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RE: {minutes} HTML WG media telecon 2013-07-23 - MSE status and bug discussion

From: Adrian Bateman <adrianba@microsoft.com>
Date: Tue, 23 Jul 2013 16:24:49 +0000
To: Paul Cotton <Paul.Cotton@microsoft.com>, "public-html-media@w3.org" <public-html-media@w3.org>
CC: "Aaron Colwell <acolwell@google.com> (acolwell@google.com)" <acolwell@google.com>, Mark Watson <watsonm@netflix.com>
Message-ID: <0c85945bb193475092692af8dd67835a@BL2PR03MB604.namprd03.prod.outlook.com>
Minutes -> http://www.w3.org/2013/07/23-html-media-minutes.html


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

                               - DRAFT -

                  HTML Media Task Force Teleconference

23 Jul 2013


      [2] http://lists.w3.org/Archives/Public/public-html-media/2013Jul/0013.html

   See also: [3]IRC log

      [3] http://www.w3.org/2013/07/23-html-media-irc


          pladd, glenn, +1.831.457.aaaa, Michael_Thornburgh,
          +1.650.458.aabb, ReimundoGarcia, +44.173.776.aacc,
          paulc, Aaron_Colwell, [Microsoft], adrianba, pal,
          stevep, +1.303.661.aadd, BobLund

          Paul Cotton

          Adrian Bateman


     * [4]Topics
         1. [5]Roll call, introductions and selection of scribe
         2. [6]Previous meeting minutes
         3. [7]Review of action items and issues
         4. [8]Media Source Extensions editor's draft
         5. [9]Pre-Last Call bugs
         6. [10]Bug 22137 - changes in number of audio tracks
            during advert insertion
         7. [11]Bug 22136 - Inband Storage for SPS/PPS in ISO BMFF
         8. [12]MSE Last Call or heart beat Working Draft
         9. [13]Candidate Last Call bugs
        10. [14]Any other business
        11. [15]Adjournment
     * [16]Summary of Action Items

   <trackbot> Date: 23 July 2013

   <scribe> ScribeNick: adrianba

   <scribe> Scribe: Adrian Bateman

Roll call, introductions and selection of scribe

   paulc: done

   <paulc> Agenda:


     [17] http://lists.w3.org/Archives/Public/public-html-media/2013Jul/0013.html

Previous meeting minutes

   paulc: don't think they need any discussion - used to drive the

Review of action items and issues

   paulc: all in the agenda

Media Source Extensions editor's draft



     [18] https://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html

   paulc: updated once by aaron on july 18 - sent a note about

Pre-Last Call bugs

   <paulc> [19]http://tinyurl.com/6pdnzej

     [19] http://tinyurl.com/6pdnzej

   paulc: divided bugs between pre-last call bugs and then last
   call - if we have time we'll look at the candidate last call

Bug 22137 - changes in number of audio tracks during advert insertion


   <trackbot> ACTION-21 -- Adrian Bateman to work with Jerry to
   review bug 22137 and provide feedback -- due 2013-07-02 --

   <trackbot> [20]http://www.w3.org/html/wg/media/track/actions/21

     [20] http://www.w3.org/html/wg/media/track/actions/21


     [21] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22137#c8


     [22] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22137

   paulc: comments suggest won't fixing?

   acolwell: yes, i'm proposing that we create a different spec to
   handle track switching independently
   ... so that other html5 media can take advantage of it
   ... the comments after comment 8 talk about what situations
   could arise
   ... my position is that i agree there could be problems but we
   should make this another spec because it is an independent
   ... agree with adrian's earlier comment suggesting marking as
   Won't Fix

   <Michael_Thornburgh> i'm on the phone too

   paulc: one of the correspondents is Michael_Thornburgh
   ... do you want to make comments?

