如何在Java中生成音效？

下面是一个可能有帮助的示例。这会产生罪恶波：

package notegenerator;

import java.io.IOException;

/**
 * Tone generator and player.
 * 
 * @author Cesar Vezga vcesar@yahoo.com
 */
public class Main {

public static void main(String[] args) throws IOException {

    Player player = new Player();

    player.play(BeachRock.getTack1(),BeachRock.getTack2());

}

 }

 package notegenerator;

 public class BeachRock {

// GUITAR
static String gs1 = "T332 A4-E4 F#5-C6 E5-A5 T166 G5 A5 F#5 A5 F5 A5 E5-A5 E3 G3 G#3 ";
static String gs2 = "A3 A3 A3 G3 E3 E3 G3 G#3 ";
static String gs3 = "A3 A3 A3 G3 E3 A3 C4 C#4 ";
static String gs4 = gs2 + gs2 + gs2 + gs3;
static String gs5 = "D4 D4 D4 C4 A3 A3 C4 D#4 ";
static String gs6 = "D4 D4 D4 C4 A3 E3 G3 G#3 ";
static String gs7 = gs4 + gs5 + gs6 + gs2 + "A3 A3 A3 G3 E3 B3 D3 D#3 ";
static String gs8 = "E4 E4 E4 D4 B3 B3 E4 B3 " + gs6 + gs2;
static String gs9 = "x E3-B3 E3-B3 E3-B3 E3-B3 E3 G3 G#3 ";
static String gs10 = gs7 + gs8 + gs9;
static String gs11 = "A3-D4 X*7 X*16 X*5 E3 G3 G#3 ";
static String guitar = gs1 + gs10 + gs11 + gs10 + gs11 + "A3 A3 A3";

// DRUMS
static String ds1 = "D2 X D3 D3 X*2 D3 X ";
static String ds2 = "D2 X D3 D3 X D3 D3 D3 ";
static String ds3 = "D2 D3 D3 D3 D3 T83 D3 D3 T166 D3 ";
static String ds4 = ds1 + ds1 + ds1 + ds2;
static String ds5 = ds1 + ds1 + ds1 + ds3;
static String ds6 = "D2*2 D3 D3 X*2 D3*2 ";
static String ds7 = "D2*2 D3 D3 X D3 D3 D3 ";
static String ds8 = ds6 + ds6 + ds6 + ds7;

static String drums = "V25 T166 X*16 " + ds4 + ds4 + ds5 + ds8 + ds4 + ds4
        + ds5 + ds8;

public static String getTack1(){
    return guitar;
}

public static String getTack2(){
    return drums;
}


}

package notegenerator;

import java.util.HashMap;

/**
 * 
 * Physics of Music - Notes
 * 
 * Frequencies for equal-tempered scale
 * This table created using A4 = 440 Hz
 * Speed of sound = 345 m/s = 1130 ft/s = 770 miles/hr
 *  
 *  ("Middle C" is C4 )
 * 
 * http://www.phy.mtu.edu/~suits/notefreqs.html
 * 
 * @author Cesar Vezga <vcesar@yahoo.com>
 *
 */
 public class Notes {


