- From: Joe Steele <steele@adobe.com>
- Date: Tue, 2 Oct 2012 09:05:53 -0700
- To: "<public-html-media@w3.org>" <public-html-media@w3.org>
- Message-ID: <542160C1-180C-47D1-BA10-DBDC5B2177B7@adobe.com>
The minutes from today teleconference are available here:
http://www.w3.org/2012/10/02-html-media-minutes.html,text
or in plain text below:
[1]W3C
[1] http://www.w3.org/
- DRAFT -
HTML Media Task Force Teleconference
02 Oct 2012
See also: [2]IRC log
[2] http://www.w3.org/2012/10/02-html-media-irc
Attendees
Present Aaron_Colwell BobLund Clarke Microsoft MikeSmith adrianba ddorwin glenn joesteele johnsim-msft markw matt pal strobe
Regrets
Chair
johnsim-msft
Scribe
joesteele
Contents
* [3]Topics
1. [4]Review action items
* [5]Summary of Action Items
__________________________________________________________
<trackbot> Date: 02 October 2012
<johnsim-msft> 2. Previous meeting minutes on Sep 18
[6]http://www.w3.org/2012/09/18-html-media-minutes.html
[6] http://www.w3.org/2012/09/18-html-media-minutes.html
<scribe> ScribeNick: joesteele
Review action items
<johnsim-msft> [7]https://www.w3.org/html/wg/media/track/
[7] https://www.w3.org/html/wg/media/track/
<johnsim-msft>
[8]https://www.w3.org/Bugs/Public/show_bug.cgi?id=17682
[8] https://www.w3.org/Bugs/Public/show_bug.cgi?id=17682
johnsim-msft: propose a solution to the clear key bug, did add
a comment a few minutes ago bug#17682
... some others we could discuss as well
<johnsim-msft> [9]http://tinyurl.com/7tfambo
[9] http://tinyurl.com/7tfambo
johnsim-msft: no analysis yet on closing these bugs
Title: HTML-Media
<scribe> Meeting: HTML Media Extensions
<johnsim-msft>
[10]https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673
container guidelines
[11]https://www.w3.org/Bugs/Public/show_bug.cgi?id=17682 clear
key [12]https://www.w3.org/Bugs/Public/show_bug.cgi?id=19208
keymessage event not needed
[13]https://www.w3.org/Bugs/Public/show_bug.cgi?id=19156
switching decoders
[10] https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673
[11] https://www.w3.org/Bugs/Public/show_bug.cgi?id=17682
[12] https://www.w3.org/Bugs/Public/show_bug.cgi?id=19208
[13] https://www.w3.org/Bugs/Public/show_bug.cgi?id=19156
johnsim: container guidelines bug
... I had an action item on this.
... new bug coming on ISO based media file formats should have
stronger guidelines when a CDM has a key in it storage
ddorwin: no preference on order
johnsim: starting with container guidelines bug
… exchanged some email on this and added to the bug
<scribe> … new bug is 19208
johnsim: this is specific to the COmmon Encryption Format
specification
... please read the bug online
... this is the proposed language for the ISOBMFF guidelines
… captures enough of how to detect encryption and extract the
metadata needed from those files
… does raise some issues about initialization and events
… there are cases where the CDM does not need to issue a key
message event
… any comments or concerns, David?
ddorwin: no comments
johnsim: next bug is bug#17682 (clear key bug)
… documents how keys and key ids are associated
<BobLund> mute
… added a brief comment to the end of the spec
<BobLund> mute me
johnsim: how clear key works should be the same as the CDM
... should be defined by the W3C since this is strictly a W3C
concept
… data blob specific to CDM is in the spec, in the case of
clear key just a key
… need to define how clearKey is initialized or any media
format is supported
… propose some draft language based on some email traffic to be
sent to general rflector
johnsim: need to add language for other formats
ddorwin: for ClearKey specific stuff, and ISO, nothing to
define just a keyid
… for other containers need to define
… this is part#1 of the bug, part#2 is the license
… this is the harder part, need to define key/keyid pairing
johnsim: there have been some proposals out there
... do you mean a defined data structure like a license being
passed down?
ddorwin: yes
… in the old version for WebM has a simple definition but this
has been removed
… need a license to provide more than one key
markw: need to say how do we support more than one key at a
time?
ddorwin: want clearKey to be as capable as other CDMs to use
for prototyping
… maybe use JSON or something
johnsim: we are talking about the analog to a license for
clearKey, requirement is that is be capable of communicating
more than one key/keyID pair
… I am a little hazy on that
… init data would have to report more than one
ddorwin: nothing that says you can't have more than one keyid
johnsim: keyed is really a meta-key which tells the server to
deliver more than one key at once
ddorwin: might need to be base64-encoded JSON but moves a
little away from original spirit
johnsim: some work on this in the webCrypto group
<ddorwin> where the spirit was to be able to easily specify a
key in JS
markw: you mean how keys are encoded? we just specify an
arrayBuffer of the raw bytes at this point
johnsim: so this action item is still open. Need to propose
license structure for clearKey
... should we move on?
