About transmitting audio by RTP

Question

Hi, there,
I want to create a simple application that transfers audio online through RTP. both the sender machine and receiver machine have public ip address. I tried JMStudio and AVTransmit2/AVReceiver2 without success till now! it drives me crazy. I really don't know what's wrong here. is there anyone really make it work?
even I can see the receiver machine keep receiving data through the port I specify to transfer data(the port is 22224), the JMStudio or AVReceiver2 on receiver machine just waiting for data, also I can see the statistic of JMStudio on sender machine reports transfer successful and the data keeping transferred. I also tried to use broadcast way, that is, changing the last part of sender's ip address to 255, still no luck! the receiver can't receive any data!
since I use Ubuntu, there is no firewall, no port is blocked. I can access from receiver to sender or vice versa using SSH. I don't think there is any connection problem, also I can see the receiver keeping receive data.
I transfer a mp3 file through RTP session. I installed mp3 plugin on both receiver machine and sender machine. I can play it using JMStudio on both receiver machine and sender machine locally.
could anyone kindly let me know how I should do, or if there is any very very simple java program to transfer anything using RTP on internet? could you please tell me your configuration if you happen to make it work?
any hint will great appreciate!
Sam

Answer 1

if you have a microphone in your pc, AVTranmit2 and AVReceive2 command should be:
on your own pc:
java AVTransmit2 dsound:// targetIP 42050
on target pc:
java AVReceive2 yourIP/42050
since the same port cannot be used simutaneously by two applications(avreceive2 and avtransmit2), the above command can only be used on two different pcs (your pc and target pc).
if you wanna execute AVReceive2 and AVTransmit2 on the same pc, you have to modify the source codes. I have done that.
commond
java AVTransmit2 dsound:// yourip 42050 42100
java AVReceive2 yourip/42050 yourip/42100
the modified source files are as follows:
/*****************AVReceive2.java**********************************/
* @(#)AVReceive2.java     1.3 01/03/13
* Copyright (c) 1999-2001 Sun Microsystems, Inc. All Rights Reserved.
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
import java.io.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
import java.util.Vector;
import javax.media.*;
import javax.media.rtp.*;
import javax.media.rtp.event.*;
import javax.media.rtp.rtcp.*;
import javax.media.protocol.*;
import javax.media.protocol.DataSource;
import javax.media.format.AudioFormat;
import javax.media.format.VideoFormat;
import javax.media.Format;
import javax.media.format.FormatChangeEvent;
import javax.media.control.BufferControl;
* AVReceive2 to receive RTP transmission using the new RTP API.
public class AVReceive2 implements ReceiveStreamListener, SessionListener,
     ControllerListener
String sessions[] = null;
RTPManager mgrs[] = null;
Vector playerWindows = null;
boolean dataReceived = false;
Object dataSync = new Object();
public AVReceive2(String sessions[]) {
     this.sessions = sessions;
protected boolean initialize() {
try {
     InetAddress ipAddr;
     SessionAddress localAddr = new SessionAddress();
     SessionAddress destAddr;
     mgrs = new RTPManager[sessions.length];
     playerWindows = new Vector();
     SessionLabel session;
     // Open the RTP sessions.
     for (int i = 0; i < sessions.length; i++) {
          // Parse the session addresses.
          try {
          session = new SessionLabel(sessions);
          } catch (IllegalArgumentException e) {
          System.err.println("Failed to parse the session address given: " + sessions[i]);
          return false;
          System.err.println(" - Open RTP session for: addr: " + session.addr + " port: " + session.port + " ttl: " + session.ttl);
          mgrs[i] = (RTPManager) RTPManager.newInstance();
          mgrs[i].addSessionListener(this);
          mgrs[i].addReceiveStreamListener(this);
          ipAddr = InetAddress.getByName(session.addr);
          if( ipAddr.isMulticastAddress()) {
          // local and remote address pairs are identical:
          localAddr= new SessionAddress( ipAddr,
                              session.port,
                              session.ttl);
          destAddr = new SessionAddress( ipAddr,
                              session.port,
                              session.ttl);
          } else {
          localAddr= new SessionAddress( InetAddress.getLocalHost(),
                    42100+2*i);
                         //session.port);
destAddr = new SessionAddress( ipAddr,
          42050+2*i);
          //session.port);
          mgrs[i].initialize( localAddr);
          // You can try out some other buffer size to see
          // if you can get better smoothness.
