- From: Adrian Bateman <adrianba@microsoft.com>
- Date: Tue, 18 Dec 2012 17:10:49 +0000
- To: Paul Cotton <Paul.Cotton@microsoft.com>, "public-html-media@w3.org" <public-html-media@w3.org>
- CC: "Aaron Colwell <acolwell@google.com> (acolwell@google.com)" <acolwell@google.com>, Mark Watson <watsonm@netflix.com>
- Message-ID: <4f446961f310480496b54ef585433527@BL2PR03MB604.namprd03.prod.outlook.com>
Minutes -> http://www.w3.org/2012/12/18-html-media-minutes.html
[1]W3C
[1] http://www.w3.org/
- DRAFT -
HTML Media Task Force Teleconference
18 Dec 2012
[2]Agenda
[2] http://lists.w3.org/Archives/Public/public-html-media/2012Dec/0027.html
See also: [3]IRC log
[3] http://www.w3.org/2012/12/18-html-media-irc
Attendees
Present
ddorwin, pal, Aaron_Colwell, markw, adrianba, paulc,
johnsim, BobLund, +1.613.287.aaaa, MartinSoukup
Regrets
Chair
Paul Cotton
Scribe
Adrian Bateman
Contents
* [4]Topics
1. [5]Roll call, introductions and selection of scribe
2. [6]Previous meeting minutes
3. [7]Review of action items
4. [8]Baseline documents and Bugzilla information
5. [9]Progression to First Public Working Draft
6. [10][MSE] Homework re: issues in the context of
upcoming FPWD
7. [11]Discussion of outstanding bugs
8. [12]Other Business
9. [13]Chair and Scribe for next meeting
10. [14]Adjournment
* [15]Summary of Action Items
__________________________________________________________
<trackbot> Date: 18 December 2012
<scribe> ScribeNick: adrianba
<scribe> Scribe: Adrian Bateman
Roll call, introductions and selection of scribe
paulc: done
Previous meeting minutes
[16]http://www.w3.org/2012/12/04-html-wg-minutes.html
[16] http://www.w3.org/2012/12/04-html-wg-minutes.html
paulc: noted
Review of action items
paulc: none apply to MSE currently
Baseline documents and Bugzilla information
[17]http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/
media-source.html
[17] http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html
paulc: prepared agenda last week - there have been a couple of
editorial changes since then
... changes made to align with pubrules
Media Source Extension bugs -> [18]http://tinyurl.com/6pdnzej
[18] http://tinyurl.com/6pdnzej
Progression to First Public Working Draft
paulc: here i pointed to bug 20253 which aaron created to
indicate the results of our dec 4 discussion
... where we said there were 7 bugs that were desirable to fix
prior to FPWD
... if you look at 20253 it indicates that the following have
been processed: 17002, 17094, 18960, 18963, and 19531
... leaving outstanding 17006, 18962
... 17006 is track language and kind
... 18962 is allow appending with XHR
adrianba: those are assigned to me
paulc: can you give us a status update?
[19]https://www.w3.org/Bugs/Public/show_bug.cgi?id=20434
[19] https://www.w3.org/Bugs/Public/show_bug.cgi?id=20434
adrianba: i filed this new bug which i think is blocking 18962
... this deals with making append() async even for ArrayBuffer
... details in the bug
acolwell: i have a concern about changing this late - have to
think about this
... seems like an IE implementation requirement
... we've implemented this without
... i do like the idea that it makes it consistent between the
stream and non-stream version
<MartinSoukup> i believe if the API is going to change, it is
better to make the change prior to FPWD
adrianba: of course we could make this sync by blocking but
we'd prefer not to do that
acolwell: i need to think about this offline
paulc: let's pop-up to the fact that adrian made the XHR bug
dependent on this
... and we need to decide how to process the move to FPWD
... practical situation is that my plan was to do a CfC in this
group (might be as simple as doing it on the phone call)
... but obviously we need to take a FPWD ready spec to the WG
and do a CfC inside the WG
... that call would normally last a week
... the working group is not meeting this week or next week
... possibly will meet on jan 3
... i proposed that we not meet on dec 20 and dec 27
... even if we went forward today, the CfC might have to be for
3 weeks
... i'm reluctant to use one week when it would overlap with
the holidays
... i think we've lost our window of opportunity - i wonder if
we should give the editors until early january to make progress
and the do CfC in early january
acolwell: what is the benefit of doing it in this group first?
