private Complex[][] GenerateGains(double[] gains, int sampleRate, int n)
{
var gainsComplex = new Complex[10][];
var low = 40;
var high = 20;
for (int i = 0; i < 10; i++)
{
if (gains[i] == 0)
{
gains[i] += 1;
}
else if (gains[i] < 0)
{
gains[i] = 1.0 / Math.Abs(gains[i]);
}
var bandFilterFactors = BasicFilter.BandPassFilterFactors(low, high, sampleRate, _filterLength, n);
for (int j = 0; j < bandFilterFactors.Length; j++)
{
bandFilterFactors[j] *= gains[i];
}
gainsComplex[i] = bandFilterFactors;
low *= 2;
high *= 2;
}
return(gainsComplex);
}
public double[] Process(WavData wavData)
{
var n = FourierHelper.GetExpandedPow2(_windowLength + _filterLength - 1);
var size = wavData.Samples.Length + n - _windowLength;
var result = new double[size];
var windows = new double[size / _windowHopSize][];
var windowsComplex = new Complex[size / _windowHopSize][];
for (int i = 0; i < windows.Length; i++)
{
windows[i] = new double[n];
windowsComplex[i] = new Complex[n];
}
if (_gain < 0)
{
_gain = 1 / Math.Abs(_gain) - 1;
}
var windowFactors = _window.WindowFactors(_windowLength);
for (int i = 0; i < windows.Length; i++)
{
for (int j = 0; j < _windowLength; j++)
{
if (i * _windowHopSize + j < wavData.Samples.Length)
{
windows[i][j] = windowFactors[j] * wavData.Samples[i * _windowHopSize + j];
}
else
{
windows[i][j] = 0;
}
}
for (int j = _windowLength; j < n; j++)
{
windows[i][j] = 0;
}
}
var freq = wavData.FormatChunk.SampleRate / _lfo;
var filterSize = _endBandFreq - _bandSize - _startBandFreq;
for (int i = 0; i < windows.Length; i++)
{
var highPass = (Math.Sin(2 * Math.PI * i * _windowHopSize / freq) * 0.5 + 0.5) * filterSize + _startBandFreq;
var lowPass = highPass + _bandSize;
var bandFilterFactors = BasicFilter.BandPassFilterFactors(lowPass, highPass, wavData.FormatChunk.SampleRate, _filterLength, n);
windowsComplex[i] = FourierTransform.FFT(windows[i]);
for (int j = 0; j < windowsComplex[i].Length; j++)
{
windowsComplex[i][j] += windowsComplex[i][j] * bandFilterFactors[j] * _gain;
}
windows[i] = FourierTransform.IFFT(windowsComplex[i]);
}
for (int i = 0; i < windows.Length; i++)
{
for (int j = 0; j < windows[i].Length; j++)
{
if (i * _windowHopSize + j < wavData.Samples.Length)
{
result[i * _windowHopSize + j] += windows[i][j];
}
}
}
return(result);
}