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Re: Updates to Web Audio API editor's draft

From: Chris Rogers <crogers@google.com>
Date: Fri, 27 Apr 2012 12:40:39 -0700
Message-ID: <CA+EzO0kLFUMjWu2s2UDTF7gKzizB5g9+aNzixeVDfQ84ZEYz=g@mail.gmail.com>
To: "Wei, James" <james.wei@intel.com>
Cc: "public-audio@w3.org" <public-audio@w3.org>
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 Oscillatorís 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?



> ****
>
> ** **
>
> 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.


> ****
>
> ** **
>
> ** **
>
> Best Regards ****
>
> ** **
>
> James ****
>
> ** **
>
> ** **
>
> *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:*
> ***
>
> https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html****
>
> ** **
>
> With some changes addressing list feedback.****
>
> ** **
>
> 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/****
>
> ** **
>
> And here's my summary:****
>
> ** **
>
> * add AudioContext .activeSourceCount attribute****
>
> * add AudioBufferSourceNode .playbackState attribute and state constants**
> **
>
> ** **
>
> 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.****
>
> ** **
>
> * createBuffer() methods can throw exceptions****
>
> ** **
>
> If it's passed illegal arguments...****
>
> ** **
>
> * add AudioContext method createMediaElementSource()****
>
> ** **
>
> Implemented in Chrome for a couple months.  This method creates a
> MediaElementAudioSourceNode from an <audio> or <video> element.****
>
> ** **
>
> * update AudioContext methods createJavaScriptNode() (clean up description
> of parameters)****
>
> ** **
>
> Previous description was confusing.****
>
> ** **
>
> * update AudioContext method createChannelSplitter() (add numberOfOutputs
> parameter)****
>
> * 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)****
>
> ** **
>
> Address list feedback about allowing the developer to choose the numbers
> of outputs and inputs for splitters and mergers.****
>
> ** **
>
> * update description of out-of-bounds AudioParam values (exception will
> not be thrown)****
>
> ** **
>
> Since parameters such as gain can be effectively un-bounded.****
>
> ** **
>
> * remove AudioBuffer .gain attribute****
>
> * remove AudioBufferSourceNode .gain attribute****
>
> * remove AudioListener .gain attribute****
>
> ** **
>
> 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.****
>
> ** **
>
> * RealtimeAnalyserNode no longer requires its output be connected to
> anything****
>
> ** **
>
> 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****
>
> ** **
>
> Effectively arbitrary convolution matrixing can be used for rich spatial
> effects.****
>
> ** **
>
> * Add Oscillator and WaveTable****
>
> ** **
>
> This was in response to list feedback.  People found the lack of
> oscillator support surprising, since it's an elementary building-block of
> synthesis.****
>
> ** **
>
> * Define default values for optional arguments in createJavaScriptNode(),
> createChannelSplitter(), createChannelMerger()****
>
> * Define default filter type for BiquadFilterNode as LOWPASS****
>
> ** **
>
> This was just a clarification of default filter type.****
>
> ** **
>
> * Cleanup AudioNode connect() and disconnect() method descriptions.****
>
> ** **
>
> API same - update to more modern IDL****
>
> ** **
>
> * Add AudioNode connect() to AudioParam method.****
>
> ** **
>
> Allows audio-rate signals to control AudioParams****
>
Received on Friday, 27 April 2012 19:41:09 GMT

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