/**
* Gabor transform (complex values)
*/
public FloatComplex[][] TGabor(float[] signal, int nbSamplesPerBar)
{
int n = signal.Length;
int nbBars = n / nbSamplesPerBar;
FloatComplex[][] TG = new FloatComplex[nbSamplesPerBar][];
var fftFoward = new FloatComplexForward1DFFT(nbSamplesPerBar);
for (int i = 0; i < nbSamplesPerBar; i++)
{
TG[i] = new FloatComplex[nbBars];
}
for (int i = 0; i < nbBars; i++)
{
int iMin = i * nbSamplesPerBar;
int iMax = (i + 1) * nbSamplesPerBar;
FloatComplex[] sub = new FloatComplex[nbSamplesPerBar];
for (int j = 0; j < iMax - iMin; j++)
{
sub[j] = new FloatComplex(signal[j + iMin], 0);
}
fftFoward.FFTInPlace(sub);
for (int j = 0; j < nbSamplesPerBar; j++)
{
TG[j][i] = sub[j];
}
}
return(TG);
}
public float[][] ES(FloatComplex[][] s, int[] indPartition, float[] valuesT, float[] valuesFS)
{
float[][] signature = new float[2][];
List <float> freqs = new List <float>();
List <float> values = new List <float>();
int nbBars = s[0].Length;
for (int i = 0; i < nbBands; i++)
{
int iMin = indPartition[i];
int iMax = Math.Min(indPartition[i + 1], s.Length);
// Band extraction :
FloatComplex[][] band = new FloatComplex[iMax - iMin][];
for (int b1 = 0; b1 < iMax - iMin; b1++)
{
band[b1] = new FloatComplex[nbBars];
for (int b2 = 0; b2 < nbBars; b2++)
{
band[b1][b2] = s[b1 + iMin][b2];
}
}
// Localisation of locales max
float[][] localesMax = getLocalesMaximum(band);
// threshold : mean + std
float threshold = Mean(localesMax[1]) + STD(localesMax[1]);
// Get frequencies upper than the threshold
for (int j = 0; j < localesMax[0].Length; j++)
{
if (localesMax[1][j] > threshold)
{
freqs.Add(valuesT[j]);
values.Add(i);
//values.Add(valuesFS[(int) (localesMax[0][j]+ iMin)]);
}
}
}
signature[0] = freqs.ToArray();
signature[1] = values.ToArray();
return(signature);
}
public static void Native(int log2FftSize, int fftRepeat)
{
int i;
int size = 1 << log2FftSize;
FloatComplex[] xy = new FloatComplex[size];
FloatComplex[] xy_out = new FloatComplex[xy.Length];
for (i = 0; i < size / 2; i++)
{
xy[i] = new FloatComplex(1.0f, 0.0f);
}
for (i = size / 2; i < size; i++)
{
xy[i] = new FloatComplex(-1.0f, 0.0f);
}
var stopwatch = Stopwatch.StartNew();
for (i = 0; i < fftRepeat; i++)
{
fft(log2FftSize, xy_out, xy);
}
stopwatch.Stop();
Console.WriteLine($"Total ({fftRepeat}): {stopwatch.ElapsedMilliseconds}");
var tpp = stopwatch.ElapsedMilliseconds / (float)fftRepeat;
Console.WriteLine($"{fftRepeat} piece(s) of {1 << log2FftSize} pt FFT; {tpp} ms/piece\n");
for (i = 0; i < 6; i++)
{
Console.WriteLine("{0}\t{1}", i, xy_out[i]);
}
}
/** Complex abs : sqrt(x^2 + y^2)
*/
private static float Abs(FloatComplex complex)
{
return((float)Math.Sqrt(Math.Pow(complex.Real, 2) + Math.Pow(complex.Imag, 2)));
}
private int sampleFrequency = 44100; // Hz
public float[][] Main(float[] signal)
{
// Variables
int n = signal.Length;
float time = n / sampleFrequency;
float barTime = 60f / bpm;
//float barTime = 0.2f;
int nbBars = (int)(time / barTime);
int nbSamplesPerBar = n / nbBars;
float[] valuesT = new float[nbBars];
for (int i = 0; i < nbBars; i++)
{
valuesT[i] = ((float)i * time) / ((float)(nbBars - 1));
}
// Gabor & audibles freq
float stepF = sampleFrequency / (float)(nbSamplesPerBar);
int nbValuesFS = (int)(fMax / stepF);
float[] valuesFS = new float[nbValuesFS + 1];
for (int i = 0; i < nbValuesFS + 1; i++)
{
valuesFS[i] = i * stepF;
}
FloatComplex[][] gabor = TGabor(signal, nbSamplesPerBar);
// Sonogram (complex)
FloatComplex[][] s = new FloatComplex[nbValuesFS][];
for (int i = 0; i < s.Length; i++)
{
s[i] = new FloatComplex[nbBars];
for (int j = 0; j < nbBars; j++)
{
s[i][j] = gabor[i][j];
}
}
// Partition
float iMinPart = (float)Math.Log(fMin);
float iMaxPart = (float)Math.Log(fMax);
float stepPart = (iMaxPart - iMinPart) / (float)nbBands;
float[] partition = new float[nbBands + 1];
for (int i = 0; i < nbBands + 1; i++)
{
partition[i] = (float)Math.Exp(iMinPart + stepPart * ((float)i));
}
int[] indPartition = new int[nbBands + 1];
for (int i = 0; i < nbBands; i++)
{
indPartition[i] = MinIndice(valuesFS, partition[i]);
}
indPartition[nbBands] = valuesFS.Length;
// Compute sound signature
float[][] signature = ES(s, indPartition, valuesT, valuesFS);
return(signature);
}
