- From: Francois Daoust <fd@w3.org>
- Date: Fri, 02 Sep 2011 08:47:15 +0200
- To: "public-web-and-tv@w3.org" <public-web-and-tv@w3.org>
Hi,
The minutes of yesterday's call are available at:
http://www.w3.org/2011/09/01-webtv-minutes.html
... and copied as raw text below.
Discussions around TV services mapping table (ISSUE-39), and first content protection use cases (ISSUE-40 and ISSUE-41).
Thanks,
Francois.
-----
Media Pipeline TF Teleconference (Web and TV IG)
01 Sep 2011
[2]Agenda
[2] http://www.w3.org/2011/webtv/wiki/MPTF/Agenda_Telco_1st_September_2011
See also: [3]IRC log
[3] http://www.w3.org/2011/09/01-webtv-irc
Attendees
Present
Kazuyuki_Ashimura, Steven_Wright, Duncan_Rowden,
Francois_Daoust, Tatsuya_Igarashi, Bob_Lund, Jan_Lindquist,
Narm_Gadiraju, Mark_Vickers, David_Corvoysier,
Russell_Berkoff, Juhani_Huttunen, Panu_Markkanen
Regrets
Chair
Clarke
Scribe
Francois
Contents
* [4]Topics
1. [5]TV services media transport mapping (ISSUE-39)
2. [6]Content delivery in distribution windows (ISSUE-40)
3. [7]Support of content owner rights (ISSUE-41)
* [8]Summary of Action Items
_________________________________________________________
Clarke: mostly only one item on the agenda, review of content
protection use cases.
Clarke: Several questions and comments around scope and definitions
on DRM.
... We'll discuss that.
... Anything else to add?
TV services media transport mapping (ISSUE-39)
<Clarke> ISSUE
39:[9]http://www.w3.org/2011/webtv/wiki/MPTF/MPTF_Discussions/TV_ser
vices_transport_mapping
[9] http://www.w3.org/2011/webtv/wiki/MPTF/MPTF_Discussions/TV_services_transport_mapping
Clarke: raised by Bob several weeks ago.
... mapping table.
... The basic idea of the use case is mapping existing traditional
TV services that TV actors and potentially regulators might want to
have, to the video element.
... Anyone who would object to accepting this use case?
Igarashi: Let me clarify. The use case assumes that Web page
provider is different from content provider?
Bob: That's one of the motivations of the use case, yes.
ISSUE-39?
<trackbot> ISSUE-39 -- TV Services and Media Transport Mapping --
raised
<trackbot> [10]http://www.w3.org/2011/webtv/track/issues/39
[10] http://www.w3.org/2011/webtv/track/issues/39
Bob: For some services, even if they are the same, you still need to
define how to translate the info at the application level.
... We don't know in advance what transport layer may be used and
how this data might be transported.
... For in-band tracks, that mapping is done by user agents. The
user agent has to recognize the data and builds the DOM objects
related to the tracks and fill it with info.
Jan: My assumption is that the UA has some capability of that type.
Some way, we need to document the mapping.
Jan: Personal opinion: for W3C it may be tricky to define
interoperability of topics that sit outside of W3C.
... There might be organizations that have that expertise.
Bob: Couple of comments. When you look at the current HTML5 draft,
section that refers to textable sourcing of inband tracks, you will
see that it explicitly references an external spec that will define
how this mapping is done.
... We've got acknowledgment from WhatWG that agree that this
mapping needs to be done.
... Question is whether this can be done in W3C.
Jan: I think it's fundamental that this be done, but from what you
tell me, W3C is not entirely agnostic to the source.
... How would you reflect this mapping?
... Let's say I take MPEG2-TS component, somehow you need to map
them to the track.
Bob: we've been doing most of our work with MPEG2. Audio mapping is
a good example.
... The mapping would describe how user agents would recognize audio
tracks. Regional stuff.
... And then there's the question for the various types of audio
track, how do you assign the "kind" attribute.
... This particular one is linked to the bug I filed on the HTML5
spec.
... Today, there's only one kind, and we may need two to do pre-mux.
... Mapping would precise which kind needs to be specified.
