<cpn> scribenick: cpn
Giri: Publishing as a snapshot in
time. We have this as an action item from the last call. Any update
from the IG co-chairs or staff?
... Any recommendations for what the group needs to do to
publish?
Kaz: We can record a resolution in the minutes of this call. If all the participants are OK, we can go ahead and publish as an IG Note.
Giri: Let's review the outstanding PR, if we approve that, then we can publish as it stands. We can revise later. Any objections?
[none]
Mark: Go ahead and publish, we can always update it.
Kaz: We don't have concrete feedback so far from Japanese members, e.g., Hybridcast. Maybe we can publish the initial version, then stakeholders can give their feedback to the published version.
Chris: Sounds good. I think the document will benefit from wider review by IG members.
<scribe> ACTION: Giri to issue the CfC to publish as IG note
<kaz> scribenick: kaz
Chris: It's taken a while, but I have
now been in contact with Marcos Caceres, one of the co-Chairs of
WICG.
... His advice was to create an explainer document, and he would
circulate with his colleagues at Mozilla.
... In the email thread with Marcos, I'm also in contact with Eric
at Apple, so I think we have good implementer support.
... I have created an initial draft of an explainer.
<cpn> https://github.com/chrisn/datacue/blob/master/explainer.md <- initial draft explainer
Chris: This is based on the
discussion thread in WICG Discourse. I plan to add some more
context and detail from the use case and requirements
document.
... But the scope is slightly different. The explainer is about the
DataCue API, whereas the use case and requirements document is
broader, about synchronization and synchronized rendering.
... So the DataCue work is one of the outputs that could come from
this TF. Other outputs we could have, such as the time marches on
algorithm in HTML.
... This isn't a new specification, but a change to that part of
HTML. That's a WHATWG thing, so would be treated separately.
... I'm pleased this is moving forward. There's additional work to
be done, which is to add detail and be more specific in the
explainer.
... Because this is WICG, we can do things the IG can't do, e.g.,
look at the API shape in more detail. A typical explainer might
contain example code to show how the API would be used.
Giri: Isn't that putting the cart before the horse? We'd want to get agreement in WICG on the API surface before talking about code.
Chris: Yes, I'm just saying that
explainer documents often contain example appliction code to show
how the API works.
... It can be in draft form, to give an indication to someone who's
not familiar with the material about the problem we're trying to
solve.
... The explainer document would then go, for example, to TAG
review, and they need us to explain the context.
... What I'd hope is that this document is something we do
collaboratively with the browser companies.
... At this point, it'll be them driving the work much more, as the
purpose of the incubation is to get the implementation
feedback.
... As a next step, we need to open up a dialogue with
representatives with the browser companies to figure out who'll be
working on this.
... We'll need a spec editor, for example. This discussion is
starting offline.
... We haven't spoken to Google or Microsoft recently, are there
people there who would want to be active in this work.
Giri: Me and you and Eric have already volunteered to shepherd this, so you want to bring in people from Google, Microsoft, and Mozilla.
Chris: Yes
<cpn> scribenick: cpn
Giri: I updated DASH-IF on our TF
progress at their F2F meeting 2 weeks ago.
... There's a good understanding that this would to apply to both
the Safari HLS and DASH use cases. DASH-IF will continue their work
around eventing, but will want to take advantage of this work
eventually.
Rob: We had 3 people from Google in the Spatial Data on the Web IG meeting at TPAC, I can suggest some contacts at Google.
Chris: Thank you. On the media side, there's also Mounir.
Rob: Joe Medley is a tech writer, also Jon Pallett had some good feedback on WebVMT.
Giri: We have one outstanding PR.
This is about restructuring the use cases, Chris has done quite a
bit. Are you satisfied with it?
... I had a look, didn't see any problems.
<kaz> PR 23
Chris: Yes, I'm happy. I wanted a representative set of use cases, and a paragraph to describe each one. I'd like to invite wider feedback for review.
