[me][tpac] draft minutes - 16 September 2019

available at:
  https://www.w3.org/2019/09/16-me-minutes.html

also as text below.

Very sorry for the delay. I thought I had sent out these draft minutes
the other day, but it seems the message didn't go out.

Thanks,

Kazuyuki

---
   [1]W3C

      [1] http://www.w3.org/

                               - DRAFT -

     Media and Entertainment IG f2f meeting at TPAC 2019 in Fukuoka

16 Sep 2019

   [2]group photo from the WoT F2F meeting on 19-20 September 2019

      [2] https://www.w3.org/me-f2f/photos/0916/DSC_3346.JPG

   Group photo from the WoT F2F meeting on 19-20 September 2019
   (Some more photos from at the [3]F2F at Hilton)

      [3] https://www.w3.org/me-f2f/photos/0916/

   [4]Agenda

      [4]
https://www.w3.org/2011/webtv/wiki/Face_to_face_meeting_during_TPAC_2019#Agenda_Monday_16_September_2019

Attendees

   Present
          Andreas_Tai, Anssi_Kostiainen, Chris_Needham,
          Daiki_Matsui, David_Fazio, Eric_Siow, Florent_Castelli,
          Gary_Katsevman, Greg_Freedman, Hiroaki_Shimano,
          Hiroshi_Fujisawa, John_Riviello, Josh_O_Connor,
          Kaz_Ashimura, Li_Lin, Mamoru_Takagi, Mark_Watson,
          Masaya_Ikeo, Masayoshi_Onishi, Nonoka_Jinushi,
          Pierre_Lemieux, Scott_Low, Shinya_Abe, Sudeep_Divakaran,
          Tatsuya_Igarashi, Xu_Song, Yongjun_Wu, Youngsun_Ryu,
          Yuki_Yamakami, Takio_Yamaoka, Akihiko_Koizuka,
          Keiichi_Suzuki, Michael_Li, Takahiro_Kumekawa,
          Chris_Cunningham, Taki_Kamiya, Jeff_Jaffe, David_Singer,
          Glenn_Adams, Hyojin_Song, Francois_Daoust, Ken_Komatsu,
          Toshiya_Nakakura, Jonathan_Devlin, Amit_Hilbuch,
          Steve_Anton, Sebastian_Kaebisch, Daniel_Peintner,
          Nigel_Megitt, Samira_Hirji, Alan_Bird, Mark_Foltz

   Remote
          Kazuhiro_Hoya, Lei_Zhai, Mark_Vickers, Yajun_Chen

   Regrets

   Chair
          Chris, Igarashi, Pierre

   Scribe
          kaz, tidoust

Contents

     * [5]Topics
         1. [6]Welcome and introduction
         2. [7]Hybridcast update
         3. [8]Media Timed Events in Hybridcast
         4. [9]Media Timed Events Task Force
         5. [10]CTA WAVE update
         6. [11]Review open issues
         7. [12]Frame accuracy synchronization (contd)
         8. [13]Professional media workflows on the web
         9. [14]Bullet Chatting
        10. [15]Joint meeting with Second Screen WG/CG
        11. [16]Joint meeting with Timed Text WG
        12. [17]Closing and wrap-up
     * [18]Summary of Action Items
     * [19]Summary of Resolutions
     __________________________________________________________

Welcome and introduction

   <inserted> scribenick: kaz

   Chris: welcome and let's get started
   ... this is a one-day meeting today
   ... starting with the general view about the MEIG
   ... [W3C Code of Ethics]
   ... [Media&Entertainment IG: Mission]
   ... apply Web technology in general to media services
   ... new use cases/requirements to drive the discussion
   ... [History of Major Initiatives]
   ... 1. 2011-2014: HTML5 Media Pipeline
   ... 2. 2011-2017: Adaptive streaming & content protection
   ... 3. 2017-2019: Media Web App Platform
   ... [Charter]
   ... scope covers almost everything
   ... end-to-end pipeline
   ... continuous experience
   ... increasing interactive media
   ... including games
   ... [Charter (cont.)]
   ... Tasks
   ... identify requirements
   ... incubation of technical
   ... review media-related deliverables
   ... coordinate with other media-related groups, e.g., MPEG,
   HbbTV, ...
   ... internationalization, accessibility, etc., are very
   important
   ... [Work Flow]
   ... new ideas & issues from Members and SDOs
   ... use cases, requirments and gap analysis
   ... but not specs themselves
   ... because this is an IG
   ... but some of the results could promote new features for
   other WGs
   ... we're encouraged to work on more and more new features
   ... [WICG]
   ... discourse forum there
   ... get implementer supporter for your idea
   ... GitHub repo for your proposed feature
   ... [Contributing to HTML and DOM]
   ... HTML WG and WHATWG
   ... [Task Forces]
   ... 2018-19: Media Timed Events TF
   ... 2016-17: Cloud Browser API TF (dormant)
   ... [Monthly conference call]
   ... 2019/2018
   ... (list of topics)
   ... [Activities for 2020]
   ... whole bunch of topics for Media WG
   ... potential candidates for adaptation
   ... MEIG can input use cases and requirements
   ... [Activities for 2020 (cont)]
   ... what will be new topics for 2020?
   ... what would be the main things?
   ... would like to capture ideas
   ... in the after noon, we'll have more open discussion
   ... [Schedule]
   ... (shows the agenda)
   ... any additions?
   ... [Resources]
   ... various links here
   ... btw, we have a new co-Chair, Pierre, here

   Pierre: involving standard activity, e.g., IETF
   ... started with HTML WG for W3C
   ... co-editor of TTML 1.0
   ... feel free to contact me and Chris (and Igarashi-san)

   Chris: would mention that Mark Vickers stepping down as a
   co-Chair
   ... has been leading the group successfully
   ... really getting the Web as the platform for media
   ... Mark will continue to participate in the MEIG

   Mark: one of the founding co-Chairs
   ... plan to stay involved as an Invited Expert
   ... the best source consolidated expertise is media, video and
   audio
   ... before HTML5 media support in the Web
   ... we've been a good source
   ... for W3C, WHATWG, Kronos, etc.
   ... we don't write specs ourselves
   ... but see what's the priority for media on the Web
   ... provide expertise
   ... communicate with media companies, etc., which are not in
   the W3C as well
   ... it takes a lot of work
   ... glad to help
   ... a lot of leadership in studio world
   ... and so on
   ... have three very strong co-Chairs
   ... and Pierre is joining
   ... aiming for HTML5 media 2.0
   ... this is really a time to better support for media
   ... Comcast, my company, provides a new rep

   John: yes, I'm here

Hybridcast update

   [20]slides

     [20]
https://www.w3.org/2011/webtv/wiki/images/d/d3/RecentAchievementHybridcast_TPAC20190916.pdf

   Ikeo: welcome to Japan!
   ... would talk about Hybridcast
   ... [Today's outline]
   ... recent achievement of hybridcast
   ... [Deployment status]
   ... [History of standardization and experiments]
   ... 2014-2019
   ... hybridcast connect deployed on some of the TV sets
   ... [Shipment of Hybridcast receivers]
   ... number of receivers over 10 million
   ... [Trial deployment "Hybridcast-Connect"
   ... what is hybridcast connect?
   ... new functions/services uses new APIs
   ... new APIs are experimentally implemented in some of the TV
   sets
   ... brought an example here
   ... a number of companies are involved
   ... [Typical Sequence by additional APIs]
   ... 5 functions
   ... 1. MediaAvailabilityAPI
   ... 2. ChannelsInfoAPI
   ... 3. StartAITAPI
   ... 4. TaskStatusAPI
   ... 5. ReceiverStatusAPI
   ... [Hybridcast Connect demo]
   ... will show a demo here
   ... (brings a TV set in front of the screen
   ... [Hybridcast-Connect demos]
   ... two demos
   ... 1 emergency alert
   ... 2. smooth guidance of catch-up
   ... [Supporsed use cases demo (1)]
   ... (Kaz adds webcam to webex)
   ... embedded buttons here on my PC
   ... press a button on the PC and get a notification on the
   smartphone

   David: accessibility consideration?
   ... would be important

   Ikeo: agree

   Pierre: API to TV? or smartphone?

