Re: [minutes] Web and TV IG F2F - TPAC Lisbon - 2016-09-19

Thanks, Francois!

I've added several photos to the minutes :)


On Mon, Sep 26, 2016 at 4:52 PM, Francois Daoust <> wrote:

> Hi Web and TV IG,
> The minutes of last week's F2F meeting are available at:
> ... and copied as raw text below for archival.
> The group held a number of joint meetings with the HTML Media Extensions
> WG, the TV Control WG, and the Timed Text WG in the morning. The Cloud
> Browser Task Force met in the afternoon. Minutes are rough and sometimes
> possibly incorrect. Feel free to get in touch to have them fixed or
> completed!
> Thanks,
> Francois.
> -----
> Web&TV IG f2f meeting in Lisbon
> 19 Sep 2016
>    See also: [2]IRC log
>       [2]
> Attendees
>    Present
>           Mohammed_Dadas(Orange), Kaz_Ashimura(W3C),
>           Mark_Vickers(Comcast), Paul_Cotton(Microsoft),
>           Francois_Daoust(W3C), Hyojin_Song(LGE),
>           Louay_Bassbouss(Fraunhofer), Cyril_Concolato(Paristech),
>           Dan_Druta(AT&T), Eric_Carlson(Apple),
>           Alexandra_Mikityuk(Deutsche_Telekom),
>           Kazuhiro_Hoya(JCBA), Satoshi_Mishimura(NHK),
>           Kinji_Matsumura(NHK), Tatsuya_Igarashi(Sony),
>           Kiyoshi_Tanaka(NTT), Shi-Gak_Kang(ETRI),
>           MiYoung_Huh(ETRI), Toshihiko_Yamakami(ACCESS),
>           Kenichi_Nunokawa(Keio_University), Tomohiro_Yamada(NTT),
>           Barry_Leiba(Huawei), JP_Abello(Nielsen),
>           Koji_Ikuno(FujiTV), Ingar_Arntzen(Norut),
>           Sungham_Kim(ETRI), Keun_Karry(IOT_Connected),
>           Jungo_Kim(Entrix), Taewon_Kim(Entrix),
>           Olivier_Thereaux(BBC), Hiroki_Endo(NHK),
>           Mark_Watson(Netflix), Jean-Pierre_Evain(EBU),
>           Nigel_Megitt(BBC), Chris_Needham(BBC),
>           Colin_Meerveld(ActiveVideo), Giridhar_Mandyam(Qualcomm),
>           John_Foliot(Deque_Systems)
>    Chair
>           Mark_Vickers
>    Scribe
>           Francois, Chris_Needham
> Contents
>      * [3]Topics
>          1. [4]Status of the action items from last TPAC
>          2. [5]Joint session with HME WG - MSE/EME requirements
>             from Cloud Browser TF
>          3. [6]Joint session with HME WG - MSE/EME update
>          4. [7]Joint session with Timed Text WG
>          5. [8]Joint session with TV Control WG
>          6. [9]Cloud Browser TF
>          7. [10]Cloud Browser TF - Joint session with Web of
>             Things IG
>          8. [11]Cloud Browser TF - interface between the cloud
>             browser and the client
>      __________________________________________________________
>    Mark_Vickers: [going through the agenda: joint session with the
>    HTML Media Extensions Working Group (HME WG), then with Timed
>    Text WG, TV Control WG and the rest of the day dedicated to
>    Cloud Browser TF]
> Status of the action items from last TPAC
>    -> [12]Kaz updates
>      [12]
>    Kaz: The TV Control CG transitioned to a TV Control WG. Meeting
>    tomorrow at TPAC.
>    ... ATSC update, Mark will talk about that.
>    ... [going through updates while scribe was fighting against
>    the polycom]
>    -> [13]Mark Vickers's Web and TV IG updates
>      [13]
> 2016Sep/att-0021/2015-09-19_WebTVIntro_v2_.pdf
>    Mark_Vickers: The Web and TV IG takes inputs from members and
>    standards orgs, discusses use cases and requirements. The IG
>    does not do specs. From requirements, we may file bug reports,
>    or kick off work on new APIs.
>    ... Active task forces will meet today, Cloud Browser TF in
>    particular.
>    ... The Media Pipeline TF is done but contributed requirements
>    for MSE/EME. It also lead to the work on Sourcing in-band
>    streams, developed in a Community Group.
>    ... That spec is not properly implemented in browsers for the
>    time being. That's still a problem, and the CG is not really
>    active for the time being, future is unclear there.
>    ... I'd like to mention the Web Media Profile work that we did
>    in the past. We put that on hold at the time, mainly because
>    HTML5 was not yet stable at the time.
>    ... There is an update here with a new Web Media API CG that I
>    chair.
>    ... The goal is to create a profile of HTML5 specs that are
>    widely supported across media devices.
>    ... I plan to present this work during a breakout session on
>    Wednesday this week.
>    ... Associated with CTA WAVE.
>    ... The Home Network TF led to the work on the Network Service
>    Discovery specification. This got abandoned due to security
>    issues.
>    ... The Timed Text TF pushed for TTM and WebVTT to be addressed
>    in the same group. There will be a joint meeting later today.
>    ... The Media APIs TF created a set of use cases and
>    requirements.
>    ... This led to the creation of the TV Control CG, which
>    transitioned to a TV Control WG earlier this year.
