See also: IRC log
<scribe> scribe: nigel
Nigel: Today we have regrets from
Thierry and Gary.
... There's been action on the TTML profile registry and the
requirements so they
... will be our main agenda topics for today.
... I don't know if anyone wants to discuss the CSS issue I
sent to the reflector
... earlier about the combination of ruby and text emphasis and
where the
... resulting marks should go?
Glenn: I don't think that's been
raised before and I don't have an immediate
... response to it either.
... It is certainly something that the spec should have
language to address so I
... think we'll have some follow-on actions.
... Do you want to post an issue on TTML2 or shall I do
that?
Nigel: I'd probably be happier if
you or possibly Cyril were to raise it as being
... stronger proponents (and more importantly more
knowledgeable) about ruby etc.
Glenn: Okay I'll file an issue and refer to your email in archives.
Nigel: Thank you.
... That means we'll defer discussion of that issue until a
later date, if we need a
... discussion on a call about it at all of course.
... Back to the agenda, I don't think there's anything on the
f2f meeting or anything
... else on CSS. We don't have Gary today so I don't think
we'll be covering
... WebVTT. Is there any other business to discuss or
particular points to make
... sure we cover today?
group: [silence]
Nigel: I should say I have to
catch a plane later so I'd appreciate closing the
... meeting by the end of the hour so I have a bit of extra
leeway.
Nigel: Thank you Glenn for merging those pull requests.
Glenn: I need to update the PR on
alphabetical ordering and make some progress
... on the other issues. My time has been completely occupied
and probably will
... be until mid-next-week on other matters, after that I
expect to get to those.
Nigel: Ok, thanks for letting us
know.
... I see from https://github.com/w3c/tt-profile-registry/pulse
that the two
... issues and pull requests we discussed last week were
closed/merged.
... Is there anything else on this right now?
Glenn: I don't have anything.
Nigel: Thank you Cyril for raising the responsive timed text and karaoke issues.
Cyril: I did not follow the template but I hope that's fine.
Glenn: The templates are for
writing follow-on more detailed descriptions.
... The issue content is free-form.
<Zakim> nigel, you wanted to mention audio subtitles
Nigel: One requirement that has
been brought to my attention today at the
... ITU/EC Accessible Europe event is to support "audio
subtitles". I've asked
... a proponent to raise the requirement as an issue or offered
to do it on her
... behalf (she's not especially technical).
... So hopefully that will be raised by the deadline next
week.
... For those unaware, this is the ability to trigger text to
speech for translation
... subtitles mixed in with hard of hearing subtitles. It could
well be that no
... spec changes are needed, but I've asked for the
requirements to be submitted
... so we can satisfy ourselves about that.
... For those unaware, this is the facility to trigger text to
speech for translations
... to support viewers unable to read the translation text,
i.e. it bridges across
... from a "subtitling culture" to a "dubbing culture" for
those to whom that provides a benefit.
... Does anyone want to discuss any of the specific issues that
have been raised
... so far?
Cyril: One small aspect to
discuss is condition.
... In the responsive design use case I tried to use the
condition element, and I
... mentioned in the issue I am not clear how condition behaves
in terms of
... processing and XML processing in general. You want to
re-use the same
... style id and define it differently depending on the
conditions.
Glenn: That's illegal in XML. You can't do that.
Nigel: I've raised this before too.
Glenn: There are different ways
to do it. You can't really switch regions, but
... you can switch animations of regions, e.g. moving a region
via conditional
... animation that achieves the same effect. You can also have
styles attached to
... regions which are conditional. You would reference multiple
styles, say you
... want to switch between A and B.
Cyril: You reference both and only one is activated.
Glenn: Exactly. It may not be the
most elegant design but technically it does
... work and I did test this. I will try to comment to the same
effect on the issue.
Cyril: Thank you.
Nigel: There's a thread about
this probably on a TTML2 issue that should be
... closed from the review stage back in the summer where I
raised the same
... question and we came to the same conclusion.
