[Minutes] Media WG call - 2022-08-16 - TPAC 2022 schedule

Hi all,

The minutes from yesterday's call, focused on preparing the agenda for 
the upcoming TPAC meeting, are available at:

... and copied as raw text below.

The chairs welcome feedback on topics and prioritization!


Media WG call
16 August 2022

    [2]IRC log.

       [2] https://www.w3.org/2022/08/16-mediawg-irc


           Alastor Wu, Bernard Aboba, Chris Needham, Eric Carlson,
           Francois Daoust, Gary Katsevman, Greg Freedman, Jer

           Matt Wolenetz

           Chris, Jer



     1. [3]TPAC 2022 schedule - Joint Media WG / WebRTC WG / Media
        & Entertainment IG meeting
     2. [4]TPAC 2022 schedule - Media WG meeting
          1. [5]MSE
          2. [6]EME
          3. [7]WebCodecs
          4. [8]Media Session
          5. [9]Autoplay policy detection
          6. [10]Picture-in-Picture
          7. [11]DataCue API
          8. [12]Sorting agenda items

Meeting minutes

    See [13]TPAC 2022 planning (#35)

      [13] https://github.com/w3c/media-wg/issues/35

   TPAC 2022 schedule - Joint Media WG / WebRTC WG / Media &
   Entertainment IG meeting

    Chris: Thanks Bernard for preparing up the Media WG / WebRTC
    WG. A number of WebCodecs/WebTransport/WebRTC issues to go
    through. More specific ones on WebCodecs for which I'm waiting
    for feedback from WebCodecs editors on which they are ready to
    … Then one Media Capabilities issue that impacts WebRTC.
    … Anything else that we should cover in that joint meeting?

    Bernard: Some of the Encoded transform issues (e.g. #121) are
    not really linked to Encoded transform in practice.
    … The two major things that we discussed in WebRTC are
    capabilities and relationship between WebCodecs and Encoded

    Chris: We had a call earlier today looking at media sessions in
    relation with media capture. I was thinking of covering that in
    the Media WG meeting. A new meeting popped up on Thursday for a
    new media CG that recently got created. I'm trying to setup the
    schedule so that we have enough breaks in the day.
    … Anything from the Media WG perspective related to WebRTC?

    Bernard: Also related to the Media & Entertainment IG.

    Jer: One thing around the detection of audio spatialisation. We
    added a bunch of stuff for HDR in Media Capabilities but sort
    of punted for audio. We may want to have a discussion with
    Media & Entertainment IG participants if they want to see
    something specific around that. This might be something that we
    asked them to take to the Web Audio Working Group, but since
    it's TPAC we can probably ask people who are around.

    Chris: Let's do all Media Capabilities all in one place. Only
    other thing from the IG is related to the DASH-IF activity on
    requirements for WebRTC and DASH streaming. I'm trying to
    assess whether there is something that needs to be discussed. I
    don't think that the IG has anything else that it wants to

   TPAC 2022 schedule - Media WG meeting


    Chris: [showing current draft schedule in Google Docs]
    … Looking for feedback from editors. Matt is willing to get
    feedback from media player developers on MSE features. If we
    plan an MSE-specific slot, is there anything that you also
    would like to add to the discussions.

    Jer: There are a bunch of MSE features that Apple is interested
    in, in particular related to memory management, e.g. purging
    buffers in low-memory conditions. Hasn't made it to the spec
    yet. That would be a good topic for discussion. We've had
    feedback from people on MSE on when memory conditions would
    change when you switch between resolutions. I think Will Law
    had feedback. Some of the issues came up in FOMS a few years
    ago. Now could be a good time to revisit these issues.

    Chris: I got some interest from DASH.js developers. I think
    that Will will be there in person as well.

    Jer: There will also be another FOMS meeting in October where
    I'm sure media features will be discussed.

    Chris: Are there other spec issues that we need to go through
    in MSE?

    Jer: Not that I know of, but Matt would be the right person to


    Chris: I'm wondering about the status of the features and
    whether the spec reflects features actually implemented. There
    was a TAG comment on the HDCP Policy Check feature.

    Greg: It's implemented in Chrome but not in Safari. I don't
    know what to do with the spec

    Jer: The TAG's comment notes that the feature is also
    implemented in Firefox. If that's true, then I think this can
    go in the spec. It's ok if Apple does not implement it. Happy
    to have a discussion on privacy concerns at TPAC but that
    should not block the feature if there are two implementations

    Chris: What about the Encryption scheme capability detection?

    Greg: I think it's done and implemented.

    Chris: OK, it may be that there is nothing to be done.

    Greg: I'm not sure that the right people will be there to
    discuss EME at TPAC.

    Chris: My concern is that we re-chartered with EME in scope so
    should be making progress on EME somehow before next
    re-chartering period next year.

    Greg: OK, let's restrict the session to 30mn and stick to the
    list you have here.


