view Source/AudioSourceFeatureExtractor.cpp @ 3:005e311b5e62

Fixed memory leak. :) Need to fix Debug FFTW now though.

/*
  ==============================================================================

    AudioSourceFeatureExtractor.cpp
    Created: 11 Aug 2014 10:41:02am
    Author:  david.ronan

  ==============================================================================
*/

#include "AudioSourceFeatureExtractor.h"
#include "ObservationData.h"
#include <math.h>
#include <cmath>
#include <algorithm>
#include <string>
//#include <windows.h>

//==============================================================================  AudioSourceFeatureExtractor
AudioSourceFeatureExtractor::AudioSourceFeatureExtractor() // m_fft(FFTSIZE)
{
	m_fft								= new FFTW(FFTSIZE);
	m_fInputBuffer						= new float[FFTSIZE];
	m_fMagnitudeSpectrum				= new float[MAGNITUDESIZE];
	m_fPreviousMagnitudeSpectrum		= new float[MAGNITUDESIZE];
	m_OutReal							= new float[FFTSIZE];
	m_OutImag							= new float[FFTSIZE];

	memset(m_fInputBuffer,       0, FFTSIZE * sizeof(float));
	memset(m_fMagnitudeSpectrum, 0, MAGNITUDESIZE * sizeof(float));
	memset(m_fPreviousMagnitudeSpectrum, 0, MAGNITUDESIZE * sizeof(float));


}

//============================================================================== ~AudioSourceFeatureExtractor
AudioSourceFeatureExtractor::~AudioSourceFeatureExtractor()
{
	if(m_fInputBuffer != nullptr)
	{
		delete m_fInputBuffer;       // memory freed up
		m_fInputBuffer = nullptr;
	}

	if(m_fMagnitudeSpectrum != nullptr)
	{
		delete m_fMagnitudeSpectrum;       // memory freed up
		m_fMagnitudeSpectrum = nullptr;
	}

	if(m_fPreviousMagnitudeSpectrum != nullptr)
	{
		delete m_fPreviousMagnitudeSpectrum;       // memory freed up
		m_fPreviousMagnitudeSpectrum = nullptr;
	}

	if (m_OutReal != nullptr)
	{
		delete[] m_OutReal;
		m_OutReal  = nullptr;
	}

	if (m_OutImag != nullptr)
	{
		delete[] m_OutImag;
		m_OutImag  = nullptr;
	}

	if (m_fft != nullptr)
	{
		delete m_fft;
		m_fft  = nullptr;
	}

}

//==============================================================================  init
void AudioSourceFeatureExtractor::Initialise(float fSampleRate)
{
	m_fSampleRate = fSampleRate;
	m_iWriteIdx = 0;

	for (int i = 1; i <= MAGNITUDESIZE; i++)
	{
		float win = ((fSampleRate / (2 * MAGNITUDESIZE)) * i);
		m_fFreqBins.push_back(win);
	}

	m_MFCC.initMFFCvariables(12, MAGNITUDESIZE, m_fSampleRate);
}

//==============================================================================  process
std::vector<ObservationData> AudioSourceFeatureExtractor::Process( const float* data, size_t numSamples)
{
	std::vector<ObservationData> observations = std::vector<ObservationData>();

	memset(m_fInputBuffer,       0, FFTSIZE * sizeof(float));
	memset(m_fMagnitudeSpectrum, 0, MAGNITUDESIZE * sizeof(float));
	memset(m_fPreviousMagnitudeSpectrum, 0, MAGNITUDESIZE * sizeof(float));
	m_iWriteIdx = 0;

	float perdiodicity = EstimatePerdiodicity(const_cast<float*>(data), numSamples);

	float entropyofenergy = EntropyOfEnergy(const_cast<float*>(data), numSamples);

	for(size_t n = 0; n < numSamples; n++)
	{
		m_fInputBuffer[m_iWriteIdx] = data[n];
		m_iWriteIdx++;

