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Playing Media with Java Media Components

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Date: Feb 27, 2009

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Recognizing media's importance to the Web, Sun Microsystems announced the Java Media Components project, which had the goal of providing basic media playback support for JavaFX applications. In this introduction to JMC, Jeff Friesen presents a basic media player and drills down into JMC to create experimental media players that show you how to introduce a custom control panel and brand each frame of a playing video. Jeff closes by introducing an advanced media player with a slick-looking and dynamic control panel.

Playing Media with Java Media Components

Recognizing media's importance to the Web, Sun Microsystems announced the Java Media Components project at its 2007 JavaOne conference. The initial goal of this successor to the stagnant Java Media Framework project was to provide basic media playback support for JavaFX applications. A future goal is to support video capture. (For a backgrounder on Java Media Components, check out former Sun employee Chet Haase's Media Frenzy blog post.)

Although Java Media Components provides the foundation for the JavaFX media classes, you can also use this technology with Swing applications, and that is the focus of this article.

You'll first learn how to obtain JMC for your Windows, Mac OS X, or Linux platform. You'll next explore a simple Swing-based media player that provides a brief introduction to the JMC Playback API.

After touring this API in greater depth, you'll explore an advanced version of the basic media player that incorporates a more interesting user interface.

Get the JMC Distribution

The easiest way to obtain JMC for the Mac OS X or Windows platform is to download and install either the NetBeans IDE 6.5 for JavaFX 1.0 or JavaFX 1.0 SDK product from javafx.com. For example, I downloaded and ran the JavaFX 1.0 SDK product's javafx_sdk-1_0-windows-i586.exe installer on my Windows XP SP3 platform.

I kept all the installation defaults except for ignoring Java SE 6 Update 11 in favor of my currently installed Java SE 6 Update 7, which is the minimum Java version required by the JavaFX SDK.

After the install, I discovered that all the JMC files, including the two crucial files listed below, are located in the c:\Program Files\JavaFX\javafx-sdk1.0\lib\desktop directory:

Additionally, this directory contains msvcp71.dll and msvcr71.dll, which are required by JMC, and which might also be present in your c:\windows\system32 (or equivalent) directory. It also contains on2_decoder.dll, which is needed to play FXM-based media—FXM is JavaFX's native video file format.

Regardless of the directory (such as c:\Program Files\JavaFX\javafx-sdk1.0\lib\desktop) that contains jmc.jar and the other required JMC files, you'll need to add jmc.jar to your classpath when compiling/running this article's example media players.

You'll also need to specify -Djava.library.path with this directory's path when running these examples.

Play Media with a Basic Media Player

The jmc.jar archive organizes its many classes into several packages. You only need to work with the com.sun.media.jmc.JMediaPlayer class, and then only with one of this class's constructors, if you want to create a basic media player that provides its own control panel. Listing 1 presents an example of a basic media player that's based on JMediaPlayer.

Listing 1 BMP.java

// BMP (Basic Media Player).java

import java.awt.EventQueue;

import java.net.URI;

import javax.swing.JFrame;

import com.sun.media.jmc.JMediaPlayer;

public class BMP extends JFrame
{
  public BMP (String mediaURI)
  {
   super ("BMP: "+mediaURI);
   setDefaultCloseOperation (EXIT_ON_CLOSE);

   JMediaPlayer mp = null;
   try
   {
     mp = new JMediaPlayer (new URI (mediaURI));
   }
   catch (Exception e)
   {
     System.out.println ("Error opening media: "+e.toString ());
     System.exit (1);
   }

   setContentPane (mp);

   pack ();
   setVisible (true);
  }

  public static void main (final String [] args)
  {
   if (args.length != 1)
   {
     System.err.println ("usage: java BMP mediaURI");
     return;
   }

   Runnable r = new Runnable ()
          {
            public void run ()
            {
             new BMP (args [0]);
            }
          };
   EventQueue.invokeLater (r);
  }
}

BMP.java uses the public JMediaPlayer(URI uri) constructor to create a media player that plays media content identified by uri. If the content is unavailable, this constructor throws a com.sun.media.jmc.MediaUnavailableException object.