Jan: I did a little diagram to understand the components and
identified 7 areas to refine.
Mav: two different directions, one is mapping, the other is more
detailed description as you suggest.
<rberkoff> Can a link in Issue-39 to the discussion be added. I
think that our usual procedure?
Bob: For each one of these boxes, how do you recognize the track
format. W3C HTML5 describes how these get exposed to the Web page.
... HTML5 is silent on format of text track. Depending on transport
stream, different things need to be specified.
... We're in the process of prototyping some of this.
Clarke: hearing some discussion on how we might do this, but no
objection to accept this as a use case.
Bob: Maybe we need to list a number of requirements. About what is
the type of work that needs to be done in the next stage.
Clarke: yes, use cases first, then requirements.
Bob: I have identified what I think needs to be standardized.
<kaz> issue-18?
<trackbot> ISSUE-18 -- Video tag support of MPEG2-TS -- raised
<trackbot> [11]http://www.w3.org/2011/webtv/track/issues/18
[11] http://www.w3.org/2011/webtv/track/issues/18
Jan: in ISSUE-18, I touched upon MPEG2-TS, may need to reformulated
in the light of the discussion here.
Clarke: yes, would be very useful as we try to extract requirements.
Bob: Jan, it looks to me that we should merge these two use cases.
Jan: Yes, that was my purpose. I did not think W3C would be the
right place for that discussion.
Clarke: may I suggest that Jan and Bob work together and see if they
can be merged?
Bob: yes
Jan: yes.
Igarashi: comment about previous discussion.
Igarashi: mapping not restricted to media formats, mapping
guidelines would be helpful.
... Beneficial for W3C to standardize such mapping.
Bob: We identified that for metadata tracks, we wanted to track them
to expose ad insertion messages, content rating messages. The
current HTML5 spec does not provide any information to differentiate
between metadata tracks.
... No way for the JavaScript to tell what's in the metadata track.
... We raised that to the HTML WG.
... I agree that it's not clear whether W3C should do that or not.
Igarashi: I think W3C should discuss how to expose this information.
Clarke: one of the points raised that it would be useful to have
participation from country orgs, or orgs that we're referencing to
alert them on what we intend to do.
Igarashi: That's correct.
... How to do [??] is out of scope for W3C.
Bob: I agree with that. Different standards. This work would
reference these standards. The work that remains to be done is point
3.
... It's not totally obvious in the case of MPEG DASH that it's been
entirely defined how this information flows here.
... So work here could be to raise a flag that something needs to be
done in that space.
... We could e.g. go back to other orgs and say that something needs
to be added.
Igarashi: think there should be more in the motivation section for
this use case.
Clarke: maybe you could communicate directly with Bob for that.
Igarashi: ok.
Content delivery in distribution windows (ISSUE-40)
<Clarke> issue
40;[12]http://www.w3.org/2011/webtv/wiki/MPTF/MPTF_Discussions/Deliv
ery_in_distribution_windows
[12] http://www.w3.org/2011/webtv/wiki/MPTF/MPTF_Discussions/Delivery_in_distribution_windows
Clarke: some of the discussion going on on the reflector seems to be
concerned that we are trying to standardize on the DRM.
... That's not the goal, we propose to standardize on the "enable"
level to make playback of protected content possible.
... What we want to enable here is a way to specify parameters that
to play a video you need to support some sort of DRM, etc.
Bob: Good clarification. No intent for a single DRM. We expect
content to be protected with different types of DRM.
... The idea is to be able to continue to use the <video> tag to
play protected content.
... Lots of details below that, but the high level need is that.
Clarke: OK, if you think that ISSUE-40 is out of scope here, please
speak up.
Narm: It might be a good idea to add a clarification along the lines
of what you just said to the issue.
... so that it's clear.
Clarke: good point.
Bob: I can, but question for the group. All the comments are on the
requirements, more than on the use cases.
<rberkoff> Issue-40 need to link back to Wiki discussion
Bob: I'm fine to add the clarification to the requirements doc.
... Is that the appropriate place to do it?
Clarke: I think so. ISSUE-40 doesn't imply any kind of DRM.
