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Re: Suggestion: Web Audio graphs that does not output sound but can write to an AudioBuffer instead

From: Alistair MacDonald <al@signedon.com>
Date: Tue, 17 Apr 2012 11:35:41 -0400
Message-ID: <CAJX8r2=YQ1c4CUGnVFO+T+s0YADDf7PRRh4MByKvdpawV4m+oQ@mail.gmail.com>
To: Per Nyblom <perny843@hotmail.com>
Cc: public-audio@w3.org
Hi Per,

Does the OfflineAudioContext Chris R. and James W. are talking about
cover the scenario you are thinking of?

Thanks again for the suggestion!


On Mon, Apr 16, 2012 at 3:36 PM, Chris Rogers <crogers@google.com> wrote:
> On Mon, Apr 16, 2012 at 12:10 PM, Raymond Toy <rtoy@google.com> wrote:
>> On Fri, Apr 13, 2012 at 1:47 AM, Per Nyblom <perny843@hotmail.com> wrote:
>>> Hello,
>>> it would be great to be able to access the generated sound data without
>>> having to send it to the speakers as well.
>>> This feature is very useful for a musical application that should render
>>> a wav-file or similar (perhaps with the help of the FileSystem API). Most
>>> existing musical applications support this "offline" rendering mode.
>>> It is also useful to be able to create AudioBuffers as an optimization of
>>> a graph. Suppose that you create a very large graph that generates a sound
>>> effect or musical instrument sound and want to reuse it. It is very
>>> convenient to be able to generate AudioBuffers to improve performance
>>> without having to do this with an external program.
>>> All this could perhaps be supported by using a subclass of AudioContext
>>> that supports methods like: renderToBuffer(AudioBuffer, bufferOffset,
>>> length) or something similar.
>>> It is important to be able to incrementally render to the buffer because
>>> of the single-threaded nature of JS (you can use Workers for this but I
>>> think it is important anyway).
>> Won't a JavaScriptNode work for this, where the node just saves the data
>> away in an audiobuffer?  Or are you saying it won't work because JS is
>> single-threaded?
>> Ray
> I think the idea of an OfflineAudioContext is what we want, because ideally
> the rendering will occur faster than real-time.
> Chris

Alistair MacDonald
SignedOn, Inc - W3C Audio WG
Boston, MA, (707) 701-3730
al@signedon.com - http://signedon.com
Received on Tuesday, 17 April 2012 15:36:13 UTC

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