		//Do normal FFT

		if(FFTSIZE == m_iWriteIdx)
		{
			//Get the peak amplitude rms and crest factor for the current frame
			float peakvalue		= 0;
			float rms			= 0;
			float crestfactor	= 0;

			for(int i=0; i < FFTSIZE; i++)
			{
				if(m_fInputBuffer[i] > peakvalue)
					peakvalue = abs(m_fInputBuffer[i]);

				rms += (m_fInputBuffer[i] * m_fInputBuffer[i]);
			}

			rms /= FFTSIZE;
			rms = sqrt(rms);

			crestfactor = peakvalue/(rms + std::numeric_limits<float>::epsilon());

			float ZCR = 0;
			float inputBuffer2[FFTSIZE] = {0.0};

			for (int i = 1; i < FFTSIZE; i++)
			{
				inputBuffer2[i] = m_fInputBuffer[i -1];
			}

			for (int i = 0; i < FFTSIZE; i++)
			{
				ZCR += (abs(Sign(m_fInputBuffer[i]) - Sign(inputBuffer2[i])));
			}

			ZCR /= (2 * FFTSIZE);

			//////////////////////////////////////////////////////////////////
			for (int i = 0; i < FFTSIZE; i++)
			{
				float multiplier = static_cast<float>(0.5 * (1 - cos(2*PI*i/(FFTSIZE -1))));
				m_fInputBuffer[i] = multiplier * m_fInputBuffer[i];
			}

			//Compute the FFT

			memset(m_OutReal, 0, sizeof(float)*FFTSIZE);
			memset(m_OutImag, 0, sizeof(float)*FFTSIZE);

			m_fft->process(m_fInputBuffer, m_OutReal, m_OutImag);

			//Compute the Magnitude
			VectorDistance(m_OutReal, 1, m_OutImag, 1, m_fMagnitudeSpectrum, 1, MAGNITUDESIZE);

			//Compute the spectral features
			float centroid	= 0;
			float spread	= 0;
			float skewness	= 0;
			float kurtosis	= 0;
			float brightness = 0;
			float rolloff85 = 0;
			float rolloff95 = 0;
			float spectralentropy = 0;
			float flatness = 0;
			float spectralcf = 0;
			float spectralflux = 0;
			std::vector<float> mfccs;

			SpectralFeatures(m_fMagnitudeSpectrum, m_fPreviousMagnitudeSpectrum, MAGNITUDESIZE, centroid, spread, skewness, kurtosis, brightness, rolloff85, rolloff95, spectralentropy, flatness, spectralcf, spectralflux);

			m_MFCC.ComputeMFCC(m_fMagnitudeSpectrum, mfccs);

			//Update for Spectral Flux
			for(int i = 0; i < MAGNITUDESIZE; i++)
			{
				m_fPreviousMagnitudeSpectrum[i] = m_fMagnitudeSpectrum[i];
			}

			//50% Hop size
			for(int i = MAGNITUDESIZE; i < FFTSIZE; i++)
			{
				m_fInputBuffer[i - MAGNITUDESIZE] = m_fInputBuffer[i];
				m_iWriteIdx = MAGNITUDESIZE;
			}

			//create an observation for this window and push it to the list of observations for this 30 sec. audio clip
			ObservationData newObservation = ObservationData(rms, peakvalue, crestfactor, ZCR, centroid, spread, skewness, kurtosis, brightness, rolloff85, rolloff95, spectralentropy, flatness, spectralcf, spectralflux, mfccs, perdiodicity, entropyofenergy);
			observations.push_back(newObservation);

		}
	}

	return observations;
}

void AudioSourceFeatureExtractor::Finalize()
{
	m_MFCC.freeMFCCmemory();
}

void AudioSourceFeatureExtractor::VectorDistance(const float* vIn1, int stride1, const float* vIn2, int stride2, float* &vOut, int strideOut, size_t nElements)
{
    //Compute remaining samples
	for (size_t i = 0; i < nElements; i++)
	{
		vOut[i* strideOut] = sqrt(vIn1[i*stride1] * vIn1[i*stride1] + vIn2[i*stride2] * vIn2[i*stride2]);
	}
}

void AudioSourceFeatureExtractor::SpectralFeatures(float* &magnitude, float* &prevmagnitude, size_t windowSize, float &centroid, float &spread, float &skew, float &kurtosis, float &brightness, float &rolloff95, float &rolloff85, float &spectralentropy, float &flatness, float &spectralcf, float &spectralflux)
{
	float summagbin = 0;
	float summag = 0;
	float sumprevmag = 0;
	float summagspread = 0;
	float summagskewness = 0;
	float summagkurtosis = 0;
	float sumbrightness = 0;
	float maxmag = 0;

	float geo = 1;
	float totalenergy = 0;
	float currEnergy95 = 0;
	float currEnergy85 = 0;
	int countFFT85 = 0;
	int countFFT95 = 0;

	float normalisedMagSumEntropy = 0;

