import ddf.minim.*;
  import ddf.minim.effects.*;
  
  Minim minim;
  AudioPlayer groove;
  ReverseEffect reffect;
  
  void setup()
  {
    size(512, 200, P3D);
    
    minim = new Minim(this);
    // try changing the buffer size to see how it changes the effect
    groove = minim.loadFile("groove.mp3", 2048);
    groove.loop();
    reffect = new ReverseEffect();
    groove.addEffect(reffect);
  }
  
  void draw()
  {
    background(0);
    stroke(255);
    // we multiply the values returned by get by 50 so we can see the waveform
    for ( int i = 0; i < groove.bufferSize() - 1; i++ )
    {
      float x1 = map(i, 0, groove.bufferSize(), 0, width);
      float x2 = map(i+1, 0, groove.bufferSize(), 0, width);
      line(x1, height/4 - groove.left.get(i)*50, x2, height/4 - groove.left.get(i+1)*50);
      line(x1, 3*height/4 - groove.right.get(i)*50, x2, 3*height/4 - groove.right.get(i+1)*50);
    }
  }
  
  void stop()
  {
    // always close Minim audio classes when you finish with them
    groove.close();
    // always stop Minim before exiting
    minim.stop();
  
    super.stop();
  }