paulc: in some ways i'm being trained by the time i've spent
monitoring the a11y task force
... the a11y tf leadership have always been careful to ensure
that they have consensus inside that group
... it would be foolish to take to the WG and then have someone
in the TF object
... so what maciej was saying is what really matters is what
the WG says
... so we could do this informally in the TF
... one possibility would be to look at TF schedule
... we could agree that on jan 8 the editors will give us a
draft FPWD with as many bugs closed as possible and on that
call, which would normally be a EME call, we would test
consensus to go to the WG
... and then we'd go to the WG at that time
... i think that is a strawman that avoids the perception we're
trying to we're trying to sneak it in
... how does that sound?
acolwell: i'm fine with that plan - can we fix more bugs in
this time?
paulc: yes, editors can always add more
acolwell: i don't want to let more bugs block us getting to
FPWD
paulc: understood
[MSE] Homework re: issues in the context of upcoming FPWD
<johnsim> +1
pal: i'm not opposed to proceed with regular draft publications
so we don't fall into the trap of always trying to fix a bug
and not publishing
... so my proposal is to simply add a note in the WD pointing
to that bug or issue
... helping the reader identify areas still under discussion
... also trying to encourage readers to provide feedback on
those issues
paulc: these are bugs 19673, 20327, 19784, 19676
... there are places identified in the spec to point to these
bugs
pal: not just limited to these bugs - could be other bugs too
paulc: looking for the minimum necessary to declare victory -
want to make you happy
... in addition to this i'd like to suggest that the editors
add a para to the status section that identifies the bugzilla
component for this draft and a link to the search for
outstanding bugs
... there are examples in other previously published working
drafts
... that will highlight up front that there are outstanding
bugs
... that along with what pal has suggested for his bugs inlined
into the document will make it very clear
... it's like adding a health warning to particular spec
sections
acolwell: i'll have to go look to add an example
adrianba: it's easy to add more to the status section - i can
help
paulc: the current html wd includes a paragraph on this
[reads from html editor's draft]
paulc: editors should look at how this has been done in the
past in this WG
acolwell: i have a concern that a couple of the bugs in the WD
as a note elevates them to indicate that they will be addressed
and in my mind not all have a convincing case
... i don't think we've discussed enough and i think it would
be misleading to indicate that these are going to change
... not sure what the right balance is
paulc: the text from pal doesn't say whether it merits
inclusion or not - just points to the bug
acolwell: but it's still up for discussion - would rather
resolve than add text not resolved
paulc: the HTML5 WD had a way for people to mark bugzilla bugs
and the editorial process put those bugs into the spec as a
marker
... WG in the past has had a low bar for doing that
acolwell: ok
paulc: if the text from pal indicated that this must change
that would be different - but it's just noting the existence of
the bug
... this is a common W3C procedure
... if someone tried to argue that because we mentioned them we
have to fix them in a particular way i wouldn't accept that
adrianba: i just wanted to emphasise that this has happened
before
... perhaps we could use ISSUE to explain why only a few bugs
are in this state
paulc: i'd rather try to have some technical issues on this
call and leave this to the editors
... anyone have anything else to say on this?
... overall plan is to get to CfC by jan 8
... acolwell are there specific bugs you'd like to discuss?
Discussion of outstanding bugs
[20]https://www.w3.org/Bugs/Public/show_bug.cgi?id=19784
[20] https://www.w3.org/Bugs/Public/show_bug.cgi?id=19784
timestampOffset with multiplexed Media Segments
pal: timestampOffset allows the start of a media segment to be
offset by a value
... the issue is that media segments that contain multiplex -
the audio may start a little earlier
... this is often done in DASH, blueray
... to support splicing of different streams
... the issue is the timestampOffset says you shall start
playback at the beginning but you always want to splice at the
video boundary not the audio boundary
... but if audio starts earlier then you end up using the audio
boundary not the video
... this is only a problem for multiplexed media
acolwell: the spec says to resolving the splice on a per stream
basis
... so the splice for each stream is resolved independently
pal: where exactly in the media segment does the splice happen
... does it mean the audio will be offset from the video
... original content has audio and video synced but has audio
start earlier to allow cross-fade splicing
acolwell: i was assuming the audio frame already in the buffer
- the cross fade would happen at the splice time?