private static final Object[] notes = {
"C0",16.35,
"C#0/Db0",17.32,
"D0",18.35,
"D#0/Eb0",19.45,
"E0",20.6,
"F0",21.83,
"F#0/Gb0",23.12,
"G0",24.5,
"G#0/Ab0",25.96,
"A0",27.5,
"A#0/Bb0",29.14,
"B0",30.87,
"C1",32.7,
"C#1/Db1",34.65,
"D1",36.71,
"D#1/Eb1",38.89,
"E1",41.2,
"F1",43.65,
"F#1/Gb1",46.25,
"G1",49.00,
"G#1/Ab1",51.91,
"A1",55.00,
"A#1/Bb1",58.27,
"B1",61.74,
"C2",65.41,
"C#2/Db2",69.3,
"D2",73.42,
"D#2/Eb2",77.78,
"E2",82.41,
"F2",87.31,
"F#2/Gb2",92.5,
"G2",98.00,
"G#2/Ab2",103.83,
"A2",110.00,
"A#2/Bb2",116.54,
"B2",123.47,
"C3",130.81,
"C#3/Db3",138.59,
"D3",146.83,
"D#3/Eb3",155.56,
"E3",164.81,
"F3",174.61,
"F#3/Gb3",185.00,
"G3",196.00,
"G#3/Ab3",207.65,
"A3",220.00,
"A#3/Bb3",233.08,
"B3",246.94,
"C4",261.63, // Middle C
"C#4/Db4",277.18,
"D4",293.66,
"D#4/Eb4",311.13,
"E4",329.63,
"F4",349.23,
"F#4/Gb4",369.99,
"G4",392.00,
"G#4/Ab4",415.3,
"A4",440.00,
"A#4/Bb4",466.16,
"B4",493.88,
"C5",523.25,
"C#5/Db5",554.37,
"D5",587.33,
"D#5/Eb5",622.25,
"E5",659.26,
"F5",698.46,
"F#5/Gb5",739.99,
"G5",783.99,
"G#5/Ab5",830.61,
"A5",880.00,
"A#5/Bb5",932.33,
"B5",987.77,
"C6",1046.5,
"C#6/Db6",1108.73,
"D6",1174.66,
"D#6/Eb6",1244.51,
"E6",1318.51,
"F6",1396.91,
"F#6/Gb6",1479.98,
"G6",1567.98,
"G#6/Ab6",1661.22,
"A6",1760.00,
"A#6/Bb6",1864.66,
"B6",1975.53,
"C7",2093.00,
"C#7/Db7",2217.46,
"D7",2349.32,
"D#7/Eb7",2489.02,
"E7",2637.02,
"F7",2793.83,
"F#7/Gb7",2959.96,
"G7",3135.96,
"G#7/Ab7",3322.44,
"A7",3520.00,
"A#7/Bb7",3729.31,
"B7",3951.07,
"C8",4186.01,
"C#8/Db8",4434.92,
"D8",4698.64,
"D#8/Eb8",4978.03

};

private HashMap<String,Double> noteMap;

public Notes(){
    noteMap = new HashMap<String,Double>();
    for(int i=0; i<notes.length; i=i+2){
        String name = (String)notes[i];
        double freq = (Double)notes[i+1];
        String[] keys = name.split("/");
        for(String key : keys){
            noteMap.put(key,  freq);
            System.out.println(key);
        }
    }
}


public byte[] getCordData(String keys, double duration){
    int N = (int) (8000 * duration/1000);
    byte[] a = new byte[N+1];
    String[] key = keys.split(" ");
    int count=0;
    for(String k : key){
        double freq = getFrequency(k);
        byte[] tone = tone(freq,duration);
            if(count==0){
               a = tone;
            }else{
               a = addWaves(a,tone);
            }
        count++;
    }

    return a;
}


public byte[] addWaves(byte[] a, byte[] b){
    int len = Math.max(a.length, b.length);
    byte[] c = new byte[len];
    for(int i=0; i<c.length; i++){
        byte aa = ( i < a.length ? a[i] : 0);
        byte bb = ( i < b.length ? b[i] : 0);

           c[i] = (byte) (( aa + bb ) / 2);
    }
    return c;
}


public double getFrequency(String key){
    Double f = noteMap.get(key);
    if(f==null){
        System.out.println("Key not found. "+key);
        f = 0D;
    }
    return f;
}

public byte[] tone(String key, double duration) {
    double freq = getFrequency(key);

    return tone(freq,duration); 
 } 

 public byte[] tone(double hz, double duration) {
        int N = (int) (8000 * duration/1000);
        byte[] a = new byte[N+1];
        for (int i = 0; i <= N; i++) {
            a[i] = (byte) ( Math.sin(2 * Math.PI * i * hz / 8000) * 127 );
        }
        return a; 
 } 


