W3C home > Mailing lists > Public > public-web-and-tv@w3.org > September 2018

Minutes from Media Timed Events Task Force call, 17 September 2018

From: Chris Needham <chris.needham@bbc.co.uk>
Date: Wed, 19 Sep 2018 19:37:21 +0000
To: "public-web-and-tv@w3.org" <public-web-and-tv@w3.org>
Message-ID: <590FCC451AE69B47BFB798A89474BB363E1A94DD@bgb01xud1006>
Dear all,

The minutes from Monday's Media Timed Events Task Force call are available [1], and copied below.

There are a few action items from the call:

1. Chris to merge the open pull requests to the use case and requirements document. [Done]
2. Giri, Charles (and all) to review the changes related to DAInty.
3. Chris to draft a message to send to the WICG Discourse forum.
4. Rob to post an issue linking to WebVMT. [Done]
5. Giri and Chris to review and add to the the use case descriptions, as needed.

The next Task Force call will be on Monday 15th October.

Kind regards,

Chris (Co-chair, W3C Media & Entertainment Interest Group)

[1] https://www.w3.org/2018/09/17-me-minutes.html

Media and Entertainment IG - Media Timed Events TF

17 Sep 2018



    Kaz_Ashimura, Chris_Needham, Mark_Vickers, Francois_Daoust, Nigel_Megitt, Rob_Smith, Giri_Mandyam, Steve_Morris



    cpn, kaz


    Agenda review
    Current status of the Media Timed Events document
    WebVMT introduction

Summary of Action Items

Summary of Resolutions

<cpn> scribenick: cpn

Agenda review

<kaz> Agenda

Giri: We have a change to the agenda today, Rob Smith could introduce WebVMT, related work.

<kaz> [fyi, the email address of the group list is public-web-and-tv@w3.org ]

Current status of the Media Timed Events document

<kaz> https://w3c.github.io/me-media-timed-events/ Media Timed Events use case document

Giri: We have 5 open issues and 3 pull requests

<kaz> https://github.com/w3c/me-media-timed-events/issues issues on GitHub

<kaz> https://github.com/w3c/me-media-timed-events/pulls PRs

Giri: #6 for use cases, are there more to be added?

<kaz> https://github.com/w3c/me-media-timed-events/issues/6 issue 6

<kaz> scribenick: kaz

Chris: We don't have a good description on the purpose, in the document
.... There are several use cases we can add, e.g., from the 3GPP use cases,
.... such as dynamic quizzes, surveys, additional web content related to a programme.

Giri: OK

Chris: I'd like to add some of them, if we're allowed to.

<cpn> scribenick: cpn

Mark: The most common use cases I hear about are: ad insertion messages, and enhanced TV (red button).

Giri: I'll assign this to myself

Nigel: There's an implication with in-band events, that the event changes the media that the user is getting.
.... A model that changes the media stream that's being consumed. Need to consider what the UX is for that, e.g, how the back button works?
.... We've talked about ad synchronization already. But also, regional services, e.g., a nation-wide news programme with segments that are regional.
.... After those, you jump back to the main programme. From a streaming point of view, you want the minimum number of encodings, and smooth playback.
.... Something we could consider as a use case here.
.... The distinction is whether you are switching the main programme stream, or accessing additional media.

Mark: Regarding meeting schedules, when we started this we didn't want to go beyond TPAC for this work.
.... For example, emsg in CMAF drives some urgency to get this in.
.... I'm concerned that we don't have the browser representatives on the call.
.... I'd like to see us move to the WICG, we know the subject matter and use cases, we don't want to miss the opportunity.
.... We have to go to the browser people, in WICG, start a topic in Discourse, then open a repo there and move the document over there.
.... We'll get more participation there, and things should move faster.

Rob: I'm proposing a break-out session at TPAC, for video metadata cues including localization, I'm trying to get the browser people involved too, to support this.

<kaz> scribenick: kaz

Chris: We could pretty quickly submit something to the Web Incubator CG.
.... The emsg support is a concrete requirement that we could progress,
.... while the IG continues to look at some more broader use cases.

Giri: OK

<cpn> scribenick: cpn

Giri: We're still on track to complete by TPAC

<tidoust> [I note the recommended steps to propose work to the WICG: https://github.com/wicg/admin/]

<tidoust> [Repo migration happens later on, and requires an Intent to migrate: https://wicg.github.io/admin/intent-to-migrate.html]

Chris: I could take an action item to open the Discourse discussion.

Mark: We just want to write a couple of paragraphs, and reference the document as work in progress.
.... My impression is that the browser vendors will respond, as it's on people's minds.

Giri: There's editors notes in the doc, so they'll see it's WIP, shouldn't be a barrier.

Chris: I'll draft something and share with you.

