Re: Screen recording needs a performance boost.

"Andrew Thompson" <u32984@uwe>
Sat, 21 Jul 2007 02:54:20 GMT
<757bca6510fc6@uwe> wrote:

I'm using robot to capture my screen in "real-time" and only able to
pull about 12fps, does anyone know how to improve the fps? Is the
while loop slowing it down?

Of course it is! The code is setting up try/catch constructs,
instantiating objects, updating a number of GUI elements,
scaling images, ..and creating a screencapture of the entire

Any help or idea's is appreciated.

Here is my altered code, and test results..

Oh, and while I recall, please post SSCCE's, rather
than code snippets..

import java.awt.*;
import javax.swing.*;

public class AnimatedScreenCapture extends JFrame {

  JLabel jLabel1;
  Robot robot;

  Rectangle rectangle1;

  int scaleX;
  int scaleY;

  public AnimatedScreenCapture() {
    super("Animated Screen Capture");
    setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    jLabel1 = new JLabel();
    jLabel1.setPreferredSize(new Dimension(400,300));
    getContentPane().add( jLabel1 );

    rectangle1 = new Rectangle(100,100);
    scaleX = Toolkit
        .width / 2;
    scaleY =Toolkit
        .height / 2;
    try {
      robot = new java.awt.Robot();
    } catch (AWTException e) {

  public void startCapture2() {
    long t0 = System.currentTimeMillis();
    int i = 0;
    int fps = 0;

    while (true) {
      long t1 = System.currentTimeMillis();
      int seconds = (int) (t1-t0)/1000;

      if (i%1000==0 && seconds>0) {
        fps = i / seconds;
        this.setTitle("FPS: " + fps);

      Image screen_capture = robot
        .getScaledInstance(scaleX, scaleY, Image.SCALE_FAST)

      jLabel1.setIcon(new ImageIcon(screen_capture));

  public static void main(String[] args) throws AWTException {
    Thread t = new Thread() {
      public void run() {
        AnimatedScreenCapture asc = new AnimatedScreenCapture();

FPS Conditions
3 original code (screen size 1024x768)
3 instantiated robot in constructor
4 replaced try/catch on division with test for 0.
20-22 screencap2 with rect of 100,100
250-290+ " " " " " and no scale
520-600+ " " " " " and no label update
540+ " " " " " and no label update/scale

It seems most of the time is taken up scaling the image
and updating the GUI. This should be done in a separate

This is not a good project for a newbie.

Andrew Thompson

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