W3C home > Mailing lists > Public > public-html-media@w3.org > March 2014

RE: {minutes} HTML WG media telecon 2014-03-04 - EME bug discussion

From: Adrian Bateman <adrianba@microsoft.com>
Date: Tue, 4 Mar 2014 17:07:37 +0000
To: Paul Cotton <Paul.Cotton@microsoft.com>, "public-html-media@w3.org" <public-html-media@w3.org>
Message-ID: <6d969e52954e4edda323d531348ac189@BL2PR03MB604.namprd03.prod.outlook.com>
Minutes -> http://www.w3.org/2014/03/04-html-media-minutes.html

   [1]W3C

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

                               - DRAFT -

                  HTML Media Task Force Teleconference

04 Mar 2014

   [2]Agenda

      [2] http://lists.w3.org/Archives/Public/public-html-media/2014Mar/0010.html

   See also: [3]IRC log

      [3] http://www.w3.org/2014/03/04-html-media-irc

Attendees

   Present
          paulc, markw, glenn, joesteele, adrianba,
          +1.425.936.aaaa, ddorwin, davide, johnsim, pal, BobLund,
          jdsmith

   Regrets
   Chair
          Paul Cotton

   Scribe
          Adrian Bateman

Contents

     * [4]Topics
         1. [5]Roll call, introductions and selection of scribe
         2. [6]NEW EME bugs since the last meeting
         3. [7]Bug 24771 - Provide guidance on object and CDM
            lifetime (including when events are guaranteed to be
            fired)
         4. [8]Bug 24873 - Current isTypeSupported() definition
            does not provide sufficient information to
            applications
         5. [9]Bug 24874 - Positive isTypeSupported() may be
            misleading (MSE vs. .src=)
         6. [10]Bug 24904 - Uint8Array parameters should not be
            modifiable after method calls return
         7. [11]EME bugs for discussion
         8. [12]Bug 17673 - Define Initialization Data for
            implementations that choose to support the ISO Base
            Media File Format
         9. [13]Bug 17750 - Define the behavior MediaKeySession
            close() and clearing the keys attribute
        10. [14]Bug 21798 - Revisit MediaKeyError codes
        11. [15]Bug 23619 - Change MediaKeyError to extend
            DOMError and use strings for error names
        12. [16]Bug 24027 - Define a generic Initialization Data
            solution for ISO Base Media File Format and/or Common
            Encryption (will be used by Clear Key)
        13. [17]Bug 24419 - Clear Key: Define license request
            format
        14. [18]Bug 24673 - Make all content type string checks
            case-sensitive
        15. [19]Any other business
        16. [20]Adjournment
     * [21]Summary of Action Items
     __________________________________________________________

   <trackbot> Date: 04 March 2014

   <paulc> Agenda:
   [22]http://lists.w3.org/Archives/Public/public-html-media/2014M
   ar/0010.html

     [22] http://lists.w3.org/Archives/Public/public-html-media/2014Mar/0010.html

   <scribe> Agenda:
   [23]http://lists.w3.org/Archives/Public/public-html-media/2014M
   ar/0010.html

     [23] http://lists.w3.org/Archives/Public/public-html-media/2014Mar/0010.html

   <scribe> ScribeNick: adrianba

   <scribe> Scribe: Adrian Bateman

Roll call, introductions and selection of scribe

   paulc: done

NEW EME bugs since the last meeting

   paulc: there are 4 of these
   ... one of them had a lot of discussion but the others not so
   much

Bug 24771 - Provide guidance on object and CDM lifetime (including
when events are guaranteed to be fired)

   [24]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24771

     [24] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24771

   <paulc>
   [25]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24771

     [25] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24771

   paulc: long proposal here - do you just want to add this to the
   list of things of comments or should david introduce the
   issues?

   ddorwin: issue came up when deciding when to GC the objects -
   could be a circular reference meaning things wouldn't get
   collected

   paulc: volunteer to review?