	//Centroid
	//////////////////////////////////////////////////////

	for (size_t i = 0; i < windowSize; i++)
	{
		//Moments
		summagbin += (m_fFreqBins[i] * magnitude[i]);
		summag += magnitude[i];
		sumprevmag += prevmagnitude[i];

		//Spectral Crest factor
		if(magnitude[i] > maxmag)
		{
			maxmag = magnitude[i];
		}

		float energy = magnitude[i] * magnitude[i];

		//Roll off + Flatness

		totalenergy += energy;
		float exponent = static_cast<float>(1.0/static_cast<float>(windowSize));

		if(energy != 0)
		{
			geo *= pow(energy, exponent);
		}
	}

	summag += std::numeric_limits<float>::epsilon();

	centroid = summagbin / summag;

	/////////////////////////////////////////////////////////

	//Spread
	//////////////////////////////////////////////////////

	for (size_t i = 0; i < windowSize; i++)
	{
		float norm = magnitude[i] / (summag + std::numeric_limits<float>::epsilon());
		float normprev = prevmagnitude[i] / (sumprevmag + std::numeric_limits<float>::epsilon());

		//Spectral Flux
		spectralflux += ((norm - normprev) * (norm - normprev));

		//Entropy
		normalisedMagSumEntropy += (norm * log(norm + std::numeric_limits<float>::epsilon()));

		//Moments
		summagspread	+= pow((m_fFreqBins[i] - centroid), 2) * norm;
		summagskewness	+= pow((m_fFreqBins[i] - centroid), 3) * norm;
		summagkurtosis	+= pow((m_fFreqBins[i] - centroid), 4) * norm;

		//Brightness
		if (m_fFreqBins[i] >= 1500)
		{
			sumbrightness += magnitude[i];
		}
	}

	spread = sqrt(summagspread);

	/////////////////////////////////////////////////////////

	//Skewness
	//////////////////////////////////////////////////////

	float spreadtemp = spread;
	spreadtemp += std::numeric_limits<float>::epsilon();

	skew = summagskewness  / pow(spreadtemp, 3);

	/////////////////////////////////////////////////////////

	//Kurtosis
	//////////////////////////////////////////////////////

	kurtosis = summagkurtosis / pow(spreadtemp, 4);

	/////////////////////////////////////////////////////////

	//Brightness
	//////////////////////////////////////////////////////

	brightness = sumbrightness / summag;

	/////////////////////////////////////////////////////////

	//Roll off 85% - 95%
	/////////////////////////////////////////////////////////

	while ((currEnergy95 <= 0.95 * totalenergy) && (countFFT95 < static_cast<int>(windowSize)))
	{
		currEnergy95 += (magnitude[countFFT95] * magnitude[countFFT95]);
		countFFT95 += 1;

		if (currEnergy85 <= 0.85 * totalenergy)
		{
			currEnergy85 += (magnitude[countFFT85] * magnitude[countFFT85]);
			countFFT85 += 1;
		}

	}

	countFFT85 -= 1;
	countFFT95 -= 1;

	//Normalization
	if (currEnergy85 <= 0)
	{
		//If we have silence then our value should be 0.
		rolloff85 = 0;
	}
	else
	{
		rolloff85 = (static_cast<float>(countFFT85) / static_cast<float>(windowSize));
	}

	//Normalization
	if (currEnergy95 <= 0)
	{
		//If we have silence then our value should be 0.
		rolloff95 = 0;
	}
	else
	{
		rolloff95 = (static_cast<float>(countFFT95) / static_cast<float>(windowSize));
	}

	/////////////////////////////////////////////////////

	//Spectral Entropy
	/////////////////////////////////////////////////////////

	spectralentropy = static_cast<float>((normalisedMagSumEntropy / log(static_cast<float>(windowSize))) * - 1);

	/////////////////////////////////////////////////////////

	/////////////////////////////////////////////////////

	//Flatness
	/////////////////////////////////////////////////////////
	if(totalenergy != 0 && geo != 0)
	{
		flatness = geo / (totalenergy / static_cast<float>(windowSize));
	}
	else
	{
		flatness = 0;
	}