If the uniform resource identifier's syntax is bad, the java.net.URI constructor throws a java.net.URISyntaxException object.

Assuming that the current directory contains BMP.java and that JavaFX 1.0 SDK has been installed to the default directory on a Windows platform, the following command line compiles this file's source code:

javac -cp "c:\Program Files\JavaFX\javafx-sdk1.0\lib\desktop\jmc.jar" BMP.java

The following command line (split across multiple lines for readability) runs the resulting basic media player application, which presents a media window and a control panel of media player controls below this window:

java -cp "c:\Program Files\JavaFX\javafx-sdk1.0\lib\desktop\jmc.jar";. 
     -Djava.library.path="c:\Program Files\JavaFX\javafx-sdk1.0\lib\desktop" 
     BMP 
     http://sun.edgeboss.net/download/sun/media/1460825906/1460825906_
3864559001_09b01828-11-500.flv

Figure 1 shows a single frame of the Flash video that's being played.

Figure 01

Figure 1 Watching the JavaFX 1.0 launch video on the basic media player

The control panel presents various controls that, from left to right, let you restart the media, seek backward in the media, play/pause the media, seek forward in the media, seek to the end of the media, auto-repeat the media after it finishes playing, adjust the volume via the slider, and mute the audio.

I've found that seek-backward and seek-forward don't work properly, and seek-to-the-end isn't even implemented.

Tour the JMC Playback API

The default control panel provided by JMediaPlayer is mostly useful, but doesn't have the classy look that's associated with Web-based media players.

Fortunately, you don't need to stick with this control panel—you can create a media player with a control panel that looks much slicker and provides more capabilities. Before you can do this, however, you need to understand JMC's Playback API.

We'll start our API tour with JMediaPlayer, which subclasses javax.swing.JComponent. Along with the aforementioned constructor, JMediaPlayer offers the following constructor and methods:

JMediaPlayer is largely a wrapper for com.sun.media.jmc.JMediaPane, another subclass of JComponent. JMediaPane provides media playback without also providing user interface controls.

This class offers the following constructors and methods:

Because I noticed that the addNotificationTime() method appears to always throw a com.sun.media.jmc.OperationUnsupportedException object, it doesn't seem possible to take advantage of notification times, which could have led to all sorts of interesting scenarios (synchronizing a window of advertisements to a playing video, for example).

We can take advantage of JMediaPane and some of its methods to create a media player with a custom control panel, which presents information not accessible via JMediaPlayer.

For example, our custom control panel can let users choose whether or not to preserve the media's aspect ratio when the player's window is resized, and also display the media's duration. Check out Listing 2.

Listing 2 XMP1.java

// XMP1 (eXperimental Media Player #1).java

import java.awt.BorderLayout;
import java.awt.EventQueue;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.net.URI;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import com.sun.media.jmc.JMediaPane;

public class XMP1 extends JFrame
{
  JMediaPane mp;

  public XMP1 (String mediaURI)
  {
   super ("XMP1: "+mediaURI);
   setDefaultCloseOperation (EXIT_ON_CLOSE);

   try
   {
     mp = new JMediaPane (new URI (mediaURI));
   }
   catch (Exception e)
   {
     System.out.println ("Error opening media: "+e.toString ());
     System.exit (1);
   }

   JPanel panel = new JPanel ();
   panel.setLayout (new BorderLayout ());
   panel.add (mp, BorderLayout.CENTER);
   panel.add (createControlPanel (), BorderLayout.SOUTH);

   setContentPane (panel);

   pack ();
   setVisible (true);
  }

  public JPanel createControlPanel ()
  {
   JPanel panel = new JPanel ();

