使用 Android 播放任意音调
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原文地址: http://stackoverflow.com/questions/2413426/
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Playing an arbitrary tone with Android
提问by Jeremy Logan
Is there any way to make Android emit a sound of arbitrary frequency (meaning, I don't want to have pre-recorded sound files)?
有没有办法让Android发出任意频率的声音（意思是，我不想有预先录制的声音文件）？
I've looked around and ToneGeneratorwas the only thing I was able to find that was even close, but it seems to only be capable of outputting the standard DTMF tones.
我环顾四周，只有ToneGenerator是我能找到的唯一接近的东西，但它似乎只能输出标准的 DTMF 音调。
Any ideas?
有任何想法吗？
回答by Steve Pomeroy
I originally found this example codeon a blog, but it had some bugs in it that generated some horrendous sounds. I've fixed the bugs and posted the resulting code here. Seems to work well for me!
我最初在博客上找到了这个示例代码，但它有一些错误，会产生一些可怕的声音。我已经修复了错误并在此处发布了结果代码。似乎对我来说效果很好！
public class PlaySound extends Activity {
// originally from http://marblemice.blogspot.com/2010/04/generate-and-play-tone-in-android.html
// and modified by Steve Pomeroy <[email protected]>
private final int duration = 3; // seconds
private final int sampleRate = 8000;
private final int numSamples = duration * sampleRate;
private final double sample[] = new double[numSamples];
private final double freqOfTone = 440; // hz
private final byte generatedSnd[] = new byte[2 * numSamples];
Handler handler = new Handler();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
@Override
protected void onResume() {
super.onResume();
// Use a new tread as this can take a while
final Thread thread = new Thread(new Runnable() {
public void run() {
genTone();
handler.post(new Runnable() {
public void run() {
playSound();
}
});
}
});
thread.start();
}
void genTone(){
// fill out the array
for (int i = 0; i < numSamples; ++i) {
sample[i] = Math.sin(2 * Math.PI * i / (sampleRate/freqOfTone));
}
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalised.
int idx = 0;
for (final double dVal : sample) {
// scale to maximum amplitude
final short val = (short) ((dVal * 32767));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
}
void playSound(){
final AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
sampleRate, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, generatedSnd.length,
AudioTrack.MODE_STATIC);
audioTrack.write(generatedSnd, 0, generatedSnd.length);
audioTrack.play();
}
}
回答by Xarph
Improving on the above code:
改进上面的代码：
Add amplitude ramp up and ramp down to avoid the clicks.
添加幅度斜坡上升和斜坡下降以避免咔嗒声。
Add code to determine when the tack has finished playing.
添加代码以确定大头针何时完成播放。
double duration = 1; // seconds
double freqOfTone = 1000; // hz
int sampleRate = 8000; // a number
double dnumSamples = duration * sampleRate;
dnumSamples = Math.ceil(dnumSamples);
int numSamples = (int) dnumSamples;
double sample[] = new double[numSamples];
byte generatedSnd[] = new byte[2 * numSamples];
for (int i = 0; i < numSamples; ++i) { // Fill the sample array
sample[i] = Math.sin(freqOfTone * 2 * Math.PI * i / (sampleRate));
}
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalized.
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalised.
int idx = 0;
int i = 0 ;
int ramp = numSamples / 20 ; // Amplitude ramp as a percent of sample count
for (i = 0; i< ramp; ++i) { // Ramp amplitude up (to avoid clicks)
double dVal = sample[i];
// Ramp up to maximum
final short val = (short) ((dVal * 32767 * i/ramp));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
for (i = i; i< numSamples - ramp; ++i) { // Max amplitude for most of the samples
double dVal = sample[i];
// scale to maximum amplitude
final short val = (short) ((dVal * 32767));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
for (i = i; i< numSamples; ++i) { // Ramp amplitude down
double dVal = sample[i];
// Ramp down to zero
final short val = (short) ((dVal * 32767 * (numSamples-i)/ramp ));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
AudioTrack audioTrack = null; // Get audio track
try {
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
sampleRate, AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT, (int)numSamples*2,
AudioTrack.MODE_STATIC);
audioTrack.write(generatedSnd, 0, generatedSnd.length); // Load the track
audioTrack.play(); // Play the track
}
catch (Exception e){
RunTimeError("Error: " + e);
return false;
}
int x =0;
do{ // Monitor playback to find when done
if (audioTrack != null)
x = audioTrack.getPlaybackHeadPosition();
else
x = numSamples;
} while (x<numSamples);
if (audioTrack != null) audioTrack.release(); // Track play done. Release track.
回答by meese
I wrapped the above wonderful solutions into a neat little package that's more useable out of the box as a simple configurable buzzer. It runs it in a background thread and has stop and play methods and a handful of options you can set.
