W3C

- DRAFT -

Audio Working Group Teleconference

05 Dec 2013

Agenda

See also: IRC log

Attendees

Present
Regrets
Chair
Olivier
Scribe
Chris Lowis

Contents


<trackbot> Date: 05 December 2013

olivier: happy to scribe if that helps.

<padenot> network issue, one second

<scribe> ScribeNick: chrislowis

Review of action items (http://www.w3.org/2011/audio/track/agenda)

olivier: start with action items

<olivier> ACTION-78

<trackbot> ACTION-78 -- Doug Schepers to Make sure web platform docs has up to date doc on web audio -- due 2013-11-21 -- OPEN

<trackbot> http://www.w3.org/2011/audio/track/actions/78

olivier: Action-78 was on shepazu

shepazu: we have a section on Web Audio, but I don't think it's up-to-date. Not sure where to go from there,

olivier: how can we help you up date it?
... do you need someone to look through it?
... or is there something in particular you need help with?

shepazu: the former.

olivier: someone to review it.

<olivier> close action-78

<trackbot> Closed action-78.

<shepazu> http://docs.webplatform.org/wiki/apis/webaudio

olivier: would someone be interested in reviewing the doc?
... any volunteer, or shall I ask on audio-dev?

mdjp: I'd be happy to take a look.

<olivier> ACTION: MDJP to review http://docs.webplatform.org/wiki/apis/webaudio, suggest updates [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action01]

<trackbot> Created ACTION-87 - Review http://docs.webplatform.org/wiki/apis/webaudio, suggest updates [on Matthew Paradis - due 2013-12-12].

olivier: Action-84 was on chrislowis and has been done.

<olivier> close ACTION-84

<trackbot> Closed ACTION-84.

<olivier> close ACTION-85

<trackbot> Closed ACTION-85.

<olivier> ACTION-86 due in 2 weeks

<trackbot> Set ACTION-86 Document the case of mediaelementaudiosource and mediastreamaudiosource nodes in offlineaudiocontext on github due date to 2013-12-19.

<olivier> ACTION-80 due in 2 weeks

<trackbot> Set ACTION-80 Remove webaudio section on example applications, photos from section on convolution, and salvage anything valuable due date to 2013-12-19.

olivier: what's the status with ACTION-80?

cwilso: just move it back a couple of weeks, and I can get round to it.

olivier: I haven't made much progress with ACTION-81. I contacted the TAG (alex) but forgot to prod them when at TPAC. I will follow up and suggest a joint meeting.

<olivier> ACTION-81 due in 4 weeks

<trackbot> Set ACTION-81 Contact tag, point them to tag issues in github, continue conversation there due date to 2014-01-02.

olivier: on ACTION-83 we could start a post on audio-dev mailing list asking for contibutions to best practice guides.

<olivier> close action-83

<trackbot> Closed action-83.

olivier: if we were to put this on web platform docs we would need shepazu's help. So I'll close action-83 for now, and put an action on mdjp to start the discussion on the list.

<olivier> ACTION: mdjp to start discussion on audio-dev list about known best practices (and tutorials), make sure to include stuff linked in chrislowis' newsletter [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action02]

<trackbot> Created ACTION-88 - Start discussion on audio-dev list about known best practices (and tutorials), make sure to include stuff linked in chrislowis' newsletter [on Matthew Paradis - due 2013-12-12].

Oscillators (phase, mathematical, etc)

olivier: Let's start with 3 and 4, and see how much time we have left.
... let me summarise:
... there were several discussions about oscillators. We agreed that "mathematical" oscillators were not as useful for audio, but that we did want to have them for other purposes (LFO etc).
... and there was a discussion about the phase of oscillators.
... that's where we were until recently. Then cwilso, you looked at the draft and saw something?

cwilso: yes, one of the issues concerned the phase, the triangle wave in the blink/webkit implementation starts in a weird place compared to the others. The other issue was whether the oscillators should be defined, and produce a mathematical wave shape. We also noticed that some of the oscillators were not going between -1 and 1
... rtoyg opened a PR, but before we can address that issue (with phase) we need to address the other issues.
... no one objected to adding the ability to have an option or ability to generating mathematical waveforms. We didn't reach a conclusion about how we'd switch between them, or whether to remove the ability to generate the aliased versions.