Giri: I suggest we use the
publication of the document to invite review, so I suggest we merge
now, then I can do the CfC.
... Call for consensus: Are there any objections to publication,
after this change is merged, as an IG note?
Nigel: A procedural question. Will you allow some time for people to check the results of that merge before publishing?
Giri: This isn't a standards track
document. Kaz said he's had trouble getting feedback from the east
Asian participants, so the CfC is away of triggering that.
... Simply merging the PR probably won't be enough to get the wider
feedback. If you'd like a few days after merging, that's
fine.
... But we want to publish before the end of the year.
Nigel: I think that would be good. If
you're seeking comments, it's worth thinking about how you'll reach
out to people.
... The SOTD in the document has an email address for comments. Can
people raise issues against the repo?
Giri: I think we'd want to point people to the GitHub issue tracker rather than the mailing list.
Nigel: Another thing is having a link to the repo at the top of the document.
Giri: Could you please file an issue to capture that?
Nigel: Yes
<nigel> Invite comments by filing issues #28
Giri: Chris, can you make that change when you merge?
Chris: Yes, that's fine.
[discussion of using email or GitHub for the CfC]
Giri: If we do the CfC today, we can
close this fairly quickly, so Thursday this week, then leave it
with the IG chairs to work with staff to publish.
... A quick note: Qualcomm is withdrawing from W3C, so I can't
participate further from the end of the year.
... I plan to be an individual contributor in the WICG.
... Chris has been acting as a co-chair, thank you. Do you want a
co-chair going forward?
<kaz> scribenick: kaz
Chris: Having a co-chair is really very helpful, good to have another point of view, and someone to work with. If someone would like to do this, I would be very grateful.
<cpn> scribenick: cpn
Mark: I believe we want to shut down the TF and move to WICG. So it's only a matter of a few weeks. A question for staff, can Giri continue to join calls while we close the TF?
Kaz: We can invite Giri as a public
observer, but I think we should publish the draft during the period
of Giri's participation, before the end of the year.
... As the first publication of this note, we need W3M approval. I
can get that quickly, when we have group consensus. We can do that
during next week.
Mark: So the Task Force won't be
finished at the end of year, as there'll be some revisions. Is it
OK to invite Giri to do those revisions, for a couple of weeks into
January?
... It would help from a continuity point of view.
<Zakim> kaz, you wanted to show an example of Note: https://www.w3.org/TR/2018/NOTE-wot-security-20181203/#toc
Kaz: I shared a WoT group note, to look at the info at the top of the document.
<nigel> Thank you!
Giri: Open discussion, if there are offshoot topics.
Giri: A topic in CTA WAVE and
DASH-IF, actually discussed at TPAC 2017, was representation from
the ePub community, there was some overlap.
... Somehow that never really materialised in the TF, were there
things not addressed, specific to that community?
Chris: I'd like to follow up with
them.
... Another topic is the frame-accurate seeking discussion in
M&E IG, which went on to discuss frame accurate rendering of
overlaid information. I think the IG should come back to
this.
... https://github.com/w3c/media-and-entertainment/issues/4
... How much interest is there among IG members to continue with
that topic?
Kaz: Possible collaboration between the media group and the publishing group?
<kaz> digital publication layout workshop minutes
Kaz: There was a workshop on digital
publication layout in September in Tokyo. The main topic was manga
/ comics.
... Some workshop participants were interested in moving animation
comics, kind of like video streams embedded in a comic
site/page.
... They're interested in how to integrate video streams and speech
recognition and speech synthesis into ePub applications.
... Their preferred approach is similar to the M&E approach in
the end. I mentioned we should collaborate a bit more.
Giri: It sounds like there's
opportunity to collaborate with the ePub efforts at W3C, publish
even broader use cases, so should be taken up at the IG
level.
... If the end goal is to feed into pre-standards work, it's
beneficial to have multiple communities working together.
