java - MIDI Java 生成困惑的声音

Question

我一直在一个项目中工作，我需要在 Java 中操作 MIDI 文件中的每个乐器。然后我决定从序列中的每条轨道获取每个 MIDI 事件并将其发送到接收器。之后，线程等待每个滴答持续的时间，然后在下一个滴答中再次执行。问题是:乐器的声音以及它们的顺序变得非常困惑。我也试着单独执行每首轨道，但它仍然一团糟!代码:

    Sequence    sequence        = MidiSystem.getSequence(new File(source));
    Synthesizer synth           = MidiSystem.getSynthesizer();

    //Gets a MidiMessage and send it to Synthesizer
    Receiver    rcv             = synth.getReceiver();

    //Contains all tracks and events from MIDI file
    Track[]     tracks          = sequence.getTracks();
    synth.open();

    //If there are tracks
    if(tracks != null)
    {
        //Verify the division type of the sequence (PPQ, SMPT)
        if(sequence.getDivisionType() == Sequence.PPQ)
        {
            int     ppq         = sequence.getResolution();
            //Do the math to get the time (in miliseconds) each tick takes 
            long    tickTime    = TicksToMiliseconds(BPM,ppq);
            //Returns the number of ticks from the longest track
            int     longestTrackTicks   = LongestTrackTicks(tracks);

            //Each iteration sends a new message to 'receiver'
            for(int tick = 0; tick < maiorTick ; tick++)
            {   
                //Iteration of each track
                for(int trackNumber = 0; trackNumber < tracks.length; trackNumber++)
                {
                    //If the number of ticks from a track isn't already finished
                    //continue
                    if(tick < tracks[trackNumber].size())
                    {
                        MidiEvent ev = tracks[trackNumber].get(tick);
                        rcv.send(ev.getMessage(),-1);
                    }
                }
                Thread.sleep(tickTime);
            }

        }
    }
    synth.close();

Answer 1

正如 ntabee 所说，Track.get(n) 返回轨道中的第 n 个事件；要按时间获取事件，您必须手动比较事件的时间。

此外，Thread.sleep() 不是很精确，可以等待比预期更长的时间。这些错误会累积起来。

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要实时更改 MIDI 消息，请告诉音序器播放您自己的 Receiver，然后对事件做任何您想做的事并将它们传递给“真正的”Receiver.