1. 捕获媒体数据的步骤：
(1) 查询CaptureDeviceManager，来定位你需要使用的媒体采集设备。
(2) 得到此设备的CaptureDeviceInfo实例。
(3) 从此CaptureDeviceInfo实例获得一个MediaLocator，并通过它来创建一个DataSource。
(4)用此DataSource创建一个Player或Processor。
(5) 启动此Player或Processor开始捕获媒体数据。
2．CaptureDeviceManager、CaptureDeviceInfo、MediaLocator
在JMF中，CaptureDeviceManager也是一个manager类,它提供给了一个列表，这个列表显示当前系统可以被使用的设备名称。同时CaptureDeviceManager可以通过查询的方法对设备进行定位并返回设备的配置信息对象CaptureDeviceInfo,它也可以通过注册的方法向列表加入一个新的设备信息，以便为JMF使用。
设备可通过CaptureDeviceManager的getDevice()方法直接获得设备控制权，设备的控制权一旦得到，就可以以此设备作为一个MediaLocator,可以通过CaptureDeviceInfo的getLocator()方法得到。
3．JMF识别的音频采集设备
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4．一个实例实现音频捕获
实例有两个文件组成。CaptureDemo.java实现
①查询、获得音频采集设备。
②捕获音频。
③将音频保存到本地文件foo.wav。
StateHelper实现处理器（processor）的状态控制管理。以下为流程图：
import java.util.Vector;
import javax.media.CaptureDeviceInfo;
import javax.media.CaptureDeviceManager;
import javax.media.DataSink;
import javax.media.Manager;
import javax.media.MediaLocator;
import javax.media.NoDataSinkException;
import javax.media.NoProcessorException;
import javax.media.Processor;
import javax.media.control.StreamWriterControl;
import javax.media.format.AudioFormat;
import javax.media.protocol.DataSource;
import javax.media.protocol.FileTypeDescriptor;
public class CaptureDemo
{
/**
* @param args
*/
public static void main(String[] args)
{
// TODO Auto-generated method stub
CaptureDeviceInfo di = null;
Processor p = null;
StateHelper sh = null;
Vector devList = CaptureDeviceManager.getDeviceList(new AudioFormat("linear",44100,16,2));
if(devList.size()>0)
{
di = (CaptureDeviceInfo)devList.firstElement();
System.out.println(di.getName());
System.out.println(di.toString());
}
else
System.exit(-1);
try
{
p = Manager.createProcessor(di.getLocator());
sh = new StateHelper(p);
}
catch(java.io.IOException ex)
{
System.exit(-1);
}
catch (NoProcessorException e)
{
// TODO Auto-generated catch block
System.exit(-1);
}
if(!sh.configure(10000))
{
System.exit(-1);
}
p.setContentDescriptor(new FileTypeDescriptor(FileTypeDescriptor.WAVE));
if(!sh.realize(10000))
{
System.exit(-1);
}
DataSource source = p.getDataOutput();
MediaLocator dest = new MediaLocator("file:///c:/foo.wav");
DataSink fileWriter = null;
try
{
fileWriter = Manager.createDataSink(source, dest);
fileWriter.open();
}
catch (NoDataSinkException e)
{
// TODO Auto-generated catch block
System.exit(-1);
}
catch(java.io.IOException ex)
{
System.exit(-1);
}
catch(SecurityException ex)
{
System.exit(-1);
}
StreamWriterControl swc = (StreamWriterControl) p.getControl("javax.media.control.StreamWriterControl");
if(swc!=null)
{
swc.setStreamSizeLimit(500000000);
}
try
{
fileWriter.start();
}
catch(java.io.IOException ex)
{
System.exit(-1);
}
sh.playToEndOfMedia(5000*1000);
sh.close();
fileWriter.close();
}
}
import javax.media.ConfigureCompleteEvent;
import javax.media.ControllerClosedEvent;
import javax.media.ControllerErrorEvent;
import javax.media.ControllerEvent;
import javax.media.ControllerListener;
import javax.media.EndOfMediaEvent;
import javax.media.Player;
import javax.media.Processor;
import javax.media.RealizeCompleteEvent;
public class StateHelper implements ControllerListener
{
Player player = null;
boolean configured = false;
boolean realized = false;
boolean prefetched = false;
boolean endOfMedia = false;
boolean failed = false;
boolean closed = false;
public StateHelper(Player p)
{
this.player = p;
p.addControllerListener(this);
}
public boolean configure(int timeOutMillis)
{
long startTime = System.currentTimeMillis();
synchronized(this)
{
if(this.player instanceof Processor)
{
((Processor)player).configure();
}
else
return false;
while(!this.configured&&!this.failed)
{
try
{
this.wait(timeOutMillis);
}
catch(InterruptedException ex)
{
}
if(System.currentTimeMillis()-startTime > timeOutMillis)
break;
}
}
return this.configured;
}
public boolean realize(int timeOutMillis)
{
long startTime = System.currentTimeMillis();
synchronized(this)
{
this.player.realize();
while(!this.realized&&!this.failed)
{
try
{
this.wait(timeOutMillis);
}
catch(InterruptedException ex)
{
}
if(System.currentTimeMillis()-startTime > timeOutMillis)
break;
}
}
return this.realized;
}
public boolean prefetch(int timeOutMillis)
{
long startTime = System.currentTimeMillis();
synchronized(this)
{
this.player.prefetch();
while(!this.prefetched&&!this.failed)
{
try
{
this.wait(timeOutMillis);
}
catch(InterruptedException ex)
{
}
if(System.currentTimeMillis()-startTime > timeOutMillis)
break;
}
}
return this.prefetched&&!this.failed;
}
public boolean playToEndOfMedia(int timeOutMillis)
{
long startTime = System.currentTimeMillis();
this.endOfMedia = false;
synchronized(this)
{
this.player.start();
while(!this.endOfMedia&&!this.failed)
{
try
{
this.wait(timeOutMillis);
}
catch(InterruptedException ex)
{
}
if(System.currentTimeMillis()-startTime > timeOutMillis)
break;
}
}
return this.endOfMedia&&!this.failed;
}
public void close()
{
synchronized(this)
{
this.player.close();
while(!this.closed)
{
try
{
this.wait(100);
}
catch(InterruptedException ex)
{
}
}
}
this.player.removeControllerListener(this);
}
public synchronized void controllerUpdate(ControllerEvent ce)
{
// TODO Auto-generated method stub
if(ce instanceof RealizeCompleteEvent)
{
this.realized = true;
}
else if(ce instanceof ConfigureCompleteEvent)
{
this.configured = true;
}
else if(ce instanceof EndOfMediaEvent)
{
this.endOfMedia = true;
}
else if(ce instanceof ControllerErrorEvent)
{
this.failed = true;
}
else if(ce instanceof ControllerClosedEvent)
{
this.closed = true;
}
else
{
return;
}
this.notifyAll();
}
}
本文转自Phinecos(洞庭散人)博客园博客，原文链接：http://www.cnblogs.com/phinecos/archive/2007/09/24/904551.html，如需转载请自行联系原作者