   Ikeo: pairing between TV and smartphone

   Igarashi: depending on the TV's implementation
   ... possibly implemented as an application on the TV side
   ... the Hybridcast connect specification itself just specify
   the protocol

   Yongjun: additional latency?

   Igarashi: remote control for playback, etc.?

   Ikeo: go back to [Typical Sequence by additional APIs]
   ... explains the sequence of communication
   ... using websocket

   Yongjun: how much latency there?

   Ikeo: TV-set dependent

   Igarashi: support all the functions?

   Ikeo: some specific functions are supported

   Igarashi: arrow keys are supported?

   Ikeo: yes
   ... would like to support all the keys included in the TV
   remote

   Igarashi: but there are too many buttons

   Ikeo: also we need to consider security
   ... e.g., to avoid unexpected change of volume
   ... here, all the 5 APIs are implemented based on HTTP

   Sudeep: infra-red remote vs this API?
   ... what kind of values are added?

   Pierre: TV implements some specific capabilities

   Igarashi: TV vendors have to implement the APIs

   Lilin: how many TVs could be controlled?

   Ikeo: more than two
   ... we'd like to handle more than one TVs
   ... but TV vendors say hundreds of mobiles can't be connected
   ... maybe 2-3
   ... TV is used within a local network
   ... user selects which would be the best one to get connected

   David: the system detects the devices available
   ... are children notified?

   Ikeo: application keep it stored in the session information
   ... the user don't have to mind

   Pierre: emergency notification itself is not included in the
   protocol
   ... its separate

   Ikeo: right
   ... these 5 APIs implemented within the device
   ... so device APIs
   ... not Web PIs

   Chris: looking at secure protocol?

   Ikeo: some solution
   ... we have two devices using some key

   Chris: second screen wg works on secure protocol
   ... so you're aware of that

   Ikeo: right
   ... the problem is HTTPs in local network
   ... tx for your comments!
   ... [Supposed use cases demo (2)]
   ... implemented as a service like Netflix or Amazon Prime Video
   ... application selects a program from a list
   ... using just one API
   ... (select a program on his smartphone)

   <MarkVickers> Q: What would the Hybridcast group like from W3C?
   New specs? Changes to specs?

   <MarkVickers> Thx

   Ikeo: launch the HTMl5 app
   ... using Dash.js

   Igarashi: can control playback, forward/backward?

   Ikeo: can be done using websocket

   <MarkVickers> While it's always interesting to see what other
   groups are doing, we have to focus on our goals to drive
   changes into W3C and increase adoption of W3C standards outside
   of W3C.

   Yongjun: device features can be controled?

   Ikeo: some of the features

   Yongjun: how many subscribers?

   Ikeo: In some research, 30% of the TV sets can connect to
   internet now and we expect these TV sets to implement this
   protocol near future

   Chris: what would the Hybridcast group like from W3C?

   <scribe> ... new specs, gap analysis?

   Ikeo: would like to combine some Hybridcast APIs to W3C
   standards
   ... e.g., playback API, as Igarashi-san mentioned
   ... between a mobile and a TV

   Kaz: kind of like the formerly proposed TV control API?

   Ikeo: yeah...

   Chris: or something like proposed by the second screen wg?

   Ikeo: we have to select web standard APIs
   ... can't create another APIs ourselves
   ... that's the second demo
   ... [Conformance Test and verification]
   ... [Conformance Test for Hybridcast-Connect]
   ... IPTV Forum Japan provides hybridcast connect standard
   ... and also test kit
   ... this is the overview
   ... (shows a diagram)
   ... emulator as the test environment

   Chris: cover the Web application?

   Ikeo: end-to-end test
   ... similar to the tests by HbbTV, etc.
   ... [Service Verification by MIC project and others]
   ... MIC is Ministry of Internal Affairs and Communications from
   the Japanese Government
   ... service verification with Hybridcast-Connect
   ... in 2018 19 companies
   ... in 2019 23 companies
   ... that's it for Hybridcast update
   ... thank you!

   Chris: what other specific things to address the gaps?
   ... relationship with the Web platform test, etc.

   Ikeo: we require some functions from Web APIs
   ... TV vendors sometimes want and sometimes not

   Chris: ok
   ... move on to the next topic

Media Timed Events in Hybridcast

   Ikeo: [Service Patterns with Hybridcast Connect]
   ... broadcasters in Japan need trigger message to switch to
   broadcast service
   ... pattern1: from mobile app to broadcasing on TV
   ... pattern2: from another app in TV to broadcasting
   ... [Media Timed Events with Hybridcast-Connect]
   ... JP broadcasters interested in media timed events (MTE)
   ... same function as the trigger message
   ... there are two possible choices
   ... (MTE data in video resource + push emergency alert
   notification) to the smartphone
   ... another option (MTE data in video resource to another app
   on TV)
   ... there are those two possible patterns

   Chris: is this emsg?
   ... in ISO container
   ... in the DASH format

   Ikeo: yes

   Igarashi: upper pattern can be realized using mobile API
   ... but what about the bottom pattern?
   ... is the TV device at the bottom same as the one on the
   right?

   Ikeo: yes
   ... in the case of Android platform, the mechanism is something
   like intent

   Igarashi: general question about MTE
   ... unclear why you want to embed events within the video
   stream

   Ikeo: main reason is the cost of access the message API from
   mobile

   Igarashi: cost of notification servers

   Ikeo: right
   ... also the accuracy

   Igarashi: do we share the same requirements?

   Yongjun: which layer to be handled?
   ... should be fragment or manifest

   Igarashi: manifest embedded event?

   Ikeo: it depends on the needs
   ... in case of outbound, MTE might be written in the manifest
   ... and there would be possible delay

   Igarashi: could be updated frequently

   Ikeo: related to cost of access transfer
   ... trade-off of accuracy and cost
   ... show another demo on MTE
   ... (select an app on his mobile)
   ... send a message using hybridcast-connect to the TV
   ... this is embedded event
   ... emergency alert shown on the upper-right of the TV

   Chris: intended to synchronization of media?

   Ikeo: this mechanism just sends an alert
   ... and the Hybridcast application on the TV can handle how to
   display it
   ... [Usecases of MTE]
   ... switch broadcasting service from OTT triggered by emergency
   message
   ... super-impose time-dependent metadata, e.g., weather icon
   and event information
   ... new style of ad-insertion on a broadcasting service
   ... [MediaTimedEvents demos]
   ... demo implementations
   ... use case 1: switch live news program on braodcasting
   service from OTT service by emergency-warning message
   ... use case 2: super-impose a weather icon on the Internet
   video

   [21]slides

     [21]
https://www.w3.org/2011/webtv/wiki/images/d/d1/MediaTimedEventsInHybridcast_TPAC20190916.pdf

   Chris: what is the requirements?

   Ikeo: would like to show the picture on the warning
   ... but sometimes overlaps with the important content (e.g.,
   peoples faces)

   Igarashi: depends on the apps
   ... for some apps, accuracy is not important

   Ikeo: we have to consider the accuracy of timing for many cases
   ... that's all

   Chris: tx!

