Media Subteam 20 April 2011

20 Apr 2011

See also: IRC log


Bob, Eric_Carlson, Frank, John_Foliot, Judy, Sean, mark, silvia


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<judy> Sean will scribe, Judy will fill in when Sean is commenting

<scribe> scribe: Sean

Issue-152 Multitrack http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Change_Proposals_Summary

Silvia and JF catching up on email

Ian has introduced some changes

yes please

Judy recommends that we maintain formal and informal communication

Judy: Good to record out discussion

Frank: On track to have a single coherent proposal, would like our CP to be against whats in the spec, rather than a CP against a CP

to consolidate into one single change

JF: if there is still difference between this group and Ian, how do we capture that

we should not let anything slip

Mark: arent we required to produce a CP against the current W3C spec

<silvia> +q

Judy, yes; typically what we do against a rolling editors vresion is comment wrt to a time stamped version

Silvia. the Wiki page is a formal record to some extent

have removed things as Ian has added them

Ian's CP is in the WHATWG spec

ours is in the Wiki

the changes are not uncontrolled

SJudy: That can be tricky

multiple moving targets dont give the record trail

unless you dive into the histories of the individual pages

email also gives some trail

we need to send things that are static

<silvia> http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Change_Proposals_Summary#Proposal_4:_Controller_proposal

Silivia: working to that

see urL

ask to work through the 'silvia's notes section

this is the proposal we are going to submit

work through the 7 points

and Silvia can prepare the email

for dicussion

all: general agreement

point 1.

make track more like text track, now recorded as a bug

Silvia - tracklist has a set of getXX functions

these are different to how text track is defined

where they are attributes

Philip suggest making a list of object with attributes for consistency

we dont need to record this as its a separate bug

JF: Q: What are the pros and cons

if it goes after LC

Eric. the issue is that philip has already filed a bug, and its just a change to the interface

we dont need to restate it

<silvia> http://www.w3.org/Bugs/Public/show_bug.cgi?id=12530

move on and leave point 1

Item 2.

it should include id, label and kind

JF: Ian was unclear about kind

what are we discussing?

Silvia its about adding ID and kind

to get a unique identifier to create a fragment url

Sean: should also have a getFragmentIRL function

Siliva: agree, but ID is still needed

Sean: have both

Eric: prefer to not have the function

problem is that there are files for which the URL for the track is not the same as the parent movie

which is another file on the server

asking a track for a URL, if its a reference to a different file; this needs to be resolved

it is also a problem that the fragment spec is not final

it seems to be something that could be done in a JS library/

Silvia can find outr which tracks exist

composing the fragment url to combine in one URL

Sean: do we need additional information?

Eric: Asking a track for a reference to itself

refering to the track from the outside is unambiguous

from the inside there is a possibility of confusion

defintion of the attribute needs to say what it refers to

Silvia getID we definitley want

get URL may be a convenience

we dont need to agree on it now to resolve 152

we need to look at the current src to see if its adequate prefix to a #id

<JF> +1 to @kind

Silvia: kind is required to discover what the content is intended for

<frankolivier> +1 to @kind

all: agree kind is necessary

Eric: one problem is how we define the media information to a kind

doesnt exist in in MP4 and Quicktime

we are working on a proposal

but hasnt been defined yet

secondly, no authoring tools to let you add it

maybe some command line tools

so it will be a while before this data shows up in files

but agree its important, but will be difficult for a while

Silvia: need it in the spec for interoperability

JF: if the additional data is in the wrapper, how is it exposed to the player

SIlvia: is the data- attribute appropriate?

eric: we need a mechanism to express a kind of an inband track

this is not on the markup

its in the media

Eric we have a bit of chicken and egg problem, but it will get solved

Silivia: there are slots in media files, but we need time to establish usage

Eric: there are fields in Quicktime files, but not standard values

mark: in mpeg-DASH they have been looking at this, and will add the necessary annotations

JF: so we do need @kind

did we not have other kinds

Silvia: thise were for text

this is AV

we need to think about other kinds

sean: clear audio sould be a kind

speech only

JF: lang, ISO language codes, there doesnt seem to be consistency

do we need to specify language codes for sign

Silvia: yes the latest ones are fairly complete for sign

so not a problem

Mark: are there others like no repetetive stimulis


Eric: that's not really a kind, but a characteristic of the asset

so slightly orthogonal issues

JF: +1

these issues need to be considered, but its not an @kind value

Eric: D Singer and I have never gotten any traction on it

we cant do it in the next 48 hrs

JF: do we have a final list

Sean: should this be an open ended list

Silvia: yes

JF: agree

Judy: can you restate the issue

eric: there is a need for content authors to decalre tha accessiility reqs that content meets, but also markup content to let the UA pick the content the user does not want

do the UAAG WG have anything relevant

Eric: the issue is that the content author needs to be able to describe the content