... That seems pretty generic to me.
Bob: OK, I'll put in some clarification text, and others can comment
whether that's suitable.
Clarke: Specifically, on ISSUE-40, any objections to accepting the
use case?
Russell: question on the use of "enforce"
Bob: suggestion for an alternative?
Clarke: what you mean is that HTML5 does not need to enforce
anything, should simply enable the use of something that does the
enforcement.
Russell: that's what I would think.
Bob: I'm open to alternatives, but that's what I had in mind with
the use of "enforce".
Clarke: Boiling down to allowing/disallowing playback is good, I
think.
Russell: sounds like license enforcement, more than DRM.
Clarke: could you suggest some alternative text?
Russell: The DRM agent can never go back to the user agent and say
"don't do this".
... Maybe the use case should be framed in terms of DRM agents.
Requirement such as the HTML5 user agent should enable DRM agents.
Bob: why don't you send that to the list?
Russell: ok, will do.
Clarke: ok, we'll wait for Russell suggestion, probably can accept
that one afterwards.
Support of content owner rights (ISSUE-41)
<Clarke> ISSUE 41:
[13]http://www.w3.org/2011/webtv/wiki/MPTF/MPTF_Discussions/Content_
owner_rights
[13] http://www.w3.org/2011/webtv/wiki/MPTF/MPTF_Discussions/Content_owner_rights
Clarke: another variation. This one mentions UltraViolet in
particular. Do you want to keep that or is there a way to keep that
more generic?
Bob: I can go either way. It's a more generic problem.
Clarke: I would prefer to have UltraViolet as an example rather than
as a use case.
[exchanged missed on UtlraViolet, licensing and re-encoding]
[scribe stepped out for a minute]
Bob: there is no re-encoding in UltraViolet, actually. ISSUE-40 is
broader than ISSUE-41.
... The comment is that if we generalize ISSUE-41, how is it
different from ISSUE-40?
Russell: DECE supports 5 different DRMs, right?
Bob: yes, but common encryption, you just give it a different
license.
Clarke: just to clarify there. In ISSUE-41, if there are different
DRMs systems available, is that negotiated before the content is
delivered?
... I'm wondering if there's something unique to ISSUE-41.
Bob: I try to tie in needs for content protection with business
needs.
... We can certainly have a discussion on whether implementations
will be different or the same between the 2.
Clarke: We should identify use cases that lead to specific
requirements.
... If there aren't any specific requirements, then maybe both
issues should be merged.
Bob: ISSUE-41 touches upon the common encryption mechanism.
<rberkoff> I agree w/Bob's description
Clarke: the idea to identify a DRM with a common encryption that
gets negotiated somehow sounds like a different requirement.
Bob: yes.
<rberkoff> yes
Juhani: If DECE requirements are to be taken into account, why don't
we ask DECE about them?
Clarke: you're suggesting DECE should write clarifications to this
use case.
Juhani: the best source of information for this would be DECE
members if we talk about a specific system.
Clarke: So we're DECE members, so don't know if you're suggesting
stronger links or not
Bob: I heard the comment to precise what needs to be standardized in
a more DECE-focused form.
Juhani: yes, if it's an example, no need to do that, but if we want
to highlight DECE as a requirement in particular, maybe there should
be a direct request to DECE to precise the requirements.
Bob: Let me take that as an action item to see how much more
specific I can get right now.
... The more specific requirements we get, the better, I think.
Clarke: OK, so we're out of time. Thanks, let's continue discussion
on the mailing-list.
[Call adjourned]
<kaz> ACTION: lund to see how much more specific issue-41
description could be [recorded in
[14]http://www.w3.org/2011/09/01-webtv-minutes.html#action01]
<trackbot> Created ACTION-74 - See how much more specific issue-41
description could be [on Bob Lund - due 2011-09-08].
Summary of Action Items
[NEW] ACTION: lund to see how much more specific issue-41
description could be [recorded in
[15]http://www.w3.org/2011/09/01-webtv-minutes.html#action01]
[End of minutes]
Received on Friday, 2 September 2011 06:47:49 UTC