static void EnumerateByFrequencies(WaveReader originalReader, WaveReader compressedReader, int numChannels, int windowSize, float samplesPerCheck, Dictionary<int, Action<float[], float[]>> comparisonMethods, long compressedSamplesToSkip)
{
originalReader.Seek(0);
compressedReader.Seek(compressedSamplesToSkip);
var fft = new ComplexFourierTransformation();
var originalQueue = new Queue<float[]> ();
var compressedQueue = new Queue<float[]> ();
using (var compressedSamplesItr = compressedReader.ReadAllSamples_Float ().GetEnumerator ())
{
foreach (var originalSamples in originalReader.ReadAllSamples_Float ())
{
if (compressedSamplesItr.MoveNext ())
{
originalQueue.Enqueue (originalSamples);
compressedQueue.Enqueue (compressedSamplesItr.Current);
if (originalQueue.Count == windowSize)
{
for (var channelCtr = 0; channelCtr < numChannels; channelCtr++)
{
var originalSamplesToTransform = originalQueue.Select (s => new Complex (s [channelCtr], 0)).ToArray ();
var compressedSamplesToTransform = compressedQueue.Select (s => new Complex (s [channelCtr], 0)).ToArray ();
fft.TransformForward (originalSamplesToTransform);
fft.TransformForward (compressedSamplesToTransform);
foreach (var kvp in comparisonMethods)
{
var fftIndex = kvp.Key;
var comparisonMethod = kvp.Value;
comparisonMethod(
new float[] { Convert.ToSingle (originalSamplesToTransform [fftIndex].Modulus) },
new float[] { Convert.ToSingle (compressedSamplesToTransform [fftIndex].Modulus) });
}
}
for (var ctr = 0; ctr < samplesPerCheck; ctr++)
{
originalQueue.Dequeue ();
compressedQueue.Dequeue ();
}
}
}
else
{
Console.WriteLine ("Compressed file is shorter");
break;
}
}
if (compressedSamplesItr.MoveNext ())
{
Console.WriteLine ("Compressed file is longer");
}
}
}
/// <summary>
/// judge the FFT result for log data.
/// </summary>
/// <param name="resDic">log data.</param>
/// <param name="rate">FFT rate.</param>
/// <returns>if all judgement is ok, return true.</returns>
private bool JudgeBifurcationAnalysisByFFT(Dictionary<double, double> resDic, double rate)
{
double maxFreq = m_param.MaxFreq;
double minFreq = m_param.MinFreq;
int maxSize = m_param.MaxInput;
ComplexFourierTransformation cft = new ComplexFourierTransformation();
int size = 4;
int divide = 1;
while (true)
{
if (resDic.Count <= size) break;
if (size >= maxSize)
{
divide = resDic.Count / maxSize + 1;
break;
}
size = size * 2;
}
double[] data = new double[size * 2];
int i = 0;
foreach (double d in resDic.Keys)
{
if (i % divide != 0) continue;
data[i * 2] = resDic[d];
data[i * 2 + 1] = 0.0;
i++;
}
cft.Convention = TransformationConvention.Matlab; // so we can check MATLAB consistency
cft.TransformForward(data);
int count = 0;
for (int j = 0; j < size; j++)
{
double d = Math.Sqrt(data[j * 2] * data[j * 2] + data[j * 2 + 1] * data[j * 2 + 1]);
if (maxFreq > d && minFreq < d) count++;
}
if ((double)count / (double)size > rate)
return true;
return false;
}
static IEnumerable<IEnumerable<float>> UpSample(WaveReader reader, int windowSize)
{
var fft = new MathNet.Numerics.Transformations.ComplexFourierTransformation ();
var determineVolumeSource = new Complex[]
{
new Complex(1, 0),
new Complex(1, 0),
new Complex(1, 0),
new Complex(1, 0),
};
fft.TransformForward(determineVolumeSource);
var determineVolumeDestination = new Complex[windowSize];
determineVolumeDestination[0] = determineVolumeSource[0];