   JButton btnPlay = new JButton ("Play");
   ActionListener alPlay = new ActionListener ()
               {
                 public void actionPerformed (ActionEvent ae)
                 {
                   mp.play ();
                 }
               };
   btnPlay.addActionListener (alPlay);
   panel.add (btnPlay);

   JButton btnPause = new JButton ("Pause");
   ActionListener alPause = new ActionListener ()
                {
                  public void actionPerformed (ActionEvent ae)
                  {
                   mp.pause ();
                  }
                };
   btnPause.addActionListener (alPause);
   panel.add (btnPause);

   JButton btnStop = new JButton ("Stop");
   ActionListener alStop = new ActionListener ()
               {
                 public void actionPerformed (ActionEvent ae)
                 {
                   mp.stop ();
                 }
               };
   btnStop.addActionListener (alStop);
   panel.add (btnStop);

   JCheckBox cbPAR = new JCheckBox ("Preserve Aspect Ratio", true);
   ChangeListener clPAR = new ChangeListener ()
               {
                 public void stateChanged (ChangeEvent ce)
                 {
                  JCheckBox cb;
                  cb = (JCheckBox) ce.getSource ();
                  mp.setPreserveAspectRatio (cb.isSelected ());
                 }
               };
   cbPAR.addChangeListener (clPAR);
   panel.add (cbPAR);

   panel.add (new JLabel ("Duration: "+mp.getDuration ()));

   return panel;
  }

  public static void main (final String [] args)
  {
   if (args.length != 1)
   {
     System.err.println ("usage: java XMP1 mediaURI");
     return;
   }

   Runnable r = new Runnable ()
          {
            public void run ()
            {
             new XMP1 (args [0]);
            }
          };
   EventQueue.invokeLater (r);
  }
}

Compile and run this experimental media player application via commands that are similar to those shown earlier.

Figure 2 shows the resulting media player's user interface.

Figure 2

Figure 2 In addition to letting you play, pause, and stop media, this custom control panel lets you determine whether the media's aspect ratio is preserved during a window resize, and reports the media's duration (in seconds).

JMediaPane internally works with the com.sun.media.jmc.MediaProvider class, which is a low-level media player control that provides access to the various controls responsible for rendering the media.

This class offers the following constructors and methods:

To create a more interesting and useful media player, you need to become familiar with the Playback API's control classes.

Although you've just encountered one such class, MediaProvider, this API also provides the following control classes: AudioControl, TrackControl, VideoControl, and VideoRenderControl.

I built an experimental media player that showcases MediaProvider, AudioControl, and VideoRenderControl. AudioControl is used to mute/unmute audio playback— audio is not MediaProvider's responsibility. VideoRenderControl is needed to render an overlay (content appearing over other content), as illustrated in Figure 3.

Figure 3

Figure 3 Each video frame is overlaid with my javajeff.mb.ca brand in its upper-left corner.

The media player (see Listing 3 for its source code) creates a television-like branding effect, in which a station logo appears near the screen's lower-right corner, via an overlay. However, the overlay is located near each video frame's upper-left corner.

Antialiasing makes the foreground text look sharp; different opacities for the background rectangle and the foreground text allow each video frame to show through.

Listing 3 XMP2.java

// XMP2 (eXperimental Media Player #2).java

import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.awt.geom.Rectangle2D;

import java.net.URI;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import com.sun.media.jmc.MediaProvider;

import com.sun.media.jmc.control.AudioControl;
import com.sun.media.jmc.control.VideoRenderControl;

import com.sun.media.jmc.event.VideoRendererEvent;
import com.sun.media.jmc.event.VideoRendererListener;

public class XMP2 extends JFrame
{
  MediaProvider mp;

  public XMP2 (String mediaURI)
  {
   super ("XMP2: "+mediaURI);
   setDefaultCloseOperation (EXIT_ON_CLOSE);

   try
   {
     mp = new MediaProvider (new URI (mediaURI));
   }
   catch (Exception e)
   {
     System.out.println ("Error opening media: "+e.toString ());
     System.exit (1);
   }

