我正在寻找可用于在运行时生成声音的 Java 代码，而不是播放现有的声音文件。
例如，生成 440 Hz、持续 2 毫秒的锯齿波形的最佳代码是什么？ 源代码赞赏！
我记得我的 Commodore 128 有一个简单的声音命令，它将声音、频率、波形和持续时间作为参数来定义声音。这在很多简单的情况下（快速而肮脏的游戏、声音实验等）都非常有效。
我正在寻找类似声音的音效，而不是音乐或 MIDI（JFugue 库很好地涵盖了这些）。
【问题讨论】：
这是一个可能有帮助的示例。这会产生正弦波：
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();
}
}
【讨论】：
您可以轻松地在 Java 中生成采样的声音数据并播放它，而无需使用本机代码。如果你在谈论 MIDI，事情可能会变得棘手，但我还没有涉足那个领域。
要生成采样的声音数据，您必须将过程倒退。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为音频做同样的事情。
首先，选择一个采样率（不是我们生成的音调的频率）。让我们选择 44100 hz，因为这可能是声卡播放速率（因此没有采样率转换，除非硬件做到这一点，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
【讨论】：
Java media framework 两者兼而有之。您可以播放录制的声音或使用 MIDI 接口合成您自己的声音和音乐。它还提供了一个混音器 API。
当然，如果您知道要播放的波形的详细信息，则可以定期“采样”该函数，并将生成的样本传递给播放 API，就好像它是预先录制的声音文件一样。
JMF 不是由 Sun 积极维护的，但有适用于各种平台的有效发行版。
我的第一台计算机是 Commodore 64，我记得 Tears for Fears 的 SID 芯片“人人都想统治世界”。我不知道this pure Java SID emulator 是否开源，但它可能会为您提供一些关于实现更高级别的 Attack-Decay-Sustain-Release 和波形功能的建议。
【讨论】：
您想要的可能不是声音 API，而是某种合成器代码，我很确定您需要比 Java 允许的更多低级声音驱动程序控制（它是一种通常在“沙箱”中运行的解释语言）。
但好消息是，在谷歌上快速搜索“java sound synthesizing”会发现一个名为JSyn 的插件，它使用本地 C 方法（我猜这是一种方法）来生成声音。它似乎可以免费用于非商业用途，也可以在商业许可证中使用。 :)
【讨论】：