I have a little program to record and playback .wav files.
In the GUI class I have the following code for the “stop” button:
private AudioCapture audCap = new AudioCapture();
stopBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
captureBtn.setEnabled(true);
stopBtn.setEnabled(false);
playBtn.setEnabled(true);
audCap.stopCapture = true; // this doesn't work
audCap.stopPlayback = true; // this does
}
}
In the AudioCapture() class I have this code for playback, which stops correctly when stop button is clicked:
class PlayThread extends Thread {
byte tempBuffer[] = new byte[10000];
public void run() {
stopPlayback = false;
try {
sourceDataLine.open(audioFormat);
sourceDataLine.start();
int cnt;
while ((cnt = audioInputStream.read(tempBuffer, 0,
tempBuffer.length)) != -1 && stopPlayback == false) {
if (cnt > 0) {
sourceDataLine.write(tempBuffer, 0, cnt);
}
}
sourceDataLine.drain();
sourceDataLine.close();
} catch (Exception e) {
e.printStackTrace();
System.exit(0);
}
}
}
I also have this code for recording/capturing, which doesn’t stop when the stop button is clicked:
class CaptureThread extends Thread {
// An arbitrary-size temporary holding buffer
byte tempBuffer[] = new byte[10000];
public void run() {
stopCapture = false;
// record as wave
AudioFileFormat.Type fileType = AudioFileFormat.Type.WAVE;
// takes user input file name and appends filetype
audioFile = new File(wavName + ".wav");
try {
while (!stopCapture) {
int cnt = targetDataLine.read(tempBuffer, 0,
tempBuffer.length);
if (cnt > 0) {
AudioSystem.write(new AudioInputStream(targetDataLine),
fileType, audioFile);
}
}
targetDataLine.stop();
targetDataLine.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
stopCature & stopPlayback are instance variables in the AudioCapture() class.
I’m using Eclipse and tried setting a break point at “while (!stopCapture)” and it never seems to get beyond this.
Does anyone know if there is anything in the code above that would cause the first method to function as expected but the second not to?
-EDIT-
I’ve tried to put a cut down version of the program into an SSCE but it still runs to a couple of hundred lines:
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.Mixer;
import javax.sound.sampled.SourceDataLine;
import javax.sound.sampled.TargetDataLine;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class audioTest extends JFrame {
private static final long serialVersionUID = 1L;
AudioCapture audCap = new AudioCapture();
public static void main(String[] args) {
new audioTest();
}
public audioTest() {
layoutTransporButtons();
getContentPane().setLayout(new FlowLayout());
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(350, 100);
setVisible(true);
}
public void layoutTransporButtons() {
final JPanel guiButtonPanel = new JPanel();
final JButton captureBtn = new JButton("Record");
final JButton stopBtn = new JButton("Stop");
final JButton playBtn = new JButton("Playback");
guiButtonPanel.setLayout(new GridLayout());
this.add(guiButtonPanel);
captureBtn.setEnabled(true);
stopBtn.setEnabled(false);
playBtn.setEnabled(true);
// Register anonymous listeners
captureBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
captureBtn.setEnabled(false);
stopBtn.setEnabled(true);
playBtn.setEnabled(false);
// Capture input data from the microphone
audCap.captureAudio();
}
});
guiButtonPanel.add(captureBtn);
stopBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
captureBtn.setEnabled(true);
stopBtn.setEnabled(false);
playBtn.setEnabled(true);
audCap.stopRecordAndPlayback = true;
}
});
guiButtonPanel.add(stopBtn);
playBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
stopBtn.setEnabled(true);
audCap.playAudio();
}
});
guiButtonPanel.add(playBtn);
}
class AudioCapture {
volatile boolean stopRecordAndPlayback = false;
AudioFormat audioFormat;
TargetDataLine targetDataLine;
AudioInputStream audioInputStream;
SourceDataLine sourceDataLine;
private String wavName;
private File audioFile;
/**
* capture audio input from microphone and save as .wav file
*/
public void captureAudio() {
wavName = JOptionPane.showInputDialog(null,
"enter name of file to be recorded:");
try {
Mixer.Info[] mixerInfo = AudioSystem.getMixerInfo();
// Select an available mixer
Mixer mixer = AudioSystem.getMixer(mixerInfo[1]);
// Get everything set up for capture
audioFormat = getAudioFormat();
DataLine.Info dataLineInfo = new DataLine.Info(
TargetDataLine.class, audioFormat);
// Get a TargetDataLine on the selected mixer.
