Re: FFT & IFFT with the Web Audio API

Den 2013-06- 05:33:42 skrev Kaustubh Joshi <kdj.tikka@gmail.com>:

> In that case better place would be at top level; provide generalised FFT  
> and iFFT as html5 API. Rather than coding some .js or plugin for FFT  
> calculation >as it is being used in my apps now.

Yes, and that's part of the purpose of this spec proposal:  
http://people.opera.com/mage/dspapi/

Specifically, the FFT and Filter interfaces closely mimic what's part of  
the Web Audio API today, except that it's exposed directly to JS.

/Marcus


>
> br,
> kdj
>
>
> On Mon, Jun 17, 2013 at 10:21 PM, Kevin Gadd <kevin.gadd@gmail.com>  
> wrote:
>> If you're going to expose a reusable FFT, there's an argument to be  
>> made that you might as well make it a commodity function so that it can  
>> be used on >>any stream of data in a TypedArray instead of specifically  
>> things that are being fed to Web Audio. After all, audio isn't the only  
>> place people use >>FFTs.
>>
>>>> -kg
>>
>>
>> On Mon, Jun 17, 2013 at 8:56 AM, Russell McClellan <russell@motu.com>  
>> wrote:
>>>
>>> On Jun 17, 2013, at 11:29 AM, Marcus Geelnard <mage@opera.com> wrote:
>>>
>>>> My original proposal was to rip the FFT part out of the analyzer node  
>>>> (it can just as well give the time domain signal only), and  
>>>> >>>>expose the FFT functionality in a JS interface instead. That way  
>>>> we would have the same functionality and performance for the  
>>>> >>>>analyzer node (when combined with the JS FFT interface), but the  
>>>> FFT primitive could be used in the ScriptProcessorNode too for a  
>>>> >>>>wide range of interesting effects (not to mention for using it  
>>>> for non-Web Audio stuff as well).
>>>
>>> As I said just last week, I think even better would be a  
>>> "SpectralProcessorNode", which would act exactly like the  
>>> ScriptProcessorNode except on >>>spectral data.  You could control  
>>> parameters like overlap, window, and fft size, and these would have  
>>> reasonable defaults.  I think just exposing an >>>FFT function would  
>>> be a little too "low-level" in character compared to the rest of the  
>>> web audio API.
>>>
>>> Thanks,
>>> -Russell
>>
>



-- 
Marcus Geelnard
Technical Lead, Mobile Infrastructure
Opera Software