RTP Cannot open local data port

Question

Hello,
I'm about to learn JMF. So I tried the example code from the sun JMF documentation(example10-1; code is appended).
The code compiles without errors but when I run it, I alway get the following error:
streams is [Lcom.sun.media.multiplexer.RawBufferMux$RawBufferSourceStream;@b9b538 : 1
sink: setOutputLocator rtp://192.168.0.6:49150/audio/1
java.io.IOException: Can't open local data port: 4800
        at com.sun.media.datasink.rtp.Handler.open(Handler.java:139)
        at Send.<init>(Send.java:60)
        at Send.main(Send.java:71)
What does that mean and what causes that kind of exception?
Thanks in advance.
MfG
Michael
****Code starts here****
class Send {
   public Send() {
      AudioFormat format = new AudioFormat(AudioFormat.LINEAR, 8000, 16, 1);
      Vector devices = CaptureDeviceManager.getDeviceList(null);
      System.out.println("DEBUG: CaptureDeviceManager returned "  + devices.size() + " devices");
      CaptureDeviceInfo di = null;
      Processor p = null;
      if(devices.size() > 0)
      di = (CaptureDeviceInfo) devices.elementAt(0);
      else
      System.exit(-1);
      System.out.println("Found: " + di.toString());
      try {
      p = Manager.createProcessor(di.getLocator());
      } catch(Exception e) {
     e.printStackTrace();
     System.exit(-1);
p.configure();
TrackControl tracks[] = p.getTrackControls();
p.setContentDescriptor(new ContentDescriptor(ContentDescriptor.RAW));
boolean encodingOk=false;
for(int i=0; i < tracks.length; i++) {
     if(!encodingOk && tracks[i] instanceof FormatControl) {
     if( ( (FormatControl)tracks[i] ).setFormat(new AudioFormat(AudioFormat.GSM_RTP, 8000, 16, 1))==null )
     tracks.setEnabled(false);
     encodingOk = true;
     else
     tracks[i].setEnabled(false);
} //for
if(encodingOk) {
     p.realize();
     DataSource source = null;
     try { Thread.sleep(1000); } catch(InterruptedException e){}
     try {
     source = p.getDataOutput();
     } catch(NotRealizedError e) {
     System.out.println("*** ERROR: Cannot realize");
     //System.exit(-1);
     try {
     String url = "rtp://192.168.0.6:49150/audio/1";
     System.out.println(url);
     MediaLocator m = new MediaLocator(url);
     DataSink sink = Manager.createDataSink(source, m);
     sink.open();
     sink.start();
     } catch(Exception e) {
     System.out.println("*** ERROR: ");
     e.printStackTrace();
     System.exit(-1);
} // if
public static void main(String[] args) {
new Send();

Answer 1

Hello,
I tried to change the port number to 22222, 66666 and 49150. With the same effekt. I found out that when I run the program for the first time after a reboot I get these errors:
javax.media.NotConfiguredError: getTrackControls cannot be called before configured
at com.sun.media.ProcessEngine.getTrackControls(ProcessEngine.java:285)
at com.sun.media.MediaProcessor.getTrackControls(MediaProcessor.java:107)
at Send.<init>(Send.java:29)
at Send.main(Send.java:71)
Exception in thread "main" javax.media.NotConfiguredError: getTrackControls cannot be called before configured
at com.sun.media.ProcessEngine.getTrackControls(ProcessEngine.java:285)
at com.sun.media.MediaProcessor.getTrackControls(MediaProcessor.java:107)
at Send.<init>(Send.java:29)
at Send.main(Send.java:71)
I have to quit the program with Ctrl-c. The next time I run it I get the IOException as described above :( .
MfG
Michael