   Ikeo: btw, we would like other devices from the app on TV
   ... during the WoT demo, we'll show home appliance demos

   Kaz: at the lunch place, Argos on the 1st floor
   ... and Wednesday breakout

   Chris: excellent

   Ikeo: we'd like to use MTE as the basis

   [break till 11am]

Media Timed Events Task Force

   [22]slides

     [22]
https://docs.google.com/presentation/d/1f8LVFY3shrUsksKWLyBVQk3icDN4zEsgV0NX9oqPXNw/edit

   Chris: [Topics]
   ... in-band timed metadata and timed event support
   ... out-of band timed metadata
   ... improving synchronization of DOM events triggered on the
   media timeline
   ... also MPEG carriage of Web resources in ISO BMFF
   ... [History]
   ... our TF started in 2018
   ... Giri Mandyam from Qualcomm preesnted work at ATSC and MPEG
   on eventing
   ... published use cases and requirements document early this
   year
   ... [Use cases for timed metadata and in-band events]
   ... MPEG-DASH specific use cases
   ... notification to media player
   ... another use case about getting matrix during playback
   ... ID3 tags: title, artist, image URLs
   ... ad insertion cues: SCTE35, SCTE214-1, 2, 3

   David: keeping web page in synch with media
   ... you got slides and talking about the slide
   ... flip the slide dec and showing

   Chris: we have something like that in the explainer

   Pierre: we heard another use case in the morning

   Chris: multiple contents and multiple events

   Pierre: do you know if the cues tied to entire content?
   ... somebody may remove the trigger

   Chris: emsg separately handles

   Pierre: can remove part of the content and it's still relevant

   Chris: right
   ... [Recommendations]
   ... allow web application to subscribe to event streams by
   event type
   ... discussion on type of event
   ... maybe some concern
   ... something we can discuss
   ... also allow web applications to create timed event/timed
   metadata cues
   ... including start time, end time and data payload

   Igarashi: in the morning, we had some discussion on in-band
   message
   ... wondering if the current W3C standards support it
   ... only the scope could be in-band events?

   Chris: there are some implementations
   ... e.g., for HbbTV
   ... exposing MPD events
   ... W3C specs don't say anything about type of events
   ... next, actual triggering
   ... when cues are parsed from the media container by the UA
   ... when the current playback position reaches the cue
   start/end on the media timeline
   ... allow cues with unknow end time
   ... and finally
   ... improving synchronization (within 20 msec on media
   timeline)

   David: covers seeking?
   ... duration of events to be understood
   ... what would happen if jump-off?
   ... very hard to handle spike events

   Chris: some of that kind of use cases for DASH
   ... absolutely right

   Igarashi: requirement might be can detect that kind of delay
   ... applications would know about the difference between
   specified timing and actual fired timing
   ... we need to improved the timing (if possible)
   ... but should identify the gap
   ... e.g., based on the timestamp

   Chris: [Current status]
   ... almost complete Task Force use cases and requirements
   ... WICG DataCue explainer in progress
   ... API spec not started yet

   Yongjun: need to revise DASH spec, etc.?

   Chris: we need to have discussion about what kind of mechanism
   is needed first
   ... do we ask the UA to give structured data, etc.
   ... question about how the different formats should match the
   need

   Mark: the issue is how to map particular data format
   ... and how to present it
   ... the reference by HTML5
   ... need to be updated
   ... based on the newest MPEG spec

   <cpn> [23]https://dev.w3.org/html5/html-sourcing-inband-tracks/

     [23] https://dev.w3.org/html5/html-sourcing-inband-tracks/

   Mark: maybe another form

   Chris: really interesting
   ... other things reference it
   ... URL spec
   ... not really standardized
   ... definitely right we need handle it
   ... in more standardized shape

   Mark: another question
   ... data cue was implemented in webkit before HTML5

   <cpn> [24]https://www.w3.org/TR/media-frags/

     [24] https://www.w3.org/TR/media-frags/

   Mark: concern about syntax and semantics

   Chris: don't know the answer now
   ... a session by the Media WG will be held

   Mark: sounds like a right place

   Chris: [MPEG Carriage of Web Resources in ISO-BMFF Containers]
   ... saw TAG advice
   ... since then people working on MPEG as ISO/IEC FDIS 23001-15

   David: probably public

   Chris: this topic is welcome to the MEIG

   David: good to have a workshop including the MEIG, ISO, etc.
   ... trying to get users of technology at the same time at the
   same place
   ... including security experts

   Pierre: what is the use case?

   David: two things
   ... carriage of web pages
   ... synchronization of media

   Pierre: but what would be the actual business cases?

   <MarkVickers> FYI, we have previously gotten permission from
   MPEG to host MPEG documents on the W3C member-only website. We
   could ask for MPEG for permission to host CMAF spec for this
   purpose.

   Pierre: btw, the community draft is available

   Igarashi: benefit of web resource embedded to MPEG
   ... possibly reduce the cost for the web servers
   ... could be beneficial

   Pierre: the offline case is weird to me

   Igarashi: one of the use cases to be addressed
   ... there are some offline use cases
   ... for packaged delivery

   Chris: [Browser support for DataCue]
   ... current support by browsers
   ... edge: HTML 5.1 DataCue attribute ArrayBuffer data;
   ... chrome: no support
   ... safari: supported
   ... firefox: no support
   ... HbbTV: HTL 5.1 (8 Oct 2015 ED) DataCue with native handling
   of player specific events
   ... [Player support for DASH and HLS events]
   ... Shaka Player: shaka.Player.EmsgEvent no internal handling
   of manifest refresh events.
   ... (some more examples)
   ... [Next steps]
   ... breakout session on Wednesday about "DataCue API and time
   marches on in HTML" at 11:00am
   ... raise issues against WHATWG HTML to propose changes to time
   marches on

   MarkW: may have people aware of the algorithm
   ... during the Media breakout

   Igarashi: in scope of the Meida WG?

   Chris: right
   ... the Media WG would take on standardization if the direction
   is correct
   ... we started a TF within MEIG and now are looking at WICG

   Igarashi: any friction?

   Chris: we're looking at the possible API design

   Igarashi: what I remember from the previous TPAC
   ... we were looking at WICG
   ... but what would be the direction now?

   Chris: we don't have enough input
   ... need more concrete feedback for the possible API
   ... in JavaScript at the moment
   ... would be good to have more involvement
   ... also would be good to have more browser vendors
   ... need to have wider discussion
   ... if we proposed issues, that should go to WHATWG
   ... increasing timing accuracy
   ... [References]
   ... (links to resources)

   Igarashi: WICG would have their meeting?

   Chris: Thu/Fri
   ... also we have a breakout session ourselves

   Igarashi: it's good timing to have discussion with them
   ... should ask the other participants about opinions as well
   ... need to get opinions from the MEIG guys

   Pierre: when would be our final report available?
   ... more input needed?
   ... anybody have any specific objections?

   Igarashi: we have not specifically asked the MEIG for opinions
   ... report itself is about requirements
   ... it's an IG Note. right?

   Chris: yes

   Pierre: the report says something is missing and to be added?
   ... shouldn't say that explicitly?

