更改 java 中的 MIDI 音量

Question

first of all changing volume is working but i got some problems while changing the volume so 1) after changing the volume like setting it to 0 (no volume) you still hearing parts of the song in the default value of the volume 2)after song changed the volume getting back to the default value of the volume

public static void setVolume(double value) {
    System.out.println();
    int CHANGE_VOLUME = 7;
    midivol =(value);
    try {
        if (synthesizer.getDefaultSoundbank() == null) {
            System.out.println(444);
                ShortMessage volumeMessage = new ShortMessage();
                for (int i = 0; i < 16; i++) {
                    volumeMessage.setMessage(ShortMessage.CONTROL_CHANGE, i, CHANGE_VOLUME,(int)(value * 127.0));
                    volumeMessage.setMessage(ShortMessage.CONTROL_CHANGE, i, 39, (int)(value * 127.0));
                    MidiSystem.getReceiver().send(volumeMessage, -1);
                }
        } else {  
             MidiChannel[] channels = synthesizer.getChannels();

              for( int c = 0; c < channels.length; c++ ) {
                 if(channels[c] != null)   channels[c].controlChange( 7, (int)( value*127.0) );
              }
        }
        music.setSequence(sequence);
    } catch (Exception e) {
            e.printStackTrace();
        }
}

playing midi:

 private void playMidi(String location) {
    double gain =Slider.musicvolume;
    music = null;
    //synthesizer = null;
    sequence = null;
    File midiFile = new File(location);
    try {
    sequence = MidiSystem.getSequence(midiFile);
        music = MidiSystem.getSequencer(false);
        music.open();
        music.setSequence(sequence);
    } catch (Exception e) {
        System.err.println("Problem loading MIDI file.");
        e.printStackTrace();
        return;
    }
    if (music instanceof Synthesizer) {
        synthesizer = (Synthesizer) music;
    } else {
        try {
            synthesizer = MidiSystem.getSynthesizer();
            synthesizer.open();
            if (synthesizer.getDefaultSoundbank() == null) {
                music.getTransmitter().setReceiver(MidiSystem.getReceiver());
            } else {
                music.getTransmitter().setReceiver(synthesizer.getReceiver());
            }
        } catch (Exception e) {
            e.printStackTrace();
            return;
        }
    }
      MidiChannel[] channels = synthesizer.getChannels();
     for (int i = 0; i < channels.length; i++) {
        channels[i].controlChange(7, (int) (gain * 127.0));
      }
     try {
        music.setSequence(sequence);
    } catch (InvalidMidiDataException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    music.setLoopCount(Sequencer.LOOP_CONTINUOUSLY);
    music.start();

}

Answer 1

volumeMessage.setMessage(ShortMessage.CONTROL_CHANGE, i, CHANGE_VOLUME,(int)(value * 127.0));
volumeMessage.setMessage(ShortMessage.CONTROL_CHANGE, i, 39, (int)(value * 127.0));
MidiSystem.getReceiver().send(volumeMessage, -1);

This code sends one message. The contents of that message are the values set by the second setMessage call, so the volume MSB is not changed at all. (And this is the wrong way of computing the LSB.)

Controller 7 is indeed for volume, but there is no exact standard for how the values are to be interpreted. Apparently, your synthesizer does not mute itself when it receives a volume of zero.

Many MIDI files do their own changes to controller 7. If your synthesizer supports Master Volume , you should send that instead.