IMtalk开发--JAVA JMF CaptureDeviceManager.getDevice空指针问题

      smack 虽然提供多媒体通信 jingle 的框架，无奈却没有发布它的API，在网上到处搜罗即便是有人在讨论都极少发布自己的源码，这让我的IMtalk开发很是受阻，没有办法，只能放弃jingle自己去开发多媒体通信，于是乎想到了jmf这样一个多媒体框架

      网上有很多人都写了测试用例，源码如下

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.HeadlessException;
import java.awt.Image;
import java.awt.Transparency;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.PixelGrabber;
import java.io.File;
import java.io.IOException;
import java.util.Vector;

import javax.imageio.ImageIO;
import javax.media.Buffer;
import javax.media.CaptureDeviceInfo;
import javax.media.CaptureDeviceManager;
import javax.media.Format;
import javax.media.MediaLocator;
import javax.media.NoPlayerException;
import javax.media.control.FrameGrabbingControl;
import javax.media.format.RGBFormat;
import javax.media.format.VideoFormat;
import javax.media.protocol.DataSource;
import javax.media.protocol.PushBufferDataSource;
import javax.media.util.BufferToImage;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JPanel;

import jmapps.jmstudio.CaptureDialog;
import jmapps.ui.PlayerFrame;
import jmapps.util.CDSWrapper;
import jmapps.util.JMFUtils;


/**
 * JMF 测试DEMO
 * @author 张立冬
 * @project IMTalk项目
 * 2010-8-14
 */
public class Demo001 extends PlayerFrame {

    public Demo001() {
        super(null, "视频捕获窗口");
    }

    DataSource dataSource;

    private CaptureDeviceInfo infor;

    private MediaLocator mediaLocator;


    String str1 = "vfw:Logitech USB Video Camera:0";
    String str2 = "vfw:Microsoft WDM Image Capture (Win32):0";

    private String url = "vfw:Microsoft WDM Image Capture (Win32):0";

    private Component com;

    private JPanel panel;

    private int captureCount = 0;

    FrameGrabbingControl controlGrabber;

    public void play() {
        if (mediaPlayerCurrent.getState() != mediaPlayerCurrent.Started) {
            mediaPlayerCurrent.start();
        }
    }

    private void init() throws NoPlayerException, IOException {
        // setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        String nameCaptureDeviceAudio = null;
        String nameCaptureDeviceVideo = null;
        CaptureDialog dialogCapture = new CaptureDialog(this, null);
        dialogCapture.show();
        if (dialogCapture.getAction() == CaptureDialog.ACTION_CANCEL)
            return;
        CaptureDeviceInfo cdi = dialogCapture.getAudioDevice();
        if (cdi != null && dialogCapture.isAudioDeviceUsed())
            nameCaptureDeviceAudio = cdi.getName();
        cdi = dialogCapture.getVideoDevice();
        if (cdi != null && dialogCapture.isVideoDeviceUsed())
            nameCaptureDeviceVideo = cdi.getName();
        dataSource = JMFUtils.createCaptureDataSource(nameCaptureDeviceAudio,
                dialogCapture.getAudioFormat(), nameCaptureDeviceVideo,
                dialogCapture.getVideoFormat());
        DataSource cdswrapper = new CDSWrapper(
                (PushBufferDataSource) dataSource);
        dataSource = cdswrapper;
        dataSource.connect();
        open(dataSource);
        JPanel controlPanel = new JPanel();
        controlPanel.setName("controlPnael is here");
        add(BorderLayout.SOUTH, controlPanel);
        JButton capture = new JButton("Capture Image");
        capture.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                mediaPlayerCurrent.stop();
                Buffer bufferFrame;
                BufferToImage bufferToImage;
                Image image;
                BufferedImage bi;
                controlGrabber = (FrameGrabbingControl) mediaPlayerCurrent
                        .getControl("javax.media.control.FrameGrabbingControl");
                bufferFrame = controlGrabber.grabFrame();
                bufferToImage = new BufferToImage((VideoFormat) bufferFrame
                        .getFormat());
                image = bufferToImage.createImage(bufferFrame);

                File out = new File("capture" + (++captureCount) + ".png");
                try {
                    bi = toBufferedImage(image);
                    ImageIO.write(bi, "png", out);
                } catch (IOException e1) {
                    e1.printStackTrace();
                }

                mediaPlayerCurrent.start();

            }
        });

        controlPanel.add(BorderLayout.CENTER, capture);

        JButton playStop = new JButton("stop");
        // add(BorderLayout.SOUTH,playControl);
        playStop.addActionListener(new ActionListener() {

            // @Override
            public void actionPerformed(ActionEvent arg0) {
                mediaPlayerCurrent.stop();

            }
        });
        controlPanel.add(BorderLayout.EAST, playStop);

        JButton playStart = new JButton("start");
        // add(BorderLayout.SOUTH,playControl);
        playStart.addActionListener(new ActionListener() {

            // @Override
            public void actionPerformed(ActionEvent arg0) {
                // mediaPlayerCurrent.stop();
                if (mediaPlayerCurrent.getState() != mediaPlayerCurrent.Started) {
                    mediaPlayerCurrent.start();
                }
            }
        });
        controlPanel.add(BorderLayout.WEST, playStart);
        addWindowListener(new WindowAdapter() {

