AudioInput Volume Control

import beads.*;
import org.jaudiolibs.beads.*;
import java.util.Arrays;
import java.io.*;
import java.net.URL;
import javax.sound.sampled.*;
import java.io.File;
AudioContext ac;
void setup() {
frameRate(200);
size(400,400);
ac = new AudioContext();
File inputFile = new File("/Users/johnwaldo/Downloads/2-11 Stop.wav");
Noise n = new Noise(ac);
String audioFileName = inputFile.getAbsolutePath();
SamplePlayer player = new SamplePlayer(ac, SampleManager.sample(audioFileName));
Gain g = new Gain(ac, 2,2);
g.addInput(player);
ac.out.addInput(g);
ac.start();
}

color fore = color(255, 102, 204);
color c = color(140, 200, 90);
color back = color(0,0,0);

void draw() {
  loadPixels();
  //set the background
  Arrays.fill(pixels, back);
  //scan across the pixels
   for(int i = 0; i < width; i++) {
    //for each pixel work out where in the current audio buffer we are
    int buffIndex = i * 4 / width;
    //then work out the pixel height of the audio data at that point
    float vOff = ac.out.getValue(0,buffIndex);
    if (vOff < .15) { 
      ac.out.setGain(ac.out.getGain()+.01);
      ac.out.setValue(ac.out.getValue(0,buffIndex)+.01);
    }
    else if(vOff > .25) { 
      ac.out.setGain(ac.out.getGain()-.01);
      ac.out.setValue(ac.out.getValue(0,buffIndex)-.01);
    }
    int vOffset = (int)((1 + ac.out.getValue(0,buffIndex)) * height / 2);
    vOffset = min(vOffset, height);
  }
  updatePixels();
}