我在android.I中做聲音分析器應用程序可以使用AudioTrack Api.i生成18 kHz至20 kHz超聲波音頻可以使用AudioRecord Api記錄音頻。但我不能知道如何計算麥克風輸入數據的頻率。我看到了多個問題How to get frequency from fft result?和Get frequency wav audio using FFT and Complex class它沒有給出正確的頻率。請幫助我。謝謝我的溝通。如何計算音頻記錄器麥克風輸入數據的頻率水平
這是我的頻率計算代碼
int bufferSizeInBytes = 1024;
short[] buffer = new short[bufferSizeInBytes];
class Recording extends Thread {
@Override
public void run() {
while (true) {
bufferReadResult = audioInput.read(buffer, 0, bufferSizeInBytes); // record data from mic into buffer
if(bufferReadResult > 0){
calculate();
}
}
}
public void calculate() {
DoubleFFT_1D fft1d = new DoubleFFT_1D(bufferSizeInBytes);//using JTransforms lib
double[] fftBuffer = new double[bufferSizeInBytes * 2];
double[] magnitude = new double[bufferSizeInBytes/2];
// copy real input data to complex FFT buffer
for (int i = 0; i < bufferSizeInBytes - 1; ++i) {
fftBuffer[2 * i] = buffer[i];
fftBuffer[2 * i + 1] = 0;
}
//perform FFT on fft[] buffer
fft1d.realForward(fftBuffer);
// calculate power spectrum (magnitude) values from fft[]
for (int i = 0; i < (bufferSizeInBytes/2) - 1; ++i) {
double real = fftBuffer[2 * i];
double imaginary = fftBuffer[2 * i + 1];
magnitude[i] = Math.sqrt(real * real + imaginary * imaginary);
}
// find largest peak in power spectrum
double max_magnitude = magnitude[0];
int max_index = 0;
for (int i = 0; i < magnitude.length; ++i) {
if (magnitude[i] > max_magnitude) {
max_magnitude = (int) magnitude[i];
max_index = i;
}
}
double freq = max_index * 44100/bufferSizeInBytes;
Log.e("AudioBEacon", "" + freq);
}
}
這是我output.Please讓我知道我做了錯誤。
02-10 12:33:04.450 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21662.0
02-10 12:33:04.451 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21317.0
02-10 12:33:04.453 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21791.0
02-10 12:33:04.471 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21748.0
02-10 12:33:04.472 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21533.0
02-10 12:33:04.474 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21834.0
02-10 12:33:04.491 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21533.0
02-10 12:33:04.493 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21705.0
02-10 12:33:04.511 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21533.0
02-10 12:33:04.512 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21447.0
02-10 12:33:04.513 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21490.0
02-10 12:33:04.531 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21576.0
02-10 12:33:04.551 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21619.0
02-10 12:33:04.591 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21877.0
02-10 12:33:04.613 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21576.0
02-10 12:33:04.633 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21920.0
02-10 12:33:04.653 17013-17063/com.org.sohamsaa.audiobeacontransmitter E/AudioBEacon: 21791.0
我的頻率範圍爲18 kHz至20 khz.but我沒有得到我的frequency.how篩選我frequency.thank你。
刪除'(INT)'投這裏:'max_magnitude =(int)的大小[I]' - 可能還有其他的問題,但是這肯定是不對的。還要注意,大多數設備在> 18 kHz時的靈敏度非常差 - 麥克風通常在15 kHz以上響應較差,抗干擾濾波器可能會進一步降低音量。 –
@保羅 - [R感謝您的回覆,我刪除(INT),但它不工作,我產生14 kHz的頻率,但我不getting.This是我的日誌結果 E/AudioBEacon:861.0 E/AudioBEacon: 21404.0 E/AudioBEacon:21705.0 E/AudioBEacon:21447.0 E/AudioBEacon:215.0 E/AudioBEacon:21705.0 E/AudioBEacon:344.0 E/AudioBEacon:473.0 E/AudioBEacon:430.0 – Siddharthan
是什麼窗函數怎麼做? – Siddharthan