audiotransmit.java

The audioTransmit class is a simple wrapper that can be programmed to take audio input from a source

/*
 * @(#)AudioTransmit.java	1.7 01/03/13
 *
 * Copyright (c) 1999-2001 Sun Microsystems, Inc. All Rights Reserved.
 *
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 * 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
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 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
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 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
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import java.awt.*;
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 java.io.*;

public class AudioTransmit {

    // Input MediaLocator
    // Can be a file or http or capture source
    private MediaLocator locator;
    private String ipAddress;
    private String port;

    private Processor processor = null;
    private DataSink  rtptransmitter = null;
    private DataSource dataOutput = null;
    
    public AudioTransmit(MediaLocator locator,
			 String ipAddress,
			 String port) {
	
	this.locator = locator;
	this.ipAddress = ipAddress;
	this.port = port;
    }

    /**
     * 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 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;
		rtptransmitter.close();
		rtptransmitter = null;
	    }
	}
    }

    private String createProcessor() {
	if (locator == null)
	    return "Locator is null";

	DataSource ds;
	DataSource clone;

	try {
	    ds = Manager.createDataSource(locator);
	} catch (Exception e) {
	    return "Couldn't create DataSource";
	}

	// Try to create a processor to handle the input media locator
	try {
	    processor = 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";

	boolean programmed = false;
      AudioFormat afmt;

	// Search through the tracks for a Audio track
	for (int i = 0; i < tracks.length; i++) {
	    Format format = tracks[i].getFormat();
	    if (  tracks[i].isEnabled() &&
		  format instanceof AudioFormat &&
		  !programmed) {
		afmt = (AudioFormat)tracks[i].getFormat();
                       AudioFormat ulawFormat =   new AudioFormat(AudioFormat.DVI_RTP);
                                              // afmt.getSampleRate(), 
                                              // afmt.getSampleSizeInBits(),
                      // afmt.getChannels());
                       // 8000,4,1);
            
		tracks[i].setFormat (ulawFormat);
		System.err.println("Audio transmitted as:");
		System.err.println("  " + ulawFormat);
		// Assume succesful
		programmed = true;
	    } else
		tracks[i].setEnabled(false);
	}

	if (!programmed)
	    return "Couldn't find Audio track";

	// Set the output content descriptor to RAW_RTP
       ContentDescriptor cd = new ContentDescriptor(ContentDescriptor.RAW_RTP);
       processor.setContentDescriptor(cd);

	// Realize the processor. This will internally create a flow
	// graph and attempt to create an output datasource for ULAW/RTP
	// Audio frames.
	result = waitForState(processor, Controller.Realized);
	if (result == false)
	    return "Couldn't realize processor";

	
	// Get the output data source of the processor
	dataOutput = processor.getDataOutput();
	return null;
    }

    // Creates an RTP transmit data sink. This is the easiest way to create
    // an RTP transmitter. The other way is to use the RTPSessionManager API.
    // Using an RTP session manager gives you more control if you wish to
    // fine tune your transmission and set other parameters.
    private String createTransmitter() {
	// Create a media locator for the RTP data sink.
	// For example:
	//    rtp://129.130.131.132:42050/Audio
	String rtpURL = "rtp://" + ipAddress + ":" + port + "/audio";
	MediaLocator outputLocator = new MediaLocator(rtpURL);

	// Create a data sink, open it and start transmission. It will wait
	// for the processor to start sending data. So we need to start the
	// output data source of the processor. We also need to start the
	// processor itself, which is done after this method returns.
	try {
	    rtptransmitter = Manager.createDataSink(dataOutput, outputLocator);
	    rtptransmitter.open();
	    rtptransmitter.start();
	    dataOutput.start();
	} catch (MediaException me) {
	    return "Couldn't create RTP data sink";
	} catch (IOException ioe) {
	    return "Couldn't create RTP data sink";
	}
	
	return null;
    }


    /****************************************************************
     * 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 synchronized 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 AudioTransmit class
     ****************************************************************/
    
    public static void main(String [] args) {
	// We need three parameters to do the transmission
	// For example,
	//   java AudioTransmit file:/C:/media/test.mov  129.130.131.132 42050
	
	if (args.length < 3) {
	    System.err.println("Usage: AudioTransmit <sourceURL> <destIP> <destPort>");
	    System.exit(-1);
	}
	
	// Create a Audio transmit object with the specified params.
	AudioTransmit at = new AudioTransmit(new MediaLocator(args[0]),
					     args[1],
					     args[2]);
	// 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 AudioTransmit
	try {
	    Thread.currentThread().sleep(60000);
	} catch (InterruptedException ie) {
	}

	// Stop the transmission
	at.stop();

	System.err.println("...transmission ended.");
	
	System.exit(0);
    }
}