   Michael_Thornburgh: my concerns is mostly making sure the use
   case is addressed
   ... if the solution is another spec to make it possible that's
   ... i'm particularly concerned that the stalling behaviour is
   part of the MSE spec
   ... and you want to avoid stalls at append time
   ... if in some proposed solution in a different spec that
   allows for timed track switching, this correctly maps to append
   time stalling behaviour then that would be okay

   acolwell: my intention was that MSE talks about what tracks are
   taking into account during playback
   ... so stalls only happen if tracks playing don't have content
   ... this other proposed mechanism would specify when the switch
   ... and track switch would happen as if they were being done
   ... but because you provide the data ahead of time, the media
   engine knows a switch is coming up
   ... however that spec addresses switching then it will allow
   for a window around the switch where it doesn't have to match

   Michael_Thornburgh: that sounds reasonable

   <pal> is this great information provided by Aaron captured
   somewhere in the specification?

   acolwell: to pal's question, how stalls happened and what
   happens when a track is enabled or disabled is in the spec
   ... so this new spec would specify a track switch in terms of
   how tracks currently are enabled or disabled
   ... so MSE would work with that
   ... tracks enabled get added to active source buffers and
   affect stalling

   <Michael_Thornburgh> +q

   acolwell: when removed gets removed from active source buffers
   and doesn't have to have data for playback

   Michael_Thornburgh: the other issue is having more than two
   ... probably ought to be some indication in the spec that
   sourcebuffers > 2 should be supported

   acolwell: i have concerns about mandating that

   adrianba: IE11 supports more than two sourcebuffers

   acolwell: i have concerns about specifying how many need to be
   supported - this is a quality of implementation issue
   ... don't need to put this in the spec

   pal: section 2.2 requires 3 source buffers, right?

   acolwell: that's not at the same time

   pal: think there should be an OR in the spec - reader probably
   thinks it is an AND
   ... if we think use case A is essential but the spec doesn't
   mandate the requirement for use case A then it isn't a quality
   of implementation issue

   BobLund: i agree with what pierre just said
   ... if this is a must to support then a requirement is there

   <Michael_Thornburgh> Bob said what i was about to say

   BobLund: what about non-normative text that lays out the use
   case and explains the need for support for more source buffers

   paulc: have we strayed away from the original bug?

   Michael_Thornburgh: marking this won't fix should be contingent
   on another spec

   paulc: would someone take an action to file an HTML5 bug
   proposing to solve in HTML 5.1 or a separate extension spec
   ... do the editors know what kind of non-normative text would
   be required?

   acolwell: no, this would be the first case of doing this - some
   example text would be useful

   paulc: adrian, do you have an idea?

   adrianba: happy to take an action to add some text - don't
   think it is needed but if it is needed to get consensus to
   resolve this bug then okay

   paulc: does anyone want to volunteer to file the bug for the
   other use case

   Michael_Thornburgh: i will file that bug

   <pal> should I file a bug against Section 2.2 re: there should
   be an "OR"

   <scribe> ACTION: Michael_Thornburgh to file bug describing
   timed track changes [recorded in


   <trackbot> Error finding 'Michael_Thornburgh'. You can review
   and register nicknames at

     [24] http://www.w3.org/html/wg/media/track/users%3E.

   paulc: this will send mail to public-html-admin - you could
   send mail to public-html asking for people's opinions about if
   such a spec would be useful

   adrianba: seems like it would be in scope for the media task
   force too

   paulc: yes, but i think we want to get broad review

   pal, sure - create the editorial bug - will deal as LC issue

   <scribe> ACTION: adrianba to propose non-normative text and
   resolve 22137 [recorded in


   <trackbot> Created ACTION-28 - Propose non-normative text and
   resolve 22137 [on Adrian Bateman - due 2013-07-30].

   pal: happy to create a bug for the OR issue

   paulc: believe that resolves 22137

Bug 22136 - Inband Storage for SPS/PPS in ISO BMFF


     [26] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22136


   <trackbot> ACTION-22 -- Adrian Bateman to work with jerry to
   confirm the proposal in 22136 is acceptable -- due 2013-07-02
   -- OPEN

