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