to avoid conflicts with other meetings I want to attend.
Nigel: Any groups that we want to avoid clashes with? Or hold joint meetings with?
Andreas: The last 2 times we
joined the Web & TV IG. In 2016 it was official, in 2015 it
was
... a Chair's report. I assume it would be useful to try not to
clash with that group.
Nigel: Agreed.
Andreas: We have also discussed
CSS related issues so we should think about requesting
... a joint meeting.
Nigel: Yes let us certainly do
that, with the scope being to present styling
requirements
... for subtitles and captions that cannot currently be met by
CSS.
... OK I will complete the form asking for any 2 days and
avoiding the groups we just mentioned.
... If anyone has other points to raise on this, or
constraints, please let me know.
... The other thing I need to mention is that if anyone has
difficulty attending the meeting
... in person, perhaps because of travel difficulties, please
let me know in case W3C can
... assist e.g. with remote attendance.
Nigel: Last week we discussed the
process, and the Chair was urged to discuss it with the
Editor.
... That happened, and other conversations also. As a result I
would like to reiterate that
... we have a process that we agreed previously,
https://github.com/w3c/ttml2/blob/gh-pages/EDITING.md#ttml2-editing-guidelines
Nigel: And we should stick to
that. A reminder that as a normal rule aside from minor
... editorial changes pull requests will be left open for a
minimum of 3 days before merging
... and if anyone wishes to request extra review time then that
will normally be granted up
... to 14 days.
... As Chair I also would ask that everyone is as flexible as
possible in allowing the Group
... to make progress given that we are past our London-agreed
deadline already.
Pierre: What is the policy on pull requests when somebody submits one, in terms of best practice?
Nigel: First of all the Editor
has requested a branch naming convention, which is a
convenience, but
... for me not a primary requirement.
... Secondly if a totally different proposal for an issue is
made then it should be in a different
... branch with a different Pull Request. However if
modifications need to be made on a
... Pull Request they should be made on that request's source
branch.
Philippe: Sorry I can't stay longer. Bye everyone [leaves]
Nigel: In the agenda I noted that
we have passed our self-imposed deadline for publishing
... a WD for WR and that there may be a need to review the
priorities of issues and possible
... drop the axe on some of them now. Andreas, you wanted to
raise this also?
Andreas: In London we set a
positive schedule, which we have missed, but I do not
know
... where we stand and how far away are we from what we
originally planned, and then
... what is the new realistic deadline and how it can be
acheived?
Nigel: OK, that's an important question, thank you.
Pierre: Before we consider
deferring issues we should think about the best process
for
... disposing of issues going forward. We should talk about the
process for going forward
... with TTML2. In London we discussed a process, where we went
through TTML1 issues
... and marked them as "discussed and agreed" and those have
not yet been fixed.
Nigel: You're asking about the editorial progress in implementing those issues?
Pierre: Yes.
Glenn: As a blanket statement
that is not correct. Some of the discussed and agreed
issues
... have been closed, others are effectively done and marked as
To close? which I would
... have closed if we did not wish to wait for consensus before
closing an issue.
... There are a couple of discussed and agreed issues that have
had work done but not been
... updated. So progress is being made, but it is not
complete.
... The list I am working from is the open issues under the
TTML2 WR milestone, which
... is showing 58 open, of which 4 are marked as "to close?" so
that could be turned into
... 54 pretty soon.
Nigel: And where are we up to with those 54?
Glenn: I've been prioritising the
Discussed and agreed first. There are some that come from
... TTML1 changes that are not raised yet, for example #221 on
TTML1 and Andreas's
... pull request which I processed further last night. So there
are a couple of TTML1 issues
... that we need to bring in. Otherwise I am making my way
through this. There are quite
... a few that have had some work done that need to be wrapped
up, for example around 5
... issues that pertain to the new annex defining semantics of
display extent, which we
... talked about quite a bit in London, so those can be dealt
with by wrapping up that work.
... I'd say that most of these 54 have had a fair amount of
discussion and some may
... require more technical discussion in the group than others.
Maybe a third should be
... fairly straightforward to wrap up.
Nigel: That would be around 18
being 54/3.
... Given that there's a fair amount of effort to do, the
obvious thing to me would be
... to bring in more editorial effort by other group members
than the Editor to draft
... pull requests to resolve issues.