for (var sampleCtr = 1; sampleCtr < windowSize; sampleCtr++)
determineVolumeDestination[sampleCtr] = Complex.FromModulusArgument(0,0);
fft.TransformBackward(determineVolumeDestination);
var multiplier = determineVolumeDestination[0].Real;
var sampleQueue = new Queue<float[]>();
for (var sampleCtr = 0; sampleCtr < 2; sampleCtr++)
sampleQueue.Enqueue(new float[reader.NumChannels]);
foreach (var samples in reader.ReadAllSamples_Float().Select(s => s.ToArray()))
{
sampleQueue.Enqueue(samples);
if (sampleQueue.Count == 4)
{
var expanded = new float[windowSize / 2][];
for (var ctr = 0; ctr < windowSize / 2; ctr++)
expanded[ctr] = new float[reader.NumChannels];
for (var channelCtr = 0; channelCtr < reader.NumChannels; channelCtr++)
{
var samplesToTransform = sampleQueue.Select(s => new Complex (s[channelCtr], 0)).ToArray();
fft.TransformForward (samplesToTransform);
var samplesToTransformBack = new Complex[windowSize];
samplesToTransformBack[0] = samplesToTransform[0];
samplesToTransformBack[1] = samplesToTransform[1];
samplesToTransformBack[1].Modulus /= 2;
samplesToTransformBack[samplesToTransformBack.Length - 1] = samplesToTransform[1];
samplesToTransformBack[samplesToTransformBack.Length - 1].Modulus /= 2;
samplesToTransformBack[samplesToTransformBack.Length - 1].Argument *= -1;
for (var ctr = 2; ctr < samplesToTransformBack.Length - 1; ctr++)
samplesToTransformBack[ctr] = Complex.FromModulusArgument(0, 0);
fft.TransformBackward(samplesToTransformBack);
for (var ctr = 0; ctr < windowSize / 2; ctr++)
expanded[ctr][channelCtr] = Convert.ToSingle(samplesToTransformBack[ctr + windowSize / 4].Real / multiplier);
}
foreach (var simplified in expanded)
yield return simplified;
sampleQueue.Dequeue();
sampleQueue.Dequeue();
}
}
}
public void SetUp()
{
cft = new ComplexFourierTransformation();
rft = new RealFourierTransformation();
}
public static IEnumerable<float[]> DownSample(IEnumerable<float[]> samplesEnumerator, int numChannels, int windowSize, Action<float[]> highSampleCallback)
{
var fft = new MathNet.Numerics.Transformations.ComplexFourierTransformation ();
var determineVolumeSource = new Complex[windowSize];
for (var sampleCtr = 0; sampleCtr < windowSize; sampleCtr++)
determineVolumeSource[sampleCtr] = new Complex(1, 0);
fft.TransformForward(determineVolumeSource);
var determineVolumeDestination = new Complex[]
{
determineVolumeSource[0],
Complex.FromModulusArgument(0,0),
Complex.FromModulusArgument(0,0),
Complex.FromModulusArgument(0,0)
};
fft.TransformBackward(determineVolumeDestination);
var dcMultiplier = determineVolumeDestination[0].Modulus;
var ratio = (1d / Convert.ToDouble(windowSize)) * 2d * Math.PI;
for (var sampleCtr = 0; sampleCtr < windowSize; sampleCtr++)
{
var sampleCtrDouble = Convert.ToDouble(sampleCtr);
determineVolumeSource[sampleCtr] = new Complex(Math.Cos(sampleCtrDouble * ratio), 0);
}
fft.TransformForward(determineVolumeSource);
determineVolumeDestination = new Complex[]
{
Complex.FromModulusArgument(0,0),
determineVolumeSource[1],
Complex.FromModulusArgument(0,0),
determineVolumeSource[determineVolumeSource.Length - 1],
};
fft.TransformBackward(determineVolumeDestination);
var midMultiplier = determineVolumeDestination.Select(s => s.Modulus).Max();
/*// This only works when windowsize is 8
for (var sampleCtr = 0; sampleCtr < windowSize; sampleCtr++)
{
var abs = sampleCtr % 2 == 1 ? 1 : 0;
