private List <PossibleHeldNote> GetHeldNotesFromFrequencyBand(FrequencyBand newFrequencyBand)
{
List <PossibleHeldNote> heldNotes = new List <PossibleHeldNote>();
FrequencyBand.FBPoint lastValidPoint = null;
float amplitudeSum = 0;
int amplitudesN = 0;
float timeDelta = newFrequencyBand.FBPoints[1].Time - newFrequencyBand.FBPoints[0].Time;
foreach (FrequencyBand.FBPoint fbPoint in newFrequencyBand.FBPoints)
{
if (fbPoint.MinimumSquaredErrorToPrevious < MaximumSquaredError)
{
if (lastValidPoint == null)
{
lastValidPoint = fbPoint;
}
amplitudeSum += fbPoint.Amplitude;
amplitudesN++;
}
else
{
if (lastValidPoint != null)
{
float timeDifference = fbPoint.Time - lastValidPoint.Time;
if (timeDifference > MinimumTimeWidth)
{
PossibleHeldNote heldNote = new PossibleHeldNote();
heldNote.StartTime = lastValidPoint.Time;
heldNote.EndTime = fbPoint.Time - timeDelta;
float amplitudeMeanValue = amplitudeSum / amplitudesN;
heldNote.AmplitudeMeanValue = amplitudeMeanValue;
heldNote.Applicability = amplitudeMeanValue;
heldNotes.Add(heldNote);
}
lastValidPoint = null;
}
amplitudeSum = 0;
amplitudesN = 0;
}
}
return(heldNotes);
}
private void AddFrequencyToFrequencyBand(FrequencyBand frequencyBand, float time, float[] spectrum)
{
int numberOfSpectrumBands = frequencyBand.SpectrumBands.Count;
float[] frequencyValues = new float[numberOfSpectrumBands];
for (int i = 0; i < numberOfSpectrumBands; i++)
{
frequencyValues[i] = spectrum[frequencyBand.SpectrumBands[i]];
}
frequencyBand.AddAmplitudes(time, frequencyValues);
}
private void CreateFrequencyBands()
{
float firstKey = 16; // C2
float lastKey = 75; // B6
for (float i = firstKey; i < lastKey; i += 0.5f)
{
float lowestFrequency = GetFrequency(i);
float highestFrequency = GetFrequency(i + 1);
int lowestFFTBand = (int)Math.Floor(lowestFrequency / fftFrequencyBandWidth);
int highestFFTBand = (int)Math.Ceiling(highestFrequency / fftFrequencyBandWidth);
FrequencyBand frequencyBand = new FrequencyBand();
for (int j = lowestFFTBand; j <= highestFFTBand; j++)
{
frequencyBand.AddSpectrumBand(j);
}
frequencyBands.Add(frequencyBand);
}
}