void RealInverseRealFFT(int NumSamples, float *In, float *Out){
// Remap to RealFFTf() function
int i;
HFFT hFFT = GetFFT(NumSamples);
float *pFFT = new float[NumSamples];
// Copy the data into the processing buffer
pFFT[0] = In[0];
for(i=1; i<NumSamples/2; i++){
pFFT[i] = In[i];
pFFT[NumSamples - i] = In[i];
}
pFFT[NumSamples/2] = In[NumSamples/2];
// Perform the FFT
RealFFTf(pFFT, hFFT);
// Copy the data into the output
for(i=1;i<NumSamples/2;i++) {
Out[i]=pFFT[hFFT->BitReversed[i]];
}
// Handle the (real-only) DC
Out[0] = pFFT[0];
delete [] pFFT;
ReleaseFFT(hFFT);
}
/*
* Real Fast Fourier Transform
*
*/
void RealFFT(int NumSamples, float *RealIn, float *RealOut, float *ImagOut)
{
// Remap to RealFFTf() function
int i;
HFFT hFFT = GetFFT(NumSamples);
float *pFFT = new float[NumSamples];
// Copy the data into the processing buffer
for(i=0; i<NumSamples; i++)
pFFT[i] = RealIn[i];
// Perform the FFT
RealFFTf(pFFT, hFFT);
// Copy the data into the real and imaginary outputs
for(i=1;i<(NumSamples/2);i++) {
RealOut[i]=pFFT[hFFT->BitReversed[i] ];
ImagOut[i]=pFFT[hFFT->BitReversed[i]+1];
}
// Handle the (real-only) DC and Fs/2 bins
RealOut[0] = pFFT[0];
RealOut[i] = pFFT[1];
ImagOut[0] = ImagOut[i] = 0;
// Fill in the upper half using symmetry properties
for(i++ ; i<NumSamples; i++) {
RealOut[i] = RealOut[NumSamples-i];
ImagOut[i] = -ImagOut[NumSamples-i];
}
delete [] pFFT;
ReleaseFFT(hFFT);
}
void RealFFT(size_t NumSamples, const float *RealIn, float *RealOut, float *ImagOut)
{
auto hFFT = GetFFT(NumSamples);
Floats pFFT{ NumSamples };
// Copy the data into the processing buffer
for(size_t i = 0; i < NumSamples; i++)
pFFT[i] = RealIn[i];
// Perform the FFT
RealFFTf(pFFT.get(), hFFT.get());
// Copy the data into the real and imaginary outputs
for (size_t i = 1; i<(NumSamples / 2); i++) {
RealOut[i]=pFFT[hFFT->BitReversed[i] ];
ImagOut[i]=pFFT[hFFT->BitReversed[i]+1];
}
// Handle the (real-only) DC and Fs/2 bins
RealOut[0] = pFFT[0];
RealOut[NumSamples / 2] = pFFT[1];
ImagOut[0] = ImagOut[NumSamples / 2] = 0;
// Fill in the upper half using symmetry properties
for(size_t i = NumSamples / 2 + 1; i < NumSamples; i++) {
RealOut[i] = RealOut[NumSamples-i];
ImagOut[i] = -ImagOut[NumSamples-i];
}
}
void ComputeSpectrumUsingRealFFTf(float *buffer, HFFT hFFT, float *window, int len, float *out)
{
int i;
if(len > hFFT->Points*2)
len = hFFT->Points*2;
for(i=0; i<len; i++)
buffer[i] *= window[i];
for( ; i<(hFFT->Points*2); i++)
buffer[i]=0; // zero pad as needed
RealFFTf(buffer, hFFT);
// Handle the (real-only) DC
float power = buffer[0]*buffer[0];
if(power <= 0)
out[0] = -160.0;
else
out[0] = 10.0*log10(power);
for(i=1;i<hFFT->Points;i++) {
power = (buffer[hFFT->BitReversed[i] ]*buffer[hFFT->BitReversed[i] ])
+ (buffer[hFFT->BitReversed[i]+1]*buffer[hFFT->BitReversed[i]+1]);
if(power <= 0)
out[i] = -160.0;
else
out[i] = 10.0*log10f(power);
}
}
