Message-ID: <8D53104ECD0CD211AF4000A0C9D60AE3511F54@probe-2.acclaim-euro.net>
From: Shawn Hargreaves <ShawnH AT Probe DOT co DOT uk>
To: djgpp AT delorie DOT com
Subject: Re: sound spectrum analysis
Date: Thu, 11 Feb 1999 09:52:32 -0000
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Reply-To: djgpp AT delorie DOT com

Cminnican writes:
> I am interested in writing some code to analyse sound in realtime 
> through the line in input on my soundcard. I would like to be able 
> to extract certain frequencies from the incoming sound and use these 
> values to create visual effects that respond to the music as it is 
> playing. 

You need to do a Fourier analysis of the input data. That's quite a
complex operation, but you can probably find some code for it on the
net (sorry, I don't know where). Alternatively, you should be able
to find descriptions of the algorithm in a computing or math textbook:
check the library.

> Any help would be appreciated such as how to receive data from the 
> line in 

The Allegro library (http://www.talula.demon.co.uk/allegro) can do 
this for you. Look at the akaitest program for some example code.


	Shawn Hargreaves.