>    ... In terms of active Task Forces:
>    ... 1. GGIE (Glass-to-Glass Internet Ecosystem) working on
>    identifying new technical work from media capture to
>    consumption.
>    ... Main requirements are around content identification.
>    ... In addition to that, the active work has transitioned to
>    IETF drafts.
>    ... It's about addressing media segments directly with IPv6
>    addresses. The top of the address would be an identifier for
>    the content, then more details as you go down through the rest
>    of the address.
>    ... There's work going on there. In the IETF since it touches
>    on IP address.
>    ... From a W3C perspective, the TF is a bit on hold.
>    ... 2. The Cloud Browser TF is really active. Led by Alexandra.
>    The afternoon will be dedicated to this TF.
>    ... This work also brings some MSE requirements.
> Joint session with HME WG - MSE/EME requirements from Cloud Browser
> TF
>    Alexandra: We kicked off the TF in January this year. Our goal
>    was to identify the use cases and requirements for the
>    interface between the client device and the cloud part.
>    ... We are done with the architecture. We basically started to
>    work on the use cases.
>    ... We have started to work on EME and MSE because it's a
>    complex topic. We need to do some more work on the use cases.
>    ... This is just a first draft.
>    ... For MSE/EME, the magic somehow happens in the cloud.
>    ... The terminal is "dumb", it cannot do a lot.
>    ... 3 different use cases have been identified.
>    ... The first use case does not bring new requirements for MSE,
>    it's meant for legacy devices.
>    ... The second use case remotes the API. Things are transparent
>    for the client.
>    ... The third use case is the most interesting here.
>    ... When the browser is fully in the cloud and when the MSE
>    magic fully happens in the cloud, this creates new
>    requirements.
>    ... Some of the actions still need to be performed by the
>    client.
>    ... The client needs to send requests on behalf of the cloud
>    browser.
>    ... We're looking at solutions to inject identifiers.
>    ... Another requirement is that the client should be able to
>    signal the available bitrate data to the cloud browser.
>    ... There should also be a way for the Web application to e.g.
>    change the timestamps or manipulate the data somehow.
>    ... A fourth requirement: there is no way for the client to
>    know which XHR request is getting appended by calls to
>    appendBuffer.
>    ... This appendBuffer method should be able to signal to the
>    client only the changes to the data.
>    ... Another requirement: the client loads the chunks in any
>    order. The chunk ordering must be made available to the client
>    and the different resources must be made distinguishable for
>    the CB client.
>    ... One last requirement: XHR data does not necessarily
>    correspond with appendBuffer. The browser needs to be notified
>    about what and when data can be removed.
>    ... Now looking at EME, again the third use case is the one
>    creating new requirements.
>    ... There needs to be a way to associate the IP address of the
>    cloud browser with the address of the client, because both will
>    request the keys at license servers.
>    plh: I'm wondering how that translates into requirements for
>    EME.
>    ... We don't care about the details of what keys contain. This
>    is opaque to the spec.
>    Alexandra: The key server could block things because it
>    receives requests to use the same key from different addresses.
>    plh: My feeling is that this seems to be a requirement on the
>    license server. But the EME spec does not address this.
>    Paul_Cotton: The fact that the license server may be depending
>    on the IP address of the cloud browser. EME does not know
>    anything about that. That may be the case for some EME
>    implementations.
>    ... Why does the client also need to talk to the License
>    Server?
>    Alexandra: There is a more intelligent use case that does not
>    appear on this slide where the cloud browser generates the UI
>    and the video stream is processed by the client.
>    Paul_Cotton: OK, I do not know whether that's feasible but now
>    I understand.
>    Mark_Vickers: The keys may also be retrieved by the cloud
>    browser and used by the client.
>    plh: I don't think that works at all. Imagine a "play" event,
>    since you're not playing the video on the cloud browser but
>    rather on the client, you don't get the "play" event.
>    Alex: Yes, that's one of the MSE requirements I mentioned
>    earlier.
>    Paul_Cotton: In effect, what you want is you want to take part
>    of the MSE/EME logic and move it over into another process and
>    define the interface between these two different processes.
>    ... You need to define all the communication going back and
>    forth.
>    ... The logic is very event driven, events need to flow back.
>    Mark_Vickers: Note there are products that are deployed and
>    used, done in a proprietary for the time being. Right now,
>    MSE/EME cannot be supported, at least not in any standard way.
>    ... The idea of the Cloud Browser TF is to see whether we can
>    standardize across these groups.
>    plh: This is somewhat sorcery to me.
>    ... Take the Youtube UI, there's an interface on top of the
>    video.
>    Colin: We render the UI in the cloud and send the video to the
>    client.
>    plh: How do you do compositing?
>    Colin: We manage to do it on the client
>    Alexandra: There is of course some code that runs on the
>    client.
>    Mark_Vickers: This is an industry that is using Web
>    technologies and does not get a lot of visibility in the W3C
>    world.
>    ... It's used by millions across the world.
>    ... MSE/EME is just one of the problems.
>    ... That's a very interesting space. CE devices often have
>    longer lifetime than browser on desktops, the cloud solution
>    helps alleviate these constraints.
>    Alexandra: [clarifying the cloud browser architecture]
>    Mark_Vickers: MSE is running in a "normal" way from a cloud
>    browser perspective, and you're worried about relaying what is
>    happening on the front.
>    ... That could just be a detail of your HTML user agent.
>    ... In other words, it could be below the Web level. But if you
>    do that, you cannot develop clients that are independent of the
>    cloud browser part.
>    Alexandra: Right.