void EffectNoiseRemoval::FillFirstHistoryWindow()
{
int i;
for(i=0; i < mWindowSize; i++)
mFFTBuffer[i] = mInWaveBuffer[i];
RealFFTf(mFFTBuffer, hFFT);
for(i = 1; i < (mSpectrumSize-1); i++) {
mRealFFTs[0][i] = mFFTBuffer[hFFT->BitReversed[i] ];
mImagFFTs[0][i] = mFFTBuffer[hFFT->BitReversed[i]+1];
mSpectrums[0][i] = mRealFFTs[0][i]*mRealFFTs[0][i] + mImagFFTs[0][i]*mImagFFTs[0][i];
mGains[0][i] = mNoiseAttenFactor;
}
// DC and Fs/2 bins need to be handled specially
mSpectrums[0][0] = mFFTBuffer[0]*mFFTBuffer[0];
mSpectrums[0][mSpectrumSize-1] = mFFTBuffer[1]*mFFTBuffer[1];
mGains[0][0] = mNoiseAttenFactor;
mGains[0][mSpectrumSize-1] = mNoiseAttenFactor;
}
void PowerSpectrum(size_t NumSamples, const float *In, float *Out)
{
auto hFFT = GetFFT(NumSamples);
Floats pFFT{ NumSamples };
// Copy the data into the processing buffer
for (size_t i = 0; i<NumSamples; i++)
pFFT[i] = In[i];
// Perform the FFT
RealFFTf(pFFT.get(), hFFT.get());
// Copy the data into the real and imaginary outputs
for (size_t i = 1; i<NumSamples / 2; i++) {
Out[i]= (pFFT[hFFT->BitReversed[i] ]*pFFT[hFFT->BitReversed[i] ])
+ (pFFT[hFFT->BitReversed[i]+1]*pFFT[hFFT->BitReversed[i]+1]);
}
// Handle the (real-only) DC and Fs/2 bins
Out[0] = pFFT[0]*pFFT[0];
Out[NumSamples / 2] = pFFT[1]*pFFT[1];
}
void PowerSpectrum(int NumSamples, const float *In, float *Out)
{
int i;
HFFT hFFT = GetFFT(NumSamples);
float *pFFT = new float[NumSamples];
// Copy the data into the processing buffer
for(i=0; i<NumSamples; i++)
pFFT[i] = In[i];
// Perform the FFT
RealFFTf(pFFT, hFFT);
// Copy the data into the real and imaginary outputs
for(i=1;i<NumSamples/2;i++) {
Out[i]= (pFFT[hFFT->BitReversed[i] ]*pFFT[hFFT->BitReversed[i] ])
+ (pFFT[hFFT->BitReversed[i]+1]*pFFT[hFFT->BitReversed[i]+1]);
}
// Handle the (real-only) DC and Fs/2 bins
Out[0] = pFFT[0]*pFFT[0];
Out[i] = pFFT[1]*pFFT[1];
delete [] pFFT;
ReleaseFFT(hFFT);
}
void PowerSpectrum(int NumSamples, float *In, float *Out)
{
#ifdef EXPERIMENTAL_USE_REALFFTF
// Remap to RealFFTf() function
int i;
HFFT hFFT = GetFFT(NumSamples);
float *pFFT = new float[NumSamples];
// Copy the data into the processing buffer
for(i=0; i<NumSamples; i++)
pFFT[i] = In[i];
// Perform the FFT
RealFFTf(pFFT, hFFT);
// Copy the data into the real and imaginary outputs
for(i=1;i<NumSamples/2;i++) {
Out[i]= (pFFT[hFFT->BitReversed[i] ]*pFFT[hFFT->BitReversed[i] ])
+ (pFFT[hFFT->BitReversed[i]+1]*pFFT[hFFT->BitReversed[i]+1]);
}
// Handle the (real-only) DC and Fs/2 bins
Out[0] = pFFT[0]*pFFT[0];
Out[i] = pFFT[1]*pFFT[1];
delete [] pFFT;
ReleaseFFT(hFFT);
#else // EXPERIMENTAL_USE_REALFFTF
int Half = NumSamples / 2;
int i;
float theta = M_PI / Half;
float *tmpReal = new float[Half];
float *tmpImag = new float[Half];
float *RealOut = new float[Half];
float *ImagOut = new float[Half];
for (i = 0; i < Half; i++) {
tmpReal[i] = In[2 * i];
tmpImag[i] = In[2 * i + 1];