Andreas: I understand it is
important for some people to reach Recommendation by the
end
... of the year. One way to handle this with so many open
issues is to mark some issues
... as being less high priority so the TTML2 spec would still
be valid if we did not address them.
Pierre: Going down one path you
hinted at, I've heard folks from Netflix being really
keen
... on completing this work, and Movielabs, and the BBC and
perhaps others. I'd be
... surprised if we couldn't find resources there to help work
on editing the document.
... That's a path that perhaps we should explore.
Glenn: There are two issues to
separate: one is generating draft text to incorporate,
and
... the second is doing final editing on that if necessary. We
need the former more, which
... is to generate pull requests to resolve particular issues.
I have said on multiple occasions
... that I welcome other members generating pull requests to be
contributed for inclusion.
... If other resources are available that's what I'd like to
see done.
Pierre: I think it needs to be
more than that because if the Editor is unable to process all
those
... pull requests then we would be in a similar situation.
Nigel: To be clear, my comment
earlier was about one individual both drafting and
merging
... rather than just merging. However it certainly is common
practice in W3C to have
... multiple Editors for a specification and I would encourage
that, and Philippe has indicated
... to me that he would support that. It removes the
opportunity for bottlenecks. However
... I think Glenn has mentioned before that he would like to
retain a single view for
... consistency.
Pierre: If this is something that
the group wants then the Chair could ask proponents for
... more editing help.
Glenn: I should mention that I have cleared my schedule in May to deal with issues.
Pierre: I would recommend that
the Chair assigns issues to specific people to dispose
of,
... and separately I recommend raising the issue with
proponents regarding resource
... availability for providing more Editing.
Nigel: It is not clear to me why
the Chair needs to assign issues - if proponents are
... interested in taking on an issue then I suggest they do so,
as a first step add a comment
... to the issue stating the intention to resolve. In general
in W3C we work on the natural selection model where things that
people are interested in get resolved. Assigning issues
proactively will prevent other interested parties from
contributing, so I am not in favour of doing that.
Pierre: There are some open pull requests, for example one on TTML1 raised in February.
Andreas: The TTML1 one was
requested in London within two weeks otherwise Glenn
would
... propose something else. I tried to fix it as soon as
possible but then it seemed it was
... not needed that urgently. It's not a big issue for me. In
terms of getting more people
... involved it would be more motivating for people if we deal
with pull requests in time.
Glenn: Thank you for providing
that input very quickly. It was then waiting for me to do
... final editing. So in terms of final editing I have been
giving it some thought and finally
... made the changes I thought were necessary yesterday. There
are also some comments
... on an earlier commit.
... One of the issues I have is that issues seem to need full
group discussion before closing.
Nigel: In fact that can be done
on the issue.
... It does not need the group to discuss it in a
meeting.
... By the way we do not have a group policy for how long pull
requests should take to
... process, but it seems reasonable to me that it should be
days or a small number of weeks
... and that "months" is too long.
David_Ronca: Looking at the WR,
there are comments that first it was March, and now it
... looks like it will be June, and I don't see any strong way
that we can ensure we will
... publish the WR in June. We are beginning to get the
perception that we will never get
... there. We have a lot of time and money invested in this
project, and nobody can move
... until we make progress. I don't feel like we're leaving
this meeting today having made
... progress.
Nigel: What progress are you hoping for?
David_Ronca: Perhaps some
agreement on how we can meet WR in June.
... I agree that we need to delegate issues out. We need to
start making some hard decisions
... about what's in or what's out. If there's some way that we
can contribute more to try to
... get these resolved then I would.
Nigel: Working backwards that
means that we need to have pull requests open or merged
... for all issues to be met in the WR by the end of May so
that the group has enough time
... to review and get to consensus on publishing those
resolutions as a WD. If there are
... remaining issues open at that point without pull requests
then we would need to make
... hard decisions at that point.
Pierre: Issues raised externally will not go away, they will still need to be addressed.
Nigel: That's true, however we do
have an opportunity to resolve external issues between
... WD and CR.
Glenn: The disposition can be a deferral.
David_Ronca: I would hate to begin work on an issue and find someone else is doing it.