            // @Override
            public void windowClosing(WindowEvent e) {
                mediaPlayerCurrent.close();
                dataSource.disconnect();
                System.out.println("exit.....");
                System.exit(0);

            }
        });
    }

    public static boolean hasAlpha(Image image) {
        // If buffered image, the color model is readily available
        if (image instanceof BufferedImage) {
            BufferedImage bimage = (BufferedImage) image;
            return bimage.getColorModel().hasAlpha();
        }
        // Use a pixel grabber to retrieve the image's color model;
        // grabbing a single pixel is usually sufficient
        PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);
        try {
            pg.grabPixels();
        } catch (InterruptedException e) {
        }

        // Get the image's color model
        ColorModel cm = pg.getColorModel();
        return cm.hasAlpha();
    }

    public static BufferedImage toBufferedImage(Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }

        // This code ensures that all the pixels in the image are loaded
        image = new ImageIcon(image).getImage();

        // Determine if the image has transparent pixels; for this method's
        // implementation, see e661 Determining If an Image Has Transparent
        // Pixels
        boolean hasAlpha = hasAlpha(image);

        // Create a buffered image with a format that's compatible with the
        // screen
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment
                .getLocalGraphicsEnvironment();
        try {
            // Determine the type of transparency of the new buffered image
            int transparency = Transparency.OPAQUE;
            if (hasAlpha) {
                transparency = Transparency.BITMASK;
            }

            // Create the buffered image
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(image.getWidth(null), image
                    .getHeight(null), transparency);
        } catch (HeadlessException e) {
            // The system does not have a screen
            System.err.println("The system does not have a screen!");
            System.exit(-1);
        }

        if (bimage == null) {
            // Create a buffered image using the default color model
            int type = BufferedImage.TYPE_INT_RGB;
            if (hasAlpha) {
                type = BufferedImage.TYPE_INT_ARGB;
            }
            bimage = new BufferedImage(image.getWidth(null), image
                    .getHeight(null), type);
        }

        // Copy image to buffered image
        Graphics g = bimage.createGraphics();

        // Paint the image onto the buffered image
        g.drawImage(image, 0, 0, null);
        g.dispose();

        return bimage;
    }

    private MediaLocator autoDetect() {// 自动识别功能函数
        MediaLocator ml = null; // 视频采集设备对应的MediaLocator
        VideoFormat currentFormat = null;// 用户定制获得视频采集设备支持的格式
        Format setFormat = null;// 用户定制视频采集设备输出的格式
        Format[] videoFormats = null;// 视频采集设备支持的所有格式
        System.out.println(" AutoDetect for VFW");// VFW:微软的 Video for Windows
        // 获得当前所有设备列表
        Vector deviceList = CaptureDeviceManager.getDeviceList(null);
        CaptureDeviceInfo device = CaptureDeviceManager.getDevice(url);
        if (deviceList != null) {
            // 根据设备列表，找出可用设备名称
            for (int i = 0; i < deviceList.size(); i++) {
                try {
                    CaptureDeviceInfo di = (CaptureDeviceInfo) deviceList
                            .elementAt(i);
                    // 如果设备名称以vfw开头
                    if (di.getName().startsWith("vfw:")) {
                        // 获得所有支持RGB格式
                        videoFormats = di.getFormats();
                        for (int j = 0; j < videoFormats.length; j++) {
                            // 我们只需要第一种RGB格式
                            if (videoFormats[j] instanceof RGBFormat) {
                                currentFormat = (RGBFormat) videoFormats[i];
                                break;
                            }
                        }
                        if (currentFormat == null) {
                            System.err.println("Search For RGBFormat Failed");
                            System.exit(-1);
                        }
                        // 通过设备，获得MediaLocator，这个很重要
                        ml = di.getLocator();
                    }
                } catch (Exception npe) {
                    System.err.println("Unable to get Processor for device");
                    System.exit(-1);
                }
            }
        } else {
            System.err.println("No Capture Device OK");
            System.exit(-1);
        }
        mediaLocator = ml;
        return ml;// 返回可用的设备medialocator
    }

    public static void main(String[] args) throws NoPlayerException,
            IOException {
        Demo001 demo = new Demo001();
        demo.setSize(100, 100);
        demo.autoDetect();
        demo.init();
        demo.play();
        demo.setVisible(true);
    }
}

 

但是跑起来却报了这样一个错

 

 AutoDetect for VFW
Exception in thread "main" java.lang.NullPointerException
	at cn.zld.imtalk.client.test.Demo001.play(Demo001.java:79)
	at cn.zld.imtalk.client.test.Demo001.main(Demo001.java:304)

 

 我是直接将它的压缩文件里面的JAR文件导入的，在网上找了下，说是只要将jmf安装目录下的jar文件导入就可以了，我试了下发现果然可以了，分析了下原因所在，发现与JAR文件同一个目录下有一下properties文件，这应当是它初始化的一些配置信息，再次尝试不替换JAR文件，只是将安装目录下的properties文件改动，发现果然可以用了，这应该是问题的所在