<olivier> https://github.com/WebAudio/web-audio-api/issues/127#issuecomment-24507931

olivier: it is true that we don't have a suggestion for how to request the mathematically correct oscillator.
... do you have a link to the PR?

<olivier> https://github.com/WebAudio/web-audio-api/pull/270

<rtoyg_> https://github.com/WebAudio/web-audio-api/pull/270

<olivier> ?

olivier: the PR rtoyg submitted is an addition to the oscillator text.
... I think we're saying that we need to have a way to request mathematical oscillators first, then PR270 makes sense.
... could I ask rtoyg to issue a PR to add an interface to request mathematical oscillators, and then explain the phasing.
... and to extend that for the "regular" case.

cwilso: I think we need to extend the spec to show how PeriodicWave is used to generate the oscillators.

padenot: actually we use some kind of band-limited impulse train internally to generate the oscillators in FF.
... we should be able to compete on implementation right?

cwilso: we should look at what the actual differences are - I'm not saying we really need to specify the implementation. It may not be about competing on implementation, but rather on computational efficiency.
... but we will need to specify what happens to changes and values and amplitudes etc.

padenot: I've thought about how to define that, but no clear plans as such yet.

olivier: so, we should specify what is observable, and not how it's done? (although I'm not sure the TAG would agree with that...).
... I don't think we're going to clear this all up here. But it looks like padenot, cwilso or rtoyg could look at the spec, suggest an interface for how to select the generation mechanism for oscillators, and to clarify the spec. Volunteers?

padenot: that's ok with me.

<olivier> ACTION: padenot to look at current implementations, and draft interface to request mathematical oscillator (issues/127) and specify phase (base on PR 270) [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action03]

<trackbot> Created ACTION-89 - Look at current implementations, and draft interface to request mathematical oscillator (issues/127) and specify phase (base on pr 270) [on Paul Adenot - due 2013-12-12].

stop() and stop() again (https://github.com/WebAudio/web-audio-api/issues/15#issuecomment-28328601)

olivier: the issue with this one, as I understand it, is that the spec says that stop() can only be called once. Which is fine in most cases, but in the issue above, it explains a problem with issuing 'stop' after you've already scheduled a 'stop' - e.g. to change the time when something should be stopped.
... this sounds like a reasonable use case. 1) do you agree, and 2) if so, when and how do we fix this?

cwilso: I think the spec follows what the current implementation is. If we're going to change it we should do that in v1

olivier: let me push back a little. At the moment, you can only call stop once, which is a problem in some cases. But adding the ability to call it twice wouldn't be backwards incompatible?

cwilso: that's partly true, but if the developer has implemented something to work around this, then a change may invalidate that code.

olivier: do we have any consensus that this is a valid and common use case?
... not hearing a lot of support for that, but could someone take a look at it, and see what it would take to make a change to the spec, and what problems it would cause?

cwilso: I can take this one, I think

olivier: that's great. It's not urgent, but it would be good to talk about it again, maybe not on the next call though.

<olivier> ACTION: cwilso to look into https://github.com/WebAudio/web-audio-api/issues/15 - assess how complex the change would be (and ideally suggest PR to spec) [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action04]

<trackbot> Created ACTION-90 - Look into https://github.com/webaudio/web-audio-api/issues/15 - assess how complex the change would be (and ideally suggest pr to spec) [on Chris Wilson - due 2013-12-12].

<olivier> ACTION-90 due in 5 weeks

<trackbot> Set ACTION-90 Look into https://github.com/webaudio/web-audio-api/issues/15 - assess how complex the change would be (and ideally suggest pr to spec) due date to 2014-01-09.

Issues triage

olivier: I'd like to suggest that having more clarity and sorting/triage of the issues would be a good thing.
... maybe we could organise a distributed session to hack away at the remaining issues once we've triaged.