   <markw> I will review it too, but I am also not a browser
   vendor

   joesteele: i could review but not sure if my input would be as
   useful - not a browser vendor

   paulc: perhaps someone from Microsoft can take a look at this

Bug 24873 - Current isTypeSupported() definition does not provide
sufficient information to applications

   [26]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24873

     [26] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24873

   paulc: filed recently - does this fall into the same category?

   ddorwin: not being able to detect if the browser has
   capabilities needed - adrian mentioned this in one of the other
   bugs

   <joesteele> +q

   ddorwin: first two paragraphs says what it is - the rest says
   why
   ... two changes - one if to add capability string and the other
   is changing the return type to have three states
   ... somewhat like canPlayType though doesn't have to be
   ... those are independent but work well together

   joesteele: seems to reintroduce something we discussed at the
   beginning
   ... decided early on the key systems shouldn't have this info
   because it was too complicated

   ddorwin: some of the same issues but this is more targeted
   specifically at audio vs video
   ... but we decided not to 'abuse' the key system name

   joesteele: maybe i'm not understanding capability - do you mean
   things like HDCP
   ... is this something where this platform is not at all capable
   or not right now
   ... because if not right now then you'd need to call again

   ddorwin: no, i wasn't thinking about HDCP which can take a
   couple of seconds
   ... this is supposed to return quickly
   ... many key systems support multiple levels of robustness

   <ddorwin> The old capability detection bug:
   [27]https://www.w3.org/Bugs/Public/show_bug.cgi?id=16611

     [27] https://www.w3.org/Bugs/Public/show_bug.cgi?id=16611

   adrianba: not sure what the capability string contains - what
   if it is more than one thing - should it be a string or
   something else?

   ddorwin: it is key system specific - could have a key system
   specific separator
   ... could have an array of strings but just as easy to be comma
   separated

Bug 24874 - Positive isTypeSupported() may be misleading (MSE vs.
.src=)

   [28]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24874

     [28] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24874

   ddorwin: result of isTypeSupported doesn't say if it works with
   MSE or with src=
   ... filed to track this issue

   paulc: questions?

Bug 24904 - Uint8Array parameters should not be modifiable after
method calls return

   [29]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24904

     [29] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24904

   paulc: provided the beginning of the march part of the thread

   [30]http://lists.w3.org/Archives/Public/public-html-media/2014M
   ar/0002.html

     [30] http://lists.w3.org/Archives/Public/public-html-media/2014Mar/0002.html

   paulc: most recent suggestion to raise this as a TAG issue

   <joesteele> +1 to email discussion

   paulc: shall we let this continue in email? this problem exists
   in other places too

EME bugs for discussion

   paulc: all the bugs that had postings since our last meeting
   ... agenda item 7 includes implemented bugs since last time (4
   bugs)
   ... agenda item 8 is bugs waiting for editors (6 bugs)
   ... agenda item 9 is low pri bugs
   ... plan to step through the items in #6 and ignore the others
   today

Bug 17673 - Define Initialization Data for implementations that
choose to support the ISO Base Media File Format

   [31]https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673

     [31] https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673

   adrianba: we think we should move ahead with changing this as
   discussed in recent meetings to see if people like the text
   ... (that's Microsoft's position)

   <joesteele> no objection

   paulc: any comments?
   ... any objections to trying this out?
   ... okay, this one is assigned to the editors to do

   adrianba: i'm happy to make the change

   ddorwin: i'll file a specific bug about the "CENC" string - i
   suspect we'll need to change isTypeSupported too

Bug 17750 - Define the behavior MediaKeySession close() and clearing
the keys attribute

   [32]https://www.w3.org/Bugs/Public/show_bug.cgi?id=17750

     [32] https://www.w3.org/Bugs/Public/show_bug.cgi?id=17750

   paulc: comment from adrian on feb 21

   <joesteele> +q

   adrianba: we reviewed this and think we're proposing the
   correct answer - we need someone to check our working

   ddorwin: no specific objections

   markw: looks okay - i will check with our implementers

   joesteele: i had raised a question above about cached keys
   being released
   ... not clear to me that we agree that keys can be cached
   ... might be off topic for this bug

   adrianba: i think loadSession implies there are cached keys
   otherwise what could you load
   ... i think there is a question beyond just consistency with
   other specs - we proposed a solution that does impact what
   order things can execute in
   ... so there is something EME specific to review here too

   glenn: haven't looked at the detail but curious if there is a
   need for promises here?

