Audio volume control (increase or decrease) in Java

Question

How do I increase the volume of an outgoing wav audio stream using Java? I'm having issues with various Java TTS engines and the output volume of the synthesized speech. Is there an API call or a doo-hickey.jar I can use to pump up the volume?

Answer 1

If you're using the Java Sound API, you can set the volume with the MASTER_GAIN control.

import javax.sound.sampled.*;

AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(
    new File("some_file.wav"));
Clip clip = AudioSystem.getClip();
clip.open(audioInputStream);
FloatControl gainControl = 
    (FloatControl) clip.getControl(FloatControl.Type.MASTER_GAIN);
gainControl.setValue(-10.0f); // Reduce volume by 10 decibels.
clip.start();

Answer 2

You can adjust volume using a GainControl, try something like this after you have opened the line

FloatControl volume= (FloatControl) line.getControl(FloatControl.Type.MASTER_GAIN); 

Answer 3

public final class VolumeControl
{

    private VolumeControl(){}

    private static LinkedList<Line> speakers = new LinkedList<Line>();

    private final static void findSpeakers()
    {
        Mixer.Info[] mixers = AudioSystem.getMixerInfo();

        for (Mixer.Info mixerInfo : mixers)
        {
            if(!mixerInfo.getName().equals("Java Sound Audio Engine")) continue;

            Mixer mixer         = AudioSystem.getMixer(mixerInfo);
            Line.Info[] lines   = mixer.getSourceLineInfo();

            for (Line.Info info : lines)
            {

                try 
                {
                    Line line = mixer.getLine(info);
                    speakers.add(line);

                }
                catch (LineUnavailableException e)      { e.printStackTrace();                                                                                  } 
                catch (IllegalArgumentException iaEx)   {                                                                                                       }
            }
        }
    }

    static
    {
        findSpeakers();
    }

    public static void setVolume(float level)
    {
        System.out.println("setting volume to "+level);
        for(Line line : speakers)
        {
            try
            {
                line.open();
                FloatControl control = (FloatControl)line.getControl(FloatControl.Type.MASTER_GAIN);
                control.setValue(limit(control,level));
            }
            catch (LineUnavailableException e) { continue; }
            catch(java.lang.IllegalArgumentException e) { continue; }



        }
    }

    private static float limit(FloatControl control,float level)
    { return Math.min(control.getMaximum(), Math.max(control.getMinimum(), level)); }

}