>    Mark_Vickers: If you want to do a spec to define the interface
>    between the front and back part of your pipeline, it seems to
>    me that you need a separate spec, not embed it in MSE.
>    ... The JS player in the MSE model makes a decision about
>    bitrates based on bandwidth and so on. Doesn't the client need
>    to live with whatever the bandwidth of the cloud browser is?
>    Alex: That's one of the questions. Could the client communicate
>    current bandwidth metrics to the cloud browser?
>    [Discussion on manipulating the data available on the client
>    from the cloud browser, linked to one the MSE requirements]
>    plh: I think you'll have to have limitations. You're not going
>    to send video bits back to the Web app, that's not efficient.
>    ... For instance, if you take EME, you cannot take the bits
>    coming out of EME and put them in a canvas. That would defeat
>    the point of EME.
>    ... In most cases, the client is not going to modify the bits
>    coming out of MSE, so you should be fine.
>    Mark_Vickers: I think that's a good first taste of this cloud
>    browser world.
>    ... We welcome the vendors doing it who joined the discussion
>    the Cloud Browser TF. I'm really glad that people are
>    discussing this in W3C.
> Joint session with HME WG - MSE/EME update
>    Paul_Cotton: Both specs are at Candidate Recommendation phase.
>    That's where we focus on testing to check implementations.
>    ... MSE is more advanced. We had a CfC last week to request
>    publication of MSE as Proposed Recommendation.
>    ... The CfC passed, so I sent the transition request on
>    Saturday last week.
>    ... We're anticipating going the call for review to the AC
>    soon. We're busy assembling the transition request.
>    ... All of the relevant information is publicly available today
>    (issues, test suite, test results, spec).
>    ... We're hoping to get a final Recommendation of MSE first
>    week of November.
>    ... That would give us the first MSE Recommendation.
>    ... EME is not quite as far along in the process as MSE.
>    ... It's been published as Candidate Recommendation as well.
>    ... Since then, editors have made a number of editorial
>    changes.
>    ... There's a lot of testing that still needs to be done for
>    EME.
>    ... We have had a series of tests submitted by Google some time
>    ago but these tests need to be converted to Web Platform Tests
>    format.
>    ... Mark Watson from Netflix has been doing a lot of this work.
>    ... When I talk about the results of the W3C test suite, you
>    can check the archives of the mailing-list.
>    ... It is not clear to me or Philippe what the results are so
>    far. Implementers seem to have chosen different features in the
>    spec.
>    ... I hope we'll have a better perspective within two weeks.
>    ... We already have a number of formal objections recorded for
>    EME and note there will be a public demonstration on Wednesday.
>    ... I think that's the status with EME. I cannot give you a
>    prediction as to when we can go to the Director for a
>    transition to Proposed Recommendation.
>    ... I should note that the charter for the HTML Media
>    Extensions WG expires end of September, meaning next week.
>    plh: Let's be clear. If I don't have a clear plan as to when
>    the spec is going to be finished, I cannot tell whether the
>    Director will approve the extension. This is serious.
>    ... On the one hand, we have people telling us not to finish
>    EME. On the other hand, if people who care about EME do not
>    inject resources to finalize the spec, I cannot go and ask the
>    Director to extend the charter.
>    Giri: From a broadcaster perspective, we've identified a hang
>    up from a crypto perspective on EME.
>    ... Do we need an EME version 2?
>    ... Why talk about version 2 if we still don't know whether
>    version 1 is going to be done in the end.
>    Paul_Cotton: There are 10s of features that we triaged out of
>    v1. Version 1 does not solve everything that the community
>    wants.
>    Giri: Would it make sense to include features in v1 right away
>    since it's not done yet?
>    plh: No, let's be clear. I cannot recommend the Director to let
>    the work on EME continue if we cannot get version 1 out soon.
>    Mark_Watson: Two problems. For testing, there's not a lot of
>    things that remain and it should be easy to work on a proper
>    plan to finalize the test suite.
>    ... Another problem is implementations, which fail some of the
>    tests.
>    ... If we go ahead with progress on the Recommendation track,
>    we may not get implementers feedback that could improve the
>    spec. I'm fine with this approach, just noting that.
>    ... I also note that DRM on the Web is a market need.
>    Mark_Vickers: I think that we must finish v1. That's absolutely
>    necessary.
>    ... In terms of motion: committing testing resources should be
>    easy to do. For spec compliance, there are 4 codebases that we
>    are talking about, and I don't see what I can do there. I'd
>    like to hear from them what their implementation plans are.
>    Paul_Cotton: I made a suggestion this morning that bugs should
>    be opened against implementations so that we can at least point
>    out these bugs when we face the Director.
>    Mark_Vickers: Third thing is that I see some editing going on
>    today.
>    Paul_Cotton: That's really editorial and normally that's done.
>    David mentioned last week that he was done.
>    Mark_Vickers: Is there more we should be doing?
>    plh: How long is it going to take? That's the question.
>    Mark_Vickers: I guess that's what the F2F should discuss here
>    at TPAC.
>    plh: If we don't have interop, the motivation for W3C is going
>    way down. We need to solve this for version 1. And we need to
>    do it fast.
>    <Zakim> wseltzer, you wanted to comment on politics
>    Wendy: On the politics front, clearly there are some people who
>    are misconceiving the role of W3C here.
>    ... Even if the market wants DRM, that does not necessarily
>    mean that W3C should recommend something in the area.
