Processing.org and GSVideo: capture, frame difference and dump

FrameDifferencingDump.java

import codeanticode.gsvideo.*;

int numPixels;
int[] previousFrame;
GSCapture video;
GSMovieMaker mm;
int fps = 15;

void setup() {
  size(640, 480);
  frameRate(fps);
  video = new GSCapture(this, width, height);
  video.play();  
  numPixels = video.width * video.height;
  previousFrame = new int[numPixels];
  loadPixels();
  mm = new GSMovieMaker(this, width, height, "drawing.ogg", GSMovieMaker.THEORA, GSMovieMaker.MEDIUM, fps);
  mm.setQueueSize(50, 10);
  mm.start();
}

void draw() {
  if (video.available()) {
    video.read();
    video.loadPixels();
    
    int movementSum = 0;
    for (int i = 0; i < numPixels; i++) {
      color currColor = video.pixels[i];
      color prevColor = previousFrame[i];
      int currR = (currColor >> 16) & 0xFF;
      int currG = (currColor >> 8) & 0xFF;
      int currB = currColor & 0xFF;
      int prevR = (prevColor >> 16) & 0xFF;
      int prevG = (prevColor >> 8) & 0xFF;
      int prevB = prevColor & 0xFF;
      int diffR = abs(currR - prevR);
      int diffG = abs(currG - prevG);
      int diffB = abs(currB - prevB);
      movementSum += diffR + diffG + diffB;
      pixels[i] = 0xff000000 | (diffR << 16) | (diffG << 8) | diffB;
      previousFrame[i] = currColor;
    if (movementSum > 0) {
      updatePixels();
      mm.addFrame(pixels);
    }
  }
}

void keyPressed() {
  if (key == ' ') {
    mm.finish();
    exit();
  }
}