我将上述绝妙的解决方案包装成一个整洁的小包，它作为一个简单的可配置蜂鸣器开箱即用。它在后台线程中运行它，并具有停止和播放方法以及您可以设置的一些选项。
It's up on JCenter so you can add it to your dependencies list like this
它在 JCenter 上，因此您可以像这样将其添加到您的依赖项列表中
compile 'net.mabboud:android-tone-player:0.2'
and you use it like this for a continuous buzzer
你像这样使用它来发出连续的蜂鸣声
ContinuousBuzzer tonePlayer = new ContinuousBuzzer();
tonePlayer.play();
// just an example don't actually use Thread.sleep in your app
Thread.sleep(1000);
tonePlayer.stop();
or a buzzer played only once and you can set frequency and volume like this
或者蜂鸣器只播放一次，你可以像这样设置频率和音量
OneTimeBuzzer buzzer = new OneTimeBuzzer();
buzzer.setDuration(5);
// volume values are from 0-100
buzzer.setVolume(50);
buzzer.setToneFreqInHz(110);
回答by extreme
Since there is a bug in some older android versions that causes a memory leak when using MODE_STATIC, I modified Xarph's answer above to use MODE_STREAM. Hopefully it will help some.
由于在使用 MODE_STATIC 时一些较旧的 android 版本中存在导致内存泄漏的错误，因此我修改了上面 Xarph 的答案以使用 MODE_STREAM。希望它会帮助一些人。
public void playTone(double freqOfTone, double duration) {
//double duration = 1000; // seconds
// double freqOfTone = 1000; // hz
int sampleRate = 8000; // a number
double dnumSamples = duration * sampleRate;
dnumSamples = Math.ceil(dnumSamples);
int numSamples = (int) dnumSamples;
double sample[] = new double[numSamples];
byte generatedSnd[] = new byte[2 * numSamples];
for (int i = 0; i < numSamples; ++i) { // Fill the sample array
sample[i] = Math.sin(freqOfTone * 2 * Math.PI * i / (sampleRate));
}
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalized.
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalised.
int idx = 0;
int i = 0 ;
int ramp = numSamples / 20 ; // Amplitude ramp as a percent of sample count
for (i = 0; i< ramp; ++i) { // Ramp amplitude up (to avoid clicks)
double dVal = sample[i];
// Ramp up to maximum
final short val = (short) ((dVal * 32767 * i/ramp));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
for (i = i; i< numSamples - ramp; ++i) { // Max amplitude for most of the samples
double dVal = sample[i];
// scale to maximum amplitude
final short val = (short) ((dVal * 32767));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
for (i = i; i< numSamples; ++i) { // Ramp amplitude down
double dVal = sample[i];
// Ramp down to zero
final short val = (short) ((dVal * 32767 * (numSamples-i)/ramp ));
// in 16 bit wav PCM, first byte is the low order byte
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
AudioTrack audioTrack = null; // Get audio track
try {
int bufferSize = AudioTrack.getMinBufferSize(sampleRate, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
sampleRate, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, bufferSize,
AudioTrack.MODE_STREAM);
audioTrack.play(); // Play the track
audioTrack.write(generatedSnd, 0, generatedSnd.length); // Load the track
}
catch (Exception e){
}
if (audioTrack != null) audioTrack.release(); // Track play done. Release track.
}
回答by Raju yourPepe
Modified Code Based on Singhaks' answer
根据 Singhaks 的回答修改代码
public class MainActivity extends Activity {
private final int duration = 30; // seconds
private final int sampleRate = 8000;
private final int numSamples = duration * sampleRate;
private final double sample[] = new double[numSamples];
private final double freqOfTone = 440; // hz
private final byte generatedSnd[] = new byte[2 * numSamples];
Handler handler = new Handler();
private AudioTrack audioTrack;
private boolean play = false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
8000, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, numSamples,
AudioTrack.MODE_STREAM);
}
@Override
protected void onResume() {
super.onResume();
// Use a new tread as this can take a while
Thread thread = new Thread(new Runnable() {
public void run() {
handler.post(new Runnable() {
public void run() {
playSound();
genTone();
}
});
}
});
thread.start();
}
void genTone(){
// fill out the array
while(play){
for (int i = 0; i < numSamples; ++i) {
// float angular_frequency =
sample[i] = Math.sin(2 * Math.PI * i / (sampleRate/freqOfTone));
}
int idx = 0;
// convert to 16 bit pcm sound array
// assumes the sample buffer is normalised.
for (double dVal : sample) {
short val = (short) (dVal * 32767);
generatedSnd[idx++] = (byte) (val & 0x00ff);
generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
}
audioTrack.write(generatedSnd, 0, numSamples);
}
}
void playSound(){
play = true;
audioTrack.play();
}
}
回答by simou
Here's another blog demoing a simple synth plus some UI
这是另一个博客，演示了一个简单的合成器和一些 UI
You might also be interested in csound or pdlib (pure data lib) for android.
