/// <summary>
/// Compute a 1D real-symmetric fast fourier transform.
/// </summary>
/// <param name="data"></param>
/// <param name="direction"></param>
public static void RFFT(float[] data, FourierDirection direction)
{
if (data == null)
{
throw new ArgumentNullException("data");
}
Fourier.RFFT(data, data.Length, direction);
}
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
}
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);
}