>    ... There are valid concerns, e.g. around the possibility to
>    investigate these interfaces from a security perspective.
>    Giri: We seem to have interop issues. Past experience in
>    Geolocation WG, we went through a lot of pain due to interop
>    issues, but that did not mean the spec died.
>    ... Do we need to put some statement in favor of the charter
>    extension?
>    plh: You need to finish the spec.
>    Mark_Watson: I have a bit of a concern if we say that the fact
>    that there are external protests should influence our internal
>    process. I'm all fine to addressing the issues that have been
>    raised against EME rationally, of course.
>    Mark_Vickers: I would add that there is an interoperability
>    milestone that has been achieved already with MSE/EME, even
>    though it involves polyfills which is not entirely acceptable.
>    ... We have deployments on the Web, using different codecs,
>    different DRMs.
>    ... There used to be zero interoperability. Now we have content
>    that is independent of DRM that can be deployed across the
>    world.
>    ... I'm not saying that's enough, but that's unprecedented in
>    the video world.
>    Paul_Cotton: [without Chair hat off]. I find it frustrating
>    that W3C can charter a group like this, go to CR and then
>    decide to kill the group. I find it phenomenal that after
>    having chaired this group for several years, we hear that this
>    work is at risk because it's not making enough progress,
>    especially given the progress that was made in the last few
>    months.
>    plh: With all due respect, previous re-chartering has been
>    painful and something that I do not want to reproduce. I need a
>    proper plan.
>    Mark_Watson: That seems like the usual way of doing
>    specifications though. We don't have a lot of control on the
>    implementation front. Other groups just carry on while there
>    are issues to resolve.
>    Mark_Vickers: For example, Web Crypto.
>    plh: My problem today is that we don't even know what we're
>    lacking in terms of implementation.
>    ... I'm not blaming people here who have been active of course.
>    ... Don't tell me it's important to you if you did not put
>    resources into it since April.
>    Jean-Pierre_Evain: We all know that standardisation is about
>    masochism and frustration. Nothing new here.
>    Paul_Cotton: I would suggest that those of you who are in the
>    room and interested show up for the HME meeting today and
>    tomorrow and contribute to the work.
>    [coffee break, back at 11:00]
> Joint session with Timed Text WG
>    nigel: The TTWG was rechartered earlier this year
>    ([14] with
>    no significant change in scope.
>    ... The TTWG is working on a draft of a Note, available as an
>    Editor's Draft at
>    [15] for mapping
>    between TTML and WebVTT.
>    ... The TTWG has published a Note listing profiles of TTML and
>    initiated a process to update the media type registration to
>    allow richer description of which profiles of TTML a processor
>    needs to support in order to process any given document.
>    ... The TTWG published earlier this year a Recommendation for
>    Internet Media Subtitles and Captions, consisting of a Text
>    profile and an Image profile of TTML 1. This is known as IMSC
>    1.
>    ... The TTWG is currently focusing on TTML 2 with amongst
>    others, the goal of supporting the text layout requirements of
>    every script globally. The group intends to update IMSC to IMSC
>    2 to incorporate changes that are appropriate for this use
>    case, from TTML 2.
>      [14]
>      [15]
>    Mark_Vickers: Some people talk about simplification of IMSC1.
>    You talk about adding new features.
>    Nigel: I'm not aware of on-going plans to simplify IMSC1.
>    Giri: We're still struggling in the broadcast world with
>    timestamped events. Is this being addressed by the on-going
>    re-chartering process?
>    Nigel: Let' come back to that question
>    nigel: WebVTT's current status is Working Draft.
>    Mark_Vickers: Is the CG still active?
>    Nigel: Yes, it is. Some participants have moved on.
>    nigel: There has been increasing usage of various profiles of
>    TTML by other standards bodies including SMPTE, EBU, DVB, ARIB
>    and HbbTV.
>    Nigel: There's also some work going on at MPEG on CMAF.
>    ... There's a general issue with video media and timed text.
>    There can be mismatches between the aspect ratio of the video
>    and the rectangular box that is to contain timed text.
>    ... That affects positioning.
>    ... Then there's a general question on the management of time.
>    Andreas_Tai: I'd like to address one issue that I think could
>    fit within the mission of the Web and TV IG to identify gaps in
>    existing technology.
>    ... The issue is on how to make use of TextTrack and
>    TextTrackCue interfaces
>    ... To add a TextTrack to a media element, there are attributes
>    that you can use.
>    ... What is missing though is some way to identify the MIME
>    type of the track.
>    ... One solution would be to add a "type" attribute to the
>    track element.
>    ... That would be similar to the "type" attribute to the source
>    element.
>    ... A TextTrack is a set of TextTrackCue. These cues are
>    defined in a format independent way.
>    ... There are some events for when a cue gets active and when
>    it becomes inactive.
>    ... Apart from the Edge browser, there is no way to initialize
>    a generic TextTrackCue.
>    ... What is implemented is a specialization of the
>    TextTrackCue, in other words a VTTCue.
>    ... You can initialize a VTTCue and then tweak it, which is
>    probably not the way that it should work.
>    ... What could be done is to make sure that there is a
>    constructor for a generic TextTrackCue.
>    ... We could go further and add an attribute for the payload.
>    Also we could define a new API for specialised TextTrackCue
>    (e.g. SubtitleCue or HTMLCue that got discussed last year).
>    ... I'm not sure what the Web and TV IG could do here, but that
>    sounds like the right place to gather requirements.