   JPanel panel = new JPanel ();
   panel.setLayout (new BorderLayout ());
   panel.add (new MediaPanel (mp), BorderLayout.CENTER);
   panel.add (createControlPanel (), BorderLayout.SOUTH);

   setContentPane (panel);

   pack ();
   setVisible (true);
  }

  public JPanel createControlPanel ()
  {
   JPanel panel = new JPanel ();

   JButton btnPlay = new JButton ("Play");
   ActionListener alPlay = new ActionListener ()
               {
                 public void actionPerformed (ActionEvent ae)
                 {
                   mp.play ();
                 }
               };
   btnPlay.addActionListener (alPlay);
   panel.add (btnPlay);

   JButton btnPause = new JButton ("Pause");
   ActionListener alPause = new ActionListener ()
                {
                  public void actionPerformed (ActionEvent ae)
                  {
                   mp.pause ();
                  }
                };
   btnPause.addActionListener (alPause);
   panel.add (btnPause);

   JButton btnStop = new JButton ("Stop");
   ActionListener alStop = new ActionListener ()
               {
                 public void actionPerformed (ActionEvent ae)
                 {
                   mp.pause ();
                   mp.setMediaTime (0.0);
                 }
               };
   btnStop.addActionListener (alStop);
   panel.add (btnStop);

   JCheckBox cbMute = new JCheckBox ("Mute");
   ChangeListener clMute = new ChangeListener ()
               {
                 public void stateChanged (ChangeEvent ce)
                 {
                   JCheckBox cb;
                   cb = (JCheckBox) ce.getSource ();
                   AudioControl ac;
                   ac = mp.getControl (AudioControl.class);
                   ac.setMute (cb.isSelected ());
                 }
               };
   cbMute.addChangeListener (clMute);
   panel.add (cbMute);

   panel.add (new JLabel ("Duration: "+mp.getDuration ()));

   return panel;
  }

  public static void main (final String [] args)
  {
   if (args.length != 1)
   {
     System.err.println ("usage: java XMP2 mediaURI");
     return;
   }

   Runnable r = new Runnable ()
          {
            public void run ()
            {
             new XMP2 (args [0]);
            }
          };
   EventQueue.invokeLater (r);
  }
}

class MediaPanel extends JPanel
{
  private AlphaComposite ac1 =
   AlphaComposite.getInstance (AlphaComposite.SRC_OVER, 0.1f);

  private AlphaComposite ac2 =
   AlphaComposite.getInstance (AlphaComposite.SRC_OVER, 0.3f);

  private Dimension frameSize;

  private Font font = new Font ("Arial", Font.BOLD, 16);

  private Rectangle frame = new Rectangle (0, 0, 0, 0);

  private Rectangle2D r2d = new Rectangle2D.Double (0.0, 0.0, 0.0, 0.0);

  private VideoRenderControl vrc;

  MediaPanel (MediaProvider mp)
  {
   vrc = mp.getControl (VideoRenderControl.class);
   if (vrc == null)
   {
     System.err.println ("no video renderer control");
     System.exit (-1);
   }
   frameSize = vrc.getFrameSize ();
   VideoRendererListener vrl;
   vrl = new VideoRendererListener ()
      {
        public void videoFrameUpdated (VideoRendererEvent vre)
        {
          repaint ();
        }
      };
   vrc.addVideoRendererListener (vrl);
   setPreferredSize (new Dimension (frameSize.width/2, frameSize.height/2));
  }

  protected void paintComponent (Graphics g)
  {
   frame.width = getWidth ();
   frame.height = getHeight ();
   vrc.paintVideoFrame (g, frame);

   double ar1 = frame.width/(double) frameSize.width;
   double ar2 = frame.height/(double) frameSize.height;

   double x, y;

   if (ar1 < ar2)
   {
     x = (frame.width-frameSize.width*ar1)/2+10.0;
     y = (frame.height-frameSize.height*ar1)/2+10.0;
   }
   else
   {
     x = (frame.width-frameSize.width*ar2)/2+10.0;
     y = (frame.height-frameSize.height*ar2)/2+10.0;
   }
   
