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POJMF: Setting FPS for webcam
 

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  1. POJMF: Setting FPS for webcam
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    <p>I have a webcam (actually 3) and java program to capture the frames. However, I have yet to find a way to set the FPS. For example, when I'm setting the FPS using a new <code>VideoFormat</code> and I can see that it is correctly applied by <code>camFormat.intersects(newFormat)</code>. However, when I get frames from the camera (either by the <code>BufferTransferHandler</code> or by manually fetching), I get more frames than the selected FPS.</p> <p>Is there perhaps a way to poll if a new frame is ready?</p> <p><strong>I found a little more information, so I'm editing this. It seems the source of the problems is the Microsoft WDM Image Capture driver. In VirtualDub capture mode, I can select each separate webcam and I can select WDM. When I select WDM, I get the same options as in the <em>Custom Format</em> dialog in JFM, and it doesn't capture at full FPS either. However,</strong> <code>CaptureDeviceManager.getDeviceList</code> <strong>seems to only return the WDM driver and not the individual webcams (and two microphones inside webcams but not the sound card microphone). Why is this?</strong></p> <p>It strikes me odd that I can specify the framerate, but I can't find a way to actually enforce it, even after days of searching the internet and trying different example code. Every example I find will just either request frames at its own pace or not care about fps at all.</p> <p>My test class:</p> <p>Run, use the top button to (re)open the Format Control window (internal to JMF), and try to change the fps. It's also odd that besides the non-functional fps field, other fields like the resolution field are also non-functional (as it is overridden by the resolution field in the "Custom Format..." window.</p> <pre><code>import java.awt.BorderLayout; import java.awt.Component; import java.awt.Dimension; import java.awt.EventQueue; import java.awt.Graphics; import java.awt.Image; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowEvent; import java.awt.event.WindowListener; import java.awt.image.BufferedImage; import java.util.Vector; import javax.media.Buffer; import javax.media.CaptureDeviceInfo; import javax.media.CaptureDeviceManager; import javax.media.ControllerAdapter; import javax.media.ControllerClosedEvent; import javax.media.ControllerErrorEvent; import javax.media.Manager; import javax.media.MediaLocator; import javax.media.Player; import javax.media.RealizeCompleteEvent; import javax.media.StartEvent; import javax.media.StopEvent; import javax.media.control.FormatControl; import javax.media.control.FrameGrabbingControl; import javax.media.format.FormatChangeEvent; import javax.media.format.VideoFormat; import javax.media.format.YUVFormat; import javax.media.util.BufferToImage; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JOptionPane; public class CaptureTest extends JComponent implements ActionListener, WindowListener, Runnable { public static void main(String[] args) { Runnable r = new Runnable() { @Override public void run() { new CaptureTest(); } }; EventQueue.invokeLater(r); } Player player; FrameGrabbingControl grabber; FormatControl formatControl; final JFrame frame; public Image image; public CaptureTest() { setLayout(new BorderLayout()); Vector&lt;?&gt; deviceVector = CaptureDeviceManager.getDeviceList(new YUVFormat()); final CaptureDeviceInfo[] deviceList = new CaptureDeviceInfo[deviceVector.size()]; for (int i = 0; i &lt; deviceList.length; i++) { deviceList[i] = (CaptureDeviceInfo)deviceVector.get(i); System.out.println("Capture Device found: " + deviceList[i].getName()); } frame = new JFrame("Capture test"); frame.addWindowListener(this); { JButton b = new JButton("Format Control"); b.setEnabled(true); b.addActionListener(this); frame.add(b, BorderLayout.NORTH); } { setPreferredSize(new Dimension(640, 480)); frame.add(this, BorderLayout.CENTER); } ControllerAdapter cl = new ControllerAdapter() { @Override public void realizeComplete(RealizeCompleteEvent rce) { formatControl = (FormatControl)player.getControl("javax.media.control.FormatControl"); grabber = (FrameGrabbingControl)player.getControl("javax.media.control.FrameGrabbingControl"); Component co = formatControl.getControlComponent(); if (co != null) { player.stop(); JDialog d = new JDialog(frame, "Format Control", true); d.add(co); d.pack(); d.setLocationRelativeTo(frame); d.setVisible(true); d.dispose(); player.start(); } System.out.println("realizeComplete: " + formatControl.getFormat()); } @Override public void formatChange(FormatChangeEvent fce) {} @Override public void start(StartEvent se) {} @Override public void stop(StopEvent se) {} @Override public void controllerError(ControllerErrorEvent cee) { System.err.println(cee.getMessage()); System.err.println("Caused by: " + cee.getSource()); System.exit(0); } @Override public void controllerClosed(ControllerClosedEvent cce) {} }; MediaLocator ml = deviceList[0].getLocator(); try { Manager.setHint(Manager.PLUGIN_PLAYER, Boolean.TRUE); player = Manager.createPlayer(ml); player.addControllerListener(cl); player.start(); } catch (Exception e) { e.printStackTrace(); JOptionPane.showMessageDialog(frame, "Could Not Create Player", "ERROR", JOptionPane.ERROR_MESSAGE); } frame.pack(); frame.setVisible(true); new Thread(this).start(); } public void grab() { if (grabber == null) return; Buffer buf = grabber.grabFrame(); // System.out.println(fps.getFPS() + "\t" + buf.getFormat()); BufferToImage b2i = new BufferToImage((VideoFormat)buf.getFormat()); BufferedImage bi = (BufferedImage)b2i.createImage(buf); if (bi != null) { setImage(bi); repaint(); } } public void setImage(Image im) { image = im; Dimension size = new Dimension(im.getWidth(null), im.getHeight(null)); setPreferredSize(size); setSize(size); } @Override public void paintComponent(Graphics g) { if (image != null) g.drawImage(image, 0, 0, this); } @Override public void run() { while (true) { grab(); Thread.yield(); } } @Override public void actionPerformed(ActionEvent e) { Component co = formatControl.getControlComponent(); if (co != null) { player.stop(); JDialog d = new JDialog(frame, "Format Control", true); d.add(co); d.pack(); d.setLocationRelativeTo(frame); d.setVisible(true); d.dispose(); player.start(); } } @Override public void windowOpened(WindowEvent e) {} @Override public void windowClosing(WindowEvent we) { if (player != null) { player.stop(); player.close(); } System.exit(0); } @Override public void windowClosed(WindowEvent e) {} @Override public void windowIconified(WindowEvent e) {} @Override public void windowDeiconified(WindowEvent e) {} @Override public void windowActivated(WindowEvent e) {} @Override public void windowDeactivated(WindowEvent e) {} } </code></pre>
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