>    ... We propose a breakout session on Wednesday to discuss these
>    issues.
>    Mark_Vickers: There is some history on that issue.
>    ... Another question is to understand what the user agent has
>    to do with text tracks that come within the transport stream.
>    ... This relates to the [16]Sourcing In-band Media Resource
>    Tracks from Media Containers into HTML spec that is currently
>    in limbo.
>    ... It's referenced by HTML5 but not implemented yet.
>    ... We need a place to publish standard mapping between
>    transport standards and HTML5 types.
>      [16]
>    Giri: There are some timing issues that become problematic with
>    TextTrackCue. There are additional delays triggered by the user
>    agent having to process the cues and so on.
>    ... Is the effort on TextTrackCue going to look into that?
>    ... e.g. for tuning into a channel.
>    ... There are other approaches, e.g. creating a new type of
>    cues, possibly done in CMAF.
>    Andreas_Tai: I think the "type" attribute would address some of
>    this. The question for me is where should be the home of this
>    issue.
>    Giri: I also encourage you not to start with WebVTT, but rather
>    with TTML, SMPTE, beecause that's what the broadcaster world
>    uses.
>    Andreas_Tai: To be clear, I don't propose to improve support
>    for VTTCue. The TextTrackCue exists independently of that and
>    we shouldn't be using VTTCue here.
>    Glenn_Adams: The VTTCue was meant to be generic although
>    implementations have not implemented the generic aspects of it.
>    DataCue was the closest thing to it.
>    Andreas_Tai: I encourage people to come on Wednesday to discuss
>    this. I think the Web and TV IG is the right place to gather
>    requirements.
>    Nigel_Megitt: Another topic I wanted to touch upon, is
>    requirements for audio(video) description.
>    [presenting a requirements draft document]
>    Nigel_Megitt: My intent is for TTML2 to support this. The
>    intent is that any mixing directive would be addressed by Web
>    Audio.
>    ... I submitted this doc to the Timed Text WG and to the Web
>    and TV IG.
>    ... A couple of other things to mention: one of the things that
>    have been missing is how you implement accessibility
>    requirements for subtitles.
>    -> [17]BBC Subtitle Guidelines
>      [17]
>    -> [18]EBU-TT Live Interoperability Toolkit
>      [18]
>    Nigel_Megitt: From an EBU perspective, there's a draft
>    specification around live interoperability toolkit to generate
>    EBU-TT documents.
>    Mark_Vickers: Thanks for the great update!
> Joint session with TV Control WG
>    Chris_Needham: The purpose of the WG is to work on an API for
>    sourcing media, such as TV and radio from broadcast, IPTV, or
>    other sources, allow their presentation onto HTML media
>    elements, and be agnostic of underlying transport streams.
>    ... It started in 2013-2014 within the Web and TV IG with a
>    couple of use cases related to tuner control. Following this,
>    we created a Community Group (2014-2016) to gather requirement,
>    compare existing APIs and draft an initial version of the TV
>    Control API specification.
>    ... Mozilla was active in that group as part of their Firefox
>    OS for TV effort.
>    ... We transitioned to a Working Group in April 2016 and
>    published a First Public Working Draft of the spec, which is
>    basically the same version as the one developed by the CG.
>    ... The spec addresses different features: enumeration of
>    tuners and sources, channel selection, playback, Conditional
>    Access Modules, Timeshifted plabyack, recording, etc.
>    ... The WG may decide to split some of these features out of
>    the main spec.
>    ... [showing examples of API usage]
>    ... The interesting part here is the ability to associate the
>    MediaStream to a video element in HTML5.
>    ... In terms of current work and next steps, there's some
>    effort to adapt the API to radio devices.
>    ... We'd like to support radio as TV with this API.
>    ... It brings some new requirements in terms of new information
>    to expose.
>    ... We also collaborate with the Auto BG.
>    ... User privacy is a big thing that we identified in the
>    group. At the moment, the spec does not define the execution
>    context that it runs under.
>    ... There's a question as to whether the API is tied to the
>    runtime of the device, or whether the API is exposed to more
>    general applications.
>    ... Some features could be fine for device runtime, but
>    probably not for general application runtime.
>    ... Also, what are the access controls to media and metadata,
>    coming from content providers and broadcasters?
>    Giri: Will you be considering application-driven ad-insertion
>    as part of this topic?
>    Chris_Needham: From a broadcaster perspective, this is highly
>    relevant yes.
>    Giri: Are you thinking about integrating the Permissions API
>    for features that could require a more privileged / device
>    specific context?
>    Chris_Needham: That's a good question. I guess we'll want to
>    reduce the number of interactions with the user.
>    ... Integrating with the Permissions API seems like a resonable
>    approach.
>    Giri: In ATSC, we've been considering that broadcasters could
>    stream their own application, similar model as in HbbTV.
>    ... In that model, user privacy is somewhat less of a concern.
>    The open web is not really the target.
>    Chris_Needham: I agree.
>    ... Issues for the group: there is a lack of editorial effort.
>    There is an open opportunity for anyone to take on the editor's
>    role.
>    ... It would be interesting to know who's looking at this API
>    from TV industry groups, such as ATSC.
>    ... More generically, we need more feedback from industries on
>    whether we're going on the right direction and support that
>    effort.
>    Mark_Vickers: Do you see this running only on tuner-centric
>    devices? Or also on devices that do not have a tuner?
>    Chris_Needham: I see this as a sourcing API. I have a slight
>    concern about this being too tight to the tuner hardware.