          BufferControl bc = (BufferControl)mgrs[i].getControl("javax.media.control.BufferControl");
          if (bc != null)
          bc.setBufferLength(350);
          mgrs[i].addTarget(destAddr);
} catch (Exception e){
System.err.println("Cannot create the RTP Session: " + e.getMessage());
return false;
     // Wait for data to arrive before moving on.
     long then = System.currentTimeMillis();
     long waitingPeriod = 30000; // wait for a maximum of 30 secs.
     try{
     synchronized (dataSync) {
          while (!dataReceived &&
               System.currentTimeMillis() - then < waitingPeriod) {
          if (!dataReceived)
               System.err.println(" - Waiting for RTP data to arrive...");
          dataSync.wait(1000);
     } catch (Exception e) {}
     if (!dataReceived) {
     System.err.println("No RTP data was received.");
     close();
     return false;
return true;
public boolean isDone() {
     return playerWindows.size() == 0;
* Close the players and the session managers.
protected void close() {
     for (int i = 0; i < playerWindows.size(); i++) {
     try {
          ((PlayerWindow)playerWindows.elementAt(i)).close();
     } catch (Exception e) {}
     playerWindows.removeAllElements();
     // close the RTP session.
     for (int i = 0; i < mgrs.length; i++) {
     if (mgrs[i] != null) {
mgrs[i].removeTargets( "Closing session from AVReceive2");
mgrs[i].dispose();
          mgrs[i] = null;
PlayerWindow find(Player p) {
     for (int i = 0; i < playerWindows.size(); i++) {
     PlayerWindow pw = (PlayerWindow)playerWindows.elementAt(i);
     if (pw.player == p)
          return pw;
     return null;
PlayerWindow find(ReceiveStream strm) {
     for (int i = 0; i < playerWindows.size(); i++) {
     PlayerWindow pw = (PlayerWindow)playerWindows.elementAt(i);
     if (pw.stream == strm)
          return pw;
     return null;
* SessionListener.
public synchronized void update(SessionEvent evt) {
     if (evt instanceof NewParticipantEvent) {
     Participant p = ((NewParticipantEvent)evt).getParticipant();
     System.err.println(" - A new participant had just joined: " + p.getCNAME());
* ReceiveStreamListener
public synchronized void update( ReceiveStreamEvent evt) {
     RTPManager mgr = (RTPManager)evt.getSource();
     Participant participant = evt.getParticipant();     // could be null.
     ReceiveStream stream = evt.getReceiveStream(); // could be null.
     if (evt instanceof RemotePayloadChangeEvent) {
     System.err.println(" - Received an RTP PayloadChangeEvent.");
     System.err.println("Sorry, cannot handle payload change.");
     System.exit(0);
     else if (evt instanceof NewReceiveStreamEvent) {
     try {
          stream = ((NewReceiveStreamEvent)evt).getReceiveStream();
          DataSource ds = stream.getDataSource();
          // Find out the formats.
          RTPControl ctl = (RTPControl)ds.getControl("javax.media.rtp.RTPControl");
          if (ctl != null){
          System.err.println(" - Recevied new RTP stream: " + ctl.getFormat());
          } else
          System.err.println(" - Recevied new RTP stream");
          if (participant == null)
          System.err.println(" The sender of this stream had yet to be identified.");
          else {
          System.err.println(" The stream comes from: " + participant.getCNAME());
          // create a player by passing datasource to the Media Manager
          Player p = javax.media.Manager.createPlayer(ds);
          if (p == null)
          return;
          p.addControllerListener(this);
          p.realize();
          PlayerWindow pw = new PlayerWindow(p, stream);
          playerWindows.addElement(pw);
          // Notify intialize() that a new stream had arrived.
          synchronized (dataSync) {
          dataReceived = true;
          dataSync.notifyAll();
     } catch (Exception e) {
          System.err.println("NewReceiveStreamEvent exception " + e.getMessage());
          return;
     else if (evt instanceof StreamMappedEvent) {
     if (stream != null && stream.getDataSource() != null) {
          DataSource ds = stream.getDataSource();
          // Find out the formats.