Giri: https://github.com/w3c/me-media-timed-events/issues/5 terminology

Chris: The issue mentions "media timeline" I think we can close.

<kaz> https://w3c.github.io/me-media-timed-events/#terminology 2. Terminology

<kaz> scribenick: kaz

Giri: https://github.com/w3c/me-media-timed-events/issues/3 DAInty
.... There are 2 pull requests relating to this

https://github.com/w3c/me-media-timed-events/pull/12 pullrequest 12

https://github.com/w3c/me-media-timed-events/pull/13 pullrequest 13

Chris: Yes, #12 adds a description of DAInty based on discussion from the last TF call.


Chris: And #13 summarises the requirements for an emsg / DASH event API.

Giri: OK. It's hard to preview using the diff, so let's merge these and review.
.... regarding issue #1, we don't really have to care about this ourselves,
.... this will be up to the spec editors, as things progress.

https://github.com/w3c/me-media-timed-events/issues/1 issue 1

Chris: OK.

<cpn> scribenick: cpn

WebVMT introduction

https://www.w3.org/2011/webtv/wiki/images/8/8f/WebVMTIntro180917.pdf Rob's slides

Rob: I'm Rob Smith from AwayTeam Software, Invited Expert in the Spatial Data on the Web Interest Group.
.... WebVMT is aimed at the mobile video market, dashcams, drones, etc.
.... Proprietary formats in use for dash-cam data, speed, acceleration, and geolocation.
.... These are embedded into the MPEG files, and needs a proprietary video player.
.... Standards exist within MPEG, there's format specific data in MPEG.
.... I want something for the Web, that can be used with WebM and Ogg video.
.... We have a format based on WebVTT. It's an annotated map, can share location in a web friendly format.
.... Can rapidly index video archives: does this geolocation appear in this video archive? Useful for web crawlers and search engines.
.... Drones as sensor platforms.
.... What browser support is required? Pass the track data, generate metadata cues. I'm currently puzzling over this.
.... Is WebVMT data a special case, or is there a generic approach?
.... Pass as text or as a structured object with a specific interface?
.... This is the main topic for my proposed TPAC discussion.
.... http://webvmt.org gives a clear overview of the concept and technical demos.
.... We're currently in incubation in the W3C strategy funnel.
.... It's monitored by the Spatial Data on the Web IG at W3C, and OGC.
.... Next steps are evaluation and then chartering a group for Rec track.
.... I'm interested in identifying communities who can use this. Write the format more formally for TPAC.
.... Want to find key players to standardise, discuss applications for it.
.... Paritipating in the OGC testbed activities.

<kaz> scribenick: kaz

Chris: With the DataCue API for emsg events, the message has blob for payload,
.... so it's up to the application to know how to extract the data.
.... Is there any schema description?

Rob: It's on my list to do.

<cpn> scribenick: cpn

Kaz: Thank you for presenting. I used to work for the geolocation WG. Could this handle acceleration and orientation as well?

Rob: Yes. Orientation is on the list of features to include, from an augmented reality point of view.
.... Direction, pan, tilt, etc. Superimposing information on top of video requires orientation.
.... For acceleration, the dashcam market is a good example.
.... The format is XML-like.

Kaz: The geolocation work is now in the Device and Sensors WG, you might want to look at that.

Nigel: I suggest it might be more useful to look at the API side of things than the serialization format.
.... There are other formats than WebVTT, others more XML-like
.... Lack of a schema makes WebVTT is difficult to validate.
.... Having a model you can express as an API may be more useful.
.... For example, extending the TextTrackCue with additional metadata.

Mark: I want to underline what Nigel said, the W3C's main concern is the API between applications and the browser.

Rob: That's one of the drivers for WebVMT, to get away from encodings into specific media formats.

Nigel: You may want to choose a data model and API rather than a serialization format.

<MarkVickers> The other thing I'd add is you should add a section on privacy & security. Geolocation is considered very private data.

Giri: Thank you Rob, and all for participating. If we feel this should be added to our to document, please add an issue.

Chris: Next call is October 15th, the week before TPAC.

<kaz> [adjourned]

Summary of Action Items
Summary of Resolutions
[End of minutes]
Minutes formatted by David Booth's scribe.perl version 1.152 (CVS log)
$Date: 2018/09/19 18:27:59 $

This e-mail (and any attachments) is confidential and
may contain personal views which are not the views of the BBC unless specifically stated.
If you have received it in
error, please delete it from your system.
Do not use, copy or disclose the
information in any way nor act in reliance on it and notify the sender
Please note that the BBC monitors e-mails
sent or received.
Further communication will signify your consent to
Received on Wednesday, 19 September 2018 19:39:00 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 17:57:40 UTC