	/////////////////////////////////////////////////////////

	//Spectral Crest Factor
	/////////////////////////////////////////////////////////

	if(summag != 0)
	{
		spectralcf = maxmag / summag;
	}
	else
	{
		spectralcf = 0;
	}
}

void AudioSourceFeatureExtractor::ConvolveFunction(float* &z, float *x, float *y, size_t &lenz, size_t lenx, size_t leny)
{
	// computes cross-correlation of two vectors, takes 2 vectors of the same length and computes 2*length-1 lags

	float *zptr,s,*xp,*yp;
	size_t n_lo, n_hi;

	lenz = lenx + leny - 1;

	z = new float[lenz];

	zptr = z;

	for (size_t i = 0; i < lenz; i++)
	{
		s = 0.0;
		n_lo = 0 > (i - leny + 1 ) ? 0 : (i - leny + 1);
		n_hi = (lenx - 1) < i ? (lenx - 1): i;
	    xp = &x[0] + n_lo;
		yp = &y[0] + i - n_lo;

		for (size_t n = n_lo; n <= n_hi; n++)
		{
			s += *xp * *yp;
			xp++;
			yp--;
		}

		*zptr=s;
		zptr++;
	}
}

void AudioSourceFeatureExtractor::XCorr(float *&output, float* input1, float* input2, size_t  &outputlen, size_t inputlen, size_t  maxLag = 0)
{
    // TODO: adapt for different sizes

    // find next power of 2 for efficient FFT
    size_t fftSize = 1;
    while (fftSize < 2*static_cast<size_t>(inputlen)-1)
    {
        fftSize *= 2;
    }

	FFTW fft1 = FFTW(fftSize);
	FFTW fft2 = FFTW(fftSize);

    // allocate space for FFTW processing
    float *in1 = new float[fftSize];
    float *in2 = new float[fftSize];

    // output from FFT is only up to Nyquist frequency
    float *out1Real = new float[fftSize];
    float *out1Imag = new float[fftSize];
    float *out2Real = new float[fftSize];
    float *out2Imag = new float[fftSize];

	memset(in1, 0, sizeof(float)*fftSize);
    memset(in2, 0, sizeof(float)*fftSize);
    memset(out1Real, 0, sizeof(float)*fftSize);
    memset(out1Imag, 0, sizeof(float)*fftSize);
    memset(out2Real, 0, sizeof(float)*fftSize);
    memset(out2Imag, 0, sizeof(float)*fftSize);

    // copy input to allocated arrays
    for (size_t i = 0; i < static_cast<size_t>(inputlen); ++i)
    {
        in1[i] = input1[i];
        in2[i] = input2[i];
    }

	fft1.process(in1, out1Real, out1Imag);
	fft2.process(in2, out2Real, out2Imag);

    // multiply out1*conj(out2) in FFT domain
    fftwf_complex *product = static_cast<fftwf_complex*>(fftwf_malloc(sizeof(fftwf_complex)*fftSize));
    for (size_t i = 0; i < fftSize; ++i)
    {
        product[i][0] = (out1Real[i]*out2Real[i] + out1Imag[i]*out2Imag[i]);
        product[i][1] = (out1Imag[i]*out2Real[i] - out1Real[i]*out2Imag[i]);
    }

    // compute IFFT

	// do FFT, adapted from iTraktorLib "FFTW.h"
    fftw_iodim dim;
    dim.n = fftSize;
    dim.is = 1;
    dim.os = 1;

    fftwf_plan plan;

    float *result = static_cast<float*>(fftwf_malloc(sizeof(float)*fftSize));
    plan = fftwf_plan_guru_dft_c2r(1, &dim, 0, nullptr, product, result, FFTW_ESTIMATE);
    fftwf_execute_dft_c2r(plan, product, result);
    fftwf_destroy_plan(plan);

    // copy real part of result back to output array, normalize by FFT size
    if (maxLag == 0 || maxLag >= static_cast<size_t>(inputlen))
    {
        maxLag = static_cast<size_t>(inputlen)-1;
    }

    output = new float[2 * maxLag + 1];
	outputlen = 2 * maxLag + 1;

    for (size_t i = fftSize - maxLag; i < fftSize; ++i)
    {
        output[i - fftSize + maxLag] = result[i] / fftSize;
    }

    for (unsigned i = 0; i <= static_cast<unsigned>(maxLag); ++i)
    {
        output[i + maxLag] = result[i] / fftSize;
    }

	fftwf_free(result);
	fftwf_free(product);

