public void AdjustBeat(List<double[]> features, ref DetectStatus ds, ref BeatStatus bs)
{
int nstep = (int)Math.Floor(ds.SamplePerSec * (60 / bs.BpmDancer));
double maxe = 0; int maxs = -1;
for (int s = 0; s < nstep; s += 2)
{
double e = 0;
for (int i = 0; i < _bandLimits.Length; i++)
{
for (int j = 0; j < features[i].Length; j++)
{
double peakValue = 1 - (j % (s + nstep)) / (double)nstep;
e += Math.Pow(features[i][j] * peakValue, 2) * _bandWeights[i];
}
}
if (maxe < e)
{
maxe = e; maxs = s;
}
}
int beatStartSample = maxs;
bs.BeatTickRaw = bs.SampleStartTick + beatStartSample * 1000 / ds.SamplePerSec;
}
public List<double[]> DetectBpm(double[] sig, ref DetectStatus ds, ref BeatStatus bs)
{
// 必要数の入力を複素数に変換
int n = (int)Math.Floor(Math.Log(sig.Length, 2));
int size = (int)Math.Pow(2, n > 14 ? 14 : n); // limit of AForge.NET
Complex[] input = new Complex[size];
for (int i = 0; i < size; i++)
{
input[i] = new Complex(sig[i], 0);
}
// Bpm検出処理
List<Complex[]> filtered = filterBank(input);
List<Complex[]> windowed = hwindow(filtered, 0.2);
List<Complex[]> differentiated = diffrect(windowed);
List<Complex[]> dft = timeCombPre(differentiated);
double rBpm = timeCombRough(dft, ref ds);
int maxBand = -1;
double b2 = timeComb(dft, 0.1, rBpm - 1, rBpm + 1, ds.SamplePerSec, ref maxBand);
bs.BpmRaw = b2;
List<double[]> features = new List<double[]>();
for (int i = 0; i < _bandLimits.Length; i++)
{
double[] f = Array.ConvertAll<Complex, double>(differentiated[i], c => c.Re);
features.Add(f);
}
//double[] features = Array.ConvertAll<Complex, double>(differentiated[maxBand], c => c.Re);
return features;
}
/// <summary>各BPM候補でエネルギーを算出</summary>
private double timeCombRough(List<Complex[]> dft, ref DetectStatus ds)
{
int n = dft[0].Length;
int nbands = _bandLimits.Length;
double maxe = 0; double bpmResult = 0;
int ei = 0;
for (double bpm = ds.MinBpm; bpm <= ds.MaxBpm; bpm += ds.BpmAcc)
{
/// Initialize energy and filter to zero(s)
double e = 0;
Complex[] fil = new Complex[n];
for (int i = 0; i < fil.Length; i++) fil[i] = new Complex(0, 0);
/// Calculate the difference between peaks in the filter for a certain tempo
int nstep = (int)Math.Floor(ds.SamplePerSec * 60 / bpm);
/// Set every nstep samples of the filter to one
for (int i = 0; i < _npulses && i * nstep < fil.Length; i++)
{
fil[i * nstep] = new Complex(1, 0);
}
/// Get the filter in the frequency domain
FourierTransform.FFT(fil, FourierTransform.Direction.Forward);
/// Calculate the energy after convolution
for (int i = 0; i < nbands; i++)
{
double sum = 0;
for (int j = 0; j < fil.Length; j++)
{
Complex c = fil[j] * dft[i][j];
sum += Math.Pow(c.Re, 2) + Math.Pow(c.Im, 2);
}
e += sum * _bandWeights[i];
}
/// Set the energy to DetectStatus
lock (ds.BpmEnergies)
{
ds.BpmEnergies[ei] = (1 - _energyDecay) * ds.BpmEnergies[ei] + _energyDecay * e;
}
if (maxe < ds.BpmEnergies[ei])
{
maxe = ds.BpmEnergies[ei];
bpmResult = bpm;
}
ei++;
}
return bpmResult;
}