          RTPControl ctl = (RTPControl)ds.getControl("javax.media.rtp.RTPControl");
          System.err.println(" - The previously unidentified stream ");
          if (ctl != null)
          System.err.println(" " + ctl.getFormat());
          System.err.println(" had now been identified as sent by: " + participant.getCNAME());
     else if (evt instanceof ByeEvent) {
     System.err.println(" - Got \"bye\" from: " + participant.getCNAME());
     PlayerWindow pw = find(stream);
     if (pw != null) {
          pw.close();
          playerWindows.removeElement(pw);
* ControllerListener for the Players.
public synchronized void controllerUpdate(ControllerEvent ce) {
     Player p = (Player)ce.getSourceController();
     if (p == null)
     return;
     // Get this when the internal players are realized.
     if (ce instanceof RealizeCompleteEvent) {
     PlayerWindow pw = find(p);
     if (pw == null) {
          // Some strange happened.
          System.err.println("Internal error!");
          System.exit(-1);
     pw.initialize();
     pw.setVisible(true);
     p.start();
     if (ce instanceof ControllerErrorEvent) {
     p.removeControllerListener(this);
     PlayerWindow pw = find(p);
     if (pw != null) {
          pw.close();     
          playerWindows.removeElement(pw);
     System.err.println("AVReceive2 internal error: " + ce);
* A utility class to parse the session addresses.
class SessionLabel {
     public String addr = null;
     public int port;
     public int ttl = 1;
     SessionLabel(String session) throws IllegalArgumentException {
     int off;
     String portStr = null, ttlStr = null;
     if (session != null && session.length() > 0) {
          while (session.length() > 1 && session.charAt(0) == '/')
          session = session.substring(1);
          // Now see if there's a addr specified.
          off = session.indexOf('/');
          if (off == -1) {
          if (!session.equals(""))
               addr = session;
          } else {
          addr = session.substring(0, off);
          session = session.substring(off + 1);
          // Now see if there's a port specified
          off = session.indexOf('/');
          if (off == -1) {
               if (!session.equals(""))
               portStr = session;
          } else {
               portStr = session.substring(0, off);
               session = session.substring(off + 1);
               // Now see if there's a ttl specified
               off = session.indexOf('/');
               if (off == -1) {
               if (!session.equals(""))
                    ttlStr = session;
               } else {
               ttlStr = session.substring(0, off);
     if (addr == null)
          throw new IllegalArgumentException();
     if (portStr != null) {
          try {
          Integer integer = Integer.valueOf(portStr);
          if (integer != null)
               port = integer.intValue();
          } catch (Throwable t) {
          throw new IllegalArgumentException();
     } else
          throw new IllegalArgumentException();
     if (ttlStr != null) {
          try {
          Integer integer = Integer.valueOf(ttlStr);
          if (integer != null)
               ttl = integer.intValue();
          } catch (Throwable t) {
          throw new IllegalArgumentException();
* GUI classes for the Player.
class PlayerWindow extends Frame {
     Player player;
     ReceiveStream stream;
     PlayerWindow(Player p, ReceiveStream strm) {
     player = p;
     stream = strm;
     public void initialize() {
     add(new PlayerPanel(player));
     public void close() {
     player.close();
     setVisible(false);
     dispose();
     public void addNotify() {
     super.addNotify();
     pack();
* GUI classes for the Player.
class PlayerPanel extends Panel {
     Component vc, cc;
     PlayerPanel(Player p) {
     setLayout(new BorderLayout());
     if ((vc = p.getVisualComponent()) != null)
          add("Center", vc);
     if ((cc = p.getControlPanelComponent()) != null)
          add("South", cc);
     public Dimension getPreferredSize() {
     int w = 0, h = 0;
     if (vc != null) {
          Dimension size = vc.getPreferredSize();
          w = size.width;
          h = size.height;
     if (cc != null) {
          Dimension size = cc.getPreferredSize();
          if (w == 0)
          w = size.width;
          h += size.height;
     if (w < 160)
          w = 160;
     return new Dimension(w, h);
public static void main(String argv[]) {
     if (argv.length == 0)
     prUsage();
     AVReceive2 avReceive = new AVReceive2(argv);
     if (!avReceive.initialize()) {
     System.err.println("Failed to initialize the sessions.");
     System.exit(-1);
     // Check to see if AVReceive2 is done.