... One thing you can do to simplify it from the authoring
perspective is to
... reference one style from the content and have that style
itself reference the
... conditionalised styles.
... For example paragraphStyle -> (bigParagraphStyle,
smallParagraphStyle)
... where each of those is conditionalised so the style tree
resolution handles
... the complexity and the content just needs to reference
paragraphStyle.
Cyril: Thank you.
Pierre: So I think the question
is if the condition mechanism is adequate to
... satisfy the use cases we have in front of us. We don't have
to decide that on
... this call, but I would ask that question.
... Since we have had two people raise similar feedback.
Glenn: Just as a note on that
point there is no real way that we can have a
... conditionalised syntax mechanism that makes something
syntactically present
... or not because XML itself would require that feature or you
would need a
... macro processor or something that you run the document
through before
... feeding it to your XML system. I don't view that as very
practical. We maybe
... just need to do a better job with examples in the spec.
There is some language
... that emphasises it is the semantics.
Cyril: An example would help, I searched for one but could not find one.
Glenn: Good point.
Pierre: Maybe the right way to
start is to compose practical examples and see
... where that leads us in refining the spec.
Glenn: Sure. That may be the ultimate outcome of this issue for example.
Pierre: Exactly, especially as we
have two participants who support this use
... case it would be good to put together concrete
examples.
Cyril: I agree with what's been
said - most of the requirement does not need
... new things in TTML, just clarifications.
... One thing I added was the ability to conditionally split
content. Is there anything
... that already can do this?
Nigel: I've thought about this
too and have similar use cases. The one suggestion
... that I think Glenn made some time ago is that there could
be conditional
... br elements, but I don't think that completely achieves the
result. Instead
... you're conditionally changing the timing of presentation,
and I don't think I've
... seen that expressed so clearly before. Though those with
long memories
... may remember a demo I gave at TPAC (maybe 2015?) where the
user had a
... slider to adjust the text size, and depending on the size,
the amount of visible
<cyril> yes 2015
Nigel: text varied so it always
occupied one line, but the rate of change was adjusted
... to keep up with the audio.
... That was in Sapporo I believe.
... That could be considered an example of responsive display
and I don't know
... how you could do that using condition alone.
... Assuming that duplicating a lot of content is undesirable
of course.
Cyril: I would be interested to see that demo if you have it.
Nigel: I have it but only on my computer so maybe its one for the f2f!
Cyril: In this demo and the
conditional breaking of events, I see some commonality
... with the karaoke use case in the sense that if you provide
more granularity
... in the timing then the processor can do something more with
it. I call that
... internal timing with markers that are not used all the
time.
Glenn: What do you mean by "event"? We don't have that in TTML.
Cyril: For example a p with a begin and end is an event.
Glenn: How about a span with a begin and end?
Cyril: Yes, something that is displayed on the screen for some time.
Glenn: I guess we'd call it active temporal interval or something.
Cyril: You see why I called it "event" because that's simpler!
Glenn: Yes I see
... The "event" as you use it is a little different because it
implies a semantic
... consistency or relatedness whereas an active interval is
like the smallest
... timeslices that divide up all the begin and end times that
apply in the whole
... document so you could have active intervals generated by
unrelated content
... simply because they have intersecting activation or
deactivation times.
Nigel: Yes
... That idea of the marker is something I've thought about in
the past but
... never taken any further. The other useful construct to
observe or be aware of
... is the idea of a pseudo selector that affects things in the
future vs things in
... the past, which WebVTT has.
... That's quite a powerful idea in this context. I'm not clear
if it does everything
... that's needed but it's pretty easy to see how it is useful
for karaoke for example.
... It's a different way to think about the problem, I'm not
sure if it addresses the use case.
Cyril: I agree Nigel. The marker
is similar to one of the tags in WebVTT where you
... can set a tag to affect anything, e.g. a speaker, and it
does not affect the
... display. Is it the v tag?