   Chris: solution design to be done by WICG
   ... our TF could continue editorial changes
   ... everybody, please join in

CTA WAVE update

   (we're delayed by 30mins)

   [25]slides

     [25]
https://drive.google.com/file/d/1-mAhZe8s2TRDygCW1fPc-aJkvA1yCTH1/view?usp=sharing

   John: John Riviello from Comcast
   ... quick update on CTA WAVE
   ... [The Web Appliction Video Ecosystem Project]
   ... aims, focuses, ...
   ... [Supporting a fragmented OTT world]
   ... fragmentation impacts content providers and device makers
   ... [Brief history]
   ... CEA initiated the GIVE project in 2015
   ... CEA becomes CTA in Nov. 2015
   ... [Steering Committee]
   ... technical WG
   ... CSTF for content specification
   ... DPCTF for testable requirements
   ... HATF for reference application framework
   ... [WAVE bridges media standards & web standards]
   ... [Curent WAVE Membership]
   ... many members
   ... overlapping with W3C Members
   ... [What is the Common...]
   ... [WAVE COntent Spec & Published CMAF Media Profiles]
   ... [Media Profile Approval]
   ... profiles are added
   ... typically updated once a year
   ... [WAVE Content Specification 2018 AMD 1 - Video Profiles]
   ... [WAVE Content Spec 2018 AMD 1 - Audio Profiles]
   ... [WAVE Programs and Live Linear...]
   ... [Anticipated WAVE Content Spec 2019 Updates]
   ... [Test SUite: COntent Verification Tool]
   ... verification content
   ... shared with DASH-IF conformance validator
   ... [CSTF - Specification Process]
   ... annual f2f meeting
   ... [Links]
   ... links for resources
   ... [HATF: HTML5 API...]
   ... What We Do in the HATF]
   ... playback audio-video media
   ... [HATF Work Plan]
   ... W3C Web Media API CG
   ... [HTML5 APIs: Reference Platform]
   ... one content format but multiple devices
   ... [HATF Specs]
   ... snapshots
   ... Web Media API snapshop (WMAS)
   ... CTA and W3C co-publishing

   Igarashi: what do you mean?

   John: working on the same document

   Igarashi: not WG but CG?
   ... it's not "W3C Recommendation" but "CG Report"

   Francois: fyi, there will be discussion about W3C process
   during this week

   Alan: part of the plenary on Wednesday

   John: [Anticipated Web Media API 2019 Snapshot Updates]
   ... update to ECMAScript 7
   ... CSS snapshot 2018
   ... [HATF Testing Framework]

   <MarkVickers> FYI on referencing WAVE specs: ATSC references
   the WAVE WMAS as published by CTA, which is referencable. The
   W3C version of the WMAS spec, like all CG specs, includes
   boilerplate language that it should not be referenced.

   John: WMAS Testing Suite Updates]
   ... [Abstracted Device Playback Model]
   ... (skips some slides)
   ... [Spec Highlights and Outline Dec 2018]
   ... [Promisses in Spec for 2019 and beyond]
   ... [Test Sutie: RFPs]
   ... [Q&A]
   ... questions?

   Igarashi: what are you going to talk about "type1 player"?
   ... any room for W3C standardization?
   ... if you have any specific requirements, the MEIG can discuss
   that
   ... btw, what is the "Content Model Format"?

   Chris: question around testing
   ... is the work related to the web platform testing?

   Pierre: should we put that on the agenda for the afternoon?

   all: ok

Review open issues

   Chris: we use GitHub to manage issues
   ... most of the issues will be covered in the afternoon jointly
   with the other WGs
   ... but one specific issue here about frame accurate
   synchronization and seeking

   Francois: [Related GitHub Issues]
   ... issue 4, 5, 21
   ... the main issue is #4 frame accurate seeking of HTML5
   MediaElement
   ... [Categories of Use cases]
   ... 2 different use cases
   ... seeking and rendering
   ... [Main Seeking Use Cases]
   ... non-linear edition in a browser
   ... can be cloud-based
   ... collaborative review
   ... evidence playback by camera and video
   ... [Seeking Gaps]
   ... currentTime is not precise enough to identify individual
   frames
   ... also no way to seek to the next/prev frame in the generic
   case
   ... just matter of time
   ... when is going to be the next frame
   ... [Main Rendering Use Cases]
   ... dynamic content insertion (splicing)
   ... video overlays
   ... media playback synchronized with map animations
   ... synchronization between audio and timed text, e.g., karaoke
   ... synchonized playback across users/devices

   Igarashi: requirements for time seeking?

   Francois: this is rather rendering issues

   Pierre: sample alignment and duration
   ... current web platform doesn't allow frame-accurate timing

   Francois: [Rendering Gaps]
   ... currentTime is not precise enough to identify individual
   frames
   ... also timestampOffset is not precise to identify frame
   boundaries
   ... it's hard to track media timeline frame by frame
   ... in any case there is no mechanism to handle frame accuracy
   ... also synchronization between video and audio
   ... if you look at global synchronization
   ... no way to tie the rendering of a video frame to the local
   wall clock

   <MarkVickers> Following up on earlier question: It has always
   been the intention of WAVE to contribute back to W3C any new
   tests and also any changes to the W3C test runner. WAVE
   representatives met with the W3C test group at TPAC 2018. There
   was an issue opened on April 2, 2019:
   [26]https://github.com/web-platform-tests/wpt/issues/16214
   There was a PR entered on June 12, 2019:
   [27]https://github.com/web-platform-tests/rfcs/pull/23

     [26] https://github.com/web-platform-tests/wpt/issues/16214
     [27] https://github.com/web-platform-tests/rfcs/pull/23

   [lunch till 1:30pm]

Frame accuracy synchronization (contd)

   Francois: continue the slides
   ... [Rendering Gaps that Remain]
   ... currentTime is not precise enough
   ... timestampOffset is not precise enough
   ... three following requirements deleted
   ... [Seeking Gaps that remain]
   ... [Next Steps?]
   ... what do we want to do?
   ... follow up on MTE recommendations around synchronization?
   who?
   ... wrete a UCR document on frame accurate synch? who?
   ... feed needs back into WHATWG and Media WG? who?
   ... different possible groups to bring ideas to
   ... possibly machine learning group?
   ... discussion with different people on Wednesday

   Chris: production use cases?

   Pierre: put together a presentation
   ... what's happening about a lot professional asset
   ... have some demo as well

   MarkW: the problem is probably how to identify individual frame
   ... could be ended up with overlaps

   Chris: we need rationale

   Igarashi: (asks new comers to sing up with the attendees list)
   ... btw, this proposal includes two different points
   ... because the difficulty for realization is quite different
   ... depending on theperformance of the browsers and the
   hardware

   Francois: maybe write two documents or might be simply continue
   discussion
   ... there are different use cases
   ... some of them might be out of scope

   Pierre: sound and video synchronization is a use case
   ... not even possible currently
   ... there is no API for that purpose today

   Igarashi: that requirement is related to time seeking
   ... different from synchronization itself

   Pierre: when you say "seeking", it's API level. right?

   Igarashi: currently there is no way for requirements to specify
   how quickly browsers should behave

   Pierre: it's largely implementation-dependent?

   Igarashi: yeah
   ... current time issue and synchronization are different issues
   ... wonder if any other W3C specs handle that kind of
   performance
   ... how fast browsers are expected to render the data
   ... we need to talk about performance

   Pierre: sounds like you're interested in making contribution :)

   Yongjun: need some mechanism to handle frame jumping
   ... not only at the beginning
   ... if we care about one case, we may miss another case

   Igarashi: ad-insertion seamlessly?
   ... accuracy of seeking is important for many use cases
   ... but we should distinguish time seeking accuracy

   Pierre: if there is a stream and also another stream starts, in
   that case, need for frame accuracy

   Igarashi: that's true

Professional media workflows on the web

   Pierre: very timely topic
   ... proposal by MovieLabs
   ... increasing popularity
   ... [Web applications are coming to profesisonal media
   workflows]
   ... why?
   ... web applications have become mainstream
   ... web platform media capabilities are tantalizingly close
   ... profesisonal audiovisual assets are moving to the cloud
   ... [Why move audio-visual assets to the cloud?]
   ... instead of using UPS
   ... now available immediately on the cloud
   ... it's more secure actually
   ... and of course more efficient
   ... [Today]
   ... previsualization, visual effects, grading, editing,
   localization, mastering, qualit check, archival, distribution
   ... [tomorrow]
   ... all of them will be on the cloud (and can be accessed via
   web applications)
   ... [demo]
   ... ownzones
   ... content already on the cloud
   ... there is an editor here
   ... (for audio and timed text)
   ... (going back to the presentation)
   ... [Some steps of the workflow remain out of reach of web
   applications]
   ... gaps exist in the web platform
   ... what's missing?
   ... that's it

   Chris: we have many items, so don't want to dive into the
   details

   Yongjun: as far as I know, people use MSE

   Igarashi: video editing using browser
   ... requirements for rendering related to multiple video
   clipping
   ... handle frames seamlessly

   Pierre: we need volunteers

   MarkW: not volunteering myself but support the use cases

   Scott: folks here might want to consider local content

   Igarashi: local content using browser?

