Change color of line based on song frequency.

edited December 2016 in Library Questions


I am trying to write a code that will use a song's frequency to change the color of a line that moves across the campus to create some sort of abstract picture. Currently, I am stumped on how to achieve this effect. If anyone has any advice on how to do this, it would be much appreciated.

This is my code currently (which probably has a great amount of errors in it; I'm still new to processing):

import ddf.minim.*; import ddf.minim.signals.*; import ddf.minim.analysis.*; import ddf.minim.effects.*; float k; float r; float g; float b;

Minim minim; AudioPlayer player; FFT fft;

void setup() { size( 800, 600 );

minim = new Minim( this );

player = minim.loadFile("Little Secrets.mp3");;
fft = new FFT( player.bufferSize(), player.sampleRate() );


void draw() {

float x = map( player.position(), 0, player.length(), 0, width );

float e = 0;
for ( int i = 0; i < fft.specSize(); i++ ) {
    e += abs( fft.getBand( i ) ) / 1000;


{ int k = color(r-e,g/e,b+e); float r = red(pixels[k]); float g = green(pixels[k]); float b = blue(pixels[k]);


stroke( color(r-e, g/e, b+e) );
strokeWeight (5);
line( x, 0, x, height );


void stop() { player.close(); minim.stop(); super.stop(); }



  • One - format your code.
    Two - Since you already know about FFT, what exactly is it that stumps you? You want the color to changed based on frequency, but for what frequency what color should be there? Read about HSB also.
    P.S. I did not know what link to give for HSB, so I gave one to the color tutorial.

  • @jpnielsen -- agreed with LoG -- if you are trying to change a color, start with the Color Tutorial is the best link. Also, look specifically at the reference page for colorMode() for HSB color, and the map() reference for how to map something (like audio values) to something else (like HSB color values).

    P.S. "campus" -> "canvas"

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