var sign = sampleCtr % 4 > 1 ? 1 : -1;
determineVolumeSource[sampleCtr] = new Complex(abs * sign, 0);
}*/
ratio = (1d / Convert.ToDouble(windowSize)) * 4d * Math.PI;
for (var sampleCtr = 0; sampleCtr < windowSize; sampleCtr++)
{
var sampleCtrDouble = Convert.ToDouble(sampleCtr);
determineVolumeSource[sampleCtr] = new Complex(Math.Cos(sampleCtrDouble * ratio), 0);
}
fft.TransformForward(determineVolumeSource);
determineVolumeDestination = new Complex[]
{
Complex.FromModulusArgument(0,0),
Complex.FromModulusArgument(0,0),
determineVolumeSource[2],
Complex.FromModulusArgument(0,0),
};
fft.TransformBackward(determineVolumeDestination);
var highMultiplier = determineVolumeDestination.Select(s => s.Modulus).Max();
var sampleQueue = new Queue<float[]>();
for (var sampleCtr = 0; sampleCtr < windowSize / 4; sampleCtr++)
sampleQueue.Enqueue(new float[numChannels]);
var maxOriginalSample = 0.0;
var maxLowFrequencySample = 0.0;
using (var sampleEnumerator = samplesEnumerator.GetEnumerator())
{
int samplesFromSource;
do
{
samplesFromSource = 0;
while (sampleQueue.Count < windowSize)
{
if (sampleEnumerator.MoveNext())
{
sampleQueue.Enqueue(sampleEnumerator.Current.ToArray());
samplesFromSource++;
}
else
sampleQueue.Enqueue(new float[numChannels]);
}
var simplified = new float[][]
{
new float[numChannels],
new float[numChannels]
};
var filtered = new float[windowSize / 2][];
for (var sampleCtr = 0; sampleCtr < windowSize / 2; sampleCtr++)
filtered[sampleCtr] = new float[numChannels];
for (var channelCtr = 0; channelCtr < numChannels; channelCtr++)
{
maxOriginalSample = Math.Max(
maxOriginalSample,
sampleQueue.Select(s => Math.Abs(s[channelCtr])).Max());
var samplesToTransform = sampleQueue.Select (s => new Complex (s [channelCtr], 0)).ToArray ();
fft.TransformForward (samplesToTransform);
var samplesToTransformBack = new Complex[]
{
samplesToTransform[0],
samplesToTransform[1],
samplesToTransform[2],
samplesToTransform[samplesToTransform.Length - 1]
};
samplesToTransformBack[0].Modulus /= dcMultiplier;
samplesToTransformBack[1].Modulus /= midMultiplier;
samplesToTransformBack[2].Modulus /= highMultiplier;
samplesToTransformBack[3].Modulus /= midMultiplier;
fft.TransformBackward(samplesToTransformBack);
simplified[0][channelCtr] = Convert.ToSingle(samplesToTransformBack[1].Real);
simplified[1][channelCtr] = Convert.ToSingle(samplesToTransformBack[2].Real);
for (var filterCtr = 3; filterCtr < (samplesToTransform.Length - 1); filterCtr++)
samplesToTransform[filterCtr] = Complex.FromModulusArgument(0, 0);
fft.TransformBackward(samplesToTransform);
for (var sampleCtr = 0; sampleCtr < windowSize / 2; sampleCtr++)
filtered[sampleCtr][channelCtr] = Convert.ToSingle(samplesToTransform[sampleCtr + (windowSize / 4)].Real);
}
maxLowFrequencySample = Math.Max(
maxLowFrequencySample,
simplified.SelectMany(s => s).Select(Math.Abs).Max());
foreach (var samples in simplified)
yield return samples;
foreach (var samples in filtered)
highSampleCallback(samples);
while (sampleQueue.Count > windowSize / 2)
sampleQueue.Dequeue();
} while (samplesFromSource > (windowSize / 4));
}
/*Console.WriteLine("Loudest sample in source: {0}", maxOriginalSample);
Console.WriteLine("Loudest sample in low frequency: {0}", maxLowFrequencySample);
//Console.WriteLine("Loudest sample in high frequency: {0}", maxHighFrequencySample);
Console.WriteLine();*/
}