}
FFT(Half, 0, tmpReal, tmpImag, RealOut, ImagOut);
float wtemp = float (sin(0.5 * theta));
float wpr = -2.0 * wtemp * wtemp;
float wpi = -1.0 * float (sin(theta));
float wr = 1.0 + wpr;
float wi = wpi;
int i3;
float h1r, h1i, h2r, h2i, rt, it;
for (i = 1; i < Half / 2; i++) {
i3 = Half - i;
h1r = 0.5 * (RealOut[i] + RealOut[i3]);
h1i = 0.5 * (ImagOut[i] - ImagOut[i3]);
h2r = 0.5 * (ImagOut[i] + ImagOut[i3]);
h2i = -0.5 * (RealOut[i] - RealOut[i3]);
rt = h1r + wr * h2r - wi * h2i;
it = h1i + wr * h2i + wi * h2r;
Out[i] = rt * rt + it * it;
rt = h1r - wr * h2r + wi * h2i;
it = -h1i + wr * h2i + wi * h2r;
Out[i3] = rt * rt + it * it;
wr = (wtemp = wr) * wpr - wi * wpi + wr;
wi = wi * wpr + wtemp * wpi + wi;
}
rt = (h1r = RealOut[0]) + ImagOut[0];
it = h1r - ImagOut[0];
Out[0] = rt * rt + it * it;
rt = RealOut[Half / 2];
it = ImagOut[Half / 2];
Out[Half / 2] = rt * rt + it * it;
delete[]tmpReal;
delete[]tmpImag;
delete[]RealOut;
delete[]ImagOut;
#endif // EXPERIMENTAL_USE_REALFFTF
}
void RealFFT(int NumSamples, float *RealIn, float *RealOut, float *ImagOut)
{
#ifdef EXPERIMENTAL_USE_REALFFTF
// Remap to RealFFTf() function
int i;
HFFT hFFT = GetFFT(NumSamples);
float *pFFT = new float[NumSamples];
// Copy the data into the processing buffer
for(i=0; i<NumSamples; i++)
pFFT[i] = RealIn[i];
// Perform the FFT
RealFFTf(pFFT, hFFT);
// Copy the data into the real and imaginary outputs
for(i=1;i<(NumSamples/2);i++) {
RealOut[i]=pFFT[hFFT->BitReversed[i] ];
ImagOut[i]=pFFT[hFFT->BitReversed[i]+1];
}
// Handle the (real-only) DC and Fs/2 bins
RealOut[0] = pFFT[0];
RealOut[i] = pFFT[1];
ImagOut[0] = ImagOut[i] = 0;
// Fill in the upper half using symmetry properties
for(i++ ; i<NumSamples; i++) {
RealOut[i] = RealOut[NumSamples-i];
ImagOut[i] = -ImagOut[NumSamples-i];
}
delete [] pFFT;
ReleaseFFT(hFFT);
#else
int Half = NumSamples / 2;
int i;
float theta = M_PI / Half;
float *tmpReal = new float[Half];
float *tmpImag = new float[Half];
for (i = 0; i < Half; i++) {
tmpReal[i] = RealIn[2 * i];
tmpImag[i] = RealIn[2 * i + 1];
}
FFT(Half, 0, tmpReal, tmpImag, RealOut, ImagOut);
float wtemp = float (sin(0.5 * theta));
float wpr = -2.0 * wtemp * wtemp;
float wpi = -1.0 * float (sin(theta));
float wr = 1.0 + wpr;
float wi = wpi;
int i3;
float h1r, h1i, h2r, h2i;
for (i = 1; i < Half / 2; i++) {
i3 = Half - i;
h1r = 0.5 * (RealOut[i] + RealOut[i3]);
h1i = 0.5 * (ImagOut[i] - ImagOut[i3]);
h2r = 0.5 * (ImagOut[i] + ImagOut[i3]);
h2i = -0.5 * (RealOut[i] - RealOut[i3]);
RealOut[i] = h1r + wr * h2r - wi * h2i;
ImagOut[i] = h1i + wr * h2i + wi * h2r;
RealOut[i3] = h1r - wr * h2r + wi * h2i;
ImagOut[i3] = -h1i + wr * h2i + wi * h2r;
wr = (wtemp = wr) * wpr - wi * wpi + wr;
wi = wi * wpr + wtemp * wpi + wi;
}
RealOut[0] = (h1r = RealOut[0]) + ImagOut[0];
ImagOut[0] = h1r - ImagOut[0];
delete[]tmpReal;
delete[]tmpImag;
#endif //EXPERIMENTAL_USE_REALFFTF
}