Nigel: Well you could assign
yourself to it, and also add a comment so if anyone else
is
... working on it then they can mention that.
Glenn: Also I would suggest asking me in case I've already put some thinking into it.
Pierre: That's inefficient. If you've already begun to think about it you should assign the issue to yourself.
David_Ronca: I would agree with
that - if we can assign resource to make a sprint on this
... then I would like to see issues assigned, and non-assigned
issues need to be assigned
... to somebody.
... I'm actually willing to try to get my team to make some
contributions to push through
... this. I want to do it efficiently. I would appreciate if
every issue being worked on has an
... assignee. Is that a reasonable request?
Glenn: Yes, they should at least do a first attempt to read the comments. I will go through
<atai> +1
Glenn: and see if I have given
anything significant thought and not documented then I
may
... assign it to myself.
David_Ronca: That would make it much easier because then I can filter the unassigned issues.
Glenn: I need to do a pass
through and review the current status.
... There's also a label "Request help" so it might be useful
to make more use of that label.
David_Ronca: Glenn please could you assign the ones you are working on to yourself?
Glenn: Sure, that seems
reasonable.
... I'll do it this week or next week.
Nigel: Okay, that seems like good
progress, so we have a way to identify what needs
... working on and when something is already being worked on,
some offers of more
... effort, and some offline discussions to have. Thanks.
David_Ronca: I have to drop off now. [leaves]
Andreas: Me too. [leaves]
Glenn: I'd like to raise #292.
Update note regarding ISOBMFF and DASH.
Glenn: This is an issue pointed
out by Mike on email recently, with reference to DASH,
... ISO BMFF, CMAF and so forth. I committed this directly
since it is an informative change.
... If that is acceptable I would like to close it.
Mike: It's editorial, not a big deal, thanks.
Nigel: I'm happy with it
too.
... I've closed that issue.
... Apologies Mike we haven't been able to get around to your
question about
... unversioned normative references, and now we have no staff
on the call to assist.
Mike: That's okay, it can wait
until we have Thierry of Philippe on the call.
... I noticed that some references have versions or dates and
some don't and wonder how
... we deal with those.
Glenn: For tracking and
transparency purposes we should probably open an issue on
this
... post it as a question, adding the "question" label.
Mike: Sure I'll do that.
... It may result in changes of some sort but I'm happy to
start with a question.
Nigel: Can we raise the inline boxes issue?
[css-inline] Define the content area of inline boxes
Nigel: Am I correct in
understanding that the proposal on the issue is essentially the
same
... semantic that we want with a different syntax?
Glenn: They have not yet proposed
any semantic. They would also have to deal with the
... fact that height and width do not currently apply to
non-replaced inline boxes. There's
... nothing in CSS so far that alters that. The second thing is
if there are keywords that would
... satisfy our needs. I think we should not make our work
dependent on their process.
Nigel: My proposal is that we define the semantic that we want and add it to the CSS issue.
Glenn: We can do that. First we
need to agree what we want to achieve. We need a concrete
... proposal on our side. We have two action items, first as
agreed in London to change
... the semantics of bpd and ipd so it does not trigger the
inline block semantic and second
... to define a way using bpd or a keyword to mean what we want
it to mean. When we have
... that at least in an ED we can provide a reference to that
for the CSS folk.
Nigel: Those are both things you have been working on Glenn - where are we up to on them?
Glenn: Yes.
Ways to make span background height be lineHeight
Glenn: I will assign that to
myself and create a new issue to track the agreement to
add
... a new keyword to the display property called inlineBlock
and change the semantics in a
... few places that had automatically triggered that
behaviour.
... Since it changes something we've had for a while some
implementations like TTPE will
... need to be changed accordingly.
Nigel: I've assigned #150 to you
Glenn. This also affects #146 and #163.
... In my view the separation of inline block semantics is the
resolution to #146.
Inline block semantics impacts text wrapping
Glenn: You're right, yes.
Nigel: I see you're already
assigned to #146.
... On the point about HDR I see that I have just received an
email from a colleague
... giving me the go-ahead to make a BBC submission to add to
the annex about HDR an
... alternate way to convert sRGB using hybrid-log gamma. I
will do that shortly.
Glenn: Is this a replacement text?
Nigel: No it's an additional method.
