[futurebasic] Re: [FB] Audio Spectrum/ Amplitude plot

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From: Robert Covington <artlythere@...>
Date: Tue, 10 Apr 2012 09:51:09 -0400
Greetings Yoshiyuki

On Apr 9, 2012, at 11:54 AM, Yoshiyuki Hasegawa wrote:

>  or is it simple frequency analysis?

Simple kind or amplitude plot

> Some frequency analysis is conducted also by Visualizer of iTunes.
> Sorry if the direction of me differs from you.
> Questions. (in case of simple frequency analysis)
> 1. Audio track displayed as one level (one band)?

Yes or two if stereo (L and R)

> 2. Do you conduct frequency analysis of the audio track, and display the results (many bands) ?

No need for that, though I could make a filter which did things according to the band amplitude or frequency.

> Below, the method of audio processing general frequency analysis are described.
> 1. I think that it is best to use "Core Audio" in order to perform audio processing.
>    The numerical value acquired by "Core Audio" is CG-ized, and is displayed.
>    Though regrettable, I have not challenged "Core Audio" yet.

Probably is the route.

> 2. A sound and seeing the images separate, and are processed separately, and, finally it should synchronize with them in consideration of each the latency.

My need is mostly for timing...

I just need to be able to play the audio...display the amplitude (or overall frequency/time) and then a tracking-timing array will accept key frame points, and I'll match up the images to a time track.

Visually, the addition of a frequency or amplitude wave plot would help the user, including myself, to know what part of the audio they are dealing with roughly.

If you have used Audacity, and you open up an AIFF,  or other, the plot they show is what I am after.
> 3. The method of conducting frequency analysis has some types.

Thanks for the links!

> Octave or FFT changes with last purposes.
> I think that the archive of "Core Audio" probably have sample code.
> If "Core Audio" is held, it will be expected that it is comparatively easy.

I downloaded a lot of examples, but it's rather complicated for me.
> Acoustics is my special field, it may be able to be given to a slight degree.
> I am pleased if it becomes helpful.
> Yoshiyuki. 

Thank you much for your post! Sorry for delay in reply.