   Graphics2D g2d = (Graphics2D) g;
   g2d.setRenderingHint (RenderingHints.KEY_ANTIALIASING,
              RenderingHints.VALUE_ANTIALIAS_ON);
   g2d.setComposite (ac1);
   g2d.setPaint (Color.black);
   r2d.setFrame (x, y, 125.0, 50.0);
   g2d.fill (r2d);
   g2d.setComposite (ac2);
   g2d.setFont (font);
   g2d.setPaint (Color.yellow);
   g2d.drawString ("javajeff.mb.ca", (int) x+10, (int) y+30);
  }
}

Unlike JMediaPlayer and JMediaPane, MediaProvider isn't a component. As a result, Listing 3 declares a MediaPanel instance that will serve as the Swing component on which video frames are rendered.

This class's constructor is passed a MediaProvider instance so that a VideoRenderControl instance can be obtained.

The VideoRenderControl instance is obtained via a call to MediaProvider's getControl() method. A com.sun.media.jmc.event.VideoRendererListener is registered with this control so that it will repaint the MediaPanel component each time the videoFrameUpdated() method is invoked.

The repaint() method call within videoFrameUpdated() triggers a request to Swing to invoke MediaPanel's paintComponent() method.

This method first invokes VideoRenderControl's public abstract void paintVideoFrame(Graphics g, Rectangle rect) method to render the video frame. It then renders the previously discussed overlay.

The paintComponent() method has the potential to be called extremely often—more than 100,000 times for a 30-frame-per-second/60-minute video.

If it creates even one object, we'll probably end up with a huge number of objects in the heap.

This could result in garbage collection activity that disrupts playback. To reduce this possibility, paintComponent() reuses objects (such as frame).

There is another point of interest within paintComponent()— specifically, the calculation of the overlay's upper-left corner coordinates.

Because each video frame will be rendered at the correct aspect ratio and in the center of the media panel, it's necessary to calculate the actual video frame size and media panel aspect ratios (width/height) and use them in calculations that help determine the proper coordinates.

There are two more items to consider. First, stopping a media stream requires calls to pause() followed by setMediaTime() with a 0.0 argument because MediaProvider doesn't provide a stop() method.

Second, muting the audio requires an AudioControl instance because MediaProvider doesn't provide a setMute() method.

The Playback API contains many more classes and interfaces to explore. For example, the com.sun.media.jmc.JMediaView class describes yet another Swing component for integrating a media player into a Swing GUI.

However, our exploration of the Playback API has come to an end for reasons of brevity and also because I've presented sufficient material for use in constructing an advanced media player.

Play Media with an Advanced Media Player

Modern media players feature slick-looking and dynamic control panels. For example, they often employ opacity, gradients, and reflections to make their control panels look high tech.

Also, it's common for a control panel to fade into view over the media whenever the mouse pointer enters the player window and disappear when the mouse pointer exits this window.

Take a look at Figure 4.

Figure 4

Figure 4 You can play/pause the media and observe its progress.

The control panel, which fades into view whenever the mouse enters the window, consists of a play/pause button and a progress bar.

A timer performs the fade by repeatedly adjusting the opacity and painting these controls. As the media plays, a blue-to-cyan gradient is painted to show that portion of the media that's already played—the progress bar's black area indicates the portion of the media that's yet to play.

Check out Listing 4 to explore this media player's source code.

