- From: Raphaël Troncy <raphael.troncy@eurecom.fr>
- Date: Mon, 28 Nov 2011 08:38:55 +0100
- To: Media Fragment <public-media-fragment@w3.org>
Dear all,
For the record, the minutes of last week phone telecon were not yet sent
although many actions have already been performed. There are ready for
review at http://www.w3.org/2011/11/23-mediafrag-minutes.html (and in
text format below).
Raphaël
-------------
[1]W3C
[1] http://www.w3.org/
Media Fragments Working Group Teleconference
23 Nov 2011
[2]Agenda
[2]
http://lists.w3.org/Archives/Public/public-media-fragment/2011Nov/0057.html
See also: [3]IRC log
[3] http://www.w3.org/2011/11/23-mediafrag-irc
Attendees
Present
Silvia, Chris_(irc), Raphael, Thomas, Davy, Yves, Philip,
(irc), Erik
Regrets
Erik
Chair
Raphael
Scribe
raphael
Contents
* [4]Topics
1. [5]1. Admin
2. [6]UA Test Cases
3. [7]3. Status of the Implementation Report
4. [8]4. AOB
* [9]Summary of Action Items
_________________________________________________________
<trackbot> Date: 23 November 2011
<doublec> I'm here but not on phone, sorry
1. Admin
Next Tuesday, the specification will be published as a CR
<silvia> yay!
<doublec> great!
Raphael: the group will be closed at the end of the year
... we need to satisfy the exit criteria of CR, i.e. getting 2
implementations of all features to move forward
... Goal: we jhave
... about 10 test cases to approve for the UA
[10]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases.html
[10] http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases.html
<foolip> Will we consider polyfills implementations, or only native
browser/server implementations?
<tomayac> hooray for polyfills ;-)
not only browser implementations, but all, including polyfills
Thomas work should be included in an implementation report
<silvia> foolip: it's the W3C :-)
<foolip> You'd never get away with that if it were for any other
browser feature, say document.querySelector.
<silvia> foolip: that's the HTML WG :-)
Thomas: I think they should be a valid implementation
Raphael: how much time you have to work on an implementation report?
<foolip> I think polyfills are great and useful, and respect
tomayac's work, but don't think it's acceptable.
<foolip> In other words, if there are any features which don't have
2 implementation not counting polyfills, they should be dropped from
the spec.
why don't you want to count the polyfills Philip ? I don't get this
...
<foolip> Specifically #track cannot be done with a polyfill yet
<tomayac>
[11]http://tomayac.com/mediafragments/implementationtests.html
[11] http://tomayac.com/mediafragments/implementationtests.html
they are absolutely valid implementations
<foolip> The point of requiring implementations is to prove that
it's possible to implement and ship. polyfills don't prove that,
they don't have to deal with all of the internal issues you'd find
in a native implementation
<tomayac> foolip, i fully agree
<scribe> ACTION: Davy starting from
[12]http://tomayac.com/mediafragments/implementationtests.html to
generate a EARL report [recorded in
[13]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action01]
[12] http://tomayac.com/mediafragments/implementationtests.html
<trackbot> Created ACTION-241 - Starting from
[14]http://tomayac.com/mediafragments/implementationtests.html to
generate a EARL report [on Davy Van Deursen - due 2011-11-30].
[14] http://tomayac.com/mediafragments/implementationtests.html
<tomayac> we're discussing your points
<tomayac> foolip, raphael postponed the discussion to later in the
call
UA Test Cases
[15]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases.html
[15] http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases.html
Only the reviewed test cases are used in the implementation report
<davy>
[16]http://www.w3.org/2008/WebVideo/Fragments/TC/results/ua/SynoteMe
diaFragmentPlayer-report
[16]
http://www.w3.org/2008/WebVideo/Fragments/TC/results/ua/SynoteMediaFragmentPlayer-report
<doublec> an example of an issue might be hitting the 'end' time in
temporal fragments. The HTML media API doesn't provide a way to
immediately stop playback on an end time which a polyfill will have
trouble doing.
Davy: no, the non reviewed test cases are also used
<doublec> whereas a native api can get to the low level (hopefully)
to do it
Davy: the individual implementation reports contain all test cases
... but the global report only take the reviewed test cases
Raphael: the unreviewed TC starts at TC0095 until TC0102
[17]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases.html
[17] http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases.html
scribe: 8 test cases
<foolip> doublec, does Firefox support stopping at the (exact) end
time?