   <ddorwin> Does the proposed spec change related to spinning the
   event loop mean MediaKeys construction will prevent any other
   tasks (from any other spec) from being processed? Is that
   desirable?

   adrianba: i don't think promises apply here - this is about
   multiple async tasks interacting with each other

   <glenn> sleep(0)

   adrianba: spinning the event loop is like VB6 DoEvents - it
   lets other things run

   paulc: is there an editor to implement this?

   adrianba: i can do this

Bug 21798 - Revisit MediaKeyError codes

   [33]https://www.w3.org/Bugs/Public/show_bug.cgi?id=21798

     [33] https://www.w3.org/Bugs/Public/show_bug.cgi?id=21798

   adrianba: we can live with not solving this in this version but
   if someone comes up with a workable proposal then we are okay
   with that

   ddorwin: i will make a proposal

Bug 23619 - Change MediaKeyError to extend DOMError and use strings
for error names

   [34]https://www.w3.org/Bugs/Public/show_bug.cgi?id=23619

     [34] https://www.w3.org/Bugs/Public/show_bug.cgi?id=23619

   <ddorwin> Open issue in DOM4 on the future of DOMError:
   [35]http://www.w3.org/TR/dom/#interface-domerror

     [35] http://www.w3.org/TR/dom/#interface-domerror

   adrianba: while the spec continues to have DOMError, we think
   we're using it correctly
   ... we also prefer to keep systemCode

   <joesteele> +1 to keeping it in the spec as-is

   ddorwin: i don't object to system code and the inclusion
   requires that we define an additional type - if people want to
   keep it then that is fine - it is already in the spec

   paulc: what is next?

   ddorwin: if nobody wants to eliminate this type then we
   resolve, fixed

   paulc: proposal is to mark it fixed

   <ddorwin> done

Bug 24027 - Define a generic Initialization Data solution for ISO
Base Media File Format and/or Common Encryption (will be used by
Clear Key)

   [36]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24027

     [36] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24027

   paulc: mark agreed to add a concrete proposal - in comment 6
   ... some dialogue here - what is the current state?

   markw: i didn't see the questions from joe and david so i need
   to catch up and reply to their points

   joesteele: i should reply in the bug - i wasn't clear from
   david's last question why you wouldn't want to use the MAC - i
   would guess that the CDM would say key not available

   ddorwin: some confusion about what the MAC was earlier in
   thread - agree - question is do the existing algorithms deal
   with this

Bug 24419 - Clear Key: Define license request format

   [37]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24419

     [37] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24419

   paulc: is this ready to move to the "to be implemented" list?

   ddorwin: need to implement the license request format first

Bug 24673 - Make all content type string checks case-sensitive

   [38]https://www.w3.org/Bugs/Public/show_bug.cgi?id=24673

     [38] https://www.w3.org/Bugs/Public/show_bug.cgi?id=24673

   ddorwin: we find that the content type and the codecs have
   different requirements
   ... so we might need non-normative text

   adrianba: seems fine - just need text to add

   paulc: do we need concrete text in the bug or just move forward
   - better to move ahead

   ddorwin: will make this dependent on the "CENC" bug that I said
   I will file

Any other business

   paulc: i said we'd skip the other bugs unless someone objects -
   now is the time if you want to
   ... in 10 days i'll evaluate where we stand for the topic bugs
   for discussion in the next meeting

   adrianba: different topic, are people planning to attend the
   F2F meeting to discuss EME?