pal:
[21]https://docs.google.com/open?id=0Bz7s0dhnv-7HYjhadTktTGhrd2
M
... [describes illustration]
[21] https://docs.google.com/open?id=0Bz7s0dhnv-7HYjhadTktTGhrd2M
acolwell: the timestamp offset is the value that is added to
the timestamp in the media, not a reference to the start
... it just adds to timestamp values
pal: i don't think mp4 allows negative offsets
acolwell: the current spec says for video the splice happens
where you want it
... say frame 1 starts at 33ms you replace frame 4 and move on
... for audio the cross-fade would happen between frame 4 of
original content and frame 1 of new content
... and so wherever they overlap a cross-fade would happen
... if you don't implement cross-fade then frame 4 would be
dropped
... and if there was a gap silence would be inserted
pal: i think the key is that even though it is audio/video
multiplex, the splicing is resolve per stream type
... that is key
... second, i understand how if the video frame is some offset
into the segment you can reduce the timestamp offset by a
similar amount to make sure you have alignment
... how do you tell it to start on the video frame?
acolwell: by the nature of how the html element the first video
frame will be displayed before playback starts
... when it loads it automatically displays first frame
pal: by construction there is always a sync on the video frame
acolwell: the first frame is always displayed when the element
is ready for playback
pal: when you hit play you wouldn't want audio to start with
the overhang
acolwell: i think that's an implementation detail probably
inconsistent with browsers today
... think that's a HTML issue not media source
... and it's a tiny time
pal: yes, you can notice 23ms
... sounds like all that's needed is informative guidance to
implementors
... that timestampOffset will work as is but might need
examples perhaps with diagram of how to use it?
paulc: please can you attach the pdf to the bug
pal: yes
paulc: do i take it that we have some level of consensus to
deal with this bug 19784 that we don't believe we have a
technical problem in the spec but the difficulty could be
resolved with further explanatory material?
acolwell: it sounds like an example that shows how this
scenario would be resolved is required and then a note on
implementors that at the beginning of playback possibly
trimming the initial part of audio
paulc: perhaps the right tactic might be to get this possible
resolution into the bugzilla bug
... so that if it is not in FPWD then people would see that
proposed disposition
... leave it to acolwell and pal about how to get this into
bugzilla
... does the explanation for 19784 cascade to other bugs?
pal: no
paulc: so it was independent then
pal: yes i picked this one because it was independent
paulc: good, then we made progress
Other Business
paulc: not going to cover anything else
Chair and Scribe for next meeting
paulc: neither groups will meet dec 25 or jan 7
... jan 8 would normally be EME group
... but you should expect to see a combined agenda
... so i can give update on MSE candidate FPWD document
... so that i can take this to the working group
acolwell: is there a day we should get this published?
paulc: would the previous week some time be okay?
... by jan 4?
acolwell: i think that's fine
paulc: editors will deliver on or before jan 4
... if it doesn't happen we'll adapt
... want a stable document, consider a different URL for that
doc
... don't want the item out for CfC to change under the
decision
Adjournment
paulc: wish everyone happy holidays - if you're travelling,
travel safe
... we'll talk again jan 8
Summary of Action Items
[End of minutes]
From: Paul Cotton
Sent: Thursday, December 13, 2012 6:17 PM
To: public-html-media@w3.org
Cc: Aaron Colwell <acolwell@google.com> (acolwell@google.com); Adrian Bateman; Mark Watson
Subject: {agenda} HTML WG media telecon 2012-12-18 - media source extension bugs and FPWD
The HTML WG media teleconference meeting will occur on 2012-12-18 for up to 60 minutes from 15:00Z to 16:00Z.
http://timeanddate.com/s/2afd
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
http://www.w3.org/2012/12/04-html-wg-minutes.html
3. Review of action items
https://www.w3.org/html/wg/media/track/
None
4. Baseline documents and Bugzilla information
a) Media Source Extensions editor's draft:
http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html
Status as of Dec 13: Last updated on Dec 13.
http://lists.w3.org/Archives/Public/public-html-media/2012Dec/0024.html
b) Media Source Extension bugs:
http://tinyurl.com/6pdnzej
Status as of Dec 12: 13 bugs (see list at end of agenda)
5. Progression to First Public Working Draft
a) Bug 20253 - Publish Media Source Extensions FPWD
https://www.w3.org/Bugs/Public/show_bug.cgi?id=20253
Note: Depends on bugs 17006, 18962 and 19673.
b) [MSE] Homework re: issues in the context of upcoming FPWD
http://lists.w3.org/Archives/Public/public-html-media/2012Dec/0017.html
6. Discussion of outstanding bugs
7. Other Business
8. Chair and Scribe for next meeting
9. 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
13 bugs found.
