Java example source code file (TestPreciseTimestampRendering.java)

This example Java source code file (TestPreciseTimestampRendering.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

audio, audioformat, audioinputstream, exception, midi, nothing, random, sf2instrument, sf2instrumentregion, sf2layerregion, sf2sample, sf2soundbank, shortmessage, simpleinstrument, simplesoundbank, sound, test, util

The TestPreciseTimestampRendering.java Java example source code

/*
 * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/* @test
 @summary Test rendering when using precise timestamps */

import java.util.Arrays;
import java.util.Random;

import javax.sound.midi.MidiChannel;
import javax.sound.midi.Receiver;
import javax.sound.midi.ShortMessage;
import javax.sound.midi.Soundbank;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;

import com.sun.media.sound.AudioFloatConverter;
import com.sun.media.sound.AudioSynthesizer;
import com.sun.media.sound.ModelAbstractChannelMixer;
import com.sun.media.sound.ModelChannelMixer;
import com.sun.media.sound.SF2Instrument;
import com.sun.media.sound.SF2InstrumentRegion;
import com.sun.media.sound.SF2Layer;
import com.sun.media.sound.SF2LayerRegion;
import com.sun.media.sound.SF2Sample;
import com.sun.media.sound.SF2Soundbank;
import com.sun.media.sound.SimpleInstrument;
import com.sun.media.sound.SimpleSoundbank;
import com.sun.media.sound.SoftSynthesizer;

public class TestPreciseTimestampRendering {

    public static AudioFormat format = new AudioFormat(44100, 16, 1, true,
            false);

    public static SF2Soundbank createTestSoundbank() {
        // Create impulse instrument
        // used to measure timing of note-on playback
        SF2Soundbank soundbank = new SF2Soundbank();
        float[] data = new float[100];
        Arrays.fill(data, 0);
        data[0] = 1.0f;
        byte[] bdata = new byte[data.length * format.getFrameSize()];
        AudioFloatConverter.getConverter(format).toByteArray(data, bdata);

        SF2Sample sample = new SF2Sample(soundbank);
        sample.setName("Test Sample");
        sample.setData(bdata);
        sample.setSampleRate((long) format.getSampleRate());
        sample.setOriginalPitch(69);
        soundbank.addResource(sample);

        SF2Layer layer = new SF2Layer(soundbank);
        layer.setName("Test Layer");
        soundbank.addResource(layer);
        SF2LayerRegion region = new SF2LayerRegion();
        region.setSample(sample);
        layer.getRegions().add(region);

        SF2Instrument ins = new SF2Instrument(soundbank);
        ins.setName("Test Instrument");
        soundbank.addInstrument(ins);
        SF2InstrumentRegion insregion = new SF2InstrumentRegion();
        insregion.setLayer(layer);
        ins.getRegions().add(insregion);

        return soundbank;
    }

    public static Soundbank createTestSoundbankWithChannelMixer() {
        SF2Soundbank soundbank = createTestSoundbank();

        SimpleSoundbank simplesoundbank = new SimpleSoundbank();
        SimpleInstrument simpleinstrument = new SimpleInstrument() {

            public ModelChannelMixer getChannelMixer(MidiChannel channel,
                    AudioFormat format) {
                return new ModelAbstractChannelMixer() {
                    boolean active = true;

                    public boolean process(float[][] buffer, int offset, int len) {
                        for (int i = 0; i < buffer.length; i++) {
                            float[] cbuffer = buffer[i];
                            for (int j = 0; j < cbuffer.length; j++) {
                                cbuffer[j] = -cbuffer[j];
                            }
                        }
                        return active;
                    }

                    public void stop() {
                        active = false;
                    }
                };
            }

        };
        simpleinstrument.add(soundbank.getInstruments()[0]);
        simplesoundbank.addInstrument(simpleinstrument);

        return simplesoundbank;
    }

    public static void main(String[] args) throws Exception {
        test(createTestSoundbank());
        test(createTestSoundbankWithChannelMixer());
    }

    public static void test(Soundbank soundbank) throws Exception {

        // Create instance of synthesizer using the testing soundbank above
        AudioSynthesizer synth = new SoftSynthesizer();
        AudioInputStream stream = synth.openStream(format, null);
        synth.unloadAllInstruments(synth.getDefaultSoundbank());
        synth.loadAllInstruments(soundbank);
        Receiver recv = synth.getReceiver();

        // Set volume to max and turn reverb off
        ShortMessage reverb_off = new ShortMessage();
        reverb_off.setMessage(ShortMessage.CONTROL_CHANGE, 91, 0);
        recv.send(reverb_off, -1);
        ShortMessage full_volume = new ShortMessage();
        full_volume.setMessage(ShortMessage.CONTROL_CHANGE, 7, 127);
        recv.send(full_volume, -1);

        Random random = new Random(3485934583945l);

        // Create random timestamps
        long[] test_timestamps = new long[30];
        for (int i = 1; i < test_timestamps.length; i++) {
            test_timestamps[i] = i * 44100
                    + (int) (random.nextDouble() * 22050.0);
        }

        // Send midi note on message to synthesizer
        for (int i = 0; i < test_timestamps.length; i++) {
            ShortMessage midi_on = new ShortMessage();
            midi_on.setMessage(ShortMessage.NOTE_ON, 69, 127);
            recv.send(midi_on,
                    (long) ((test_timestamps[i] / 44100.0) * 1000000.0));
        }

        // Measure timing from rendered audio
        float[] fbuffer = new float[100];
        byte[] buffer = new byte[fbuffer.length * format.getFrameSize()];
        long firsts = -1;
        int counter = 0;
        long s = 0;
        long max_jitter = 0;
        outerloop: for (int k = 0; k < 10000000; k++) {
            stream.read(buffer);
            AudioFloatConverter.getConverter(format).toFloatArray(buffer,
                    fbuffer);
            for (int i = 0; i < fbuffer.length; i++) {
                if (fbuffer[i] != 0) {
                    if (firsts == -1)
                        firsts = s;

                    long measure_time = (s - firsts);
                    long predicted_time = test_timestamps[counter];

                    long jitter = Math.abs(measure_time - predicted_time);

                    if (jitter > 10)
                        max_jitter = jitter;

                    counter++;
                    if (counter == test_timestamps.length)
                        break outerloop;
                }
                s++;
            }
        }
        synth.close();

        if (counter == 0)
            throw new Exception("Nothing was measured!");

        if (max_jitter != 0) {
            throw new Exception("Jitter has occurred! "
                    + "(max jitter = " + max_jitter + ")");
        }

    }

}