W3C

- DRAFT -

Audio Incubator Group Teleconference

04 Oct 2010

See also: IRC log

Attendees

Present
+1.978.314.aaaa, +1.617.584.aabb, +1.510.334.aacc, +1.206.819.aadd, +1.978.314.aaee, +1.617.584.aaff, Shepazu
Regrets
Chair
Al MacDonald
Scribe
F1LT3R

Contents


<rikrd_> hi f1lt3r

<rikrd_> the telecon starts in 20min, right?

<scribe> scribe: F1LT3R

<chrislo> Is the UK bridge number working today? I'm getting "the number is not in service".

MikeSmith, shepazu: any ideas on the UK bridge?

Conference code : 28346

Is anyone else getting a lot of noise?

<joeberkovitz> yes

is it still going on?

<joeberkovitz> just stopped

hmmm prehaps it was my phone

<rikrd_> ok, that seems to have been me, then

<Dick> yes there is a bit of static on the line this end

<joeberkovitz> i hear nothing

did everybody get on to the call?

<rikrd_> yes

<chris> yes

<joeberkovitz> yes

<Dick> yes

<chrislo> No

<chrislo> UK Bridge line is not working.

chrislo, we'll try and keep you up to date on irc, and i will look into the uk bridge later today

<chrislo> Thanks.

trackbot, start telecon

<trackbot> Date: 04 October 2010

<chrislo> F1LT3R: The only update I have is that we are running a XG Audio workshop for generating use cases at the BBC on Wednesday.

chrislo, that's great! :)

Standing Wave: http://github.com/maxl0rd/standingwave3

<chrislo> F1LT3R: I'll try and make notes in the form of http://www.w3.org/2005/Incubator/audio/wiki/Audio_API_Use_Cases

chrislo, perfect

Webkit Web Audio Spec: One node for all filters?

rikrd: I think from the API point of view, I think filters like IIR and QUAD could be the same thing node?

Chris Rogers: So we could give different settings to the same node? That's possible, but one of the things that might be more difficult to implement, if you give it a 100 pole IIR filter, do you intend to change those dynamically?

rikrd: That's a good point. I think in most cases that would be constant. But we should discuss this on the email thread.

Chris Rogers: I would think for the convolver it should be unchanging, but for the biquad nodes you could change the params dynamically. Maybe there is some way we can put it into a single filter node, but we will have to consider the use cases.

joeberkovitz: Can you dynamically change the parameters of any node in this API?

Chris Rogers: I have been considering using parameter control curves that run as part of the compiled code, that are programmed in JavaScript.

joeberkovitz: I can tell you what we found to be useful. I think we found that the cubic spline interpolation and linear interpolation allowed us to add a good set of functionality to our application.

Chris Rogers: What about looping automation?

joeberkovitz: In our software, we allow several loop points.

Chris Rogers: Lets talk about these things on the email list.

Webkit Web Audio Spec: Replace RealTimeAnalyzer with FFTNode?

Chris Rogers: It might be possible to get rid of the RealTimeAnalyzer. We could use the JavaScript processor node to do the FFT.

Al: What are the performance concerns with FFT in JavaScript?

Chris Rogers: You would definitely have problems running say, 100 FFTs in JavaScript. So perhaps we should leave the RealTimeAnalyzer in.

rikrd: If we are going to have a RealTimeAnalyzer we should have a basic FFTNode.

joeberkovitz: Do we need complex output in the frequency domain?

rikrd: In my work, I need it for use with things like spacial analysis.

Chris Rogers: We can try just doing it in JS and see if it is effecient enough, if not perhaps we can revisit this later.

Chris Rogers: I will do some testing and see if the graphics are as smooth as they were without processing in JavaScript.

Webkit Web Audio Spec: Allowing Filters/FFT on JS Arrays

rikrd: These node we have are really useful to process all kinds of signals, not just for audio.

Chris Rogers: What types of processing and what type of data?

rikrd: You use convolver nodes or fft to process data. For example: finding the energy of a cymbal.

Chris Rogers: I am going to have to program something like this for testing purposes and I think it will be useful in allowing you to work along the lines of your suggestions.

shepazu: Could you use the GPU to do some of the processing for audio?

Chris Rogers: The GPU tends not to be that much faster in terms of processing, and adds latency which is a major issue in audio. So I do not see much of an advantage in doing this.

rikrd: It is also not as parallelizable.

Status of <device>: Did Robin Berjon follow up with WHATWG/HTMLWG? : http://dev.w3.org/html5/html-device/

<shepazu> http://lists.w3.org/Archives/Public/public-html/2010Sep/0228.html

shepazu: I know Robin did follow up on this, but I am not certain what the current status is right now. I do not thinkit has gone any further since our last telecon. But the expectation is that the DAP WG will be the group working on this.

<shepazu> http://www.w3.org/2009/dap/

<shepazu> http://dev.w3.org/2009/dap/api-perms/

<shepazu> http://dev.w3.org/2009/dap/device/

Chris Rogers: It would be nice if there was a standard for this, but we can still put this in the API for future considerations.

shepazu: I will do some more research on where this is, and find out if progress is still being made with <device>.

starting an Audio WG

shepazu: The incubator group should be focused more on audio in the web, and it is more appropriate to be working on the API within the working group. I am proposing that this group should draw up a charter for a Working Group and get it launched.
... Is there any decent on the idea of drawing up a charter and launching a Working Group?

Room: *long pause* (no decent registered)

Resolution: this group will draw up a charter to start a new Audio Working Group.

Status of high-resolution timers/media synchronization

Chris Rogers: we can pull in which ever high resolution timers the OS provides. What is more important is fleshing out how the API would integrate with this.

Summary of Action Items

[End of minutes]

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Found Scribe: F1LT3R
Inferring ScribeNick: F1LT3R
Default Present: +1.978.314.aaaa, +1.617.584.aabb, +1.510.334.aacc, +1.206.819.aadd, +1.978.314.aaee, +1.617.584.aaff, Shepazu
Present: +1.978.314.aaaa +1.617.584.aabb +1.510.334.aacc +1.206.819.aadd +1.978.314.aaee +1.617.584.aaff Shepazu
Found Date: 04 Oct 2010
People with action items: 

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