Corrupted image in applet from web cam

Question

Hi there I created a little webcam server application that listens to port 8080 for requests, then displays an image. The image is jpeg encoded frame grabbed from a logitech web cam using the java media framework. I got the code from this forum.
I have tried it across a 56kb modem on four different computers. On three the applet displays the images without problems. On the fourth the image is corrupted like it didn't receive all the data.
Anyone have any idea why this occurs in one and not the others
Here's some of the source
The applet just uses getImage( http://[host]:8080 )
and media tracker with a thread sleeping for a second
public class WebCamServer extends JFrame
     // class variables
     private HttpServer webserver;
     private int port = 80;
     private ServerSocket server;
     private ImageIcon gfr;
     private Color backcolour = new Color( 255, 255, 255 );     
     private Player player = null;
     private MediaLocator ml = null;
     private JPanel campanel = null;
     public boolean active = false;
     public Buffer buf = null;
     public VideoFormat vf = null;
     public BufferToImage btoi = null;
     public Image img = null;
public WebCamServer()
          // initialise Frame with this heading and font
          super( "eyespyfx - Web Cam Server" );
          setFont( new Font( "Verdana", Font.PLAIN, 12 ) );
          // initialise web server
          startServer();
          // set up ServerSocket to listen for requests on port 8080
          try
               server = new ServerSocket( 8080 );
          catch( IOException e )
               System.err.println( "Server Socket Error" );
               System.err.println( e.getMessage() );
               shutdown();
          // set frame icon to gfr.gif
          gfr = new ImageIcon( "gfr.gif" );
          this.setIconImage( gfr.getImage() );
          // get content pane set a layout
          java.awt.Container c = getContentPane();
          c.setLayout( new BorderLayout( 0, 0 ) );
          // create panel to hold web cam image
          campanel = new JPanel();
          campanel.setLayout( new BorderLayout( 0, 0 ) );
          campanel.setPreferredSize( new Dimension( 320, 240 ) );
          // locate web cam from JMF Registry
          ml = new MediaLocator( "vfw://0" );
          // set lightweight renderer for improved framerate
          Manager.setHint( Manager.LIGHTWEIGHT_RENDERER, new Boolean(true) );
          try
               // create realized video player
               player = Manager.createRealizedPlayer( ml );
               //start player
               player.start();
               Component comp;
               // display the visual component
               if ( ( comp = player.getVisualComponent() ) != null )
                    campanel.add( comp, BorderLayout.CENTER );
          catch (Exception e)
               System.err.println( "Exception in creating or displaying player" );
               System.err.println( e.getMessage() );
          // add campanle to the frame
          c.add( campanel, BorderLayout.CENTER );
          // size & colour of frame
          c.setBackground( backcolour );
          setBounds( 0, 0, 0, 0 );
          setResizable( false );
          setSize( 350, 250 );
          show();
          // active set to true - means software is listening for image requests
          active = true;
     // Thread listener for image requests
     public void execute()
          // while active is true          
          while ( active )
               try
                    // client connects
                    ClientApplet newclient = new ClientApplet( server.accept(), this );
                    // Grab a frame
                    FrameGrabbingControl fgc = (FrameGrabbingControl) player.getControl("javax.media.control.FrameGrabbingControl");
                    buf = fgc.grabFrame();
                    // Convert it to an image
                    btoi = new BufferToImage((VideoFormat)buf.getFormat());
                    img = btoi.createImage(buf);
                    // set client thread with image
                    newclient.setImage( img );
                    // start the client thread
                    newclient.start();
               catch( IOException e )
                    e.printStackTrace();
                    System.exit( 1 );
// ClientApplet class to manage each Client Applet as a thread
class ClientApplet extends Thread
     // class variables
     private Socket connection;
     private PrintWriter out;
     private BufferedReader in;
     private WebCamServer control;
     protected boolean threadSuspended = true;
     public Image img;
     // constructor creates a socket on port 8080
     public ClientApplet( Socket s, WebCamServer t )
          connection = s;          
          control = t;
     // grabbed frame set as output image
     public void setImage( Image img )
          this.img = img;
public void run()
          // image is buffered to create a 2D graphics object               
          BufferedImage bi = new BufferedImage(240, 180, BufferedImage.TYPE_INT_RGB);
          Graphics2D g2 = bi.createGraphics();
          g2.drawImage(img, null, null);
          OutputStream out = null;
          // create an output stream to the socket
          try
               out = connection.getOutputStream();
          catch ( IOException io)
               System.out.println("Error getting socket output stream");
               System.err.println( io.getMessage() );
          // create jpeg encoder on output stream
          // set the image as a parameter
          JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
          JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(bi);
          param.setQuality(0.25f,false);
          encoder.setJPEGEncodeParam(param);
          // encode the image through the output stream
          // close IO connections
          try
               encoder.encode(bi);
               out.close();
               connection.close();
          catch ( IOException ioe )
               System.out.println("JPGE IO exception");
               System.err.println( ioe.getMessage() );
          // end of thread image is served to webpage or applet
}

Answer 1

Hi,
I don't know how to solve this problem,
but I want to ask you how you managed to get
FrameGrabbingControl which is not null.
I use Logitech QickCam and everytime when I try to get a FrameGrabbingControl from the Player it returns me null?
Can you help me?
have you any ideas why I get null?
WebCamLocator - is OK. If I can use it to record a video clip. But I can't take a single frame..
Manager.setHint( Manager.LIGHTWEIGHT_RENDERER, new Boolean(true) );
Player WebCamPlayer = Manager.createRealizedPlayer(WebCamLocator);
WebCamPlayer.start();
FrameGrabbingControl fgc = (FrameGrabbingControl)WebCamPlayer.getControl("javax.media.control.GrabbingControl");
Buffer buf = fgc.grabFrame();