     try {
     while (!avReceive.isDone())
          Thread.sleep(1000);
     } catch (Exception e) {}
     System.err.println("Exiting AVReceive2");
static void prUsage() {
     System.err.println("Usage: AVReceive2 <session> <session> ...");
     System.err.println(" <session>: <address>/<port>/<ttl>");
     System.exit(0);
}// end of AVReceive2
/****************************AVTransmit2.java****************************/
* @(#)AVTransmit2.java     1.4 01/03/13
* Copyright (c) 1999-2001 Sun Microsystems, Inc. All Rights Reserved.
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
import java.awt.*;
import java.io.*;
import java.net.InetAddress;
import javax.media.*;
import javax.media.protocol.*;
import javax.media.protocol.DataSource;
import javax.media.format.*;
import javax.media.control.TrackControl;
import javax.media.control.QualityControl;
import javax.media.rtp.*;
import javax.media.rtp.rtcp.*;
import com.sun.media.rtp.*;
public class AVTransmit2 {
// Input MediaLocator
// Can be a file or http or capture source
private MediaLocator locator;
private String ipAddress;
// private int portBase;
     private int localPortBase;
     private int remotePortBase;
private Processor processor = null;
private RTPManager rtpMgrs[];
private DataSource dataOutput = null;
public AVTransmit2(MediaLocator locator,
               String ipAddress,
               String localPB,
               String remotePB,
               Format format) {
Integer int1 = Integer.valueOf(remotePB);
if(int1 != null)
     this.remotePortBase = int1.intValue();
     this.locator = locator;
     this.ipAddress = ipAddress;
     Integer int2 = Integer.valueOf(localPB);
     if (int2 != null)
     this.localPortBase = int2.intValue();
* Starts the transmission. Returns null if transmission started ok.
* Otherwise it returns a string with the reason why the setup failed.
public synchronized String start() {
     String result;
     // Create a processor for the specified media locator
     // and program it to output JPEG/RTP
     result = createProcessor();
     if (result != null)
     return result;
     // Create an RTP session to transmit the output of the
     // processor to the specified IP address and port no.
     result = createTransmitter();
     if (result != null) {
     processor.close();
     processor = null;
     return result;
     // Start the transmission
     processor.start();
     return null;
* Stops the transmission if already started
public void stop() {
     synchronized (this) {
     if (processor != null) {
          processor.stop();
          processor.close();
          processor = null;
          for (int i = 0; i < rtpMgrs.length; i++) {
          rtpMgrs[i].removeTargets( "Session ended.");
          rtpMgrs[i].dispose();
private String createProcessor() {
     if (locator == null)
     return "Locator is null";
     DataSource ds;
     DataSource clone;
     try {
     ds = javax.media.Manager.createDataSource(locator);
     } catch (Exception e) {
     return "Couldn't create DataSource";
     // Try to create a processor to handle the input media locator
     try {
     processor = javax.media.Manager.createProcessor(ds);
     } catch (NoProcessorException npe) {
     return "Couldn't create processor";
     } catch (IOException ioe) {
     return "IOException creating processor";
     // Wait for it to configure
     boolean result = waitForState(processor, Processor.Configured);
     if (result == false)
     return "Couldn't configure processor";
     // Get the tracks from the processor
     TrackControl [] tracks = processor.getTrackControls();
     // Do we have atleast one track?
     if (tracks == null || tracks.length < 1)
     return "Couldn't find tracks in processor";
     // Set the output content descriptor to RAW_RTP
     // This will limit the supported formats reported from
     // Track.getSupportedFormats to only valid RTP formats.
     ContentDescriptor cd = new ContentDescriptor(ContentDescriptor.RAW_RTP);
     processor.setContentDescriptor(cd);
     Format supported[];
     Format chosen;
     boolean atLeastOneTrack = false;
     // Program the tracks.
     for (int i = 0; i < tracks.length; i++) {
     Format format = tracks[i].getFormat();
     if (tracks[i].isEnabled()) {
          supported = tracks[i].getSupportedFormats();
          // We've set the output content to the RAW_RTP.