   <trackbot> [27]http://www.w3.org/html/wg/media/track/actions/22

     [27] http://www.w3.org/html/wg/media/track/actions/22

   jdsmith: i had asserted that the standard wasn't mature enough
   but we're withdrawing that
   ... it is as mature as our spec
   ... i propose a SHOULD and proposed text in the bug

   <paulc> Proposed text:

     [28] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22136#c13

   jdsmith: think aaron's proposal is pretty close

   stevep: could of things we notice - one is that switching from
   SPS/PPS it could be made more generic
   ... HEVC allows other things in that configuration record
   ... we'd like it to be a MUST
   ... for interop reasons
   ... so that implementations can process any content

   paulc: reason for MUST for the first and SHOULD for the second?

   jdsmith: the first is an existing standard - we think the draft
   requires decoders to support this in multiple locations

   paulc: usually discourage groups from arguing over MUST and
   SHOULD this early
   ... one idea would be to make them both MUST and then mark at

   acolwell: we should probably rework the text based on my recent
   fixes to the byte stream format so that it is in terms of what
   the user agent should do
   ... sounds like this is about complying content so we need to
   rework into "the UA must do" style

   paulc: which bug caused this?

   acolwell: 22117


     [29] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22117

   paulc: whatever text we have, this needs to be looked at in the
   context of that bug

   adrianba: this whole section is optional in the spec - won't
   come into play for CR exit criteria

   paulc: bbc is asking for a MUST and for the reference to be

   pal: section 12.2 is only for the implementations that choose
   to do so
   ... if you choose to do this - SHOULD vs. MUST

   adrianba: can live with it but don't think this will affect

   stevep: our tests suggest this is easy to implement

   acolwell: agree with adrian - can live with must but if we run
   across implementations that can't support with hardware then
   they won't do this - you can put a MUST but it doesn't mean all
   implementations will do it - we will be constrained by devices

   pal: to the original question - concerned that there are two
   implementers saying it cannot be implemented
   ... from a content creation standpoint - if it says MUST i can
   assume it is always there but it might not be there and that is
   something i should know
   ... SHOULD means probably there but might not be

   <ReimundoGarcia> should

   paulc: is there anyone that can't live with it being a SHOULD?

   <paulc> steve

   stevep: our problem is that a SHOULD means that things that
   could implement it won't
   ... we won't serve to devices that don't support it

   acolwell: don't think we can answer this question right now

   <pal> waht about adding a note stating that DASH requires this

   acolwell: as implementers have concerns that there would be
   devices we could support MSE on without this
   ... we should indicate that this might not be supported - could
   change to MUST later

   pal: what about adding a note saying this feature is required
   in this other specification

   acolwell: don't believe MSE says it must be able to support all
   of DASH

   adrianba: proposal: make this a should with a note that
   describes that DASH content might not play back without this

   paulc: you'll get to see the text and can file a last call
   ... proposal is editors 22136 resolved as fix with text that
   was proposed by jerry, amended with note that DASH content
   might not playback with this support, also amended with aaron's
   comment about in terms of UA

   <scribe> ACTION: acolwell to work with jerry to add text for
   22136 into the spec [recorded in


   <trackbot> Created ACTION-29 - Work with jerry to add text for
   22136 into the spec [on Aaron Colwell - due 2013-07-30].

MSE Last Call or heart beat Working Draft publication

   paulc: chairs are trying to get heartbeat publications for all



     [31] http://lists.w3.org/Archives/Public/www-archive/2013Jul/0040.html

   scribe: leaving heartbeat to one side, we anticipated that at
   this stage we'd ask the task force and then the working group
   to go into last call
   ... we need to ask the editors to create an last call draft at
   a unique URL
   ... then ask the task force for approval to forward to WG for a
   ... how long will it take the editor's to produce the last

   acolwell: won't take long once we have the two edits done
   ... an hour or less after that we have the doc

   paulc: we can get approval from TF either through email or do
   it in two weeks at the meeting
   ... recommend that the TF permits me to do whichever occurs
   ... if editors get draft done this week - run a CfC by email so
   we get done as early as possible
   ... otherwise we can do it at the next meeting
   ... so worst case approve no later than 2 weeks from now

   acolwell: works for me


   paulc: antipating editors will close out these two bugs and
   announce they are done - if they supply me with a candidate LC
   doc i will start CfC in TF
   ... after that closes will discuss with co-chairs
   ... and make sure happens at WG level
   ... clear?