Listing 4 AMP.java

// AMP (Advanced Media Player).java

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import java.awt.geom.GeneralPath;
import java.awt.geom.Rectangle2D;

import java.net.URI;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

import com.sun.media.jmc.MediaProvider;

import com.sun.media.jmc.control.VideoRenderControl;

import com.sun.media.jmc.event.VideoRendererEvent;
import com.sun.media.jmc.event.VideoRendererListener;

public class AMP extends JFrame
{
  MediaProvider mp;

  public AMP (String mediaURI)
  {
   super ("AMP: "+mediaURI);
   setDefaultCloseOperation (EXIT_ON_CLOSE);

   try
   {
     mp = new MediaProvider (new URI (mediaURI));
   }
   catch (Exception e)
   {
     System.out.println ("Error opening media: "+e.toString ());
     System.exit (1);
   }

   setContentPane (new MediaPanel (mp));

   pack ();
   setVisible (true);
  }

  public static void main (final String [] args)
  {
   if (args.length != 1)
   {
     System.err.println ("usage: java AMP mediaURI");
     return;
   }

   Runnable r = new Runnable ()
          {
            public void run ()
            {
             new AMP (args [0]);
            }
          };
   EventQueue.invokeLater (r);
  }
}

class MediaPanel extends JPanel
{
  private AlphaComposite ac1 =
   AlphaComposite.getInstance (AlphaComposite.SRC_OVER, 0.1f);

  private AlphaComposite ac2 =
   AlphaComposite.getInstance (AlphaComposite.SRC_OVER, 0.3f);

  private ControlPanel cp;

  private Dimension frameSize;

  private Font font = new Font ("Arial", Font.BOLD, 16);

  private MediaProvider mp;

  private Rectangle frame = new Rectangle (0, 0, 0, 0);

  private Rectangle2D r2d = new Rectangle2D.Double (0.0, 0.0, 0.0, 0.0);

  private VideoRenderControl vrc;

  MediaPanel (MediaProvider mp)
  {
   this.mp = mp;

   cp = new ControlPanel ();

   addMouseListener (new MouseAdapter ()
            {
              public void mouseClicked (MouseEvent me)
              {
                cp.update (me.getX (), me.getY ());
              }

              public void mouseEntered (MouseEvent me)
              {
                cp.show ();
              }

              public void mouseExited (MouseEvent me)
              {
                cp.hide ();
              }
            });

   vrc = mp.getControl (VideoRenderControl.class);
   if (vrc == null)
   {
     System.err.println ("no video renderer control");
     System.exit (-1);
   }
   frameSize = vrc.getFrameSize ();
   VideoRendererListener vrl;
   vrl = new VideoRendererListener ()
      {
        public void videoFrameUpdated (VideoRendererEvent vre)
        {
          repaint ();
        }
      };
   vrc.addVideoRendererListener (vrl);
   setPreferredSize (new Dimension (3*frameSize.width/4,
                    3*frameSize.height/4));
  }

  protected void paintComponent (Graphics g)
  {
   super.paintComponent (g);

   frame.width = getWidth ();
   frame.height = getHeight ();
   vrc.paintVideoFrame (g, frame);

   double ar1 = frame.width/(double) frameSize.width;
   double ar2 = frame.height/(double) frameSize.height;

   double x, y;

   if (ar1 < ar2)
   {
     x = (frame.width-frameSize.width*ar1)/2+10.0;
     y = (frame.height-frameSize.height*ar1)/2+10.0;
   }
   else
   {
     x = (frame.width-frameSize.width*ar2)/2+10.0;
     y = (frame.height-frameSize.height*ar2)/2+10.0;
   }
   
