[Cloud Browser] minutes - 28 June 2017

available at:
  https://www.w3.org/2017/06/28-webtv-minutes.html

also as text below.

Thanks,

Kazuyuki

---

   [1]W3C

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

                               - DRAFT -

             Media and Entertainment IG - Cloud Browser TF

28 Jun 2017

   See also: [2]IRC log

      [2] http://www.w3.org/2017/06/28-webtv-irc

Attendees

   Present
          Alexandra, Colin, Kaz, Chris

   Regrets
   Chair
          Alexandra

   Scribe
          kaz

Contents

     * [3]Topics
         1. [4]UI scale
         2. [5]UI visibility timing
         3. [6]Media capabilities
         4. [7]Identification
         5. [8]MSE issues
         6. [9]Accessibility
         7. [10]TPAC 2017
         8. [11]Next call
     * [12]Summary of Action Items
     * [13]Summary of Resolutions
     __________________________________________________________

   alex: during the previous call
   ... we had a brief chat on the IG Note
   ... we can start over with the use cases
   ... have 2 points

   colin: updating the wiki page

   alex: quality of experience/service
   ... also MSE stuff
   ... let's go through the use case wiki

UI scale

   colin: not in a formal description yet
   ... starting with "UI scale"
   ... resolution like a scroll bar
   ... could be scaled down in a cloud browser
   ... what is different with the cloud browser solution?
   ... that is the first use case

   alex: in your view, what would be the impact for APIs?

   colin: you could look up device pixel ratio, etc.
   ... and user resolution
   ... prefer using guidelines for this

   kaz: possible collaboration between a cloud browser and another
   screen like a smartphone?
   ... possibly included in "displayed in another way (e.g. in a
   PiP)"

   colin: yes, but Cloud Browser doesn't know how to send that
   information (at the moment)

   kaz: maybe we need another channel or connection for that
   purpose

   coline: yeah
   ... so would see existing guidelines for that kind of
   requirements

   alex: possible control channel between the cloud browser and
   the server
   ... but we also would see guidelines because this need is not
   the first one

   colin: cloud browser and abstract orchestration layer
   ... two different levels
   ... same for the devicePixelRatio as well

   alex: we can decide use cases and requirements first
   ... and then think about what kind of APIs are needed

   colin: ok
   ... let's move ahead

UI visibility timing

   colin: "UI visibility timing"
   ... when does the end user sees the UI screen?
   ... Since the UI is terminated in the cloud it is hard to tell
   when the user actually sees it.

   alex: interesting

Media capabilities

   kaz: fine
   ... but maybe we should call these topics as "difficulties" or
   "issues" as the starting point of concrete/detailed use case
   descriptions

   colin: ok
   ... (move ahead)
   ... on a cloud browser solution you would also like to know
   which types are played natively on the client device and which
   are transcoded.
   ... some examples of codec



   var support = videoElement.canPlayType('type=\'video/mp4;
   codecs="avc1.42E01E, mp4a.40.2"\); if (support == "probably")
   console.log("natively supported") else if (support ==
   "virtually") console.log("supported by transcoding")

   ]]

   colin: existing APIs could be extended for cloud browser

Identification

   colin: identification is also a problem with cloud browser
   ... for example, with geolocation api
   ... how to identify the cloud browser and its device?
   ... also we need a means to analyze the problems

   alex: we need to clarify our requirements and also existing
   APIs (=gap analysis)

   colin: and the WG side should make decision about concrete APIs
   ... will update these description to generate proper use cases

   (chris joins)

   chris: will check the minutes
   ... any concrete expectation from me?

   colin: now we're talking about Quality of Service/Experience

   kaz: "Quality" could include accessibility. right?

   colin: right. but we have another separate section for
   accessibility

   chris: what is the difference between QoE and accessibility?

   kaz: maybe we could ask Chris to review all the use cases
   including QoS/QoE, couldn't we?

   colin: indeed related to each other

   chris: accessibility/usability viewpoint

   colin: "usability" has some specific meaning for broadcasting

   alex: there is another viewpoint from telecommunication as well
   ... QoS may include latency issue
   ... another question is
   ... have you thought about latency and packet loss?