   <markw> yes, I'll be there

   <BobLund> I'll be there

   paulc: [lists attendees from TF who already plan to attend]

   <paulc>
   [39]https://www.w3.org/2002/09/wbs/40318/html-april-2014/result
   s

     [39] https://www.w3.org/2002/09/wbs/40318/html-april-2014/results

   paulc: if you can't attend might be helpful to fill out the
   registration form saying so

   joesteele: i may have a conflict - probably be on the phone at
   least

   ddorwin: would be nice if we knew which day to minimise travel

   <paulc>
   [40]https://www.w3.org/wiki/HTML/wg/2014-04-Agenda#Potential_To
   pics

     [40] https://www.w3.org/wiki/HTML/wg/2014-04-Agenda#Potential_Topics

   paulc: if you put it on the potential topics list then we can
   reserve that time
   ... meeting is tues/wed

   <BobLund> Tue or Wed AM

   <paulc> April 8-9

   paulc: does anyone have a pref for which day

   johnsim: if the meeting is wed AM i might be able to attend

   paulc: any objections to wed AM?

   <BobLund> Wed AM is good

   adrianba: works for me

   paulc: would it be worth asking dsinger about attending?

   pal: excellent idea

   paulc: i'll propose on the draft agenda - should i ask for 9 to
   11?
   ... i'll figure this out

Adjournment

   paulc: talk to you in 2 weeks

Summary of Action Items

   [End of minutes]


-----Original Message-----
From: Paul Cotton [mailto:Paul.Cotton@microsoft.com] 
Sent: Monday, March 3, 2014 6:06 PM
To: public-html-media@w3.org
Subject: {agenda} HTML WG media telecon 2014-03-04 - EME bug discussion

The HTML WG media teleconference meeting will occur on 2014-03-04 for up to 60 minutes from 15:00Z to 16:00Z.
 
http://timeanddate.com/s/2jfn    
 
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
Feb 18: http://www.w3.org/2014/02/18-html-media-minutes.html
Feb 4: http://www.w3.org/2014/02/04-html-media-minutes.html
Jan 28: http://www.w3.org/2014/01/28-html-media-minutes.html

3. Review of action items and issues
https://www.w3.org/html/wg/media/track/ 

a) ACTION-61: Work with wendy to make sure we get a security review [ Paul ]
https://www.w3.org/html/wg/media/track/actions/61
Status: Paul reached out to Wendy again on Jan 23:
http://lists.w3.org/Archives/Public/public-html-media/2014Jan/0056.html

b) ACTION-62: Report back about the plan for 20944 due 2013-12-15 [ Paul ]
https://www.w3.org/html/wg/media/track/actions/62
Status: No action yet but see developments on 20944:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=20944#c34
and subsequent replies.

4. EME status and bugs
 
a) Encrypted Media Extensions editor's draft
 http://dvcs.w3.org/hg/html-media/raw-file/tip/encrypted-media/encrypted-media.html
Last updated on Feb 24.

b) Encrypted Media Extensions bugs: 
http://tinyurl.com/7tfambo
Status as of Mar 3: 22 bugs

5. NEW EME bugs since the last meeting

a) Bug 24771 - Provide guidance on object and CDM lifetime (including when events are guaranteed to be fired)
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24771

b) Bug 24873 - Current isTypeSupported() definition does not provide sufficient information to applications
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24873 

c) Bug 24874 - Positive isTypeSupported() may be misleading (MSE vs. .src=)
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24874 

d) Bug 24904 - Uint8Array parameters should not be modifiable after method calls return
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24904 
See also the thread at:
http://lists.w3.org/Archives/Public/public-html-media/2014Mar/0002.html  