	if(in1 != nullptr)
	{
		delete[] in1;
		in1 = nullptr;
	}

	if(in2 != nullptr)
	{
		delete[] in2;
		in2 = nullptr;
	}

	if(out1Real != nullptr)
	{
		delete[] out1Real;
		out1Real= nullptr;
	}

	if(out1Imag != nullptr)
	{
		delete[] out1Imag;
		out1Imag= nullptr;
	}

	if(out2Real != nullptr)
	{
		delete[] out2Real;
		out2Real= nullptr;
	}

	if(out2Imag != nullptr)
	{
		delete[] out2Imag;
		out2Imag= nullptr;
	}
}

float AudioSourceFeatureExtractor::EstimatePerdiodicity(float* data, size_t numSamples)
{
	float periodicity = 0.0;
	float* downsampleddata = new float[numSamples];
	memset(downsampleddata, 0, sizeof(float)*numSamples);
	float* xcorr = nullptr;

	for(size_t k = 0; k < numSamples; k++)
	{
		downsampleddata[k] = data[k];
	}


	EnvelopeCurve(downsampleddata, downsampleddata, numSamples, m_fSampleRate);

	int startLag = static_cast<int>(floor(static_cast<float>(60.0 / 480.0 * m_fSampleRate)));
	int endLag = static_cast<int>(floor(static_cast<float>(60.0 / 30.0 * m_fSampleRate)));
	int thresh = static_cast<int>(floor(static_cast<float>(.2 * m_fSampleRate)));	

	size_t xcorrlen = 0;
	XCorr(xcorr, downsampleddata, downsampleddata, xcorrlen, numSamples, endLag);

	int i = static_cast<int>(floor(xcorrlen / 2));

	std::vector<float> temp;
	for(size_t j = i; j < xcorrlen; j++)
	{
		temp.push_back(xcorr[j]);
	}

	std::vector<float> temp2;
	for(size_t j = static_cast<size_t>(std::max(1,startLag)); j < static_cast<size_t>(std::min(endLag,static_cast<int>(temp.size()))); j++)
	{
		temp2.push_back(temp[j]);
	}

	int maxIdx = 0;
	float maxVal = std::numeric_limits<float>::lowest();
	for(size_t j =0; j < temp2.size(); j++)
	{
		if(temp2[j] > maxVal)
		{
			maxIdx = j;
			maxVal = temp2[j];
		}
	}

	int from = std::max(1, maxIdx-thresh);
	int to = std::min(static_cast<int>(temp2.size()), maxIdx+thresh);

	float minValInRange = std::numeric_limits<float>::max();

	for(size_t j = static_cast<size_t>(from); j < to; j++)
	{
		if(temp2[j] < minValInRange)
		{
			minValInRange = temp2[j];
		}
	}

    periodicity = (maxVal-minValInRange);

	std::string dave = "Periodicity " + std::to_string(periodicity) + "\n";
	//OutputDebugString(dave.c_str());

	if(xcorr != nullptr)
	{
		delete[] xcorr;
		xcorr = nullptr;
	}

	if(downsampleddata != nullptr)
	{
		delete[] downsampleddata;
		downsampleddata = nullptr;
	}

	return periodicity;
}

void AudioSourceFeatureExtractor::DownSampler(float* data, float* &out, size_t lenIn, size_t &lenOut, float currentSampleRate, float futureSampleRate)
{
	////Low pass our data before we decimate
	//const int filterlength = 101;
	//float* tempdata = new float[lenIn];
	//memset(tempdata, 0, sizeof(float)*lenIn);

