我在生成特定頻率的聲音時遇到了一些麻煩。我已經設置了我的應用程序,以便您可以在搜索欄上來回滑動以選擇特定的頻率,然後應用程序使用該頻率生成音調。頻率音調發生器播放錯誤的聲音
我目前正在聽到一個音調很好,但它是一個完全不同的頻率比你設置它。 (並且我知道問題不在於將搜索欄中的值傳遞到「音調生成過程」,所以它必須是我生成音調的方式。)
此代碼有什麼問題? 感謝
private final int duration = 3; // seconds
private final int sampleRate = 8000;
private final int numSamples = duration * sampleRate;
private final double sample[] = new double[numSamples];
double dbFreq = 0; // I assign the frequency to this double
private final byte generatedSnd[] = new byte[2 * numSamples];
...
void genTone(double dbFreq){
// fill out the array
for (int i = 0; i < numSamples; ++i) {
sample[i] = Math.sin(2 * Math.PI * i/(sampleRate/dbFreq));
}
// 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_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT, numSamples,
AudioTrack.MODE_STATIC);
audioTrack.write(generatedSnd, 0, generatedSnd.length);
audioTrack.play();
}
一個完全瘋狂的猜測在這裏:也許你需要使用「無符號字節」?在這種情況下,由於缺少Java中的無符號字節,您可以使用此處描述的技術:http://stackoverflow.com/questions/11088/what-is-the-best-way-to-work-around-事實 - 所有-java-bytes-are-signed – DigCamara 2013-03-22 20:18:36