在java中改变midi音量

Question

首先，改变音量是有效的，但我在改变音量时遇到了一些问题，所以 1）在改变音量（比如将其设置为 0（无音量））之后，您仍然可以在音量 2 的默认值中听到部分歌曲)在歌曲改变音量后恢复到音量的默认值

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();
        }
}

播放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);

此代码发送一个消息。该消息的内容是第二次setMessage 调用设置的值，因此卷MSB 根本没有改变。 （这是计算 LSB 的错误方法。）

Controller 7 确实适用于音量，但对于如何解释这些值没有确切的标准。显然，当您的合成器接收到零音量时，它不会自行静音。

许多 MIDI 文件对控制器 7 进行自己的更改。如果您的合成器支持 Master Volume，您应该发送它。