   Scott: not necessarily on the cloud
   ... how to handle frame accuracy on the local devices

   Pierre: help document the issues?
   ... take a first step
   ... somebody needs to take the lead
   ... this is listing the current issues

   Gary: interested

   Chris: thank you

   Samira: gathering data
   ... we have a few ideas
   ... one of them is adding attribute to video tags
   ... somebody from Google also proposed media container
   ... my first question is
   ... would you have any thoughts
   ... will host a session on Wednesday

   Chris: related to content representation
   ... quite a lot of valuables
   ... we'll talk about caption later

   Andreas: where to standardize 360 video, etc.
   ... we have a presentation on that later in the afternoon
   ... also a session on Wednesday
   ... possibly tomorrow as well

   Chris: anybody aware of MPEG format update?

   David: whole bunch of work

   <tidoust>
   [28]https://mpeg.chiariglione.org/standards/mpeg-i/omnidirectio
   nal-media-format

     [28]
https://mpeg.chiariglione.org/standards/mpeg-i/omnidirectional-media-format

   <scottlow> [29]https://mpeg.chiariglione.org/standards/mpeg-i

     [29] https://mpeg.chiariglione.org/standards/mpeg-i

   <dsinger> [30]https://mpeg.chiariglione.org

     [30] https://mpeg.chiariglione.org/

   Andreas: TTWG has liaison with MPEG
   ... but just one part of scenarios
   ... inband information
   ... doesn't sort the issues about outband captioning

   <Joshue108> There are also accessibility requirements around
   how 360 is standardised.

   Andreas: possibly discuss that tomorrow?

   Samira: possible
   ... how many content producers, providers, here?
   ... what block you?

   Song: China Mobile

   Igarashi: VR content protection?

   Samira: can be represented as VR
   ... magic window scenario
   ... just wanted to bring this discussion up

   Chris: what's the natural home for this discussion?
   ... first candidate is Timed Text

   Samira: just wanted to share the ideas since this is an IG

   Josh: There are accessibility requirements if 360 is to be
   standardised, around an architecture that will support
   accessibiity and multimodal requirements.

   Andreas: would like to come back later in the afternoon
   ... where to do it
   ... really difficult to find a right place

   Chris: related to accessibility

   Sudeep: Chair of the Web&Networks IG
   ... will have our meeting tomorrow
   ... please drop by
   ... interested in Media Timed Event as well
   ... network latency
   ... very happy to give inputs

   Chris: interesting questions
   ... very close relationship with this group
   ... having a Web interface
   ... webrtc stream for multiple different sources
   ... it is stuff we've been implementing
   ... not necessarily synchronized with each other

   Sudeep: how should we bring back?

   Chris: GitHub issues
   ... also we have monthly IG calls
   ... have media-related topics

   Josh: particular accessibility issue in synch with video stream

   Chris: yeah

   Josh: bunch of stuff

   <Joshue108>
   [31]https://www.w3.org/WAI/APA/wiki/Accessible_RTC_Use_Cases

     [31] https://www.w3.org/WAI/APA/wiki/Accessible_RTC_Use_Cases

   Josh: can put resource on what I'm working on (above)
   ... related to this group
   ... different modality channels based on user's preference,
   TTS, braille, etc.

   (kaz remembers the MMI Architecture and SCXML, which are used
   to integrate multiple modality channels :)

   Chris: any other issues?

   Igarashi: local packaging?
   ... publishing group is working on packaged media
   ... playback locally
   ... on a local storage
   ... might be with very high resolution of time

   Chris: seems we need another gap analysis

   <tidoust> [Note the breakout session on Web Packaging planned
   on Wednesday:
   [32]https://w3c.github.io/tpac-breakouts/sessions.html#wpack]

     [32] https://w3c.github.io/tpac-breakouts/sessions.html#wpack

Bullet Chatting

   Song: Song Xu from China Mobile
   ... would give a presentation about bullet chatting
   ... Michael from Dwango as well

   <cpn> [33]https://w3c.github.io/danmaku/index_en.html

     [33] https://w3c.github.io/danmaku/index_en.html

   [34]proposal

     [34] https://w3c.github.io/danmaku/index_en.html

   <scribe> scribenick: tidoust

   Song: Interactive tool for video broadcasting over the
   Internet. Use cases: see reviews of group users. Real-time
   interaction, engagement for young generation, to show social
   presence.
   ... Implementation is difficult because you need to compute the
   positioning and animation of bullet chatting, rendered in DOM
   or Canvas and overlaid on top of the video.
   ... Strong demand for this type of applications, particularly
   in Asia
   ... Standardization would improve UX, reduce the difficulty in
   implementation.
   ... We suggest to define a standard format for bullet curtain.
   ... We started an analysis to identify gaps. No specific API
   introduced for the time being.
   ... Bullet chatting is basically floating text over the screen
   with four attributes:
   ... mode, basic properties, timeline, and container (typically
   the video)
   ... [going through Bullet Chatting Proposal document]
   ... During streaming, two main ways to present: chatting room
   or bullet chatting.
   ... Advantages of bullet chatting display are that there is a
   wider display area and it does not require the user to move her
   eyes.
   ... The movement from right to left allows users to read
   content quickly (and again without moving her eyes).
   ... Sometimes, it's not only about comments, it can be text to
   improve the feeling of horror videos for instance.
   ... Also used to share messages in stadiums on a big wall.

   Michael: I'm from Dwango. Use cases and requirements for our
   current service Niconico.
   ... Niconico is a streaming Web site launched in 2006. Since
   its inception, its unique feature has been its comment system.
   ... [showing a demo]
   ... allows to create a user experience.

   Pierre: Who specifies at what vertical position the bullet
   curtain appears?
   ... Do you foresee that to be done at the client side?

   Song: No, done on the server side

   Pierre: So the format has all the positioning information.

   Michael: In the current implementation, clients do the
   rendering, and they all have the same algorithm, so
   deterministic.

   Pierre: If things were standardized at W3C, would the
   positioning be imposed by the server?

   Michael: Currently, we'd like the client to have the ability to
   position the comments.

   Pierre: So the client receives the comments and decides where
   to lay them out.

   Igarashi: You want to let the browser do the whole rendering?

   Michael: No, the Web application.
   ... Goal of the standardization is to have a shared format for
   bullet curtains, because many providers have a similar comments
   system (Niconico, Bilibili, etc.)

   Song: First step is to define an interoperability format. If
   there is a way to involve the browser vendors, then great,
   second step.

   MarkW: Browsers would want to know why something cannot be done
   in JS.

   David: And you could possibly do it with WebVTT / TTML.

   Song: For advanced features, there are things that TTML does
   not address. Happy to talk with TTML folks though.

