<trackbot> Date: 09 January 2012

<scribe> Scribe: Olivier

[meeting convenes]

Use Case Scenarios

Al: at earlier meeting we decided the best way to divide up the work was through the use case and requirements document

<Alistair> http://www.w3.org/2011/audio/wiki/Use-Cases

<quinnirill> hmm, I can't join, it says the call is full

<jon> same

<jon> hi joe

[meeting reconvened on another teleconference port]

<roc> er

<roc> what was the number?

<shepazu> oops

<quinnirill> Zakim: +??P8 is me

<joeberkovitz> zakim: 1.978.314.aaaa is me

<joeberkovitz> zakim: +1.978.314.aaaa is me

joe: will do a bulk transfer of known de facto requirements of our (music) world onto this document

… will drag in some aspects of UC6

… may end up talking about envelopes, samples etc in UC5

Olivier: I created the UC skeleton arbitrarily, we may end up merging some

… mostly wanting to see if any is missing

Al: is accessibility a use case?

Chris: think that's a cross-UC requirement

???: how about visualisation

… sound, music visualisation

Doug: song recognition (a la Shazam, etc)

… could that be done?

Chris: mostly happens on the server side

Al: interesting is the question of microphone input

<scribe> ACTION: Doug to find status of microphone input work [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action01]

<trackbot> Created ACTION-10 - Find status of microphone input work [on Doug Schepers - due 2012-01-16].

Chris: I actually don't like "microphone" input, can be any kind of line input

Doug: other potential UC - was wondering about background sound

Chris: like a <bgsound> tag?

Doug: was wondering if media context for a given tab has to be the same as the dom context. What if sound continued from one page to another

… without having to reload all the resources

Chris: no idea how that would work re- security or implementation

… there is a document associated with the script execution context

Al: LocalStorage is shared

<Zakim> shepazu, you wanted to ask a strange use-case question

Doug: sound effects for clicking a button?

… UI sounds

Olivier: somehow already included in the game UC, but could add one

Chris: it's interesting as a UC in itself - interaction with CSS

Matthew: can we combine UC3 (mixing) and UC6 (playing virtual instruments)

Chris: may be useful to keep them separate - high level vs low level

Suggested: change UC3 to "production tool" instead of "mixing tool"

<joeberkovitz> olivier: i was the speaker at 16:26 and 16:27

Al: would like to know who's going to be working on which for the week to come

Joe: will take 5, probably going into 6

Chris: can take on 3, maybe not this week

Al: can look into visualisation
... should we give ourselves 2 weeks?

Olivier: sounds reasonable, the earlier the better

Chris: speaking of UC1 - anyone familiar with chat in 2nd life? seems like a fairly sophisticated example

… something we'd want to replicate in HTML

Joe: how do you abstract that?

Chris: 3D world where voices are spatialized

… how to interact with e.g webgl

Latency

Olivier: was wondering if people have requirements for latency, and ideas about testability

Chris: it is tricky to test, you could create some kind of mechanical rig (very complex to test)

… really hard to test, but it is really important (e.g in games)

… keypress to sound latency in games is going to be really important, equivalent to frame-rate with graphics

… if we want to take on media and game applications into the web, latency is a key question

Al: this issue crosses in to how many sounds you can play at once

… (and drop rate)

… agree with Chris that we need something in our requirements

… ditto for music

Chris: hard to achieve a hard latency limit. Maybe have some guidance

… can be informative

Chris: in smartphone world for instance there is a big hardware discrepancy in Android phones, for example

Doug: traditionally steer clear of performance stuff at w3c

… it's not usually a question of conformance

doug: we should optimise in the spec as soon as possible

Chris: relevant to the discussion of js only versus natively

… analogy with CSS 3D animations

… expectation that they will be smooth, and that's where implementations compete

… and no mention of frame rate in the spec

doug: could be, down the road if it became an issue

Chris: continuing on the analogy, there is nothing in CSS 3D animation impeding making it smooth / hardware accelerated

doug: [notes he's looking for hardware manufacturers to join in and help us spec things that can be accelerated easily/well]

