Androidで任意のトーンを再生する
Androidが任意の周波数の音を発する方法はありますか（つまり、事前に録音された音ファイルを持ちたくありません）？
私は周りを見回しましたが、 ToneGenerator だけがそれを見つけることができました。
何か案は？
私はもともとブログで このサンプルコード を発見しましたが、いくつかの恐ろしい音を生成するバグがいくつかありました。バグを修正し、結果のコードをここに投稿しました。私にとってはうまくいくようです！
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();
}
}
上記のコードの改善：
クリックを避けるために、振幅の増加と減少を追加します。
コードを追加して、タックの再生がいつ終了するかを判断します。
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.
上記のすばらしいソリューションを、シンプルで設定可能なブザーとしてすぐに使用できるすてきな小さなパッケージにラップしました。バックグラウンドスレッドで実行し、停止および再生メソッドと設定可能ないくつかのオプションを備えています。
JCenterにあるため、このように依存関係リストに追加できます。
compile 'net.mabboud:Android-tone-player:0.2'
連続ブザーにこのように使用します
ContinuousBuzzer tonePlayer = new ContinuousBuzzer();
tonePlayer.play();
// just an example don't actually use Thread.sleep in your app
Thread.sleep(1000);
tonePlayer.stop();
または、ブザーを1回だけ鳴らして、このように周波数と音量を設定できます
OneTimeBuzzer buzzer = new OneTimeBuzzer();
buzzer.setDuration(5);
// volume values are from 0-100
buzzer.setVolume(50);
buzzer.setToneFreqInHz(110);
MODE_STATICを使用しているときにメモリリークを引き起こすバグが古いAndroidバージョンにあるため、上記のXarphの答えを変更してMODE_STREAMを使用しました。
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.
}
Singhaksの回答に基づいた修正コード
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();
}
}
シンプルなシンセといくつかのUIをデモする別のブログ
また、Android用のcsoundまたはpdlib（純粋なデータライブラリ）にも興味があるかもしれません。
この役立つライブラリをご覧ください
https://github.com/karlotoy/perfectTune
使いやすい
これを依存関係に追加します
compile 'com.github.karlotoy:perfectTune:1.0.2'
そして、あなたはこれを次のように使用します：
PerfectTune perfectTune = new PerfectTune();
perfectTune.setTuneFreq(desire_freq);
perfectTune.playTune();
曲を停止するには：
perfectTune.stopTune();
Do major（16 notes）
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();
}
}
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);
}
// synth_frequencyに任意の値を追加してサウンドを変更できます。たとえば、ランダム変数を追加してサウンドを取得できます
これにはいくつかのプログラムがありますが、それらはひどいです。私はいくつかを測定しました：
http://www.endolith.com/wordpress/2009/11/24/Android-audio-applications/
だから、彼らがすることは何もしないでください。 ：D