I have to run the code twice

Question

I'm running a jmf class that will register a camera(attached to the computer) and show picture from the camera. My problem is that first time i run the code i get the following error:
"java.io.IOException: java.lang.Error: Couldn't initialize capture device
javax.media.NoDataSourceException: Error instantiating class: com.sun.media.protocol.v4l.DataSource : java.io.IOException: java.lang.Error: Couldn't initialize
capture device"
but the next time i run the code everything works properly.

Answer 1

ok sorry
Here comes the code:
//package JMF;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.media.*;
import javax.media.format.*;
import javax.media.protocol.*;
//import com.sun.media.protocol.v4l.*;
public class GetVid extends Frame implements ActionListener, ItemListener, WindowListener,
ControllerListener {
CaptureDeviceInfo videoCDI = null;
String videoDeviceName = null;
Player dualPlayer;
Format videoFormat;
DataSource ds; //of the capture devices
public GetVid(String title) {
super(title);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
dispose();
MenuBar mb = new MenuBar();
setMenuBar(mb);
Menu menuConfigure = new Menu("Configure");
mb.add(menuConfigure);
Menu menuAction = new Menu("Action");
mb.add(menuAction);
/* menu items for Configure */
MenuItem menuItemSetting = new MenuItem("Capture Device");
MenuItem menuItemSetting2 = new MenuItem("Register Device");
menuItemSetting.addActionListener(this);
menuItemSetting2.addActionListener(this);
menuConfigure.add(menuItemSetting);
menuConfigure.add(menuItemSetting2);
/* menu items for Action */
MenuItem a1 = new MenuItem("Capture");
a1.addActionListener(this);
menuAction.add(a1);
MenuItem a2 = new MenuItem("Play");
a2.addActionListener(this);
menuAction.add(a2);
MenuItem a3 = new MenuItem("Stop");
a3.addActionListener(this);
menuAction.add(a3);
public void actionPerformed(ActionEvent ae) {
String command = ae.getActionCommand().toString();
if (command.equals("Register Device")) {
registerDevices();
else if (command.equals("Capture Device")) {
//registerDevices();
captureDevices();
else if (command.equals("Play")) {
play();
else if (command.equals("Capture")) {
capture();
else if (command.equals("Stop")) {
stop();
void captureDevices() {
CaptureDeviceDialog cdDialog = new
CaptureDeviceDialog(this, "Capture Device", true);
cdDialog.show();
if (!cdDialog.hasConfigurationChanged())     {
return;
//configuration has changed, update variables.
videoCDI = cdDialog.getVideoDevice();
if (videoCDI!=null) {
videoDeviceName = videoCDI.getName();
//Get formats selected, to be used for creating DataSource
videoFormat = cdDialog.getVideoFormat();
void registerDevices() {
//V4LAuto v4la = new V4LAuto();
CaptureDeviceInfo cdi = null;
try {
cdi = new com.sun.media.protocol.v4l.V4LDeviceQuery(0);
if ( cdi != null && cdi.getFormats() != null &&
cdi.getFormats().length > 0) {
// Commit it to disk. Its a new device
if (CaptureDeviceManager.addDevice(cdi)) {
System.err.println("Added device " + cdi);
CaptureDeviceManager.commit();
} catch (Throwable t) {
System.err.println(t);
if (t instanceof ThreadDeath)
throw (ThreadDeath)t;
void capture() {
if (videoCDI==null)     {
captureDevices();
try {
if (!(videoCDI==null)) {
ds = Manager.createDataSource(videoCDI.getLocator());
dualPlayer = Manager.createPlayer(ds);
dualPlayer.addControllerListener(this);
dualPlayer.start();
else
System.out.println("CDI not found.");
catch (Exception e) {
System.out.println(e.toString());
void play() {
try {
FileDialog fd = new FileDialog(this, "Select File", FileDialog.LOAD);
fd.show();
String filename = fd.getDirectory() + fd.getFile();
dualPlayer = Manager.createPlayer(new MediaLocator("file:///" + filename));
System.out.println("Adding controller listener");
dualPlayer.addControllerListener(this);
System.out.println("Starting player ...");
dualPlayer.start();
catch (Exception e) {
System.out.println(e.toString());
void stop() {
if (dualPlayer!=null) {
dualPlayer.stop();
dualPlayer.deallocate();
public synchronized void controllerUpdate(ControllerEvent event) {
System.out.println(event.toString());
if (event instanceof RealizeCompleteEvent) {
Component comp;
System.out.println("Adding visual component");
if ((comp = dualPlayer.getVisualComponent()) != null)
add ("Center", comp);
System.out.println("Adding control panel");
if ((comp = dualPlayer.getControlPanelComponent()) != null)
add("South", comp);
validate();
public void itemStateChanged(ItemEvent ie) {}
public void windowActivated(WindowEvent we) {}
public void windowClosed(WindowEvent we) {}
public void windowClosing(WindowEvent we) {}
public void windowDeactivated(WindowEvent we) {}
public void windowDeiconified(WindowEvent we) {}
public void windowIconified(WindowEvent we) {}
public void windowOpened(WindowEvent we) {}
public static void main(String[] argv) {
GetVid myFrame = new GetVid("Java Media Framework Project");
myFrame.show();
myFrame.setSize(300, 300);