>    ... If other groups could review the spec and provide feedback
>    on how well it aligns for other sources, that would be great.
>    Mark_Vickers: So you're saying that this should work in
>    situations where there are no tuners but that this hasn't been
>    done yet?
>    Chris_Needham: Correct.
>    Mark_Vickers: Another question. The notion BBC2 is independent
>    of its delivery mechanism. Is the name going to be BBC2 or will
>    it be tied to the tuner and source?
>    Chris_Needham: I don't think that's an aspect that the group
>    has particularly been looking at. It may be that these things
>    vary, e.g. for regional reasons.
>    ... At the moment, the way the API is structured is that BBC2
>    streamed through a given source is different from BBC2 streamed
>    through another source.
>    Mark_Vickers: So I don't have a name that is independent?
>    Chris_Needham: Not currently.
>    ... In our meeting tomorrow, we do have a session on
>    integrating with metadata vocabularies. I think that's an
>    important aspect to cover.
>    ... Existing published metadata should be available for use.
>    Mark_Vickers: Yes, that's a problem I'm familiar with. Right
>    now, there's no way to correlate sources with published data.
>    Chris_Needham: Anyone with an interest on that topic would be
>    more than welcome.
>    Tatsuya_Igarashi: Comment on ad-insertion. The current spec
>    does not really address this problem.
>    Chris_Needham: Correct.
>    Mark_Vickers: Thanks for the report. This concludes the plenary
>    part of the F2F. Next on: the Cloud Browser TF.
>    [lunch break]
> Cloud Browser TF
>    alexandra: [introduces the cloud browser tf]
>    ... the task force's mission is to look at use cases for a
>    cloud browser architecture
>    ... and requirements for interfaces between the cloud browser
>    and client
>    ... you can see the high level architecture on the Cloud
>    Browser TF wiki page
>    ... The cloud browser is a flexible approach supporting
>    different ways of being deployed
>    Colin: The browser runs in a cloud environment and streams the
>    UI to the runtime environment
>    ... This displays the stream and sends information to the
>    cloud, eg, keypress or tuner information
>    ... Also streaming of out-of band media
>    Alexandra: We have dependencies on other groups, such as HTML
>    Media Extensions, TV Control, Multi-device timing,
>    Accessibility platform architecture
>    ... are there others to add to this list?
>    Louay: Also the Second Screen WG, which has two specs: the
>    Presentation API and Remote Playback API
>    ... We can reference the existing use cases, which are be the
>    same
>    ... Maybe there will be additional requirements for the cloud
>    browser
>    <Louay> -> [19]Second Screen Use Cases and Requirements
>      [19]
>    Alexandra: [some discussion of what are dependencies and what
>    is related work]
>    ... I want the group to discuss what our final goals are,
>    different approaches
>    ... Looking at what we've done so far, Deutsche Telekom have
>    been looking at the TV Control API
>    ... We've written a Cloud Browser introduction on the TF page
>    ... It clearly describes what the CB is
>    ... The introduction needs reviewing
>    ... We'll produce an official document from this after TPAC
>    ... We're now half-way through use case and requirements, with
>    a plan to finish by end of march
>    ... There are open questions, eg in terminology: zero-client or
>    runtime environment
>    Dan: Why not just call it the cloud browser client
>    Colin: This introduces some ambiguity
>    ... [Presents [20]Introduction cloud browser]
>      [20]
> TF/Introduction_cloud_browser
>    Alexandra: I'd like people to review the [21]Cloub Browser
>    architecture
>      [21]
> TF/Architecture
>    Alexandra: [ presents an overview of the architecture page ]
>    ... There are four approaches
>    ... For each approach, we've assigned functionality between the
>    cloud environment, cloud browser, and client
>    ... This work is ready to be finalised
>    Dan: How important is synchronisation, and has that been
>    considered, eg, keeping the UI in sync with the media?
>    Alexandra: We have a use case for that
>    Colin: It is very important, it needs to be precise
>    Dan: How do you handle failures on the UI side, eg, if
>    connectivity for the UI is lost?
>    Colin: This currently depends on the implementation, but would
>    need to be standardised
>    Dan: Although you're trying to be stateless, this would some
>    tiny piece of state information
>    Alexandra: Synchronisation is also important for accessibility
>    John_Foliot: Is the primary use case here for video, or as a
>    general purpose browser?
>    ... What is the input mechanism? A traditional computer has a
>    keyboard or pointer or touch interface
>    Alexandra: So far we've focused on video delivery, and input
>    with a remote control
>    ... It's not a remote desktop, more a TV user interface
>    Colin: We don't have solutions yet for DRM bridging
>    ... So far we've focused on architecture, but we should define
>    new use cases
>    Cyril: What about subtitles?
>    Colin: If these are rendered by the cloud browser, it's easy,
>    but needs synchronisation at if rendering in the client
>    ... Similar case for advertisements
>    Louay: If you send the timelines for both streams, need to
>    ensure all streams are in sync
>    ... We should clarify synchronisation of multiple streams to a
>    single device, and synchronisation for companion devices
>    Ingar: If the cloud browser means moving functionality to the
>    cloud, then synchronisation also moves to the cloud
>    Alexandra: We can capture these as several use cases
>    John_Luther: Is it a goal to standardise the control protocols?
