Java剪辑不起作用 [英] Java clip not working
问题描述
有人可以帮我理解为什么下面这段代码不起作用吗？
Can someone please help me understand why this code below doesn't work?
我通过调用方法 start（）<启动剪辑/ code>。此方法为剪辑创建一个新线程以运行。但是，不，它似乎没有播放任何东西。
I start the clip by calling method start(). This method creates a new thread for the clip to run. However, no it doesn't seem to play anything.
代码编译没有任何错误...
The code is compiled without any error...
public class Audio
{
private Clip clip;
private Thread thread;
public Audio (String audioFile)
{
AudioInputStream audioStream = null;
URL audioURL = this.getClass().getClassLoader().getResource(audioFile);
// Obtain audio input stream from the audio file and load the information
// into main memory using the URL path retrieved from above.
try { audioStream = AudioSystem.getAudioInputStream(audioURL); }
catch (Exception e)
{
e.printStackTrace();
System.exit(1);
}
try
{
// Retrieve the object of class Clip from the Data Line.
this.clip = AudioSystem.getClip();
// Load the audio input stream into memory for future play-back.
this.clip.open(audioStream);
}
catch (LineUnavailableException e)
{
e.printStackTrace();
System.exit(1);
}
catch (IOException e)
{
e.printStackTrace();
System.exit(1);
}
}
public void start()
{
Runnable r = new Runnable() {
public void run()
{
loop();
}
};
thread = new Thread(r);
thread.start();
}
public void loop ()
{
// Rewind the media to the beginning of the clip.
this.clip.setFramePosition(0);
// Continuously play the clip.
this.clip.loop(Clip.LOOP_CONTINUOUSLY);
try
{
Thread.sleep(5000);
} catch (InterruptedException e)
{
e.printStackTrace();
}
}
更新
我发现了问题！问题是因为音频文件。我使用了不同的音频文件，我可以用上面的代码听到声音。
I found the problem! The problem is because of the audio file. I used a different audio file and I can hear the sound with the code above.
编译的代码没有任何错误或警告真的很烦人。我通过获取音频格式检测到问题，然后将其传递给类DataLine.Info的对象。然后，从数据线中检索剪辑。
It is just really annoying that the code compiled without any error or warning. I detected the problem by getting the audio format, then pass it to an object of class DataLine.Info. Then, retrieve the clip from the Data Line.
因此，基本上不是通过以下方式获取剪辑：
So, basically instead of getting the clip by:
this.clip = AudioSystem.getClip();
我会得到以下剪辑：
AudioFormat format = audioStream.getFormat();
DataLine.Info info = new DataLine.Info(Clip.class, format);
this.clip = (Clip) AudioSystem.getLine(info);
当我用这个编译时，Java抛出以下错误：
When I compiled with this, Java threw below error:
没有行匹配接口Clip支持格式PCM_SIGNED 48000.0 Hz，24 bit
No line matching interface Clip supporting format PCM_SIGNED 48000.0 Hz, 24 bit
所以，我替换了音频文件，它有效！
So, I replaced the audio file, and it worked !
推荐答案
clip.loop 是一个非阻塞的电话。也就是说，一旦你调用它（并且它完成了它的工作），它将返回，这意味着你的线程将退出，除非有另一个非守护程序线程在运行，否则JVM将退出。
clip.loop is a non-blocking call. That is, once you call it (and it does what it does), it will return, this means your thread will exit and, unless there is another non-daemon thread running, the JVM will exit.
我原本以为你可以使用 Clip＃drain 来阻止它直到剪辑完成，但从技术上讲，这个剪辑赢了在正常意义上完成......
I had thought you might be able to use Clip#drain to cause it to block until the clip had completed, but technically, the clip won't complete...in the normal sense.
相反，我设置了自己的循环......
Instead, I set up my own loop...
public void start() {
Runnable r = new Runnable() {
public void run() {
while (true) {
clip.setFramePosition(0);
clip.start();
clip.drain();
}
}
};
thread = new Thread(r);
thread.start();
}
现在，这可能是一个问题，因为线程是一个非守护进程线程，永远不会结束......而不是而（true）{你应该设置某种 volitle 你设置为 false 的标志并帮助终止循环......
Now, this could be an issue, because the Thread is a non-daemon thread and will never end...Instead of while (true) { you should setup some kind volitle flag which you set to false and help terminate the loop...
例如......
import java.io.IOException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
import javax.sound.sampled.LineUnavailableException;
public class Audio {
private Clip clip;
private Thread thread;
private volatile boolean keepPlaying = true;
public static void main(String[] args) {
Audio audio = new Audio("Kalimba.wav");
audio.start();
try {
Thread.sleep(5000);
} catch (InterruptedException ex) {
}
audio.stop();
}
public Audio(String audioFile) {
AudioInputStream audioStream = null;
URL audioURL = this.getClass().getClassLoader().getResource(audioFile);
// Obtain audio input stream from the audio file and load the information
// into main memory using the URL path retrieved from above.
try {
audioStream = AudioSystem.getAudioInputStream(audioURL);
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
}
try {
// Retrieve the object of class Clip from the Data Line.
this.clip = AudioSystem.getClip();
// Load the audio input stream into memory for future play-back.
this.clip.open(audioStream);
} catch (LineUnavailableException e) {
e.printStackTrace();
System.exit(1);
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
}
public void stop() {
if (thread != null) {
keepPlaying = false;
clip.stop();
thread.interrupt();
}
}
public void start() {
Runnable r = new Runnable() {
public void run() {
while (keepPlaying) {
clip.setFramePosition(0);
clip.start();
clip.drain();
}
}
};
thread = new Thread(r);
thread.start();
}
}
已更新
上面的例子（恕我直言）有一些问题，可以用简单的对象监视器修复。
There a few things wrong with the above example (IMHO), which can be fixed with a simple object monitor.
因此，我们可以使用 Clip＃而不是功能，只需使用 volatile 标志和而循环。循环 Object＃wait 和 Object＃notify ，例如
So, instead of a volatile flag and a while loop, we can use the Clip#loop functionality and simply use Object#wait and Object#notify instead, for example
import java.io.IOException;
import java.net.URL;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
import javax.sound.sampled.LineUnavailableException;
public class Audio {
private Clip clip;
private Thread thread;
private final Object loopLock = new Object();
public static void main(String[] args) {
Audio audio = new Audio("Music.wav");
audio.start();
try {
Thread.sleep(5000);
} catch (InterruptedException ex) {
}
audio.stop();
}
public Audio(String audioFile) {
AudioInputStream audioStream = null;
URL audioURL = this.getClass().getClassLoader().getResource(audioFile);
// Obtain audio input stream from the audio file and load the information
// into main memory using the URL path retrieved from above.
try {
audioStream = AudioSystem.getAudioInputStream(audioURL);
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
}
try {
// Retrieve the object of class Clip from the Data Line.
this.clip = AudioSystem.getClip();
// Load the audio input stream into memory for future play-back.
this.clip.open(audioStream);
} catch (LineUnavailableException e) {
e.printStackTrace();
System.exit(1);
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
}
public void stop() {
synchronized (loopLock) {
loopLock.notifyAll();
}
}
public void start() {
Runnable r = new Runnable() {
public void run() {
clip.setFramePosition(0);
clip.loop(Clip.LOOP_CONTINUOUSLY);
synchronized (loopLock) {
try {
loopLock.wait();
} catch (InterruptedException ex) {
}
}
clip.stop();
}
};
thread = new Thread(r);
thread.start();
}
}
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