Re: Updates to Web Audio API editor's draft

James, thanks for your feedback.

On Wed, Apr 25, 2012 at 7:32 PM, Wei, James <james.wei@intel.com> wrote:

>  Quick feedback for the update: ****
>
> ** **
>
> **1.       **For activeSourceCount, if it only includes
> AudioBufferSourceNode, activeBufferSourceCount may be better? Or should
> also include Oscillator and ElementSourceNode.
>
Yes, this might be more accurate.



> ****
>
> **2.       **For Oscillator’s type, currently CUSTOM is the last one,
> will it be better to let CUSTOM to be 0 so we can extend the types in
> future more easily?
>
Good point, anybody object?



> ****
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> ** **
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> There are two typos in the spec mentioned before: ****
>
> 1.      // For implementation (in?) WebKit this will be: ****
>
> 2.      analsis(should be analysis?) in RealtimeAnalyserNode attributes
> description of fftSize.
>

Thanks, I've just fixed these two typos.


> ****
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> Best Regards ****
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> James ****
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> *From:* Chris Rogers [mailto:crogers@google.com]
> *Sent:* Wednesday, April 25, 2012 4:07 AM
> *To:* public-audio@w3.org
> *Subject:* Updates to Web Audio API editor's draft****
>
> ** **
>
> Hey folks, I've recently updated the editor's draft of the Web Audio API:*
> ***
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> https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html****
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> ** **
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> With some changes addressing list feedback.****
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> For low-level details, the actual edits are here (please see all edits
> since re-basing from Thierry Michel):****
>
> https://dvcs.w3.org/hg/audio/****
>
> ** **
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> And here's my summary:****
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> * add AudioContext .activeSourceCount attribute****
>
> * add AudioBufferSourceNode .playbackState attribute and state constants**
> **
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> ** **
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> Taken together the .activeSourceCount and .playbackState attributes allow
> developers to dynamically monitor the number of active voices.  In a busy
> game there may be many dozens of sounds playing at any given moment, and
> the exact number is constantly changing.  Based on this information about
> the number of voices,  developers can choose to drop older voices.****
>
> ** **
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> * createBuffer() methods can throw exceptions****
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> If it's passed illegal arguments...****
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> * add AudioContext method createMediaElementSource()****
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> ** **
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> Implemented in Chrome for a couple months.  This method creates a
> MediaElementAudioSourceNode from an <audio> or <video> element.****
>
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> * update AudioContext methods createJavaScriptNode() (clean up description
> of parameters)****
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> Previous description was confusing.****
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> * update AudioContext method createChannelSplitter() (add numberOfOutputs
> parameter)****
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> * update AudioContext method createChannelMerger() (add numberOfInputs
> parameter)****
>
> * update AudioChannelMerger section describing numberOfOutputs (defaults
> to 6 but settable in constructor)****
>
> * update AudioChannelSplitter section describing numberOfInputs (defaults
> to 6 but settable in constructor)****
>
> ** **
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> Address list feedback about allowing the developer to choose the numbers
> of outputs and inputs for splitters and mergers.****
>
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> * update description of out-of-bounds AudioParam values (exception will
> not be thrown)****
>
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> Since parameters such as gain can be effectively un-bounded.****
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> * remove AudioBuffer .gain attribute****
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> * remove AudioBufferSourceNode .gain attribute****
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> * remove AudioListener .gain attribute****
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> We may need to re-visit the removal of these gain attributes from the API,
> since I've found several pages out in the wild using them.  They're not
> harmful attributes, just ones I felt could be cleaned up (removed) since
> AudioGainNode can be used instead.  We may need to choose a deprectation
> path, or simply keep them.****
>
> ** **
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> * RealtimeAnalyserNode no longer requires its output be connected to
> anything****
>
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> This was in response to list feedback where it was felt to be unnecessary
> to have to connect the output of an analyser to anything, since its purpose
> is normally just to "inspect" the audio signal.****
>
> ** **
>
> * add note in Spatialization sections about potential to get arbitrary
> convolution matrixing****
>
> ** **
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> Effectively arbitrary convolution matrixing can be used for rich spatial
> effects.****
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> * Add Oscillator and WaveTable****
>
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> This was in response to list feedback.  People found the lack of
> oscillator support surprising, since it's an elementary building-block of
> synthesis.****
>
> ** **
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> * Define default values for optional arguments in createJavaScriptNode(),
> createChannelSplitter(), createChannelMerger()****
>
> * Define default filter type for BiquadFilterNode as LOWPASS****
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> This was just a clarification of default filter type.****
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> * Cleanup AudioNode connect() and disconnect() method descriptions.****
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> API same - update to more modern IDL****
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> * Add AudioNode connect() to AudioParam method.****
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> Allows audio-rate signals to control AudioParams****
>