Chris: I agree. How to start that conversation, who should we talk to?
Kaz: Can discuss with the co-chairs Tzviya and Wendy, and Ivan Herman.
<Zakim> nigel, you wanted to mention a specific lower cue timing threshold
Nigel: We've talked a few times about
the time marches on algorithm and cue firing accuracy, as opposed
to the precision of the timestamp on the cue.
... This is also being discussed in other forums. I'd like to put
forward a number: 20ms.
... This is coming from another group, who think that's
appropriate. Currently it's 250ms.
... Certainly, based on my limited testing, I found Firefox fires
easily within 20ms, but Chrome and Safari do not.
... The derivation of that figure is that it's half the duration of
a frame at 25 fps.
... So if you're at 25 fps and you fire the event within +/- 20ms,
you'll be frame accurate.
... Obviously, higher frame rates do exist, but from a human
perception point of view, if you use this to drive caption timing
or audio timing, it's small enough that most humans won't be able
to identify shorter time periods.
... This is a tentative proposal, something to consider as a
figure. I say that in the interest of trying to work towards long
term alignment. I don't want W3C to come to one figure, and other
standards bodies have another.
... I say this in the interest of working towards long term
alignment. I wouldn't want other SDOs to have a different figure
than W3C.
Mark: This came up at TPAC, the
suggestion was to send a pull request to the WHATWG with a spec
change, including your motivation,
... rather than anything this group would do, or working through
WICG.
Nigel: Yes, there was an issue about how we contribute to WHATWG.
Chris: I wrote about that here: https://github.com/w3c/media-and-entertainment/issues/11.
Nigel: I agree with Mark, that would be a good way to move things forward.
Chris: Do we need this forum, not to
do the spec work, but more as a coordination point?
... Not just for time marches on, but also with the WICG work.
Rob: Coming back to the frame
accurate seeking issue, this chimes with a fairly important set of
use cases for WebVMT.
... I've just raised two of these with the Open Geospatial
Consortium (OGC).
... The use case I originally suggested to this group, which was
discounted as you were more interested in the rendering side.
... I've raised ideas in OGC on search by location in a video
archive, could be used for drone maintenance in a remote
location,
... e.g., turbines in a wind farm, search video history for frames
to show if there's any damaged turbines.
... Also, searching by metadata, for the insurance industry,
searching acceleration metadata for a particular signature which
indicates a vehicle impact, and recover a video clip at that time
from the dash-cam footage.
... It sounds like the frame accurate seeking could well be
related.
Chris: The general topic of media
synchronization is of broader interest than the event triggering
aspect. I suggest taking this back to the IG in general, do
something more focused on frame accurate seeking. If that generates
interest, could be the next stage of work for the TF.
... My proposal would be to take back to the IG. If there's
sufficient interest, we can reframe the work of the Task Force for
the next stage.
Rob: There's wider interest than just for broadcast. Could be done in the spatial data on the web IG, but important to have the collaboration.
Song: I'm new to the TF. Regarding
figures for frame accurate seeking, decreasing from 250ms to 20ms.
I'm doing uplink and downlink for UHD transmission over 5G,
currently the network latency is 200ms.
... If we work on the figures, like 20ms, but if network latency in
real environments is more like 100ms, it will affect the user
experience for the accuracy. This could be of interest.
Nigel: Regarding time marches on, and
the accuracy relative to the cue timestamp, is totally separate
from frame accurate seeking.
... Frame accurate seeking is about the amount of control you have
when seeking the video to a particular location.
... The time marches on cue firing decision is about how close to
the requested time the cue onenter and onexit events will
fire
... These are separate things, we shouldn't mix them up.
Giri: Thank you everyone for working
in the TF this year. There are some action items, as well as areas
to explore for 2019.
... Thank you.
Mark: Giri, on behalf of the IG, I'd like to thank you for the exemplary work you've done chairing this group.
<nigel> +1 to Mark
<kaz> [adjourned]