ID▲<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=bug_id%20DESC&query_based_on=>
Product<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=product%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
Comp<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=component%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
Assignee<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=assigned_to%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
Status<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=bug_status%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
Resolution<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=resolution%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
Summary<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=short_desc%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
Changed<https://www.w3.org/Bugs/Public/buglist.cgi?bug_file_loc=&bug_file_loc_type=allwordssubstr&bug_id=&bug_id_type=anyexact&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&chfieldfrom=&chfieldto=Now&chfieldvalue=&component=Media%20Source%20Extensions&email1=&email2=&emailtype1=substring&emailtype2=substring&field0-0-0=noop&keywords=&keywords_type=allwords&longdesc=&longdesc_type=allwordssubstr&product=HTML%20WG&query_format=advanced&short_desc=&short_desc_type=allwordssubstr&status_whiteboard=&status_whiteboard_type=allwordssubstr&type0-0-0=noop&value0-0-0=&votes=&order=changeddate%2Ctarget_milestone%20DESC%2Cpriority%2Cbug_id&query_based_on=>
17006<https://www.w3.org/Bugs/Public/show_bug.cgi?id=17006>
HTML WG
Media So
adrianba
ASSI
---
<track> Setting track language & kind when the information is in a manifest <https://www.w3.org/Bugs/Public/show_bug.cgi?id=17006>
2012-12-05
18962<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18962>
HTML WG
Media So
adrianba
ASSI
---
Allow appending with XHR <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18962>
2012-12-05
20253<https://www.w3.org/Bugs/Public/show_bug.cgi?id=20253>
HTML WG
Media So
acolwell
ASSI
---
Publish Media Source Extensions FPWD <https://www.w3.org/Bugs/Public/show_bug.cgi?id=20253>
Sat 06:57
18400<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18400>
HTML WG
Media So
watsonm
ASSI
---
Define and document timestamp heuristics <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18400>
2012-10-22
18575<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18575>
HTML WG
Media So
acolwell
ASSI
---
Section 2. Source Buffer Model should be non-normative <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18575>
2012-10-22
18592<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18592>
HTML WG
Media So
adrianba
NEW
---
How much is "enough data to ensure uninterrupted playback" <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18592>
2012-12-04
18615<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18615>
HTML WG
Media So
acolwell
ASSI
---
Define how SourceBuffer.buffered maps to HTMLMediaElement.buffered <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18615>
2012-10-22
18642<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18642>
HTML WG
Media So
acolwell
ASSI
---
Handle timestamp overflow in append(data) <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18642>
2012-10-22
18933<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18933>
HTML WG
Media So
watsonm
ASSI
---
Segment byte boundaries are not defined <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18933>
2012-10-21
19673<https://www.w3.org/Bugs/Public/show_bug.cgi?id=19673>
HTML WG
Media So
adrianba
NEW
---
Seamless audio signal transitions at splice points <https://www.w3.org/Bugs/Public/show_bug.cgi?id=19673>
Mon 17:58
19676<https://www.w3.org/Bugs/Public/show_bug.cgi?id=19676>
HTML WG
Media So
adrianba
NEW
---
timestampOffset accuracy <https://www.w3.org/Bugs/Public/show_bug.cgi?id=19676>
2012-12-04
19784<https://www.w3.org/Bugs/Public/show_bug.cgi?id=19784>
HTML WG
Media So
adrianba
NEW
---
timestampOffset with multiplexed Media Segments <https://www.w3.org/Bugs/Public/show_bug.cgi?id=19784>
2012-12-04
20327<https://www.w3.org/Bugs/Public/show_bug.cgi?id=20327>
HTML WG
Media So
adrianba
NEW
---
Continuous splice flag <https://www.w3.org/Bugs/Public/show_bug.cgi?id=20327>
Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329
Received on Tuesday, 18 December 2012 17:13:18 UTC