	////Coefficients were taken from Matlab
	//float coeffs[filterlength] ={2.0839274e-05f, 6.6880953e-06f,-4.7252855e-05f,	-3.4874138e-05f,	7.8508412e-05f,9.7089069e-05f,-9.9197161e-05f,	-0.00020412984f,	8.2261082e-05f,	0.00035689832f,	9.4890293e-06f,	-0.00053820928f,	-0.00021722882f,	0.00070567406f,	0.00057491515f,	-0.00078844035f, -0.0010939316f,	0.00069057313f,	0.0017460365f,	-0.00030308162f,	-0.0024484061f,	-0.00047496572f,	0.0030552838f,	0.0017078921f, 	-0.0033604759f, 	-0.0033912712f, 	0.0031135236f, 	0.0054217125f, 	-0.0020499325f, 	-0.0075746416f, 	-6.7239242e-05f, 0.0094950572f, 0.0034002098f,	-0.010703080f, 	-0.0079918290f, 	0.010610434f, 0.013732497f, 	-0.0085344436f, 	-0.020346783f, 0.0036776769f,	0.027405130f,	0.0050050775f,	-0.034361813f,	-0.019287759f,	0.040615436f,	0.043452863f,-0.045583628f,	-0.093336113f,	0.048780452f,	0.31394306f,	0.45011634f,	0.31394306f,	0.048780452f,-0.093336113f,-0.045583628f,	0.043452863f,0.040615436f,-0.019287759f,	-0.034361813f,	0.0050050775f,	0.027405130f,0.0036776769f,-0.020346783f,	-0.0085344436f,	0.013732497f,	0.010610434f,	-0.0079918290f,	-0.010703080f,	0.0034002098f,	0.0094950572f,	-6.7239242e-05f,	-0.0075746416f,	-0.0020499325f,	0.0054217125f,	0.0031135236f,	-0.0033912712f,	-0.0033604759f,	0.0017078921f,	0.0030552838f,	-0.00047496572f,	-0.0024484061f,	-0.00030308162f,	0.0017460365f,0.00069057313f,	-0.0010939316f,	-0.00078844035f,	0.00057491515f,	0.00070567406f,	-0.00021722882f,	-0.00053820928f,	9.4890293e-06f,	0.00035689832f,	8.2261082e-05f,	-0.00020412984f,	-9.9197161e-05f,	9.7089069e-05f,	7.8508412e-05f,	-3.4874138e-05f,	-4.7252855e-05f,	6.6880953e-06f,	2.0839274e-05f};
	//
	//float acc;     // accumulator for MACs
 //   float* coeffp; // pointer to coefficients
 //   float* inputp; // pointer to input samples
	//float* endp = &data[lenIn -1]; // pointer to last sample
 //
 //
 //   // apply the filter to each input sample
 //   for (size_t n = 0; n < lenIn; n++ )
	//{
 //       // calculate output n
 //       coeffp = &coeffs[0];
 //       inputp = &data[filterlength - 1 + n];

	//	acc = 0.0f;
	//	for (int k = 0; k < filterlength; k++ )
	//	{
	//		if(inputp <= endp)
	//			acc += (*coeffp++) * (*inputp--);
	//		else
	//		{
	//			//When we reach the end of the buffer
	//			acc += (*coeffp++) * 0.0f;
	//			*inputp--;
	//		}
	//	}

	//	tempdata[n] = acc;
 //   }
	//int ratio = (int) (currentSampleRate / futureSampleRate);
	//
	//lenOut = lenIn / ratio;

	//out = new float[lenOut];
	//memset(out, 0, sizeof(float)*lenOut);


	//int idx = 0;
	//for(size_t i = 0; i < lenIn; i = i + ratio)
	//{
	//	out[idx] = tempdata[i];
	//	idx++;
	//}

	//if(tempdata != NULL)
	//{
	//	delete[] tempdata;
	//	tempdata = nullptr;
	//}
}

void AudioSourceFeatureExtractor::EnvelopeCurve(float* data, float* &out, size_t dataLen, float sampleRate)
{
    float release = 0.02f;
	float envelope = 0.0f;

	float gr = exp(-1 / (sampleRate * release));

    for (size_t i = 0; i < dataLen; i++)
	{
		float EnvIn = abs(data[i]);

		if(envelope < EnvIn)
		{
			envelope = EnvIn;
		}
		else
		{
			envelope = envelope * gr;
			envelope = envelope + (1 - gr) * EnvIn;
		}

		out[i] = envelope;
	}
}

void AudioSourceFeatureExtractor::Normalise(float* data, float* &out, size_t len)
{
	float maxvalue = std::numeric_limits<float>::lowest();

	for(size_t i = 0; i < len; i++)
	{
		if(data[i] > maxvalue)
			maxvalue = data[i];
	}

	for(size_t i = 0; i < len; i++)
	{
		out[i] = data[i] / maxvalue;
	}
}

float AudioSourceFeatureExtractor::EntropyOfEnergy(float* data, size_t len)
{
	float totalEnergy = 0.0;
	float totalentropy = 0.0;
	const int numSubFrames = 30;