... jumping to switching decoders bug #19156
… has been some discussion but no replies yet
ddorwin: unlike clearKey some CDMs will include decoders and/or
rendering pipelines
… this means you may be picking a decoder by picking a CDM
… this may cause a switch in the decoder being used
… what should we do in that case?
… should we spec it away?
aaron: should not spec it away at this point
… could be implementation
johnsim: could have portions encrypted and some not
aaron: thinking of the case where content comes from multiple
files
johnsim: the metadata would be from different files in this
case?
aaron: starting with unencrypted file and moving to encrypted
file, should not cause decoding to stop
ddorwin: need to specify the decoder up front
… how does media source handle this?
… currently only one key system allowed per media element
markw: currently decoder is not allowed to change
... prefer not to prevent it for now if possible
... will comment on the bug
s: /markw: will comment/aaron: will comment/
aaron: as long as you are only switching during media segment
boundaries, should avoid this problem
Aaron_Colwell: could have the CDM disable encryption when clear
frames comes through
markw: you need the CDM to be able to handle this already
this is an issue for ad-insertion
<markw> my point was just that (i) the CDM should be able to
cope with unencrypted samples and (ii) the first encrypted
sample and all subsequent samples must not depend on any
samples before the first encrypted sample
johnsim: so we will add comments to the thread on this?
ddorwin: will reply with what I heard
johnsim: moving to bug#19208
… based on the container guideline bug
… came across a case where the keyMessage event might not be
needed
… David pointed out this contradicts the spec
… bug is -- if a session is created which activates a CDM, and
key storage already has a key, no need for a keyMessage event
… David, what do you think?
ddorwin: does not violate the spirit of the spec
… but we might need to change the text of the algorithm (BMFF
text)
johnsim: you don't disagree then
ddorwin: don't have any objections, but would like feedback and
thought
... calling createSession would not cause a message to the app,
which is a little strange
johnsim: had discussions about the event corresponding to a key
successfully being extracted
… is the a need for that event (e.g. a null-key messages)
ddorwin: we have KEYERROR we could add a
ALREADY_HAVE_A_LICENSE_ERROR
… createSession could return a reference to an existing session
- need to think about that more
… would not matter so much whether you got another message then
johnsim: any other thoughts on this issue?
... going back to the list of open bugs
<ddorwin>
[14]https://www.w3.org/Bugs/Public/show_bug.cgi?id=18531
[14] https://www.w3.org/Bugs/Public/show_bug.cgi?id=18531
johnsim: renaming addKey
<ddorwin>
[15]http://lists.w3.org/Archives/Public/public-html-media/2012S
ep/0045.html
[15] http://lists.w3.org/Archives/Public/public-html-media/2012Sep/0045.html
markw: there was a couple of suggestions -- update() was the
only one commented on
... would suggest we go with that
joesteele: I like update()
ddorwin: only concern is that in the general case we are adding
a license
johnsim: you are really adding things -- more than an update
markw: update() means providing more information
<ddorwin> [16]http://dictionary.reference.com/browse/update
[16] http://dictionary.reference.com/browse/update
johnsim; connotation of providing entirely different
information and adding values
<ddorwin> [17]http://mw1.merriam-webster.com/dictionary/update
[17] http://mw1.merriam-webster.com/dictionary/update
johnsim: there are quite a few open bugs
<ddorwin> transitive verb: to bring up to date
johnsim: what is the status for the open bugs?
<johnsim-msft> [18]http://tinyurl.com/7tfambo
[18] http://tinyurl.com/7tfambo
joesteele: I did not get to the example I was to do.
[19]https://www.w3.org/Bugs/Public/show_bug.cgi?id=16540
[19] https://www.w3.org/Bugs/Public/show_bug.cgi?id=16540
johnsim: are folks attending the TPAC meeting?
ddorwin: yes I will be
joesteele: I am not going at this point
johnsim: encourage everyone on the call with open bugs to
resolve or start a thread on these bugs ASAP
… want to reach closure at TPAC or before if possible
ddorwin: many are editorial
johnsim: would be great to pull out the substantial bugs
… design questions, etc
… any that sit at the top of the list as needs resolving?
ddorwin: the clearKey bug must be resolved
<adrianba> we don't have to close every bug - we need to ensure
the document covers the desired scope before we ask for FPWD
ddorwin: needKey is another one
johnsim: which is the needKey?
ddorwin: will try to get the other bug I need to file out
… and send an email
ddorwin: no major changes to the spec in these bugs
johnsim: concern about the specs fitting together?
… new segments from other key systems, etc.
ddorwin: MSE is another source for the URL should work
together, might need to discuss advanced use cases
markw: will scribe for next meeting
ddorwin: TPAC is on the 29th
johnsim: next EME call will be the last one before the TPAC
... would like to discuss how we can use the TPAC to advance
the spec on the next call
... would like to resolve as many bugs as possible before than
as well
... David the issues you raised we should really resolve
... raises our chances of coming out with a good draft
... pretty much done
joesteele: bye all
Summary of Action Items
[End of minutes]
Joe Steele
steele@adobe.com
Received on Tuesday, 2 October 2012 16:06:51 UTC