Nigel: I'm not sure if its the
same thing but I recall a way to affect the display
... within a cue.
Glenn: We can add metadata of
course in TTML but there are no presentation
... semantics in that.
Nigel: That's true, I think this
use case does want to allow for some presentational
semantics.
... There's another question, which is are we expecting all
players to
... honour this or is it okay for specific players aware of
this functionality to do it?
... Another question about marker is how it fits within the
nested span structure
... that's used in TTML to define ruby presentation?
... There are loads of questions like that I suspect - I'm not
raising it as a blocker,
... just throwing it on the table as something to be aware
of.
... To add more about the BBC's use cases, we definitely have
this vertical vs
... horizontal kind of issue, also square video.
... For example think about a video posted to twitter, which
was originally 16x9
... but appears in the preview as square!
Cyril: At least for Netflix there
are two aspects that this Responsive Design
... technology could help. One of them is regarding the use of
the Timed Text
... content in the workflow, having a single document for
multiple use cases
... simplifies the workflow - one processing. The other is the
final delivery to
... the client, where receiving one document makes it easier to
adjust.
... These are two different sub-use cases. You can imagine
receiving one document
... from the studio and delivering multiple documents to the
client.
... The solutions may be simpler than presenting one document
in different ways.
... I just wanted to highlight that.
Nigel: +1
Cyril: In the lifecycle of the document there are two places where this could be useful.
Glenn: This has an echo of an
earlier conversation that the group had a very
... long time ago pertaining to language where we discussed if
multiple language
... versions should be in the same document or in separate
documents.
... I recall at the time that for distribution to rendering
clients it is preferable to
... use a single language inside a document. But we also
recognised that at the
... authoring or content management strata it might be useful
to have multiple
... languages in the same document. Frankly I don't think we've
pursued many of
... those thoughts much further since then, so this is bringing
back those issues I think.
Pierre: I think a data point here
is there is a difference between those things
... that change dynamically during presentation. Language does
not change,
... but responsive design is dynamic changes during the
presentation like
... rotating the phone for example. That may be a
differentiating point. There is
... also a continuum of say aspect ratios whereas language is a
discrete quantity.
... There are differences across those use cases.
Glenn: I note some users find
switching language mid-presentation to be useful
... but they are fewer in number. If I'm watching a film with
Russian and English
... subtitles I might want to see Russian as a learner, but go
back to the English
... if I don't catch it all. Probably a corner use case!
Cyril: Glenn raised an
interesting point about when to merge content.
... For Netflix we receive deliveries of different languages
from different vendors
... at different times, so probably not. But forced narratives
could be done in one
... document. Certainly multiple aspect ratio could be. It
makes sense when it is
... the same content displayed differently. When it is
different content we would
... use a different document. The question is still open for
forced narrative content.
Glenn: At one point in the
history of TTML we had AFXP, the authoring profile.
... When we were on a parallel path of defining them separately
we recognised that
... for AFXP it would be appropriate to have multiple languages
but for DFXP
... for distribution it would make sense to split them up. We
haven't really
... talked about authoring vs distribution profiling before but
it may come back again!
Nigel: That's a really
interesting discussion, thank you.
... If there are no more requirements to discuss, I'll move us
on in the agenda.
Nigel: Just one item from me,
which is next week's meeting. Are there any
... advanced regrets? Gary has already sent his.
group: [silence]
Nigel: Okay just confirming next
week's meeting will go ahead and after that,
... our next scheduled meeting is 10th January. Is that okay
for everyone?
group: [silence]
Pierre: Okay with me.
Nigel: And of course a reminder
we want all requirements to be raised as issues
... by the 20th December which is the date of next week's call.
I don't think that
... means they have to be opened by the beginning of the call
next week, but it
... would possibly be helpful.
... The main driver for that was to allow for adequate review
time over the break.
Nigel: Thanks everyone, meet again same time next week. Bye! [adjourns meeting]