   Graphics2D g2d = (Graphics2D) g;
   g2d.setRenderingHint (RenderingHints.KEY_ANTIALIASING,
              RenderingHints.VALUE_ANTIALIAS_ON);
   g2d.setComposite (ac1);
   g2d.setPaint (Color.black);
   r2d.setFrame (x, y, 125.0, 50.0);
   g2d.fill (r2d);
   g2d.setComposite (ac2);
   g2d.setFont (font);
   g2d.setPaint (Color.yellow);
   g2d.drawString ("javajeff.mb.ca", (int) x+10, (int) y+30);

   cp.paint (g2d);
  }

  private class ControlPanel
  {
   private final static int DELAY = 100;

   private final static double SEPARATOR = 5.0;

   private Timer showTimer;

   private float opacity = 0.0f;

   private GeneralPath gp = new GeneralPath ();

   private Control [] controls;

   ControlPanel ()
   {
     ActionListener alShow;
     alShow = new ActionListener ()
           {
             public void actionPerformed (ActionEvent ae)
             {
              opacity = opacity+0.1f;
              if (opacity >= 1.0f)
              {
                showTimer.stop ();
                opacity = 1.0f;
              }
              MediaPanel.this.repaint ();
             }
           };
     showTimer = new Timer (DELAY, alShow);

     controls = new Control [2];
     PlayPauseButton ppb = new PlayPauseButton (15.0, 15.0);
     controls [0] = ppb;
     ProgressBar pb = new ProgressBar (250.0, 12.5);
     controls [1] = pb;
   }

   void hide ()
   {
     showTimer.stop ();
     opacity = 0.0f;
     MediaPanel.this.repaint ();
   }

   void show ()
   {
     showTimer.start ();
   }

   void update (double x, double y)
   {
     if (showTimer.isRunning ())
       return;

     for (Control control: controls)
       if (control.contains (x, y))
         if (control instanceof PlayPauseButton)
         {
           PlayPauseButton ppb = (PlayPauseButton) control;

           if (mp.isPlaying ())
           {
             ppb.setButtonPlay (true);
             mp.pause ();
           }
           else
           {
             ppb.setButtonPlay (false);
             mp.play ();
           }
         }

     MediaPanel.this.repaint ();
   }

   private void paint (Graphics2D g2d)
   {
     AlphaComposite ac;
     ac = AlphaComposite.getInstance (AlphaComposite.SRC_OVER, opacity);
     g2d.setComposite (ac);

     double panelWidth = 0.0;
     double panelHeight = 0.0;
     for (Control c: controls)
     {
       panelWidth += c.getWidth ()+SEPARATOR;
       if (c.getHeight () > panelHeight)
         panelHeight = c.getHeight ();
     }

     double x = (frame.width-panelWidth)/2.0;
     double y = (frame.height-SEPARATOR-panelHeight);

     for (Control c: controls)
     {
       if (c instanceof ProgressBar)
         c.setPosition (x, y+1.5);
       else
         c.setPosition (x, y);
       c.paint (g2d);
       x += c.getWidth ()+SEPARATOR;
     }
   }

   private abstract class Control
   {
     protected double x, y, width, height;

     Control (double width, double height)
     {
      this.width = width;
      this.height = height;
     }

     abstract void paint (Graphics2D g2d);

     boolean contains (double x, double y)
     {
      if (x < this.x || x >= this.x+width)
        return false;

      if (y < this.y || y >= this.y+height)
        return false;

      return true;
     }

     double getHeight ()
     {
      return height;
     }

     double getWidth ()
     {
      return width;
     }

     void setPosition (double x, double y)
     {
      this.x = x;
      this.y = y;
     }
   }

   private class PlayPauseButton extends Control
   {
     private boolean isPlay = true;