   Michael: Use cases and requirements level for now. Possible
   solutions are still very early stage.
   ... Bullet curtain allows to create feelings such as sharing
   content with friends.
   ... Comments can be used to improve the video with artwork, or
   even to flood the video with comments.
   ... Comments have become an important part of Niconico's
   culture.
   ... Part of on-demand and live-streaming services of Niconico.
   ... Comments move right to left across at set times, based on
   the media timeline.

   Chris: If I pause the video, do the comments pause?

   Michael: Yes.
   ... Comments are clipped to the edge of the player (or to an
   arbitrary region).
   ... When the video loads, comments are loaded from the server
   and rendered.
   ... If a user submits a comment, it appears immediately to the
   user, and gets shared to other viewers.
   ... Seeking to the same time in the same video will have the
   same comment appear at the same time and at the same position.
   ... As if the comments were part of the video, comments scale
   with the video in particular.
   ... Comments can be interactive (e.g. context menu)

   MarkW: Layout problem (HTML is good at it), animation problem
   (Web Animations), but the thing is Web Animations ties
   animations to the wall clock, whereas here animation is tied to
   the media clock.
   ... That may be a useful gap to identify

   Chris: Came earlier during Francois' presentation. Tying
   non-media content rendering to media timeline.

   Igarashi: Some requirements about positioning the subtitles.
   ... Client decides arbitrary where to position the comments.

   Michael: Yes.

   Igarashi: Content provider does not care about positioning of
   subtitles.

   Sangwhan: Aside from Web, do you also want to handle support
   for native players?
   ... That would change perspectives.

   Michael: We do have native apps, so we'd be interested with a
   solution that covers that space too.

   Sangwhan: According to Mark's idea, if it's tied to the
   animation timeline in browsers, you're restricting yourself to
   Web environment.

   Kaz: When I talked to Koizuka-san from Niconico, he mentioned
   extension mechanism named "Nico-script", and that mechanism has
   capability of specifying style and position of captions. so
   that capability could be also considered at some point. maybe
   not now, though.

   <MarkVickers> I'm not staying connected for the joint meetings.
   Have a good TPAC all! -mav

Joint meeting with Second Screen WG/CG

   Chris: The Second Screen WG/CG made a lot of progress on the
   Open Screen Protocol for discovering, authenticating and
   controlling remote displays on the local network.

   MarkF: I work for Google. Been involved in Second Screen since
   2015. Second screen for the Web is the way we want to enable
   Web applications to take advantage of connected
   displays/speakers and render different types of content.
   ... Content can be a full Web page or specific media.
   ... The Presentation API enables a web page, called the
   controller, to request display of an URL on a remote display on
   the LAN.
   ... Example of a photo app that displays the loaded picture on
   a large display. You can play media, do gaming, collaboration
   tools. Pretty agnostic, but our experience shows that it's
   mainly used for media playback.
   ... The Remote Playback API allows a web page on which there is
   a media element to remote the playback of the media element on
   a second screen, either through media flinging where the URL to
   play gets sent to the remote device, or media remoting where
   the media gets streamed to the second screen.
   ... Both APIs are in Chrome.
   ... The APIs were designed to take advantage of proprietary
   protocols. To get broad adoption, we decided to develop an open
   set of protocols so that implementers could all support the
   APIs in an interoperable way.
   ... We hope to converge at the end of the Second Screen F2F
   meeting this week to v1.0 of the Open Screen Protocol.
   ... One use case for the future: enabling Web applications to
   generate their own media and present it to a connected display,
   e.g. for gaming.
   ... The Open Screen Protocol supports all sorts of use cases
   that we hope to expose to Web applications in the future.

   Yongsun: Support of QUIC in smart TVs. UDP is not supported in
   some TVs.

   Sangwhan: UDP is supported at the kernel level.

   MarkF: in our library implementation, we expose UDP but that's
   pretty much the same thing as what you get at the system level.

   Chris: One of the question that came up in our previous F2F
   meeting is around synchronization, e.g. ability to provide
   audio description on their device while they are sharing a
   media element on a second screen.
   ... Within that, there is the question of how close the
   synchronization needs to be.
   ... We worked on close synchronization between main screen and
   companion device in HbbTV.

   MarkF: Does the HbbTV specification rely on clocks?

   Chris: Yes, clock synchronization and then the devices can make
   adjustments to playback to stay in sync.

   MarkF: We need a mechanism for the two sides agree on a wall
   clock for presentation.
   ... If the HbbTV covers all of that, we can have a look for
   OSP.

   Chris: Yes, it does.

   <anssik> Open Screen Protocol issue Requirements for
   multi-device timing while streaming
   [35]https://github.com/webscreens/openscreenprotocol/issues/195

     [35] https://github.com/webscreens/openscreenprotocol/issues/195

   Chris: Some implementers have found it difficult to achieve
   that level of synchronization. It's not so widely implemented
   for now.
   ... I can provide information on how that has been done.

   MarkF: Collaboration between the protocol and the application
   levels.

   Chris: And also something that exposes the pipeline delays.

   MarkF: One of the things that seem very important is the
   establishment of a secure communication between devices, which
   could have broader implications, such as connected home
   scenarios.
   ... it could be a good foundation for that. Part of the OSP
   focus has been on authenticating devices, currently based on
   SPAKE2.
   ... We're not currently focused on enabling one piece of
   software to find out attributes of another, for instance who
   manufactured it, what does it do.

   <anssik> SPAKE2
   [36]https://datatracker.ietf.org/doc/draft-irtf-cfrg-spake2/

     [36] https://datatracker.ietf.org/doc/draft-irtf-cfrg-spake2/

   MarkF: You could take the chapter on authentication and use it
   elsewhere.
   ... We did anticipate that there may be other use cases than
   the ones we foresee, so have landed an extensibility mechanism.

   Sangwhan: Is there a registry for these capabilities?

   MarkF: Yes, it's on GitHub.
   ... You can be a presentation controller, receiver, send or
   receive media, that's all negotiable in the OSP.

   Chris: I suspect remote playback of encrypted content is a use
   case shared by different members here.

   MarkF: The API is pretty much agnostic. At the protocol level,
   we haven't tried to add support for messages to exchange to
   support encrypted media.
   ... That seems more to be a use case for the Presentation API
   where the application can create and exchange
   application-specific message commands.
   ... Remote playback of encrypted media is closely tied to
   credentials, and that's application level.

   MarkW: The thing that you don't have here is the streaming
   model where the controlling device has the decryption key and
   wants to stream the content to the receiver device.
   ... What happens to the media stream when it reaches the
   receiver? Goes to a media element or through JS processing?

   Peter: receiver is handling the decoding.

   Chris: Is there an IG recommendation that we'd want to make?

   MarkW: The most likely model for us for doing this would be to
   have a receiving web application that handles the user's
   credentials

   Chris: That would make the sync issue interesting because it is
   then at the application level.
   ... One of the issues we have with Remote Playback is that we
   want to provide a custom UI, which means that we rather want to
   use the Presentation API for that.
   ... Didn't we discuss having a Media element through the
   Presentation API that gets automatically synchronized with
   local content?

   MarkF: I believe that's correct. I don't recall the status of
   it. It came up in May 2018, I think.

   <anssik> Second Screen May 2019 F2F
   [37]https://www.w3.org/wiki/Second_Screen/Meetings/May_2019_F2F

     [37] https://www.w3.org/wiki/Second_Screen/Meetings/May_2019_F2F

   MarkF: I think we probably agreed that it should be possible.
   It probably requires a few tweaks to the protocol so that it
   knows that the remoting is part of a shared presentation.
   ... We discussed whether everything could be done in script.
   Same recommendation for synchronization. What you might be
   missing is the latency of the media rendering pipeline.

   Chris: I have seen implementations that manage to do
   synchronized playback across devices through a timing server.