          // So all the supported formats should work with RTP.
          // We'll just pick the first one.
          if (supported.length > 0) {
          if (supported[0] instanceof VideoFormat) {
               // For video formats, we should double check the
               // sizes since not all formats work in all sizes.
               chosen = checkForVideoSizes(tracks[i].getFormat(),
                                   supported[0]);//select the first supported format for convenice
          } else
               chosen = supported[0];
          tracks[i].setFormat(chosen);
          System.err.println("Track " + i + " is set to transmit as:");
          System.err.println(" " + chosen);
          atLeastOneTrack = true;
          } else
          tracks[i].setEnabled(false);
     } else
          tracks[i].setEnabled(false);
     if (!atLeastOneTrack)
     return "Couldn't set any of the tracks to a valid RTP format";
     // Realize the processor. This will internally create a flow
     // graph and attempt to create an output datasource for JPEG/RTP
     // audio frames.
     result = waitForState(processor, Controller.Realized);
     if (result == false)
     return "Couldn't realize processor";
     // Set the JPEG quality to .5.
     setJPEGQuality(processor, 0.5f);//no effect if not JPEG format
     // Get the output data source of the processor
     dataOutput = processor.getDataOutput();
     return null;
* Use the RTPManager API to create sessions for each media
* track of the processor.
private String createTransmitter() {
     // Cheated. Should have checked the type.
     PushBufferDataSource pbds = (PushBufferDataSource)dataOutput;
     PushBufferStream pbss[] = pbds.getStreams();
     rtpMgrs = new RTPManager[pbss.length];
     SessionAddress localAddr, destAddr;
     InetAddress ipAddr;
     SendStream sendStream;
     int localPort;
     int remotePort;
     SourceDescription srcDesList[];
     for (int i = 0; i < pbss.length; i++) {
     try {
          rtpMgrs[i] = RTPManager.newInstance();     
          // The local session address will be created on the
          // same port as the the target port. This is necessary
          // if you use AVTransmit2 in conjunction with JMStudio.
          // JMStudio assumes - in a unicast session - that the
          // transmitter transmits from the same port it is receiving
          // on and sends RTCP Receiver Reports back to this port of
          // the transmitting host.
          localPort = localPortBase + 2*i;
          remotePort = remotePortBase + 2*i;
          ipAddr = InetAddress.getByName(ipAddress);
          localAddr = new SessionAddress( InetAddress.getLocalHost(),
                              localPort);
          destAddr = new SessionAddress( ipAddr, remotePort);
          rtpMgrs[i].initialize( localAddr);
          rtpMgrs[i].addTarget( destAddr);
          System.err.println( "Created RTP session ("+pbss[i].getFormat().getClass() + "):"+localAddr.getControlHostAddress()
                    +":"+localAddr.getDataPort()+"->"+destAddr.getControlHostAddress()+":"+ destAddr.getDataPort());
          sendStream = rtpMgrs[i].createSendStream(dataOutput, i);     
          sendStream.start();
     } catch (Exception e) {
          return e.getMessage();
     return null;
* For JPEG and H263, we know that they only work for particular
* sizes. So we'll perform extra checking here to make sure they
* are of the right sizes.
Format checkForVideoSizes(Format original, Format supported) {
     int width, height;
     Dimension size = ((VideoFormat)original).getSize();
     Format jpegFmt = new Format(VideoFormat.JPEG_RTP);
     Format h263Fmt = new Format(VideoFormat.H263_RTP);
     if (supported.matches(jpegFmt)) {
     // For JPEG, make sure width and height are divisible by 8.
     width = (size.width % 8 == 0 ? size.width :
                    (int)(size.width / 8) * 8);
     height = (size.height % 8 == 0 ? size.height :
                    (int)(size.height / 8) * 8);
     } else if (supported.matches(h263Fmt)) {
     // For H.263, we only support some specific sizes.
     if (size.width < 128) {
          width = 128;
          height = 96;
     } else if (size.width < 176) {
          width = 176;
          height = 144;
     } else {
          width = 352;
          height = 288;
     } else {
     // We don't know this particular format. We'll just
     // leave it alone then.
     return supported;
     return (new VideoFormat(null,
                    new Dimension(width, height),
                    Format.NOT_SPECIFIED,
                    null,
                    Format.NOT_SPECIFIED)).intersects(supported);
* Setting the encoding quality to the specified value on the JPEG encoder.