Mark: MPEG-DASH is defining these roles, and sent a liaason on this question and multiple roles can be assigned

Judy: can I be put on that htread

Mark: the liason should come formally soon

it was addressed to this group

Silvia: I think there are some open issues, but we can maybe pursue them separately

maybe as a media query

Judy: the restatement was helpful

can you send the materials

Silvia: added clear audio

JF: done with kind

next item, loop

Silvia: loop is currently disabled for a combined set of elements

we have discussed how it should work

maybe we can leave it for now and discuss with ian

do we actually want loop to be solved

JF: straw poll of opinion

Eric: we should hhave it

Frank: agree

Sean: no reason not to

mark, Judy: no opinio

consensus we should have it

net item : autoplay

Judy can we be clear on the question

eric: should we ever allow autoplay for a group of media resources

silvia: we have it in the requirements

its done by single and inband multi track

but not by slaved elements

do we want it

Judy: current wording?

JF: is selective switching possible?

<silvia> http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#media-controllers - you need to scroll down to where "autoplay" is mentioned

Judy: its a distraction issue, and its not always easy to figure out how to switch it off

Eric: a non issue as it would be foolish to have separate ungrouped elements with media that should be synchronised

you always want them to play in sync

its just a question of enablement

JF: need to move on

do we have a solution today?

Eric: no

its about user agent preferences

<silvia> A http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#mediacontroller is a blocked media controller if the http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#mediacontroller is a http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#paused-media-controller, or if any of its http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#slaved-media-elements arehttp://www.whatwg.org/specs/web-apps/c

Judy: need to defer this and go to the other issues

item: some attributes are missing in the controller

Silvia. we had request to add some events, but these relate to the readyState, so we need to decide whether we need a combined readystate

it seems readystate is inconsistent

so perhaps we dont really need it,

but we can wait till the result of the bug

Eric: i think its useful

on the media controller, its not possible to find out the combined state otherwise

Frank: agree with Eric, but need more discussion

JF: does it go in the CP?

Frank: could it go in as a bug outside the CP

JF: not sure,

easier to delete it later

general consensus: should go on the controller

Silvia: will add to the CP

item 7


ended state

Silvia: : the onended event is not included, as Ian not clear what it means

think it is necessary

Eric: ended is required

Bob: agree, Mark: no opinion

consensus : keep it in

item 7

how to create controls for the combined grou

Silvia: how are the automatic controls created for a combined resource

Ian seems to thin its possible on each video element, and they will control the controller

this seems like an OK solution

its probably not possible to create one over multiple elements

Eric: my interpretation is that if show for any element, it works for all the elements

from a display point of view they will cover only one video element

JF: so this is a solved problem

return to autoplay

Judy: can we restate the question

silvia: should the controller have an autoplay idl attribute representing all the slaves

Judy: I think so

<judy> Sean: concerned that we are not clear about the semantics of the idl attribute

<judy> ...will it be controlling all of the elements, or only the first?

<judy> [others had stated that they support idl, or that they likely do]

<frankolivier> (Need to drop for another meeting)

<judy> [discussion about (un)clarity in semantics of autoplay, and how that relates to the question on which we are trying to agree on a position ]

<judy> bob: the behavior on autoplay should be the same as it would be if the media player were invoked manually

<judy> several: need communication with ian

<judy> silvia: writing him a letter

<judy> john: we seem to agree on what's needed

<judy> ...and we've gone through all 7 of silvia's bullet points

<judy> silvia: yup, have my notes, will draft letter, circulate it within the next hour

<judy> john: let's agree to state that as a consensus of the accessibility sub-group

<judy> ...let's give people 24 hours to agree on that

<judy> ...any tweaks needed, ask silvia to help with

<judy> ...for all, please send a +1 back to the list

<judy> ...thank you everyone so much, good process, good effort

<judy> judy: thanks all

<JF> hi friend

<JF> so the only thing i have not done is tell rrsagent to p art

<JF> scared to do so

Summary of Action Items

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Default Present: +1.650.862.aaaa, Judy, Sean, Frank, John_Foliot, Eric_Carlson, silvia, Bob, +1.408.540.aabb, mark
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