   colin: have not done yet

   alex: ITU recommendation on video quality and how to measure it
   ... also what is important for each user?
   ... big issue with operation
   ... big infrastructure for QoS
   ... the operator sees problems on what QoS is

   colin: need to clarify what is expected for cloud browser UI
   ... would highlight generic problems within this group

   kaz: possible intermediate proxy server for identification
   topic?

   colin: have wide channel use case
   ... you need to add some information if you have multiple cloud
   browser devices at the same geolocation

   kaz: a possible use case is a collaborative game by multiple
   users at some specific meeting room

   colin: need a mechanism of communication with each other for
   multi-user game

   alex: broadcasting vs unicasting

   colin: we should clarify delivery mechanism for each specific
   use case

MSE issues

   alex: we have problems with MSE for Cloud Browser
   ... how we could adapt MSE for Cloud Browser?

   [14]MSE use cases

     [14] https://www.w3.org/2011/webtv/wiki/Main_Page/Cloud_Browser_TF/UseCases/MSE

   [15]UC3 Cloud-based MSE support

     [15] https://www.w3.org/2011/webtv/wiki/Main_Page/Cloud_Browser_TF/UseCases/MSE#UC-3_Cloud-based_MSE_support

   alex: explains the use case
   ... MSE is complex. Cloud Browser is also complex
   ... the mixture of them would be more complex
   ... we have a lot of steps within this UC
   ... split into 4 sub use cases
   ... 3.1 Execution of XHR



   1. CB initiates a session with the CB client (session id, user
   id)

   2. The CB client requests a web application that uses MSE for
   video delivery

   3. CB executes the web application: CB parses the html and css
   data, web app sets the HTMLMediaElement

   4. The web application requests the manifest (mpd, etc.) file
   and the CB parses it

   5. The web application creates mediaSource objects and
   associates it with HTMLMediaElement

   6. mediaSource creates sourceBuffer objects that in turn append
   media segments into the SourceBuffer array with the appenBuffer
   method

   7. The web application defines the media segment URLs (with
   byte range params, video chunks id, etc.)

   8. The web application sends the XMLHTTP Requests towards the
   media host to request these media segment

   9. As the media segments are downloaded by the client, these
   XMLHTTP Requests are forwarded to the CB client by the CB.

   ]]

   alex: cloud browser doesn't know what request is being executed



   Gap1: in MSE the Web browser currently does not have any
   metadata information about the type of XHRs and therefore does
   not have any mechanisms to select the required ones.

   ]]

   colin: can understand the need but not sure how to implement it

   kaz: one possibility is bringing the requirements to the WoT WG
   later

   alex: problem with buffering, media segment, etc.
   ... would people to review this use case

   colin: will go through this uc again

Accessibility

   chris: still struggling with what is expected for accessibility
   for cloud browser

   colin: maybe there are 2 different levels: OS level and DOM
   level

   chris: any suggestions?

   colin: for desktop PC browsers, there is alternative text
   ... how can we do that with cloud browser?
   ... there is an "Introduction" page:
   [16]https://www.w3.org/2011/webtv/wiki/Main_Page/Cloud_Browser_
   TF/Introduction_cloud_browser

     [16] https://www.w3.org/2011/webtv/wiki/Main_Page/Cloud_Browser_TF/Introduction_cloud_browser

   chris: each kind of operation
   ... how to maximize the availability

   kaz: currently the topics are rather list of keywords
   ... maybe you could elaborate concrete use case description,
   Chris
   ... also we could see the Media Accessibility User Requirements
   as the starting point:
   [17]https://www.w3.org/TR/media-accessibility-reqs/

     [17] https://www.w3.org/TR/media-accessibility-reqs/

TPAC 2017

   colin: are you going to attend TPAC 2017?

   alex: still checking

   kaz: Media & Entertainment IG will have its f2f meeting on
   Monday, Nov. 6th
   ... and we're expected to have a section on cloud browser there

   colin: agenda decided?

   kaz: the IG Chairs are generating the initial agenda
   ... and will have a whole IG call shortly

Next call

   alex: next call in 2 weeks

   [adjourned]

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


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Received on Wednesday, 28 June 2017 15:41:26 UTC