Android - 使用 MIDI 文件播放 SoundFont

Question

我有一个 MIDI 文件，我使用以下代码在 android 中使用 MediaPlayer 播放了该 MIDI 文件：

val mMediaPlayer = MediaPlayer.create(context, R.raw.test_ring_1)

mMediaPlayer?.start()

它默认使用钢琴等一种乐器演奏，现在我想添加 soundfont (sf2/sf3) 文件来播放不同乐器和混响效果的 MIDI 音符。

请指导实现预期结果的方法。

Answer 1

有两个库将用于使用 SoundFont 播放 MIDI 文件。

Midi Driver

只是一个用于在 Android 上播放 MIDI 音符的合成器。您可以将它与 USB/Bluetooth-MIDI 库一起使用来创建您的 MIDI 应用程序。

支持 SoundFont2 文件。

Android MIDI Library

这个库提供了一个读取、操作和写入 MIDI 文件的接口。支持“回放”作为实时事件调度系统。此库不包含实际的音频播放或设备接口。

初始化 SF2-SoundBank

SF2Soundbank sf = new SF2Soundbank(getAssets().open("test.sf2"));
        synth = new SoftSynthesizer();
        synth.open();
        synth.loadAllInstruments(sf);
        synth.getChannels()[0].programChange(0);
        synth.getChannels()[1].programChange(1);
        recv = synth.getReceiver();

从 MIDI 文件播放 Midi 音符

MidiFile midiFile = new MidiFile(getAssets().open("test.mid"));

// Create a new MidiProcessor:
MidiProcessor processor = new MidiProcessor(midiFile);

// listen for all midi events:
processor.registerEventListener(new MidiEventListener() {
    @Override
    public void onStart(boolean fromBeginning) {

    }

    @Override
    public void onEvent(MidiEvent event, long ms) {

        if (event.getClass() == NoteOn.class) {

                NoteOn noteOn = ((NoteOn) event);

                try {
                    ShortMessage msg = new ShortMessage();
                    msg.setMessage(ShortMessage.NOTE_ON, channel, noteOn.getNoteValue(), noteOn.getVelocity());
                    recv.send(msg, ms);
                } catch (InvalidMidiDataException e) {
                    e.printStackTrace();
                }

            } else if (event.getClass() == NoteOff.class) {

                NoteOff noteOff = ((NoteOff) event);

                try {
                    ShortMessage msg = new ShortMessage();
                    msg.setMessage(ShortMessage.NOTE_ON, channel, noteOff.getNoteValue(), noteOff.getVelocity());
                    recv.send(msg, ms);
                } catch (InvalidMidiDataException e) {
                    e.printStackTrace();
                }

            }
    }

    @Override
    public void onStop(boolean finished) {

    }
}, MidiEvent.class);

// Start the processor:
processor.start();

用于定义 SF 通道的变量

private int channel = 0;

Answer 2

我已经测试过它可以工作

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    try {
        SF2Soundbank sf = new SF2Soundbank(getAssets().open("SmallTimGM6mb.sf2"));
        synth = new SoftSynthesizer();
        synth.open();
        synth.loadAllInstruments(sf);
        synth.getChannels()[0].programChange(0);
        synth.getChannels()[1].programChange(1);
        recv = synth.getReceiver();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (MidiUnavailableException e) {
        e.printStackTrace();
    }


    this.findViewById(R.id.piano).setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            int action = MotionEventCompat.getActionMasked(event);
            if (action == MotionEvent.ACTION_DOWN) {
                try {
                    ShortMessage msg = new ShortMessage();
                    msg.setMessage(ShortMessage.NOTE_ON, 0, 60, 127);
                    recv.send(msg, -1);
                } catch (InvalidMidiDataException e) {
                    e.printStackTrace();
                }
            } else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
                try {
                    ShortMessage msg = new ShortMessage();
                    msg.setMessage(ShortMessage.NOTE_OFF, 0, 60, 127);
                    recv.send(msg, -1);
                } catch (InvalidMidiDataException e) {
                    e.printStackTrace();
                }
            }
            return true;
        }
    });

    this.findViewById(R.id.woodblock).setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            int action = MotionEventCompat.getActionMasked(event);
            if (action == MotionEvent.ACTION_DOWN) {
                try {
                    ShortMessage msg = new ShortMessage();
                    msg.setMessage(ShortMessage.NOTE_ON, 1, 60, 127);
                    recv.send(msg, -1);
                } catch (InvalidMidiDataException e) {
                    e.printStackTrace();
                }
            } else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
                try {
                    ShortMessage msg = new ShortMessage();
                    msg.setMessage(ShortMessage.NOTE_OFF, 1, 60, 127);
                    recv.send(msg, -1);
                } catch (InvalidMidiDataException e) {
                    e.printStackTrace();
                }
            }
            return true;
        }
    });
}

不要忘记从下面的存储库中包含 sherlockmidi 库，示例也可以在下面的存储库中找到。

https://github.com/agangzz/SherlockMidi