Get frequency wav audio using FFT and Complex class

Question

It\'s been asked a lot, but I still stuck about implement FFT class on Android I need to process my audio data using FFT...

I already read the almost same question h

Answer 1

I already found the answer... :)

I create method to calculate array value from audio...

public double[] calculateFFT(byte[] signal)
    {           
        final int mNumberOfFFTPoints =1024;
        double mMaxFFTSample;

        double temp;
        Complex[] y;
        Complex[] complexSignal = new Complex[mNumberOfFFTPoints];
        double[] absSignal = new double[mNumberOfFFTPoints/2];

        for(int i = 0; i < mNumberOfFFTPoints; i++){
            temp = (double)((signal[2*i] & 0xFF) | (signal[2*i+1] << 8)) / 32768.0F;
            complexSignal[i] = new Complex(temp,0.0);
        }

        y = FFT.fft(complexSignal); // --> Here I use FFT class

        mMaxFFTSample = 0.0;
        mPeakPos = 0;
        for(int i = 0; i < (mNumberOfFFTPoints/2); i++)
        {
             absSignal[i] = Math.sqrt(Math.pow(y[i].re(), 2) + Math.pow(y[i].im(), 2));
             if(absSignal[i] > mMaxFFTSample)
             {
                 mMaxFFTSample = absSignal[i];
                 mPeakPos = i;
             } 
        }

        return absSignal;

    }

Then I called it in class Write Audio..

private void writeAudioDataToFile(){

        byte data[] = new byte[bufferSize];
        String filename = getTempFilename();
       FileOutputStream os = null;

        try {
                os = new FileOutputStream(filename);
        } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
        }

        int read = 0;                
        if(null != os){
                while(isRecording){
                        read = recorder.read(data, 0, bufferSize);
                        if(read > 0){
                            absNormalizedSignal = calculateFFT(data); // --> HERE ^__^
                        }

                        if(AudioRecord.ERROR_INVALID_OPERATION != read){
                                try {
                                        os.write(data);
                                } catch (IOException e) {
                                        e.printStackTrace();
                                }
                        }
                }

                try {
                        os.close();
                } catch (IOException e) {
                        e.printStackTrace();
                }
        }
}