Add support for compositing a TTML2 document onto HDR video
Pierre: The reason for removing
the to close? label was documented in the minutes.
... I will create a PR to address the current comments.
Nigel: I see that Pierre and I are assigned to this. I will create a PR for the HLG way of doing it.
Glenn: We have not discussed the name yet in the group. I think the simpler name is better.
Nigel: Pierre and I have already made clear our preference for the more specific name.
Glenn: I do not think we will need to use luminance for anything else.
Mike: Luminance is a term that
goes way beyond what we mean here so I would prefer that
... it be qualified in some manner. The original proposal was a
little verbose but we need
... something more than just luminance.
Glenn: How about luminanceGain?
Pierre: I'm happy with luminanceGain, I don't think you are Nigel?
Nigel: My test question is: can it be used in any other capacity than for PQ HDR?
Pierre: It is an absolute gain.
[some discussion]
... To get to a PQ encoded image you need absolute luminance,
which you get to with this
... metadata.
Nigel: Is it the only way it can be used?
Pierre: It can be used to create
an HDR image for other encodings than PQ.
... It does not specify anything only specific to PQ. The value
can be used for other purposes.
... The end result of applying this is that you end up with an
XYZ value with absolute
... luminance that you can then do what you want with.
... Fundamentally the issue is that sRGB is limited to 0-80
cd/m. There are schemes that
... can use a broader dynamic range. The goal is to be able to
produce images that can be
... used in any number of schemes, one of which is PQ but
conceivably others.
Nigel: And my understanding is
that XYZ is essentially canonical, so if we define
... luminanceGain to be the thing you use to get to a canonical
format then I'm happy with that.
Pierre: Yes it is the thing that gets you to absolute luminance values.
Nigel: Ok then let's go with
luminanceGain
... If there is some unexpected further problem with that then
we can deal with that later.
Pierre: I will make a PR to deal with that and the other comments.
Glenn: Ok that's good.
Nigel: I added comment
https://github.com/w3c/ttml2/issues/233#issuecomment-295787705
... What can we look at next? I think we have done enough in
the offline discussion to
... deal with the smpte discontinuous issue?
No restriction on time expression for smpte discontinuous mode
Glenn: I'll do a PR for that.
Nigel: Thank you!
... I have assigned it to you Glenn.
... Did we get anywhere on whitespace handling?
Ambiguity regarding tab (U+0009) processing in significant whitespace.
Glenn: I sent an email to Steve
Zilles because I could not resolve this by looking at the
XSL
... specification. CSS now says that a significant tab gets
mapped to spaces - I would like
... to avoid using those semantics if possible. My preference
is that if a tab is significant
... then either treat it as zero space or exactly one space but
I need other input.
Pierre: The XSL spec is really
clear - tabs are preserved but it does not say what a tab
is!
... Where do you see the ambiguity in the XSL spec?
Glenn: Two issues: one is what do the xml:space semantics mean with a tab? ...
Nigel: I just want to step in here - the explanation is in the issue. Pierre is there a problem with that?
Pierre: Yes, and I will add that
to the issue. The issue is that CSS changed. To my mind
you
... should just not put tabs in TTML documents! It doesn't say
what happens.
... A solution, regardless, is to say authors should not put
tabs in their documents.
Glenn: That's not an adequate
solution because they appear all the time. For
xml:space="default"
... we need to define whether there is a case where a tab may
appear or if it is always
... normalised to space. I think I convinced myself that tab is
mapped to space in this case.
Pierre: I'll take an action item to comment on the thread. Regardless I think tabs should not be present in the document.
Nigel: The question is not if it
should be allowed in a document but to define what to do
with
... it if it is present.
Glenn: If it is mapped to space
then we do not need to deal with it, but if it is preserved
then
... it falls into the reduced infoset and it needs some
presentation semantics. We have some
... options, to treat it as 0 space, 1 space or like CSS does,
some multiple of spaces.
Nigel: What gave rise to this issue is that if xml:space="default" some tabs are preserved.
Glenn: Only if they are the first
character of an element or the first character after a new
line.
... That was the question I posted, maybe I'll take the text of
my question to Steve and Tony
... and paste it onto the comment so that people can see what I
was asking.
Nigel: We're out of time, thanks everyone. [adjourns meeting]