    Chris: The second part is more tentative from my perspective.
    … WebCodecs in general is progressing quietly. Editors are
    discussing in calls. If we cover WebCodecs, it may just be a
    status update with any particular request where there is input
    needed. I haven't had any input on specific issues that we
    would want to cover. I had a thought on whether HDR would be
    worth covering but that's more a discussion to be had with HDR
    experts in the other group. I wasn't getting from WebCodecs
    people that they wanted to cover many things on WebCodecs.

     Media Session

    Chris: We had a call earlier today where we made some progress
    on the capture handle actions. We'll want to report on that.
    … There are a few issues that may be worth having face-to-face
    discussion about. Bigger question on Media Session and Web
    Audio, as well as the Audio Focus API although Chrome indicated
    they are not actively pursuing this for the moment.

    Eric: I think it would be good to have a discussion on audio
    focus though.

    Jer: Platforms like Android and iOS have complicated audio
    playback rules that the Web does not really handle well. The
    ability for generated audio to duck other audio rather than
    interrupt is not possible for the time being for instance.
    … Whether audio is going through the headset speaker or inbuilt
    speaker. Etc.

    Chris: OK, then a good one to include. I will extent the Media
    Session slot from 30mn to one hour then.

     Autoplay policy detection

    Chris: We published the first draft of the autoplay policy
    detection spec. Is there anything to discuss in the meeting?

    Alastor: I think most issues don't need to take time in a
    face-to-face meeting. I will review them again.

    Chris: OK. Happy to make time if there are things that you'd
    like to cover.

    Francois: Note the open issue on actually changing the autoplay
    permission. Currently out of scope for the Media WG, but we may
    want to document rationale, reply, and/or discuss again.

    Chris: Right, some related needs in my organization indeed.

    Jer: Just wanted to rant that the web is missing a playlist


    Chris: Some open issues. Francois is the main editor. I don't
    know whether Francois will be there personally or able to
    attend remotely.

    Jer: Some of them are editorial. It's going to be hard to
    define autoPictureInPictureEnabled as implementations are going
    to be different. The accessibility issue is interesting.

    Chris: Also could be interesting to have a presentation on the
    document Picture-in-Picture proposal. I'm following up with
    Tommy who's handling that, and reserving a bit of time for it.

     DataCue API

    Chris: Final one is the DataCue API, where things have been
    quiet. Looking for feedback on the proposal and intent to
    implement. Webkit has this already and the API proposal has no
    suggested changes.
    … But there's a question of which in-band media events would be
    surfaced. What would be the timed events processing model? Is
    there interest to look at this from an MSE perspective?
    … Recently, we had a discussion with ByteDance who shared
    interest in surface H.264 SEI metadata events. Again question
    on whether there is broader interest in features like that, and
    getting feedback in next steps.
    … If there's little interest, it may be that we shelve the

     Sorting agenda items

    Chris: Is that too much for the agenda? It may be that we need
    to drop some of the topics, and rather discuss them in further
    meetings anyway. I'm happy to update the agenda based on your
    own priorities.

    Eric: Question is what goes last? Because whatever goes last
    may get dumped.
    … 30mn for DataCue is probably more than it needs.

    Chris: I agree. We can combine some of the topic/s in an 30mn
    slot and move it last.
    … Unknown for me is whether Chromium people will be present for
    Media Session.
    … Thank you for the feedback on the agenda. This is helpful.
    … Is this too long for people who plan to attend remotely?

    Bernard: I'll be remote. You're planning the right duration for
    break. Similar agenda in WebRTC WG.

    Alastor: Is the Google Doc public?

    Chris: Yes, I just shared it with editors. Anything else?

    Bernard: One topic that is coming up again: integration of
    machine learning with encode and decode. Example: picture
    … It is challenging because there is pre-processing and
    post-processing but some of these things have to be integrated
    with the encoder.
    … Some suggestion to add metadata with video frames, e.g. for
    face detection.
    … I'm not sure how to add that to the WebRTC joint meeting, but
    it is something that is coming up.

    Chris: The metadata would be used in the app itself, right?

    Bernard: Yes, one example would be if you want to implement
    your own blurring mechanism. One question is whether metadata
    could be carried out of band, but it is easier in-band for
    … It's not free to add metadata in there, because it requires
    extra memory for instance.

    Chris: I'm wondering what to do with this. Where could it fit
    in the agenda and who needs to be around? Thinking about Intel
    folks for instance.

    Bernard: Yes. We can probably file/find an issue for agenda

    Chris: If we keep the Media WG / WebRTC WG joint meeting to 2h,
    we can probably add it to the agenda. Just wondering whether
    Riju can join the meeting.
    … OK, next step for me is to update the GitHub issue to align
    it better with what we discussed, and confirm with would-be

Received on Wednesday, 17 August 2022 07:15:17 UTC