* 0.5 is a good default.
void setJPEGQuality(Player p, float val) {
     Control cs[] = p.getControls();
     QualityControl qc = null;
     VideoFormat jpegFmt = new VideoFormat(VideoFormat.JPEG);
     // Loop through the controls to find the Quality control for
     // the JPEG encoder.
     for (int i = 0; i < cs.length; i++) {
     if (cs[i] instanceof QualityControl &&
          cs[i] instanceof Owned) {
          Object owner = ((Owned)cs[i]).getOwner();
          // Check to see if the owner is a Codec.
          // Then check for the output format.
          if (owner instanceof Codec) {
          Format fmts[] = ((Codec)owner).getSupportedOutputFormats(null);
          for (int j = 0; j < fmts.length; j++) {
               if (fmts[j].matches(jpegFmt)) {
               qc = (QualityControl)cs[i];
               qc.setQuality(val);
               System.err.println("- Setting quality to " +
                         val + " on " + qc);
               break;
          if (qc != null)
          break;
* Convenience methods to handle processor's state changes.
private Integer stateLock = new Integer(0);
private boolean failed = false;
Integer getStateLock() {
     return stateLock;
void setFailed() {
     failed = true;
private boolean waitForState(Processor p, int state) {
     p.addControllerListener(new StateListener());
     failed = false;
     // Call the required method on the processor
     if (state == Processor.Configured) {
     p.configure();
     } else if (state == Processor.Realized) {
     p.realize();
     // Wait until we get an event that confirms the
     // success of the method, or a failure event.
     // See StateListener inner class
     while (p.getState() < state && !failed) {
     synchronized (getStateLock()) {
          try {
          getStateLock().wait();
          } catch (InterruptedException ie) {
          return false;
     if (failed)
     return false;
     else
     return true;
* Inner Classes
class StateListener implements ControllerListener {
     public void controllerUpdate(ControllerEvent ce) {
     // If there was an error during configure or
     // realize, the processor will be closed
     if (ce instanceof ControllerClosedEvent)
          setFailed();
     // All controller events, send a notification
     // to the waiting thread in waitForState method.
     if (ce instanceof ControllerEvent) {
          synchronized (getStateLock()) {
          getStateLock().notifyAll();
* Sample Usage for AVTransmit2 class
public static void main(String [] args) {
     // We need three parameters to do the transmission
     // For example,
     // java AVTransmit2 file:/C:/media/test.mov 129.130.131.132 42050
     if (args.length < 3) {
     prUsage();
     Format fmt = null;
     int i = 0;
     MediaLocator ml = new MediaLocator(args[i]);
     // Create a audio transmit object with the specified params.
     AVTransmit2 at = new AVTransmit2(ml,
                         args[i+1], args[i+2], args[i+3], fmt);
     // Start the transmission
     String result = at.start();
     // result will be non-null if there was an error. The return
     // value is a String describing the possible error. Print it.
     if (result != null) {
     System.err.println("Error : " + result);
     System.exit(0);
     System.err.println("Start transmission for 60 seconds...");
     // Transmit for 60 seconds and then close the processor
     // This is a safeguard when using a capture data source
     // so that the capture device will be properly released
     // before quitting.
     // The right thing to do would be to have a GUI with a
     // "Stop" button that would call stop on AVTransmit2
     try {
     Thread.currentThread().sleep(60000);
     } catch (InterruptedException ie) {
     // Stop the transmission
     at.stop();
     System.err.println("...transmission ended.");
     System.exit(0);
static void prUsage() {
     System.err.println("Usage: AVTransmit2 <sourceURL> <destIP> <destPortBase>");
     System.err.println(" <sourceURL>: input URL or file name");
     System.err.println(" <destIP>: multicast, broadcast or unicast IP address for the transmission");
     System.err.println(" <destPortBase>: network port numbers for the transmission.");
     System.err.println(" The first track will use the destPortBase.");
     System.err.println(" The next track will use destPortBase + 2 and so on.\n");
     System.exit(0);
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