<doublec> I would argue that a testcase that uses smpte on a webm
file doesn't seem to make sense, given that webm is not fixed
framerate
<doublec> (referring to tc0100-ua and friends)
<doublec> foolip: it's close but not exact
<foolip> I agree, it seems to me there are no implementations of
smpte
<doublec> foolip: and depends on audio buffering on platforms
<davy>
[18]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC009
5-UA
[18]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0095-UA
<scribe> ACTION: Davy to contact Jack to get media resources to test
TC0099 and TC0100 [recorded in
[19]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action02]
<trackbot> Created ACTION-242 - Contact Jack to get media resources
to test TC0099 and TC0100 [on Davy Van Deursen - due 2011-11-30].
<foolip> doublec, fair enough :)
<doublec> foolip: which is why I knew that was a sticky point :)
<foolip> doublec, does currentTime lie or will it overshoot
somewhat?
<tomayac> currentTime is best effort i'd say
<doublec> foolip it's supposed to be accurate but one of our audio
backends cheats and only updates it after a blocking audio write on
a thread is completed
<doublec> foolip: so is limited to the granularity of the amount of
that write (this is linux)
<doublec> foolip: on android it's a complete guess
<foolip> doublec, ok, I won't object on the basis of that, seems
like a QoI issue
<doublec> yeah
<tomayac> timeupdate has no guarantees at all
<doublec> right, timeupdate is often 250ms
<tomayac> so frame-level addressing is completely impossible
<silvia> I have a problem with failing on all non-matching SMPTE
formats
<davy>
[20]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC009
9-UA
[20]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0099-UA
<doublec> tomayac: you can get better granuality doing a setInterval
and checking currentTime
<doublec> tomayac: depending on implementation
<tomayac> yepp, but again w/o guarantees
<doublec> right
<tomayac> so all that seems to make sense (and this is the only
thing i've seen people use) is 1s granualarity
<tomayac> <video> abstracts away the codec details, so can't get
down to frame-level, no notion of key frames, etc. and that's a good
thing imho :-)
<silvia> OK, I can live with failing on non-matching SMPTE formats
Davy:
[21]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC009
5-UA
[21]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0095-UA
<silvia> I'm hoping there won't be much use of SMPTE anyway
ok, and reviewed
davy:
[22]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC009
6-UA
[22]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0096-UA
<tomayac> silvia, all i've seen people use is npt, and all with
seconds
ok, and reviewed (the media resource has indeed those 2 tracks)
Davy:
[23]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC009
7-UA
[23]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0097-UA
<silvia> tomayac: yes, me too, and I've seen live streaming ppl ask
for clock, but not smpte
<tomayac> i normalize npt in non-second format to seconds, which
makes it easier w/ html5 video
ok, and reviewed
Davy:
[24]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC009
8-UA
[24]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0098-UA
ok, and reviewed
<tomayac> imho, whatever currentTime accepts, dictates what we
should do in practice (except for live streams of course)
Silvia: how the UA determines that the fragment is outside?
Davy: with the decoding pipeline, the UA knows the resolution of the
video
... I will write in the HTML what is the resolution of the media
resource (already written in the rdf file)
<silvia> can we add that resolution to the example so it's clear
it's outside?
<silvia> thx
Davy:
[25]http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC010
1-UA
... in fact 101 is incomplete since there is no name in the webm
resource
... we have to create such a resource
... how can I create this resource
[25]
http://www.w3.org/2008/WebVideo/Fragments/TC/ua-test-cases#TC0101-UA
<doublec> webm doesn't provide the ability to do that
Silvia: using mkv merge ?
<doublec> afaik
<silvia> WebM chaptering:
[26]http://matroska.org/technical/specs/chapters/index.html
[26] http://matroska.org/technical/specs/chapters/index.html
<doublec> that's matroska
<doublec> is that included in webm?
<silvia> well, it's Matroska but would work in webm
<doublec> nope
<doublec> if it's not in the webm spec, it's not supported
<silvia> not per spec, but with most tools :)
<silvia> so, also, there is work happening on putting WebVTT into
WebM, so that would likely be the better way in future
Raphael: 102 has the same problem
Davy: I will color the table in red
<Yves> 1/me taht would be great!
<Yves> s/1\/me taht would be great!//
Silvia: at some point, OGG and WebM should have WebVTT so chapter
names
... in the future, those test cases would be plausible
... hard to make the media resources now
<silvia> and Apple also wants to put WebVTT into MP4 tracks
Raphael: if no test case for the ID dimension and no implementation,
then this feature will be removed from the spec
<silvia> right now you could use quicktime chapter markers in MP4 if
you wanted to
<Yves> in CR we document what might be removed if not implemented
<Yves> or not implementable
<davy> Silvia, sounds good, I will try QuickTime to create such a
MP4
<scribe> ACTION: Silvia to search for a media resource that contains
a chapter name [recorded in
[27]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action03]
<trackbot> Created ACTION-243 - Search for a media resource that
contains a chapter name [on Silvia Pfeiffer - due 2011-11-30].