   Igarashi: I don't follow the discussion on encrypted media. You
   are not going to define how keys are exchanged in the protocol?

   MarkF: Someone with more experience on EME might be able to
   shed some lights as to what would be required.
   ... One reason we designed an extension system is that people
   interested in new features can propose them, prototype
   implementations, and then we can incorporate them in the spec
   if all goes fine. We don't have the expertise in the group.
   ... We're not defining the path for encrypted media from one
   device with another. Might work if both devices support HDCP.
   ... I think there is an open issue in our GitHub about remote
   playback and encrypted media.

   Igarashi: Arbitrary application message passing is supported?

   MarkF: Yes.
   ... In the spec, you'll see bindings between the API and the
   messages exchanged in the protocol.
   ... For instance, video.remote.prompt() requires exchanges
   messages between devices

   MarkW: Could the protocol work on TCP?

   Peter: You'd have to advertise it differently

   Igarashi: [question on security during remote playback]

   MarkF: the Remote Playback API does not require the receiver to
   be a user agent in the usual sense, it does require the
   receiver to support media playback as in the HTML spec.

   MarkW: The Presentation API requires the receiver to be able to
   render the URL, but the URL could be a non HTTP URL, custom
   schemes may be supported instead.

   MarkF: The spec defines processing of HTTPS URL, the rest is
   undefined.

   <anssik> Open Screen Protocol
   [38]https://github.com/webscreens/openscreenprotocol/

     [38] https://github.com/webscreens/openscreenprotocol/

   MarkF: We have a writeup of how the protocol interacts with
   custom schemes in the GitHub repo.

   Chris: That has been one of the extension mechanisms that we've
   been interested in for opening a Web page that has broadcast
   capability in HbbTV (perhaps Hybridcast has similar needs)

   <anssik> Custom Schemes and Open Screen Protocol
   [39]https://github.com/webscreens/openscreenprotocol/blob/gh-pa
   ges/schemes.md

     [39]
https://github.com/webscreens/openscreenprotocol/blob/gh-pages/schemes.md

   [discussion on second screen support in Hybridcast]

   MarkF: regarding authentication, we looked at J-PAKE and
   request/response challenges but we had memory concerns there so
   switched to SPAKE2 following internal discussion with security
   experts at Google.

   Peter: The protocol allows for more authentication mechanisms
   in the future.
   ... Devices can support their own mechanism.

   Igarashi: Co-chair of HTTPS in local network CG, meeting on
   Thursday morning. We haven't reached discussion on
   authentication. Would be good to align with Open Screen
   Protocol.

   Sangwhan: Is there a prototype?

   MarkF: We recently decided to add streaming to the OSP, which
   complicated things. We have a first implementation of
   Presentation API commands. No crypto because we've kept
   changing that.
   ... The library is coming. It implements the protocol. It does
   not do media rendering, it does not have JS bindings, etc.

   <anssik> Open Screen Library implementation
   [40]https://chromium.googlesource.com/openscreen/

     [40] https://chromium.googlesource.com/openscreen/

   Igarashi: If you want to apply the OSP to the broadcast
   protocol, we need to consider the case where the remote device
   is not a browser. For instance, channel change is done by the
   system, not the application.

   MarkF: Capabilities like supporting channel tuning is not in
   the OSP. If you think that the communication channel needs to
   be terminated on channel change, that can be added.

   Igarashi: In the case that some arbitrary message protocol is
   still necessary, you'd use the Presentation API, but the
   receiver may not be a browser agent.

   MarkF: seems like something for an extension.

   Chris: OK, thank you for the discussion.

   MarkF: Mostly, we want input on use cases that we haven't
   considered yet. We'd love to get feedback on the extension
   mechanism as well.

   Pierre: Thank you.

Joint meeting with Timed Text WG

   Andreas: We could start with 360 standardization

   Nigel: In TTWG, we're in the final stages of rechartering.
   ... Some things that we're considering such as karaoke.

   <Joshue108>
   [41]https://www.w3.org/WAI/APA/wiki/Accessible_RTC_Use_Cases

     [41] https://www.w3.org/WAI/APA/wiki/Accessible_RTC_Use_Cases

   Nigel: Quick agenda bashing, any topic you'd like to cover?

   Josh: accessibility use cases? See accessible RTC use cases
   document

   Chris: TTML and MSE?

   Nigel: Yes, opinions about exposing TextTracks from MSE.

   <Joshue108> apologises for throwing a curve ball to Nigel, I'm
   here for the XR bit but think this doc may still be useful as
   an FYI

   Andreas: Focus the discussion of the day on standardization of
   360 subtitles. Most of the stuff comes from an EU research
   project.
   ... To make it short, there have been extensive user tests. For
   captions, main requirement is to have subtitles that are always
   in the field of view. It's enough to have them on a 2D plane,
   no need to have them positioned in 3D.
   ... There should be some indication of where the audio source
   is positioned.
   ... Of course, you also need features present in TTML,
   TTML-IMSC profile being a good example.
   ... [demo of an application to test subtitles positioning]
   ... Lots of activity starting last year at TPAC. We started
   with a discussion in the Immersive Web CG. Then discussion
   within the TTWG, Media & Entertainment IG.
   ... In the end, we realized we needed more people from
   immersive and browser vendors.
   ... We wrote a proposal to be discussed in the WICG.
   ... There has been no comment on the WICG forum yet, so
   question is how do we proceed?
   ... Two additional activities worth noting. A colleague from
   Google proposed the creation of an Immersive Caption Community
   Group, and XR accessibility W3C workshop in November.
   ... There is awareness that something needs to be done.
   ... Hard to get enough resources to get started though.
   ... How to get time and resources from implementors?

   <Joshue108> Inclusive Design for Immersive Web Standards W3C
   Workshop Seattle Nov 5-6

   <Joshue108>
   [42]https://www.w3.org/2019/08/inclusive-xr-workshop/

     [42] https://www.w3.org/2019/08/inclusive-xr-workshop/

   Andreas: Everything is evolving, nothing really fixed.
   ... Is it really a web platform topic?
   ... Important to know when to stop if there is not enough
   interest.
   ... Apart from which group should deal with it, the question is
   also where does this solution fit?
   ... Authoring environments (Unity, Unreal), Web applications,
   WebXR API (linked to OpenXR) and 360 / XR device
   ... How to follow-up? I thought WICG would be the right place,
   but if there is not enough place, there is still the question
   of whether that's the right place. Not sure about Immersive
   Caption CG since it does not exist yet.
   ... TTWG is the right group but we need more expertise from the
   XR world.
   ... Another solution is to continue the work in a "private"
   repository.

   <Zakim> nigel, you wanted to ask what is the state of
   documentation of the requirements right now

   Nigel: What is the state of documentation in terms of the
   requirements?
   ... Describing positioning in 3D space, can I do it with audio?

   Andreas: There are documented user tests, as part of an
   European project deliverable.

   Nigel: I was thinking about requirements documentation. What is
   the problem that you're trying to solve, user needs.

   Samira: Who was the person who started the Immersive Caption
   Community Group?

   Andreas: Christopher Patnoe at Google

   Samira: OK. Another comment is that WebXR is becoming more
   stable.

   Andreas: Yes, the question for me is where should this go.
   ... The WebXR API does not know anything about what's inside
   the WebGL right now.

   Chris: Is all that's needed a delivery format and then some
   library can place that in the immersive environment?

   Igarashi: Do we need to extend APIs in the browser to support
   this?

   <igarashi> -q

   Andreas: OMAF defines a way to multiplex IMSC subtitles with
   MP4, but then it's all bound to that content format. Not sure
   it's sufficient for interoperability scenarios.