}

package notegenerator;

import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.SourceDataLine;

public class Player {

private SourceDataLine line = null;

private Notes notes = new Notes();

private long time = 250;

private double volumen = 1;

public void play(String keys) {

    byte[] data = parse(keys);

    start();

    line.write(data, 0, data.length);

    stop();

}

public void play(String... track) {

    byte[] data2 = parseAll(track);

    if (data2 != null) {
        start();

        line.write(data2, 0, data2.length);

        stop();
    }

}

private byte[] parseAll(String... track) {

    byte[] data2 = null;

    for (String t : track) {
        byte[] data1 = parse(t);
        if (data2 == null) {
            data2 = data1;
        } else {
            data2 = notes.addWaves(data1, data2);
        }
    }

    return data2;

}

private byte[] parse(String song) {
    time = 250;

    volumen = 1;

    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    String[] key = song.split(" ");

    byte[] data = null;

    for (String k : key) {
        int mult = 1;

        if (k.indexOf("*") > -1) {
            String keyAux = k.split("\\*")[0];
            mult = Integer.parseInt(k.split("\\*")[1]);
            k = keyAux;
        } else if (k.startsWith("T")) {
            time = Long.parseLong(k.substring(1));
            continue;
        } else if (k.startsWith("V")) {
            volumen =  Double.parseDouble(k.substring(1)) / 100;

            if(volumen>1) volumen = 1;
            if(volumen<0) volumen = 0;

            continue;
        }

        if (k.indexOf("-") > -1) {
            k = k.replaceAll("-", " ").trim();
            data = notes.getCordData(k, time * mult);
        } else {
            data = notes.tone(k, time * mult);
        }

        volumen(data);

        try {
            baos.write(data);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    return baos.toByteArray();

}



private void volumen(byte[] data) {
    for(int i=0; i<data.length; i++){
        data[i] = (byte) (data[i] * volumen);
    }

}

private void stop() {
    line.drain();
    line.stop();

}

private void start() {

    AudioFormat format = new AudioFormat(8000.0F, 8, 1, true, false);

    SourceDataLine.Info info = new DataLine.Info(SourceDataLine.class,
            format); // format
    // is
    // an
    // AudioFormat
    // object
    if (!AudioSystem.isLineSupported(info)) {
        System.out.println("Format not supported");
        System.exit(1);
    }

    // Obtain and open the line.
    try {
        line = (SourceDataLine) AudioSystem.getLine(info);
        line.open(format);
    } catch (LineUnavailableException ex) {
        ex.printStackTrace();
    }

    // Assume that the TargetDataLine, line, has already
    // been obtained and opened.
    int numBytesRead;

    line.start();

}

public void save(String track, String fname) throws IOException {
    byte[] data = parse(track);

    FileOutputStream fos = new FileOutputStream(fname);

    fos.write(data);
    fos.flush();
    fos.close();

}

}

您可以在 Java 中轻松生成采样的声音数据，并在不使用本机代码的情况下播放这些数据。如果你在谈论MIDI，事情可能会变得棘手，但我还没有涉足这个领域。

要生成采样的声音数据，您必须向后处理该过程。我们将像A-to-D一样工作，并随着时间的推移对连续的声音函数进行采样。您的声卡通过麦克风或线路输入对音频执行相同的操作。

首先，选择采样率（不是我们生成的音调的频率）。让我们使用44100 hz，因为这可能是声卡播放速率（因此没有采样率转换，除非硬件这样做，否则这并不容易）。

// in hz, number of samples in one second
sampleRate = 44100

// this is the time BETWEEN Samples
samplePeriod = 1.0 / sampleRate

// 2ms
duration = 0.002;
durationInSamples = Math.ceil(duration * sampleRate);

time = 0;
for(int i = 0; i < durationInSamples; i++)
{
  // sample a sine wave at 440 hertz at each time tick
  // substitute a function that generates a sawtooth as a function of time / freq
  // rawOutput[i] = function_of_time(other_relevant_info, time);
  rawOutput[i] = Math.sin(2 * Math.PI * 440 * time);
  time += samplePeriod;
}

// now you can playback the rawOutput
// streaming this may be trickier