>    Colin: Not at this stage, so far only use cases, but protocols
>    might happen outside W3C
>    Dan: Synchronisation between devices is more a requirement than
>    a use case
>    ???: I agree, and the most critical point could be latency
>    <tidoust> scribenick: tidoust
>    [session resumes]
>    Alexandra: Thanks to everyone for propositions in last session.
>    ... Continuing with the use cases now.
>    ... Core use cases are those that enable the communication
>    between the client and the cloud browser.
>    ... That includes Control, State, Session, Communication use
>    cases.
>    ... We have to think about Authentication use cases, whether we
>    have to include them in our task force or not.
>    ... Then discovery and synchronization.
>    ... The use cases appear on our Wiki.
>    ... On top of these core functions, we have essential services
>    use cases for data exchange between the client and the cloud
>    browser.
>    ... Here we have video and audio use cases, UI use cases. And
>    then of course security use cases.
>    ... Also accessibility that we need to talk about.
>    ... We put the major TV service use cases and went through them
>    to see if anything was missing from our core platform.
>    ... This should be mapped onto core and essential services use
>    cases.
>    Tashiki: My sense is that these use cases depend on how you
>    articulate the cloud browser work. For instance, you may have a
>    low-level device with rendering that happens on the cloud.
>    ... Articulating the use cases depending on the type of cloud
>    browser will give different perspectives.
>    ... Sometimes, there is very limited power to embed a browser.
>    In that case, the UI use cases viewed from a client perspective
>    seems out of scope for W3C.
>    ... I have no objection to doing the work to identify
>    requirements at W3C, but work may need to be done outside.
>    Colin: Right, when we started this work, we thought in terms of
>    use cases, but then we realized that people had different
>    things in mind when referring to cloud browsers. So we worked
>    on an architecture document to start with, instead.
>    Louay: They are two types of synchronization: multiple stream
>    synchronization and multi-device synchronization.
>    ... As a core function, we could have multi-stream
>    synchronization. Multi-device synchronization would be at the
>    essential services.
>    ... We don't need to have a use case for multi-device
>    discovery, communication and synchronization. We can reference
>    the Second Screen Presentation API there.
>    Colin: We don't use discovery in practice, but there may be a
>    future need for this.
>    Alexandra: Use cases have question marks. We still don't know
>    if we're going to include them or not.
>    Colin: Maybe this is a good opportunity to discuss whether this
>    is in scope.
>    Alexandra: What is your perspective on authentication?
>    Chris: What are the use cases that drive this?
>    Colin: I don't think we have any for authentication for the
>    time being.
>    Kang: Are we talking about authentication with a server?
>    Alexandra: We were thinking about authentication between the
>    client and a server. I don't know whether it is in scope of
>    not.
>    ... We have identified control use cases. They still have to be
>    reviewed.
>    ... TF participants are encouraged to review the use cases.
>    Others may chime in as needed. Work happens in public.
>    ... For state, we have e.g. tuner state, which relates to the
>    TV Control API.
>    ... For session, use cases are somewhat similar to the control
>    use cases and we had a discussion on whether they could be
>    merged. For the moment, we kept them separate.
>    ... For communication, we have a use case but it needs to be
>    re-written following the use case template.
>    ... I wasn't clear whether we have requirements derived out of
>    that use case.
>    Colin: Right, that still needs to be assessed.
>    Alexandra: For security, we'll discuss with the Web of Things
>    IG. Based on side discussions with Louay, maybe we do not need
>    to decide in the TF.
>    ... Discovery could be part of a multi-device use case.
>    ... Same for synchronization, where multi-stream
>    synchronization should stay here but multi-device sync should
>    be moved to multi-device use cases.
>    ... Moving on to essential services use cases. The payload
>    between the client and the cloud browser.
>    ... Here, we have identified a video use case (mse and tuner
>    use cases).
>    ... We mentioned MSE use cases in the morning during the joint
>    session with the HTML Media Extensions Working Group.
>    ... Review is missing for tuner use case.
>    ... Some low-level approach could perhaps lead to a situation
>    where no update is needed to MSE. But of course, there are
>    drawbacks with any approach.
>    ... We also have an overlapping use case for video. The
>    question is whether it's a real use case.
>    Colin: It does not seem so.
>    Alexandra: it needs to be performed by the client and not
>    provided by the API?
>    Colin: Right.
>    Alexandra: Then we have the audio. The background of this use
>    case is accessibility where you provide some sound effect. It
>    will reference the synchronization use case.
>    ... Not sure whether the group wants to address this as a use
>    case.
>    ... I'll take this to John.
>    Kang: We're also think about double streams for audio, right?
>    Colin: When we say video streams, we mean media streams.
>    Alexandra: That's a good comment, maybe we should update the
>    term.
>    ... I'm not clear whether there's an accessibility API that
>    browsers need to support.
>    ... I think the UI EPG use case can be handled as part of
>    normal function use cases. To summarize, the AIT table is
>    available on the client, but to build the EPG, we need this
>    info to be shared with the cloud browser.
>    Kang: In the IPTV case, that's not really the case.
>    Alexandra: Sometimes we get different IDs for channels and we
>    need to fuse them, that can be very tricky.
>    ... We also have the UI Switch that was brought by Entrix.
>    ... On very old browsers, we cannot deliver Youtube for
>    instance, and that's when you'll want to switch to a cloud
>    browser.
>    Colin: More generically, how you execute native applications on
>    the client. It could be through a Web browser.
>    ... In a cloud browser architecture, you would like to have
>    everything in the cloud, even the main device UI.
>    Alexandra: So, that's the interface between cloud browser and
>    client app environment.