3. Status of the Implementation Report
<silvia> I made a point that we should not remove features from the
specification that cannot now be demonstrated because we don't have
the file formats for the Web yet
<davy>
[28]http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-imp
l/
[28]
http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-impl/
<silvia> If such features cannot go into REC, at least a TR or CR
should continue to exist with these extra features
Davy: we will have 4 different implementations with Thomas
... currently, 3 levels: passed, failed and not applicable meaning
not yet implemented
... should the not applicable be just failed ones?
<Yves> having a new status 'not implemented' might be the best
Thomas: make a distinction between the implemented but failed and
the not implemented
<silvia> agree
Davy: are we the first group to face this problem? In EARL there is
not yet implemented status available
Raphael: I suggest to add a paragraph in the report to explain what
Passed, Failed and Not Applicable
Erik: all features which are weakly or not implemented should be
marked at risk
... this is the case for the clock unit for specifying time for
example
Raphael: I'm going to Davy and Chris, is clock something you plan to
cover in your implementation?
<silvia> you need a streaming server for the clock unit,
realistically
<doublec> raphael: no plans at this stage
Davy: we do that on the server
<silvia> we could ask Thomas Vander Stichele about that - he has
previously implemented such a feature
<silvia> there was a thread on our mailing list at one stage
<doublec> raphael: mainly because we don't support any video
playback that'd make it useful
<doublec> raphael: if we were to add such, I'd look at supporting it
Could you respond to this old thread, silvia, and re-activate this
contact?
<silvia> let me try...
4. AOB
Erik: we had 3 actions from yesterday
... 2 minor edits ... done by Raphael
... a last one for the WAI WG
... Silvia, the track dimension is important for the a11y community,
the mgt suggest to write a mail to the WAI WG to tell them this
feature is at risk in Media fragment
Raphael: how important is this feature (track) for WAI?
Silvia: it is not that much WAI at the moment, but more the HTML WG
... the track element in the media API
<doublec> right, we need the track HTML stuff to be implemented
before doing the media fragment track support
Silvia: the track element is a textual track, it is for WebVTT
Thomas: latest Chromium has track support ... not sure for which
format
Raphael: why browsers need to support the track element to support
the media fragment track?
Silvia: because we need to expose what are the available tracks
<doublec> silvia: I was referring to
[29]http://www.whatwg.org/specs/web-apps/current-work/multipage/vide
o.html#media-resources-with-multiple-media-tracks
[29]
http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#media-resources-with-multiple-media-tracks
<doublec> raphael: when I wrote 'we' I really meant 'I'. And I mean
the person working on track support needs to do it before I work on
adding media fragment track support (assuming they don't)
<doublec> raphael: (in firefox that is)
<silvia> I agree, that's what I was pointing out: we need #track for
the multitrack API in HTML5
<foolip> Opera is similar, we couldn't support #track without first
doing all the hard work to support the VideoTrack/AudioTrack APIs
Raphael: my question Chris is ... assuming the UA know what are the
tracks available in a given media resource, how much implementation
is to enable the selection of one of the tracks?
<doublec> raphael: I don't know yet - we don't expose tracks at all
<silvia> example is in
[30]http://www.whatwg.org/specs/web-apps/current-work/multipage/vide
o.html#assigning-a-media-controller-declaratively
[30]
http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#assigning-a-media-controller-declaratively
<scribe> ACTION: Erik to mail implementers the likelihood to get the
remaining features implemented in the coming weeks [recorded in
[31]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action04]
<trackbot> Created ACTION-244 - Mail implementers the likelihood to
get the remaining features implemented in the coming weeks [on Erik
Mannens - due 2011-11-30].
meeting adjourned
Summary of Action Items
[NEW] ACTION: Davy starting from
[32]http://tomayac.com/mediafragments/implementationtests.html to
generate a EARL report [recorded in
[33]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action01]
[NEW] ACTION: Davy to contact Jack to get media resources to test
TC0099 and TC0100 [recorded in
[34]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action02]
[NEW] ACTION: Erik to mail implementers the likelihood to get the
remaining features implemented in the coming weeks [recorded in
[35]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action04]
[NEW] ACTION: Silvia to search for a media resource that contains a
chapter name [recorded in
[36]http://www.w3.org/2011/11/23-mediafrag-minutes.html#action03]
[32] http://tomayac.com/mediafragments/implementationtests.html
[End of minutes]
_________________________________________________________
--
Raphaël Troncy
EURECOM, Multimedia Communications Department
2229, route des Crêtes, 06560 Sophia Antipolis, France.
e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com
Tel: +33 (0)4 - 9300 8242
Fax: +33 (0)4 - 9000 8200
Web: http://www.eurecom.fr/~troncy/
Received on Monday, 28 November 2011 07:39:40 UTC