求教一个关于jmf的DataSource类问题
public class TestCapture {
  public void capture() {
  Vector v = CaptureDeviceManager.getDeviceList();
  Iterator it = v.listIterator();
  CaptureDeviceInfo cdi = null;
  MediaLocator ml = null;
  Player p = null;
  while(it.hasNext()) {
  cdi = (CaptureDeviceInfo)it.next();
  if(cdi.getName().startsWith("vfw:")) {
  ml = cdi.getLocator();
  try {
  DataSource ds = Manager.createDataSource(ml);//这里出错
  try {
  p = Manager.createPlayer(ds);
  JFrame jf = new JFrame();
  jf.add(p.getVisualComponent());
  jf.setVisible(true);
  } catch (NoPlayerException e) {
  e.printStackTrace();
  }
  p.start();
  } catch (NoDataSourceException e) {
  e.printStackTrace();
  } catch (IOException e) {
  e.printStackTrace();
  }
  }
  }
}
  public static void main(String args[]) {
  new TestCapture().capture();
  }
}

代码如上，报了下面的错：

java.io.IOException: Could not connect to capture device
javax.media.NoDataSourceException: Error instantiating class: com.sun.media.protocol.vfw.DataSource : java.io.IOException: Could not connect to capture device
at javax.media.Manager.createDataSource(Manager.java:1012)
at TestCapture.capture(TestCapture.java:29)
at TestCapture.main(TestCapture.java:63)

相关的包都已经引进，局部变量Player p 用Manager.createPalyer(ml);创建就完全没问题，能看到图像，但为什么就是创建不了DataSource呢？网上关于jmf的资料少，找了半天都没找到原因，求教高手！！！

------解决方案--------------------
我也有同样的错误