Here is a simple example for obtaining an output line and playing PCM on it. When run it plays about a second long annoying beep.
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.SourceDataLine;
public class RawAudioPlay {
public static void main(String[] args) {
try {
// select audio format parameters
AudioFormat af = new AudioFormat(24000, 16, 1, true, false);
DataLine.Info info = new DataLine.Info(SourceDataLine.class, af);
SourceDataLine line = (SourceDataLine) AudioSystem.getLine(info);
// generate some PCM data (a sine wave for simplicity)
byte[] buffer = new byte[64];
double step = Math.PI / buffer.length;
double angle = Math.PI * 2;
int i = buffer.length;
while (i > 0) {
double sine = Math.sin(angle);
int sample = (int) Math.round(sine * 32767);
buffer[--i] = (byte) (sample >> 8);
buffer[--i] = (byte) sample;
angle -= step;
}
// prepare audio output
line.open(af, 4096);
line.start();
// output wave form repeatedly
for (int n=0; n<500; ++n) {
line.write(buffer, 0, buffer.length);
}
// shut down audio
line.drain();
line.stop();
line.close();
} catch (Exception e) {
throw new RuntimeException(e.getMessage(), e);
}
}
}
You see, its roughly ten lines for handling the line, half of the code is the section "generate PCM" which you can ignore if you get PCM from somehwere else. You need to pay attention to the creation of the correct AudioFormat, screw up the booleans for signed and/or endian and the PCM will sound very garbled, possibly not even recognizable.