Joe: possible to tolerate quite a high level of latency

… but it's important to know what the latency

… especially to coordinate with visual delivery

… can't coordinate if you don't know the delay

… a requirement out of UC5 will certainly be to know what the latency is

Chris: agreed

Joe: in our flash application we ask for a couple hundred milliseconds, which would be terrible for a game

Chris: 20, 30 or 50ms for a game would be acceptable, depending on platform

Al: wanted to note there will be room for competition in implementation

<Alistair> A conforming specification MUST be able to play pre-loaded sounds back at faster than a rate of 'x' milliseconds from the time the JavaScript code was executed, until the time that sound is heard through the speakers: where the audio path is not running through any external sound devices and the browser is using the default sound driver provided by the operating system.

Al: asking for opinions about that blurb

Chris: that would be setting a hard limit

… was quoted earlier as saying 50ms would be acceptable… 10ms is better!

… platforms are getting better

… for rhythm based games you really do want better than 20ms

Al: around 30ms seems to be threshold

Chris: jitter impacts as well

…you will feel the 30ms if the jitter is high

doug: consistency sometimes more important than latency

al: and probably harder to achieve than low latency

chris: agrees

Joe: proposal to try to put in what the requirements should be for jitter and latency

… and then survey and see if they deserve a special place in the spec

doug: another possible criteria
... need to think about what criteria we are going to be judging what we put in the spec

olivier: would it make sense to have a list of design principles such as hardware acceleration capability, low latency and jitter, consistency of interfaces, etc

chris: my goal is to achieve similar level of performance as a native app

olivier: not sure we can achieve same level of performance as pro software on desktop, but agree with goal in general

Joe: we have flash apps/games as a benchmark

chris: will vary between platforms

… for games we can get there

… for digital audio workstations, will be tricky

[general agreement]

f2f

<scribe> ACTION: olivier to send details of f2f logistics [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action02]

<trackbot> Created ACTION-11 - Send details of f2f logistics [on Olivier Thereaux - due 2012-01-16].

Olivier: invite all to discuss ideas for f2f agenda on the mailing-list

[adjourned]

<scribe> ACTION: joe to work on Use Case scenario 5 [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action03]

<trackbot> Created ACTION-12 - Work on Use Case scenario 5 [on Joe Berkovitz - due 2012-01-16].

<scribe> ACTION: olivier to copy Use Case scenario 1 from RTC document [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action04]

<trackbot> Created ACTION-13 - Copy Use Case scenario 1 from RTC document [on Olivier Thereaux - due 2012-01-16].

<scribe> ACTION: Alistair to work on Use Case scenario for visualisation [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action05]

<trackbot> Created ACTION-14 - Work on Use Case scenario for visualisation [on Alistair MacDonald - due 2012-01-16].

<scribe> ACTION: ChrisR to work on Use Case Scenario 3 (music production) [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action06]

<trackbot> Sorry, couldn't find user - ChrisR

<scribe> ACTION: crogers to work on Use Case Scenario 3 (music production) [recorded in http://www.w3.org/2012/01/09-audio-minutes.html#action07]

<trackbot> Created ACTION-15 - Work on Use Case Scenario 3 (music production) [on Chris Rogers - due 2012-01-16].

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Guessing input format: RRSAgent_Text_Format (score 1.00)

Found Scribe: Olivier
Inferring ScribeNick: olivier
Default Present: [IPcaller], +1.978.314.aaaa, +1.650.253.aabb, Doug_Schepers, quinnirill, olivier, joe, chris
Present: [IPcaller] +1.978.314.aaaa +1.650.253.aabb Doug_Schepers quinnirill olivier joe chris
Found Date: 09 Jan 2012
Guessing minutes URL: http://www.w3.org/2012/01/09-audio-minutes.html
People with action items: alistair chrisr crogers doug joe olivier

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