Candidate Last Call bugs

   paulc: 22432 and 22371
   ... both dealt with at jul 2 meeting
   ... proposed no change to 22432 - not implemented
   ... 22371, aaron was going to respond to the bug

   acolwell: haven't done yet - need to respond in the bug
   proposing it be created in a new doc

   paulc: like to suggest that editors go back and look at
   previous minutes and update bugs to say what our position is
   ... if someone objects to LC because of these bugs i would
   overrule because they came in after pre-LC but i think it is
   good practice to add current status in the bug

Any other business

   <pal> have a nice day

   paulc: very close to last call
   ... will tell my co-chairs that we're planning to go to LC and
   won't need heartbeat


   paulc: we're done

Summary of Action Items

   [NEW] ACTION: acolwell to work with jerry to add text for 22136
   into the spec [recorded in

   [NEW] ACTION: adrianba to propose non-normative text and
   resolve 22137 [recorded in

   [NEW] ACTION: Michael_Thornburgh to file bug describing timed
   track changes [recorded in


   [End of minutes]
From: Paul Cotton 
Sent: Monday, July 22, 2013 6:06 PM
To: public-html-media@w3.org
Cc: Aaron Colwell <acolwell@google.com> (acolwell@google.com); Adrian Bateman; Mark Watson
Subject: {agenda} HTML WG media telecon 2013-07-23 - MSE status and bug discussion

The HTML WG media teleconference meeting will occur on 2013-07-23 for up to 60 minutes from 15:00Z to 16:00Z.

Tokyo midnight, Amsterdam/Oslo 17:00, London/Dublin 16:00, New Jersey/York 11:00, Kansas City 10:00, Seattle/San Francisco 08:00.
Chair of the meeting: Paul Cotton
Scribe: TBD
(See the end of this email for dial-in and IRC info.)
== Agenda ==
1. Roll call, introductions and selection of scribe
2. Previous meeting minutes
3. Review of action items and issues

MSE-related actions are given below.
4. MSE status and bugs
a) Media Source Extensions editor's draft: 
Status as of Jul 22:  Last updated on Jul 18.

b) Media Source Extensions bugs: 
Status as of Jul 22: 4 bugs.  See list at end of this agenda.

5. Pre-Last Call bugs

a) Bug 22137 - changes in number of audio tracks during advert insertion

ACTION-21: Work with Jerry to review bug 22137 and provide feedback

Status: Closed. See Aarron’s response and subsequent responses:

b) Bug 22136 - Inband Storage for SPS/PPS in ISO BMFF

ACTION-22: Work with jerry to confirm the proposal in 22136 is acceptable

6.  MSE Last Call or heart beat Working Draft publication

7. Candidate Last Call bugs

a) Bug 22432 - Allow SourceBuffer.appendBuffer to take ownership of the ArrayBuffer

Status:  Candidate Last Call bug.  Jul 2 meeting proposed no change to spec but not yet implemented.

b) Bug 22371 - [MSE] Ogg byte streams 
Status:  Candidate Last Call bug.  Aaron offered to respond at the Jul 2 meeting.

8. Any other business
9. Chair and Scribe for next meeting
10. Adjournment
== Dial-in and IRC Details ==
Zakim teleconference bridge:
   +1.617.761.6200, conference 63342 ("media")

Supplementary IRC chat (logged):
   #html-media on irc.w3.org port 6665 or port 80
Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329
Allow SourceBuffer.appendBuffer to take ownership of the ArrayBuffer 
[MSE] Ogg byte streams 
changes in number of audio tracks during advert insertion 
Inband Storage for SPS/PPS in ISO BMFF 
4 bugs found. 

Received on Tuesday, 23 July 2013 16:26:53 UTC

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