   <igarashi> +q

   Kaz: wondering about the possible relationship with Web

   Francois: WebVMT is about tracks positioned on a map, not in
   360 videos.

   Kaz: However, there is a possibility of mapping the positioned
   map to the 360 screen and then put caption on that screen

   Andreas: It would be an option to have a subtitle format, but
   burning captions in a frame does not provide good user
   experience.

   Josh: Looking at things from an accessibility perspective. APA
   would seem a good group to talk to.

   Andreas: We talked a lot with Judy, Janina and so on.

   <Joshue108> [43]https://www.w3.org/WAI/APA/wiki/Xaur_draft

     [43] https://www.w3.org/WAI/APA/wiki/Xaur_draft

   Josh: We created a list of requirements for XR in APA.

   <samira> IW group is also discussing dom overlays so this is
   another option for subtitles

   Pierre: How many people in this group doing 360 videos and XR
   content?
   ... One possibility is that this group is not the best group to
   get feedback from.

   Andreas: I don't know, that's what all groups say ;)
   ... We need a critical mass to do it.

   Pierre: People that build apps for Oculus, are they around?

   Andreas: I spoke to some of them. They always say that they
   don't provide subtitles.
   ... Some discussion in Khronos with Unity and Epic.
   ... I talked with Immersive Web folks. We'll talk about that on
   Wednesday 11:00 during Samira's breakout session.
   ... The issue that we have is that there is not endless time to
   deal with it. The project is running out. It stops next year.
   To push a standard, it will take 2-3 more years.

   <Joshue108> There are very few testing with people with
   disabilities in this space so this is very interesting.

   Igarashi: From a content production perspective, I'm interested
   in a format, but not sure about browser support for this.

   [44]https://github.com/immersive-web/dom-overlays

     [44] https://github.com/immersive-web/dom-overlays

   Francois: Not clear to me what you want to be standardized. DOM
   overlays could be one building block.

   Andreas: Yes, DOM overlays may be a good way forward to render
   captioning thatn burning things in WebGL.

   <Zakim> nigel, you wanted to wonder what the smallest thing is
   that we need to standardise first - is it a syntax for
   expressing a 3D location?

   <Joshue108> +1 to Nigel

   Nigel: Same point. Do we have agreement that it's about a
   syntax for expressing a 3D location?

   Andreas: Actually, that's not what we need, since we want it to
   appear on a 2D plane, that is what the users want.
   ... We need a way to indicate where in the 3D space the audio
   source is coming from.

   Gary: So you need some positioning in 3D to make that possible.

   Andreas: Define a good container is another issue.

   Josh: in the User requirements document I showed you, we took a
   modular approach.
   ... This architecture does not exist yet.

   <Joshue108> [45]https://www.w3.org/WAI/APA/wiki/Media_in_XR

     [45] https://www.w3.org/WAI/APA/wiki/Media_in_XR

   Josh: We're also looking at Media requirements in XR. Not
   vetted by the APA WG yet.

   Andreas: Lots of 360 content for the time being, and a lot of
   it without captioning.

   <Joshue108> s/module approach/modular approach

   Gary: WebVTT update. I joined TTWG half a year ago. Trying to
   get WebVTT to progress. One of the big thing is an
   implementation report exists right now.
   ... Something like 6-7 issues with it.

   <atai> Link to 360 subtitle requirement
   [46]https://github.com/immersive-web/proposals/issues/40

     [46] https://github.com/immersive-web/proposals/issues/40

   Gary: Basically, we're looking at features implemented in
   browsers and in VLC. Then identify features at risk, and
   possibly remove them to get a V1 out.
   ... Then hopefully convince browser vendors to implement the
   features that we may remove.

   <gkatsev> [47]WebVTT Implementation Report

     [47] https://www.w3.org/wiki/TimedText/WebVTT_Implementation_Report

   Glenn: Any SMPTE spec that includes 3d positions of audio
   sources?

   Nigel: That's a good question.
   ... One of the things we're doing around TTML2 is adding new
   functionality in extension modules. We're trying to constrain
   the core, and then provide the rest in extensions.
   ... There are a few ones that are ongoing.
   ... [details extensions]
   ... Right now, audio/video comes to MSE but not text.

   MarkW: My personal position is that things should be
   symmetrical across media types.
   ... At least in our application, we prefer to do the rendering
   of text tracks ourselves.
   ... It would be advantageous in which the browser is aware of
   text tracks.

   Nigel: You said my sentiment much better than I could.

   Gregg: I would argue that we don't want to render them
   ourselves, but we still want to control the rendering with our
   styles.

   MarkW: Yes, we want to have enough control of the rendering,
   but we could offload the rendering to the browser, that would
   be great.

   Nigel: It's been hard to get statistics about user
   customization, or people that play back content with captions.

   MarkW: In terms of rendering, you would still want the site to
   control enabling/disabling.

   <atai> +1

   Gary: We shouldn't try to do the same thing twice. If there's
   more support to do the new generic TextTrack thing, then that's
   good.

   Pierre: Two different questions: any objection to enabling
   symmetry in MSE? Are you going to use it?

   MarkW: First question is whether people think that could be
   harmful.

   Nigel: OK, I just wanted to raise it to get feedback.

   [No concerns expressed regarding question on whether people
   think that could be harmful]

   Josh: About accessibility in WebRTC use cases, challenge of
   synchronizing some of these things together when switching to a
   different modality. That's one.

   Nigel: It would make sense to talk about live contribution to
   see where that fits. How does live contributions actually work,
   what's the mental model?
   ... Alright, I think we covered all topics.

Closing and wrap-up

   Chris: Thinking about Media Timed Events, some editorial work.
   Planned discussion on DataCue. Around bullet chatting, more
   conversation will happen this week.
   ... Some possibility to go to Timed Text WG.

   Nigel: It feels to me that this IG could be the best place to
   give guidance for that if there's no clarity in TTWG on Friday
   about that.

   Andreas: Can you explain again how you want to proceed?
   ... Draft published in the Chinese IG, what would the ideal
   next step be?

   Song: Initially, contributors were from China. Now that
   NicoNico is engaged in discussions, work could go to TTWG, or
   perhaps in another group.
   ... We want the use cases to be approved by the IG, afterwards
   we'd like to push standardization work on identified gaps.
   ... Within the next few weeks, we'll have a last version of the
   use cases.

   Andreas: OK, so this week would be a good opportunity to decide
   where this should go.

   Chris: We had a lot of discussion around synchronization today.
   Frame accurate rendering.
   ... Ability to seek accurately within videos.
   ... Some interest to follow-up, although no one volunteers.
   ... The media production use case that Pierre presented would
   be a good perspective to address this.

   Pierre: With an action on Gary to follow up with Garrett Singer
   on that.

   Chris: Secure communications between devices, we heard
   interesting stuff from Hybridcast and HTTPS in local network,
   and Second Screen. Interesting set of approaches that could be
   compared.
   ... Seems like a good fit for HTTPS in local network CG
   discussions.
   ... Clearly the immersive captioning is interesting, but not
   sure what next step in this group should be. Maybe the
   Immersive Captioning CG could be the right forum.
   ... We talked about 360 videos. That's something that the IG
   could follow on. We have liaison with MPEG. Unless you feel
   that immersive group would be a better home.

   Samira: Possibly. At this point, I'm gathering input.

   Chris: Finally, there's the timed text in MSE proposal. Would
   that sit in TTWG?

   MarkW: It would be in scope of the Media WG.

   Chris: Have I missed anything from the summary?

   Pierre: One encouragement for you to clarify the scope in Media
   Timed Events.

   Chris: And also possibly make more specific recommendations.

   Pierre: I think it helps to have something concrete.

   Chris: OK, I think that's everything, thank for your presence
   today!

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


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