您可能还对 android 的 csound 或 pdlib（纯数据库）感兴趣。
回答by Vahe Gharibyan
Do major (16 notes)
做专业（16个音符）
public class MainActivity extends AppCompatActivity {
private double mInterval = 0.125;
private int mSampleRate = 8000;
private byte[] generatedSnd;
private final double mStandardFreq = 440;
Handler handler = new Handler();
private AudioTrack audioTrack;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
protected void onResume() {
super.onResume();
// Use a new tread as this can take a while
final Thread thread = new Thread(new Runnable() {
public void run() {
byte[] tempByte = new byte[0];
for (int i = 0; i < 16 ; i++ ){
double note = getNoteFrequencies(i);
byte[] tonByteNote = getTone(mInterval, mSampleRate, note);
tempByte = concat(tonByteNote, tempByte);
}
generatedSnd = tempByte;
handler.post(new Runnable() {
public void run() {
playTrack(generatedSnd);
}
});
}
});
thread.start();
}
public byte[] concat(byte[] a, byte[] b) {
int aLen = a.length;
int bLen = b.length;
byte[] c= new byte[aLen+bLen];
System.arraycopy(a, 0, c, 0, aLen);
System.arraycopy(b, 0, c, aLen, bLen);
return c;
}
private double getNoteFrequencies(int index){
return mStandardFreq * Math.pow(2, (double) index/12.0d);
}
private byte[] getTone(double duration, int rate, double frequencies){
int maxLength = (int)(duration * rate);
byte generatedTone[] = new byte[2 * maxLength];
double[] sample = new double[maxLength];
int idx = 0;
for (int x = 0; x < maxLength; x++){
sample[x] = sine(x, frequencies / rate);
}
for (final double dVal : sample) {
final short val = (short) ((dVal * 32767));
// in 16 bit wav PCM, first byte is the low order byte
generatedTone[idx++] = (byte) (val & 0x00ff);
generatedTone[idx++] = (byte) ((val & 0xff00) >>> 8);
}
return generatedTone;
}
private AudioTrack getAudioTrack(int length){
if (audioTrack == null)
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
mSampleRate, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, length,
AudioTrack.MODE_STATIC);
return audioTrack;
}
private double sine(int x, double frequencies){
return Math.sin( 2*Math.PI * x * frequencies);
}
void playTrack(byte[] generatedSnd){
getAudioTrack(generatedSnd.length)
.write(generatedSnd, 0, generatedSnd.length);
audioTrack.play();
}
}
回答by shinta
see this helpful library
看到这个有用的图书馆
https://github.com/karlotoy/perfectTune
https://github.com/karlotoy/perfectTune
it's easy to use
很容易使用
add this to your dependencies
将此添加到您的依赖项中
compile 'com.github.karlotoy:perfectTune:1.0.2'
And you use it like this:
你像这样使用它：
PerfectTune perfectTune = new PerfectTune();
perfectTune.setTuneFreq(desire_freq);
perfectTune.playTune();
to stop the tune:
停止曲调：
perfectTune.stopTune();
回答by Singhak
float synth_frequency = 440;
int minSize = AudioTrack.getMinBufferSize(SAMPLE_RATE,
AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT);
AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
SAMPLE_RATE,
AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT,
minSize,
AudioTrack.MODE_STREAM);
audioTrack.play();
short[] buffer = new short[minSize];
float angle = 0;
while (true)
{
if (play)
{
for (int i = 0; i < buffer.length; i++)
{
float angular_frequency =
(float)(2*Math.PI) * synth_frequency / SAMPLE_RATE;
buffer[i] = (short)(Short.MAX_VALUE * ((float) Math.sin(angle)));
angle += angular_frequency;
}
audioTrack.write(buffer, 0, buffer.length);
}
// You can add arbitrary value in synth_frequency to get change sound for example you can add random variable to get sound
// 您可以在 synth_frequency 中添加任意值以获得变化的声音例如您可以添加随机变量来获得声音
回答by endolith
There are several programs for this, but they suck. I measured a few:
有几个程序可以做到这一点，但它们很糟糕。我测量了一些：
http://www.endolith.com/wordpress/2009/11/24/android-audio-applications/
http://www.endolith.com/wordpress/2009/11/24/android-audio-applications/
So don't do whatever they do. :D
所以不要做他们所做的任何事情。:D