     PlayPauseButton (double width, double height)
     {
      super (width, height);
     }

     boolean isButtonPlay ()
     {
      return isPlay;
     }

     void setButtonPlay (boolean isPlay)
     {
      this.isPlay = isPlay;
     }

     void paint (Graphics2D g2d)
     {
      g2d.setColor (Color.black);

      gp.reset ();  

      if (isPlay)
      {
        gp.moveTo (x, y);
        gp.lineTo (x, y+height);
        gp.lineTo (x+width, y+height/2.0);
        gp.lineTo (x, y);
      }
      else
      {
        gp.moveTo (x, y);
        gp.lineTo (x, y+height);
        gp.lineTo (x+width/3.0, y+height);
        gp.lineTo (x+width/3.0, y);
        gp.lineTo (x, y);

        gp.moveTo (x+2.0*width/3.0, y);
        gp.lineTo (x+2.0*width/3.0, y+height);
        gp.lineTo (x+width, y+height);
        gp.lineTo (x+width, y);
        gp.lineTo (x+2.0*width/3.0, y);
      }

      g2d.fill (gp);

      g2d.setColor (Color.white);

      g2d.draw (gp);
     }
   }

   private class ProgressBar extends Control
   {
     private final static int DELAY = 500;

     ProgressBar (final double width, double height)
     {
      super (width, height);

      ActionListener alUpdate;
      alUpdate = new ActionListener ()
              {
               public void actionPerformed (ActionEvent ae)
               {
                 MediaPanel.this.repaint ();
               }
              };
      new Timer (DELAY, alUpdate).start ();
     }

     void paint (Graphics2D g2d)
     {
      g2d.setColor (Color.black);

      gp.reset ();
      gp.moveTo (x, y);
      gp.lineTo (x+width, y);
      gp.lineTo (x+width, y+height);
      gp.lineTo (x, y+height);
      gp.lineTo (x, y);

      g2d.fill (gp);

      double ratio = mp.getMediaTime ()/mp.getDuration ();
      double widthLimit = width*ratio;

      g2d.setPaint (new GradientPaint ((float) x, (float) y,
                       Color.blue,
                       (float) (x+widthLimit),
                       (float) y, Color.cyan));

      gp.reset ();
      gp.moveTo (x, y);
      gp.lineTo (x+widthLimit, y);
      gp.lineTo (x+widthLimit, y+height);
      gp.lineTo (x, y+height);
      gp.lineTo (x, y);

      g2d.fill (gp);

      g2d.setColor (Color.white);

      gp.reset ();
      gp.moveTo (x, y);
      gp.lineTo (x+width, y);
      gp.lineTo (x+width, y+height);
      gp.lineTo (x, y+height);
      gp.lineTo (x, y);

      g2d.draw (gp);
     }
   }
  }
}

Listing 4 is largely an extension of Listing 3. The biggest difference between these listings is the extended MediaPanel class with its nested ControlPanel class.

MediaPanel interacts with ControlPanel via the latter class's show(), hide(), and update() methods to show/hide the control panel and respond to a play/pause media request.

ControlPanel's constructor creates an array of controls whose classes subclass the nested (and abstract) Control class.

Although I provided classes only for a play/pause button and a progress bar, you could easily introduce additional control classes—a speaker control to mute/unmute the audio, for example.

After the media panel paints the next video frame followed by the (previously discussed) overlay, it invokes ControlPanel's paint() method, giving the panel a chance to specify its current opacity, and to position and paint its controls (by invoking each Control instance's paint() method).

This listing reveals a problem with ProgressBar's paint() method: The method continually creates java.awt.GradientPaint objects.

Because excessive object creation can lead to annoying garbage collection pauses that disrupt media playback, you'll probably want to solve this problem by creating your own gradient.

The following Windows-oriented articles will help you get started:

The second article features a program that creates a custom gradient for its window's background, and also reflects an image over the gradient.

Because reflections are popular with media players, consider introducing this effect to Listing 4. For help in creating reflections, check out the JH Labs article, Fun with Java2D—Java Reflections.

Conclusion

Now that you've been introduced to JMC's Playback API, you might be wondering where to find this API's Javadoc.

Apart from Kirill Grouchnikov's inspirational Extended support for native video codecs in JMC blog post, I couldn't find any documentation.

For this reason, I recommend unarchiving jmc.jar and decompiling its classfiles with a product such as Java Decompiler.

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