sound playback rate

// A sound file object

var song;

var analyzer;

​

function preload() {

  // Load a sound file

  song = loadSound('music-box.mp3');

}

​

function setup() {

  createCanvas(710, 400);

  song.loop();

    // create a new Amplitude analyzer

  analyzer = new p5.Amplitude();

​

  // Patch the input to an volume analyzer

  analyzer.setInput(song);

}

​

function draw() {

  background(200);

​

  // Set the volume to a range between 0 and 1.0

  var volume = map(mouseX, 0, width, 0, 1);

  volume = constrain(volume, 0, 1);

  song.amp(volume);

​

  // Set the rate to a range between 0.1 and 4

  // Changing the rate alters the pitch

  var speed = map(mouseY, 0.1, height, 0, 2);

  speed = constrain(speed, 0.01, 4);

  song.rate(speed);

​

  // Draw some circles to show what is going on

  stroke(0);

  fill(51, 100);

  ellipse(mouseX, 100, 48, 48);

  text("<--Speed-->", width/4, 50);

  stroke(0);

  fill(51, 100);

  ellipse(100, mouseY, 48, 48);

  text("volume", 50, height/2);

    // Get the average (root mean square) amplitude

  var rms = analyzer.getLevel();

  fill(127);

  stroke(0);

​

  // Draw an ellipse with size based on volume

  ellipse(width/2, height/2, 10+rms*200, 10+rms*200);

  noFill();

  text("circle represents the amplitude of sound", width/2, height/2 - 30);

}