+1

cwilso: it sounds like a good idea. I haven't had as much time as I'd liked to work through the issues, but padenot has been doing a good job.
... but I should have more opportunity to do that.

olivier: is it good to split the issue list up, assign them in groups for other people to tag them up? Or should I leave it to you cwilso and padenot?

cwilso: I'm happy to have other people weigh in, triage and state severity etc.

olivier: I need to figure out how to do that, given that we're all busy and approaching a busy time of the year.
... I'll think about it and suggest something on the mailing list.

upcoming f2f meeting

olivier: it's the time of the year when I start thinking about f2f meetings.
... our last one was in March, and we didn't meet in TPAC.
... I think it is a good time to think about organising one in February/March next year.
... if anyone wants to host a f2f, then please get in touch.
... our recent discussion mentioned the east coast of the US, but I'm not sure if there's other events we could merge together.

shepazu: there is a plan for a joint webapp/hmtl/webapp security/native apps meeting in the bay area sometime in march - it might be that some people who are attending that would be the kind of people who would be good to attend our f2f.

olivier: do you know that date?

shepazu: no, tentative at this stage.

olivier: we also discussed having our f2f sometime around GDC too.

shepazu: yes, that would also make sense.
... if other people have suggestions they would probably override that.

olivier: we'll talk about it some more.

High Resolution Time Level 2 FPWD/LC http://www.w3.org/TR/hr-time-2/

<shepazu> "This specification defines a JavaScript interface that provides the current time in sub-millisecond resolution and such that it is not subject to system clock skew or adjustments."

olivier: do you want to talk about this shepazu ?

shepazu: /reads the summary above/
... it occured to me that this group might be interested in these specifications to see if there's any impact or opportunities.

olivier: I'm confused by the status code - is this a first and last working draft?
... could someone review the spec and get back to the group with a summary of how/if it could impact us?

cwilso: I paid a fair impact to High Resolution Time before.
... there's no changes to the DOM high-res timestamp, or anything like that, I think.
... it has some bearing on web workers though.

olivier: could you double-check that that is the case?

cwilso: sure.

<olivier> ACTION: cwilso to do a quick review of HRT L2 [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action05]

<trackbot> Created ACTION-91 - Do a quick review of hrt l2 [on Chris Wilson - due 2013-12-12].

Next meetings

olivier: AOB?
... next meetings, then.
... we discussed on the last call that the next meeting would be on the 19th.
... is that ok? And when should we have the next call after that?
... the choices seem to be the 9th or the 16th ?

<cwilso> I'm happy with the 2nd, the 9th or the 16th.

olivier: I'm not available on the 9th. Or the 16th?

16th better for me, I'm not back on the 9th.

olivier: so 19th December 2013 and 16th January 2014
... adjourned.

<olivier> Scribe: Chris Lowis

:(

<olivier> they should be public Chris

Oh yes.

Summary of Action Items

[NEW] ACTION: cwilso to do a quick review of HRT L2 [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action05]
[NEW] ACTION: cwilso to look into https://github.com/WebAudio/web-audio-api/issues/15 - assess how complex the change would be (and ideally suggest PR to spec) [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action04]
[NEW] ACTION: MDJP to review http://docs.webplatform.org/wiki/apis/webaudio, suggest updates [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action01]
[NEW] ACTION: mdjp to start discussion on audio-dev list about known best practices (and tutorials), make sure to include stuff linked in chrislowis' newsletter [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action02]
[NEW] ACTION: padenot to look at current implementations, and draft interface to request mathematical oscillator (issues/127) and specify phase (base on PR 270) [recorded in http://www.w3.org/2013/12/05-audio-minutes.html#action03]
 
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Possibly Present: Doug_Schepers IPcaller ScribeNick aaaa audio chrislowis colinbdclark cwilso gmandyam heath https inserted joined kawai mdjp olivier padenot paul___irish rtoyg rtoyg_ shepazu toyoshim trackbot
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        <dbooth> Present+ amy

Agenda: http://lists.w3.org/Archives/Public/public-audio/2013OctDec/0313.html
Found Date: 05 Dec 2013
Guessing minutes URL: http://www.w3.org/2013/12/05-audio-minutes.html
People with action items: cwilso mdjp padenot

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