Java equivalent of C# system.beep?

Question

I am working on a Java program, and I really need to be able to play a sound by a certain frequency and duration, similarly to the c# method System.Beep, I know how to use i

Answer 1

I don't think there's a way to play tunes¹ with "beep" in portable² Java. You'll need to use the javax.sound.* APIs I think ... unless you can find a third-party library that simplifies things for you.

If you want to go down this path, then this page might give you some ideas.

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^{1 - Unless your users are all tone-deaf. Of course you can do things like beeping in Morse code ... but that's not a tune.}

^{2 - Obviously, you could make native calls to a Windows beep function. But that would not be portable.}

Answer 2

I've hacked together a function that works for me. It uses a bunch of stuff from javax.sound.sampled. I've geared it to work with the audio format my system automatically gives a new Clip from AudioSystem.getClip(). There's probably all kinds of ways it could be made more robust and more efficient.

/**
 * Beeps.  Currently half-assumes that the format the system expects is
 * "PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, big-endian"
 * I don't know what to do about the sample rate.  Using 11025, since that
 * seems to be right, by testing against A440.  I also can't figure out why
 * I had to *4 the duration.  Also, there's up to about a 100 ms delay before
 * the sound starts playing.
 * @param freq
 * @param millis 
 */
public static void beep(double freq, final double millis) {
    try {
        final Clip clip = AudioSystem.getClip();
        AudioFormat af = clip.getFormat();

        if (af.getSampleSizeInBits() != 16) {
            System.err.println("Weird sample size.  Dunno what to do with it.");
            return;
        }

        //System.out.println("format " + af);

        int bytesPerFrame = af.getFrameSize();
        double fps = 11025;
        int frames = (int)(fps * (millis / 1000));
        frames *= 4; // No idea why it wasn't lasting as long as it should.

        byte[] data = new byte[frames * bytesPerFrame];

        double freqFactor = (Math.PI / 2) * freq / fps;
        double ampFactor = (1 << af.getSampleSizeInBits()) - 1;

        for (int frame = 0; frame < frames; frame++) {
            short sample = (short)(0.5 * ampFactor * Math.sin(frame * freqFactor));
            data[(frame * bytesPerFrame) + 0] = (byte)((sample >> (1 * 8)) & 0xFF);
            data[(frame * bytesPerFrame) + 1] = (byte)((sample >> (0 * 8)) & 0xFF);
            data[(frame * bytesPerFrame) + 2] = (byte)((sample >> (1 * 8)) & 0xFF);
            data[(frame * bytesPerFrame) + 3] = (byte)((sample >> (0 * 8)) & 0xFF);
        }
        clip.open(af, data, 0, data.length);

        // This is so Clip releases its data line when done.  Otherwise at 32 clips it breaks.
        clip.addLineListener(new LineListener() {                
            @Override
            public void update(LineEvent event) {
                if (event.getType() == Type.START) {
                    Timer t = new Timer((int)millis + 1, new ActionListener() {
                        @Override
                        public void actionPerformed(ActionEvent e) {
                            clip.close();
                        }
                    });
                    t.setRepeats(false);
                    t.start();
                }
            }
        });
        clip.start();
    } catch (LineUnavailableException ex) {
        System.err.println(ex);
    }
}

EDIT: Apparently somebody's improved my code. I haven't tried it yet, but give it a go: https://gist.github.com/jbzdak/61398b8ad795d22724dd