public LogarithmicSpectrum(float[] data, int bands, float minFrequency = -1, float maxFrequency = -1)
{
int dataReferenceCount = (data.Length - 1) * 2;
int fromIndex = minFrequency < 0 ? 0 : FrequencyHelper.GetIndexOfFrequency(minFrequency, dataReferenceCount).Clamp(0, data.Length - 1 - bands); // -bands since we need at least enough data to get our bands
int toIndex = maxFrequency < 0 ? data.Length - 1 : FrequencyHelper.GetIndexOfFrequency(maxFrequency, dataReferenceCount).Clamp(fromIndex, data.Length - 1);
int usableSourceData = Math.Max(bands, (toIndex - fromIndex) + 1);
Bands = new Band[bands];
double ratio = Math.Pow(usableSourceData, 1.0 / bands);
double calculation = 1;
int index = fromIndex;
for (int i = 0; i < Bands.Length; i++)
{
calculation *= ratio;
int count = Math.Max(1, ((int)calculation) - index);
float[] bandData = new float[count];
Array.Copy(data, index, bandData, 0, count);
Bands[i] = new Band(FrequencyHelper.GetFrequencyOfIndex(index, dataReferenceCount),
FrequencyHelper.GetFrequencyOfIndex(index + count, dataReferenceCount),
bandData);
index += count;
}
}
public LinearSpectrum(float[] data, int bands, float minFrequency = -1, float maxFrequency = -1)
{
int dataReferenceCount = (data.Length - 1) * 2;
int fromIndex = minFrequency < 0 ? 0 : FrequencyHelper.GetIndexOfFrequency(minFrequency, dataReferenceCount).Clamp(0, data.Length - 1 - bands); // -bands since we need at least enough data to get our bands
int toIndex = maxFrequency < 0 ? data.Length - 1 : FrequencyHelper.GetIndexOfFrequency(maxFrequency, dataReferenceCount).Clamp(fromIndex, data.Length - 1);
int usableSourceData = Math.Max(bands, (toIndex - fromIndex) + 1);
Bands = new Band[bands];
double frequenciesPerBand = (double)usableSourceData / bands;
double frequencyCounter = 0;
int index = fromIndex;
for (int i = 0; i < Bands.Length; i++)
{
frequencyCounter += frequenciesPerBand;
int count = (int)frequencyCounter;
float[] bandData = new float[count];
Array.Copy(data, index, bandData, 0, count);
Bands[i] = new Band(FrequencyHelper.GetFrequencyOfIndex(index, dataReferenceCount),
FrequencyHelper.GetFrequencyOfIndex(index + count, dataReferenceCount),
bandData);
index += count;
frequencyCounter -= count;
}
}
public GammaSpectrum(float[] data, int bands, float gamma = 2, float minFrequency = -1, float maxFrequency = -1)
{
int dataReferenceCount = (data.Length - 1) * 2;
int fromIndex = minFrequency < 0 ? 0 : FrequencyHelper.GetIndexOfFrequency(minFrequency, dataReferenceCount).Clamp(0, data.Length - 1 - bands); // -bands since we need at least enough data to get our bands
int toIndex = maxFrequency < 0 ? data.Length - 1 : FrequencyHelper.GetIndexOfFrequency(maxFrequency, dataReferenceCount).Clamp(fromIndex, data.Length - 1);
int usableSourceData = Math.Max(bands, (toIndex - fromIndex) + 1);
Bands = new Band[bands];
int index = fromIndex;
for (int i = 0; i < Bands.Length; i++)
{
int count = Math.Max(1, (((int)(Math.Pow((i + 1f) / Bands.Length, gamma) * usableSourceData))) - index);
float[] bandData = new float[count];
Array.Copy(data, index, bandData, 0, count);
Bands[i] = new Band(FrequencyHelper.GetFrequencyOfIndex(index, dataReferenceCount),
FrequencyHelper.GetFrequencyOfIndex(index + count, dataReferenceCount),
bandData);
index += count;
}
}
