Multiple Sequencers In Applet

Greenhorn

Posts: 7

posted 14 years ago

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Hi all,

There isn't a sound/audio forum here, so hopefully this is the best place to post this.

I'm working on a music applet and need to have multiple sequencers playing simultaneously. I have some test code and it works in my programming environment (I'm using the free JGrasp) but when I try to open the applet in a web browser, it doesn't play the sequencers at the same time. It only plays one sequencer at a time and switches (seems to be random) back and forth between them instead of just letting them both play together. Is there any reason why two (or more) sequencers won't play together in an applet when they do in my programming environment? Is this just simply a limitation within applets or is there some kind of work around to fix this?

I know you can do different tracks in a single sequencer, but I really need it to be separate sequencers playing simultaneously... Without getting into too much music/drum theory, I'm making a polyrhythm metronome and need to have different sequencers playing at different tempos (which you can't do with a single sequencer). If anyone has any ideas on how to get multiple sequencers to play nicely together in an applet that would be greatly appreciated.

Here is my sample program:

import java.util.*;
import javax.swing.*;
import javax.sound.midi.*;

public class MetronomeTestApplet extends JApplet
{
	public void init()
	{
		MetronomeTest metTest = new MetronomeTest();
		metTest.start();
	}
}

class MetronomeTest
{
	Sequencer sequencer1=null;
	Sequencer sequencer2=null;
	
	Sequence sequence1=null;
	Sequence sequence2=null;
	
	Track track1=null;
	Track track2=null;
	
	MidiEvent newEvent=null;
	
	int volume = 90;	
	int tempo	= 100;
	
	public MetronomeTest()
	{	
		try
		{	// SEQUENCER 1
			sequencer1 = MidiSystem.getSequencer();
			sequencer1.open();
			sequence1 = new Sequence(Sequence.PPQ, 16);
			track1 = sequence1.createTrack();
			
			ShortMessage instrumentMsg = new ShortMessage();
			instrumentMsg.setMessage(ShortMessage.PROGRAM_CHANGE, 0, 115, 0);		// 115 == woodblock
			track1.add(new MidiEvent(instrumentMsg, 0));
			
			// SEQUENCER 2
			sequencer2 = MidiSystem.getSequencer();
			sequencer2.open();
			sequence2 = new Sequence(Sequence.PPQ, 16);
			track2 = sequence2.createTrack();
			
			instrumentMsg = new ShortMessage();
			instrumentMsg.setMessage(ShortMessage.PROGRAM_CHANGE, 0, 117, 0);		// 117 == melodic tom
			track2.add(new MidiEvent(instrumentMsg, 0));
		}
		catch (Exception e) { }
	}
	
	public void destroy()
	{
		sequencer1.stop();
		sequencer1.close();
		
		sequencer2.stop();
		sequencer2.close();
	}
	
	public void start()
	{
		try
		{			
			// LOAD SEQUENCER 1			
			for (int i=0; i<4; i++)
			{
				ShortMessage noteOnMsg = new ShortMessage();
				noteOnMsg.setMessage(ShortMessage.NOTE_ON, 0, 60, volume);
				track1.add(new MidiEvent(noteOnMsg, 0 + 16*i));
				
				ShortMessage noteOffMsg = new ShortMessage();
				noteOffMsg.setMessage(ShortMessage.NOTE_OFF, 0, 60, volume);
				track1.add(new MidiEvent(noteOffMsg, 16 + 16*i));
			}
			
			// LOAD SEQUENCER 2			
			for (int i=0; i<8; i++)
			{
				ShortMessage noteOnMsg = new ShortMessage();
				noteOnMsg.setMessage(ShortMessage.NOTE_ON, 0, 60, volume);
				track2.add(new MidiEvent(noteOnMsg, 0 + 8*i));
				
				ShortMessage noteOffMsg = new ShortMessage();
				noteOffMsg.setMessage(ShortMessage.NOTE_OFF, 0, 60, volume);
				track2.add(new MidiEvent(noteOffMsg, 8 + 8*i));
			}
			
			// START SEQUENCERS
			sequencer1.setSequence(sequence1);
			sequencer1.setTempoInBPM(tempo);
			sequencer1.setLoopCount(Sequencer.LOOP_CONTINUOUSLY);
			
			sequencer2.setSequence(sequence2);
			sequencer2.setTempoInBPM(tempo);
			sequencer2.setLoopCount(Sequencer.LOOP_CONTINUOUSLY);
						
			sequencer1.start();
			sequencer2.start();
		}
		catch (Exception e) { }
	}
}

And the code for my html document:

Thanks,
-tkr

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