>    ... For security, we have EME use cases with two different
>    approaches, including a complicated one where you try to
>    duplicate things across the client and cloud browser.
>    [Discussion on accessibility requirements, in relation with the
>    Presentation API, the Remote Playback API and the Cloud Browser
>    TF. Mentioning Media User Interface Accessibility Requirements:
>    [22] ]
>      [22]
>    Alexandra: Going through essential services use cases. Most
>    need to be described (VoD, timeshift, Ad-insertion, gaming,
>    etc.)
>    ... We have added the catch-up service as well. Also the
>    OTT-based video app (amz, nflx) use case.
>    Louay: About HbbTV, maybe use Hybrid TV application, because it
>    could be HybridCast or some other standard.
>    Alexandra: OK.
>    ... The exact scope of this task force is not entirely settled
>    but that can probably be done over time.
> Cloud Browser TF - Joint session with Web of Things IG
>    Alexandra: No specific agenda, we just thought it would be
>    useful to discuss.
>    ... [presenting the cloud browser task force]
>    Joerg: Chair of the Web of Things IG.
>    ... We're coming from quite a different side. We'd like here to
>    keep you informed, not sure how much of it will be useful.
>    ... Status update and on-going AC review on the proposed Web of
>    Things WG charter.
>    ... We're trying to interconnect silos. Different application
>    domains such as consumer home, transport, health, cities, etc.
>    ... The goal is to find synergies.
>    ... IoT is very much looking at how you can share information
>    across these domains. WoT is looking at how you can develop
>    applications across these domains.
>    ... We're looking into this, e.g. because there are much more
>    Web developers than embedded developers (711000/3800 looking at
>    LinkedIn profiles).
>    ... Also we want to make applications easier to write to enable
>    the long tail marked for embedded devices. Also Web
>    technologies are useful for Web-grade multi-stakeholder
>    security.
>    ... That's quite interesting to see how we can learn from the
>    Web here.
>    ... Finally, it helps simplify the integration of embedded
>    devices.
>    ... Now, this opens a number of questions around scope. We
>    don't want to be too open and generic, and don't want to be too
>    specific either.
>    ... The first four questions we identified: discovery, how do
>    things find each other? How do things describe themselves?
>    Privacy and Security? Scripting APIs?
>    ... Standardization at the IETF is taking care of the
>    protocols.
>    ... So information can be exchanged. To be able to make
>    applications, we need to make additional building blocks.
>    ... The IG has quite a lot of different companies in there.
>    ... We started to work in Sprint 2015 on use cases and
>    requirements. This is tricky.
>    ... We're doing plugfest to prove the interoperability of our
>    proposed solutions.
>    ... Looking a bit more at the inside, we have the "Servient",
>    which can be running on the Server or on the Client.
>    ... The resource model describes what the thing can achieve.
>    ... Different protocols can be used through protocol bindings,
>    e.g. CoAP.
>    ... The Thing Description allows you to discover what that
>    thing is doing and how you can interact with it.
>    ... [going through plugfest example]
>    Alexandra: Thank you for the introduction.
> Cloud Browser TF - interface between the cloud browser and the client
>    Alexandra: When we started this work, we thought we'd be able
>    to come up with a browser API that we could propose to browser
>    vendors. So we started to work. There are lots of
>    graphic-related tasks.
>    ... The basic question is: do we try to make an API for the
>    browser? Or do we work on the level below, which could end up
>    being developed at IETF?
>    ... If we have an API, the application will need to use it,
>    which gives it more control.
>    ... [projecting some open questions on screen]
>    ... These questions might change during the discussions.
>    Louay: From my perspective, having worked on the Presentation
>    API. For now, there are different implementations of the API on
>    top of different protocols.
>    ... From an application perspective, it's the same application.
>    Of course, it's not interoperable between implementations, but
>    that's the goal of the new work being carried upon by the
>    Second Screen CG.
>    ... Here, it could be similar if we develop an abstract API
>    that could be implemented on top of different protocols.
>    ... I think this approach could work.
>    ... In the future, interoperability between different browsers
>    is better.
>    ... It may not be W3C specifications, maybe IETF specs.
>    Francois: What consumes the API? No Web runtime on the client,
>    right?
>    Colin: It depends, there may be a low-end browser runtime on
>    the client, and the app may be willing to connect to a Cloud
>    Browser.
>    Francois: OK, so you want a way to retrieve a MediaStream out
>    of a Cloud browser and then pass on events and the like in
>    between the devices. That resonates with some v2 use cases for
>    the Presentation API where the group may consider cloud-based
>    second screens.
>    Kaz: When we say API here, it does not necessarily mean a JS
>    API, right? It could be an API between the client runtime and
>    the cloud browser runtime. It would be built on top of
>    WebSockets for instance.
>    ... In the Automotive group, the group has been talking about a
>    sockets-based approach.
>    ... The Cloud Browser TF guys might want to connect with Auto
>    folks tomorrow.
>    <kaz_> [23]Vehicle Signal Server specification by the
>    Automotive WG
>      [23]
> vehicle_information_service.html
>    Alexandra: Maybe it's interesting to take a look at who would
>    like to implement this possible API in devices.
>    ... Thanks for your participation.
>    [End of minutes]

Kaz Ashimura, W3C Staff Contact for Auto, WoT, TV, MMI and Geo
Tel: +81 3 3516 2504

Received on Monday, 3 October 2016 15:35:55 UTC