6. EME bugs for discussion

a) Bug 17673 - Define Initialization Data for implementations that choose to support the ISO Base Media File Format
https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673
See recent postings since Feb 18 meeting:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673#c42 

b) Bug 17750 - Define the behavior MediaKeySession close() and clearing the keys attribute
https://www.w3.org/Bugs/Public/show_bug.cgi?id=17750
See recent response from Adrian since Feb 18 meeting:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=17750#c26 

c) Bug 21798 - Revisit MediaKeyError codes
https://www.w3.org/Bugs/Public/show_bug.cgi?id=21798
Status from Jan 28 meeting: Error codes and constants removed. New error names need to be proposed and added.
Feb 4: David said he would go through whole thread and generate a response.
See recent response from Adrian since Feb 18 meeting:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=21798#c19 

d) Bug 23619 - Change MediaKeyError to extend DOMError and use strings for error names
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23619
See recent response from Adrian since Feb 18 meeting:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23619#c10 

e) Bug 24027 - Define a generic Initialization Data solution for ISO Base Media File Format and/or Common Encryption (will be used by Clear Key)
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24027
Mark agreed added a concrete proposal after Feb 18 meeting:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24027#c6

f) Bug 24419 - Clear Key: Define license request format
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24419
Feb 4: David said he would implement the proposed solution.  But see Adrian's question:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24419#c1 

g) Bug 24673 - Make all content type string checks case-sensitive
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24673 
See Adrian and David's dialogue starting at:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24673#c2 

7. Implemented EME bugs awaiting review

a) Bug 18515 - Provide more details on behavior of the media element when the key for an encrypted block is not available
https://www.w3.org/Bugs/Public/show_bug.cgi?id=18515
Implemented and awaiting review:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=18515#c21 

b) Bug 24270 - Make MediaKeySession State Definitions and Event Summary sections non-normative
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24270

c) Bug 24323 - Rename "First Time a Key Reference is Encountered" algorithm and remove key ID checks from Container Guidelines subsections
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24323

d) Bug 24368 - Define playback behavior when the key for an encrypted block is not available for a subset of streams
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24368

8. EME bugs awaiting Editor implementation or action

a) Bug 17202 - Explicitly document how keys are to be shared
https://www.w3.org/Bugs/Public/show_bug.cgi?id=17202
Next action: David to make changes in comment 3

b) Bug 17682 - Clear Key: Document how keys and key IDs are associated
https://www.w3.org/Bugs/Public/show_bug.cgi?id=17682
Next action: David to add note.

c) Bug 23828 - HTMLSourceElement with |keySystem| attribute should create MediaKeys object for |keySystem|
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23828
Next action: Adrian to make changes (low priority - see 23827)

d) Bug 24026 - Document that URLs (destinationURL) should/may be validated and/or normalized
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24026
Next action: David to add proposed text (to bug or spec)

e) Bug 24081 - The READY state is too limiting and should be more like the PENDING state
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24081
Next action: TF to discuss David's proposal (Microsoft is supportive) 
Status from Jan 28 meeting: David to implement his proposal.

f) Bug 24216 - setMediaKeys() needs more specification
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24216
David agreed to develop a proposal:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24216#c2

9. EME bugs on hold or lower priority

a) Bug 20944 - EME should do more to encourage/ensure CDM-level interop
https://www.w3.org/Bugs/Public/show_bug.cgi?id=20944   
Next action: ACTION-62 on Paul

b) Bug 23827 - Need to add features at risk prior to entry into Candidate Recommendation
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23827
Next action: wait until LC

c) Bug 24025 - Add optional configuration parameter to MediaKeys constructor
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24025
Next action: discuss as part of 24082 below. Tied to the general extensibilty issue.
Mark added his use case on Feb 18:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24025#c9

d) Bug 24082 - Several issues discussed in the TF point to the need for defined extensibility points in EME
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24082
Next action: TF agreed that members need to propose use cases - not blocking and lower priority

e) Bug 24322 - Reorganize spec by object
https://www.w3.org/Bugs/Public/show_bug.cgi?id=24322
Next action: significant editorial change just needs editing - not blocking

10. Any other business
 
11. Chair and Scribe for next meeting

12. Adjournment
 
== Dial-in and IRC Details ==
 
Zakim teleconference bridge:
   +1.617.761.6200, conference 63342 ("media")
https://www.w3.org/Guide/1998/08/teleconference-calendar#s_5366
 
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

Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329
Received on Tuesday, 4 March 2014 17:08:15 UTC

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