targetDataLine = (TargetDataLine) mixer.getLine(dataLineInfo);
// Prepare the line for use.
targetDataLine.open(audioFormat);
targetDataLine.start();
// Create a thread to capture the microphone
Thread captureThread = new CaptureThread();
captureThread.start();
} catch (Exception e) {
System.out.println(e);
System.exit(0);
}
}
/**
* This method plays back the audio data that has
* been chosen by the user
*/
public void playAudio() {
// add file chooser
JFileChooser chooser = new JFileChooser();
chooser.setCurrentDirectory(audioFile);
int returnVal = chooser.showOpenDialog(chooser);
// retrieve chosen file
if (returnVal == JFileChooser.APPROVE_OPTION) {
// create the file
audioFile = chooser.getSelectedFile();
}
// play chosen file
try {
audioInputStream = AudioSystem.getAudioInputStream(audioFile);
audioFormat = audioInputStream.getFormat();
DataLine.Info dataLineInfo = new DataLine.Info(
SourceDataLine.class, audioFormat);
sourceDataLine = (SourceDataLine) AudioSystem
.getLine(dataLineInfo);
// Create a thread to play back the data
new PlayThread().start();
} catch (Exception e) {
e.printStackTrace();
System.exit(0);
}
}
/**
* This method creates and returns an AudioFormat object
*/
private AudioFormat getAudioFormat() {
float sampleRate = 44100.0F;
// 8000,11025,16000,22050,44100
int sampleSizeInBits = 16;
// 8,16
int channels = 1;
// 1,2
boolean signed = true;
// true,false
boolean bigEndian = false;
// true,false
return new AudioFormat(sampleRate, sampleSizeInBits, channels,
signed, bigEndian);
}
/**
* Inner class to capture data from microphone
*/
class CaptureThread extends Thread {
// An arbitrary-size temporary holding buffer
byte tempBuffer[] = new byte[10000];
public void run() {
// reset stopCapture to false
stopRecordAndPlayback = false;
// record as wave
AudioFileFormat.Type fileType = AudioFileFormat.Type.WAVE;
// take user input file name and append file type
audioFile = new File(wavName + ".wav");
try {
targetDataLine.open(audioFormat);
targetDataLine.start();
while (!stopRecordAndPlayback) {
AudioSystem.write(new AudioInputStream(targetDataLine),
fileType, audioFile);
}
targetDataLine.stop();
targetDataLine.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* Inner class to play back the data
*/
class PlayThread extends Thread {
byte tempBuffer[] = new byte[10000];
public void run() {
// reset stop button
stopRecordAndPlayback = false;
try {
sourceDataLine.open(audioFormat);
sourceDataLine.start();
int cnt;
while ((cnt = audioInputStream.read(tempBuffer, 0,
tempBuffer.length)) != -1
&& stopRecordAndPlayback == false) {
if (cnt > 0) {
sourceDataLine.write(tempBuffer, 0, cnt);
}
}
sourceDataLine.drain();
sourceDataLine.close();
} catch (Exception e) {
e.printStackTrace();
System.exit(0);
}
}
}
}
}
You don’t give all the needed information but a very likely reason is a data race in your program.
Since you are running things in different threads, you need to use some form of synchronization across threads to make sure the changes you make in one thread are visible in the other.
Typically, in your case, declaring the boolean variables volatile should be sufficient.
EDIT
One possibility is that the condition in your while loop does not get evaluated as often as you think (if at all) – you could add some logging to see what is going on: