private static void SyncLookupTableLength(int length)
{
//Debug.Assert(length < 1024 * 10);
//Debug.Assert(length >= 0);
if (length > _lookupTabletLength)
{
int level = (int)Math.Ceiling(Math.Log(length, 2));
Fourier.InitializeReverseBits(level);
Fourier.InitializeComplexRotations(level);
//_cFFTData = new Complex[ Math2.CeilingBase( length, 2 ) ];
//_cFFTDataF = new ComplexF[ Math2.CeilingBase( length, 2 ) ];
_lookupTabletLength = length;
}
}
static private void ReorderArray(double[] data)
{
//Debug.Assert(data != null);
int length = data.Length / 2;
//Debug.Assert(Fourier.IsPowerOf2(length) == true);
//Debug.Assert(length >= cMinLength);
//Debug.Assert(length <= cMaxLength);
int[] reversedBits = Fourier.GetReversedBits(Fourier.Log2(length));
for (int i = 0; i < length; i++)
{
int swap = reversedBits[i];
if (swap > i)
{
Fourier.Swap(ref data[i << 1], ref data[swap << 1]);
Fourier.Swap(ref data[i << 1 + 1], ref data[swap << 1 + 1]);
}
}
}
static private int[] GetReversedBits(int numberOfBits)
{
//Debug.Assert(numberOfBits >= cMinBits);
//Debug.Assert(numberOfBits <= cMaxBits);
if (_reversedBits[numberOfBits - 1] == null)
{
long maxBits = Fourier.Pow2(numberOfBits);
int[] reversedBits = new int[maxBits];
for (int i = 0; i < maxBits; i++)
{
int oldBits = i;
int newBits = 0;
for (int j = 0; j < numberOfBits; j++)
{
newBits = (newBits << 1) | (oldBits & 1);
oldBits = (oldBits >> 1);
}
reversedBits[i] = newBits;
}
_reversedBits[numberOfBits - 1] = reversedBits;
}
return(_reversedBits[numberOfBits - 1]);
}
public void scramble()
{
//Create necessary variables
List <short> rawWavData = backend.WAVdata; //get the data dump of wav file
int sampleRateWav = backend.sampleRate; //get samplerate of wav file
List <float[]> dataPerNote = convertRawData(rawWavData, sampleRateWav); //convert dump into split arrays
//foreach sample do: a Forward FFT, Flip the values, Backwards FFT
foreach (float[] noteSamples in dataPerNote)
{
//Forward FFT
Fourier.RFFT(noteSamples, FourierDirection.Forward);
//Flip the values, (in pairs Real and Imaginary)
float[] temporary = new float[noteSamples.Length];
for (int i = 0; i < noteSamples.Length; i += 2)
{
temporary[i] = noteSamples[noteSamples.Length - 2 - i];
temporary[i + 1] = noteSamples[noteSamples.Length - 1 - i];
}
Array.Copy(temporary, noteSamples, noteSamples.Length);
//Forward FFT and Compensate for distortion due to Fourier Transformation
Fourier.RFFT(noteSamples, FourierDirection.Backward);
for (int i = 0; i < noteSamples.Length; i++)
{
noteSamples[i] /= noteSamples.Length / 2;
noteSamples[i] = (float)Math.Round(noteSamples[i]);
}
}
//Pass on new Wav file Data
List <short> newWavData = convertNewData(dataPerNote); //convert split arrays back to dump
backend.newWavData(newWavData, rawWavData); //Send to backend
}
/// <summary>
/// Compute a 1D real-symmetric fast fourier transform.
/// </summary>
/// <param name="data"></param>
/// <param name="length"></param>
/// <param name="direction"></param>
public static void RFFT(float[] data, int length, FourierDirection direction)
{
if (data == null)
{
throw new ArgumentNullException("data");
}
if (data.Length < length)
{
throw new ArgumentOutOfRangeException("length", length, "must be at least as large as 'data.Length' parameter");
}
if (Fourier.IsPowerOf2(length) == false)
{
throw new ArgumentOutOfRangeException("length", length, "must be a power of 2");
}
float c1 = 0.5f, c2;
float theta = (float)Math.PI / (length / 2);
if (direction == FourierDirection.Forward)
{
c2 = -0.5f;
FFT(data, length / 2, direction);
}
else
{
c2 = 0.5f;
theta = -theta;
}
float wtemp = (float)Math.Sin(0.5 * theta);
float wpr = -2 * wtemp * wtemp;
float wpi = (float)Math.Sin(theta);
float wr = 1 + wpr;
float wi = wpi;
// do / undo packing
for (int i = 1; i < length / 4; i++)
{
int a = 2 * i;
int b = length - 2 * i;
float h1r = c1 * (data[a] + data[b]);
float h1i = c1 * (data[a + 1] - data[b + 1]);
float h2r = -c2 * (data[a + 1] + data[b + 1]);
float h2i = c2 * (data[a] - data[b]);
data[a] = h1r + wr * h2r - wi * h2i;
data[a + 1] = h1i + wr * h2i + wi * h2r;
data[b] = h1r - wr * h2r + wi * h2i;
data[b + 1] = -h1i + wr * h2i + wi * h2r;
wr = (wtemp = wr) * wpr - wi * wpi + wr;
wi = wi * wpr + wtemp * wpi + wi;
}
if (direction == FourierDirection.Forward)
{
float hir = data[0];
data[0] = hir + data[1];
data[1] = hir - data[1];
}
else
{
float hir = data[0];
data[0] = c1 * (hir + data[1]);
data[1] = c1 * (hir - data[1]);
Fourier.FFT(data, length / 2, direction);
}
}
public string convert(int ms, bool roundIt, bool returnUnfound, bool seperatorIsComma)
{
//read csv file for tones Dictionary
backend.setSeperator(seperatorIsComma);
Dictionary <char, double> tonesDictionary = backend.csvDictionary;
//Read the wav file for usefull values and comunicate with data layer
List <short> rawWavData = backend.WAVdata;
int sampleRateWav = backend.sampleRate;
int notes = ((rawWavData.Count * 1000) / sampleRateWav) / ms; //aantal tonen in Wav
//converteer de rawData naar floats per toon
List <float[]> dataPerNote = convertRawData(rawWavData, sampleRateWav, notes);
//RFFT toepassen en dominante frequencie zoeken
List <double> frequencyList = new List <double>();
foreach (float[] noteSamples in dataPerNote)
{
//fourier
Fourier.RFFT(noteSamples, FourierDirection.Forward);
//zoek freq
double maxAmplitude = 0;
int positie = 0;
for (int i = 0; i < noteSamples.Length; i += 2)//max en pos bepalen
{
double vermogen = Math.Sqrt((Math.Pow(noteSamples[i], 2)) + Math.Pow(noteSamples[i + 1], 2));
if (vermogen > maxAmplitude)
{
positie = i;
maxAmplitude = vermogen;
}
}
double frequency = ((positie * sampleRateWav) / (double)noteSamples.Length) / 2;//what is the frequency
//(afronden) en toevoegen
if (roundIt)
{
frequencyList.Add((Math.Round(frequency * roundPrecision) / roundPrecision));
}
else
{
frequencyList.Add(frequency);
}
}
//create return String
string returnable = "";
foreach (double frequency in frequencyList)
{
//als nog niet afgerond
double _frequency = frequency;
if (!roundIt)
{
_frequency = Math.Round(frequency, roundDecimals);
}
if (tonesDictionary.FirstOrDefault(x => x.Value == _frequency).Key == 0)//default waarde = ongevonden
{
if (!returnUnfound)
{
returnable += "? ";
}
else
{
returnable += String.Format("?\"{0}Hz\" ", _frequency);
}
}
else
{
returnable += tonesDictionary.FirstOrDefault(x => x.Value == _frequency).Key + " ";
}
}
return(returnable);
}