	//Calculate Total Energy and normalise it
	for (size_t i =0; i < len; i++)
	{
		totalEnergy += (data[i] * data[i]);
	}

	int subFrameSize = len / numSubFrames;

	for (size_t i = 0; i < numSubFrames; i++)
	{
		float val = 0.0;

		for (size_t j = 0; j < static_cast<size_t>(subFrameSize); j++)
		{
			val += (data[j + (i * subFrameSize)] * data[j + (i * subFrameSize)]);
		}

		float frameval = val / (totalEnergy + std::numeric_limits<float>::epsilon());

		totalentropy += (frameval * Log2(frameval + std::numeric_limits<float>::epsilon()));
	}

	return (totalentropy * -1);
}

void AudioSourceFeatureExtractor::PDF_getResampleKrnl(std::vector<float> freqVec, float fsProc, int nfft, int nBin, std::vector<float> &outLogFreqVec, std::vector<std::vector<float>> &outKrnl)
{
	float f1 = freqVec[0];
	float f2 = freqVec[freqVec.size() - 1];

	outLogFreqVec = LinSpace(log(f1), log(f2), nBin);
	std::vector<float> f(nfft / 2, 0.0f);

	for (size_t i = 0; i < static_cast<size_t>(nBin); i++)
	{
		outKrnl.push_back(f);
	}

	for (size_t i = 0; i < outLogFreqVec.size(); i++)
	{
		outLogFreqVec[i] = exp(outLogFreqVec[i]);
	}

	for (size_t i = 1; i < static_cast<size_t>(nBin) - 2; i++)
	{
		float freqBinLin = outLogFreqVec[i] / (fsProc / nfft);

		float nextBinUp = outLogFreqVec[i + 1] / (fsProc / nfft);

		float nextBinDown = outLogFreqVec[i - 1] / (fsProc / nfft);

		float filtWid = nextBinUp - nextBinDown;

		if (filtWid <= 2)
		{
			// log resolution is finer than linear resolution
			// linear interpolation  of neighboring bins

			float binDown = floor(freqBinLin);
			float frac = freqBinLin - binDown;
			std::vector<float> filt(nfft/2, 0.0f);
			filt[((int)binDown) - 1] = 1 - frac;
			filt[((int)binDown + 1) - 1] = frac;
			outKrnl[i][((int)binDown) - 1] = filt[((int)binDown) - 1];
			outKrnl[i][((int)binDown + 1) - 1] = filt[((int)binDown + 1) - 1];

		}
		else
		{
			float ceilNextBinDown = ceil(nextBinDown);
			float floorFreqBinLin = floor(freqBinLin);
			float ceilFreqBinLin = ceil(freqBinLin);
			float floorNextBinUp = floor(nextBinUp);

			std::vector<int> idxLow;
			std::vector<int> idxHigh;
			std::vector<int> filtIdx;

			for (size_t j = (size_t)ceilNextBinDown; j <= (size_t)floorFreqBinLin; j++ )
			{
				idxLow.push_back(j);
			}

			for (size_t j = (size_t)ceilFreqBinLin; j <= (size_t)floorNextBinUp; j++ )
			{
				idxHigh.push_back(j);
			}

			std::vector<int>::iterator it;
			it = std::unique (idxLow.begin(), idxLow.end());
			idxLow.resize(std::distance(idxLow.begin(), it));

			it = std::unique (idxHigh.begin(), idxHigh.end());
			idxHigh.resize(std::distance(idxHigh.begin(), it));

			filtIdx.reserve(idxLow.size() + idxHigh.size()); // preallocate memory
			filtIdx.insert(filtIdx.end(), idxLow.begin(), idxLow.end());
			filtIdx.insert(filtIdx.end(), idxHigh.begin(), idxHigh.end());

			std::vector<float> rampUp;
			std::vector<float> rampDown;
			for (size_t j = 0; j < filtIdx.size(); j++)
			{
				rampUp.push_back(1 - (freqBinLin - filtIdx[j]) / (freqBinLin - nextBinDown));
				rampDown.push_back(1 - (filtIdx[j] - freqBinLin) / (nextBinUp -  freqBinLin));
			}

			std::vector<float> filt;

			for (size_t j = 0; j < rampUp.size(); j++)
			{
				filt.push_back(std::min(rampUp[j], rampDown[j]));
			}

			float sumfilt = 0.0f;
			for (size_t j = 0; j < filt.size(); j++)
			{
				sumfilt += filt[j];
			}

			for (size_t j = 0; j < filt.size(); j++)
			{
				filt[j] /= sumfilt;
			}

			for (size_t j = 0; j < filtIdx.size(); j++)
			{
				outKrnl[i][filtIdx[j] - 1] = filt[j];
			}
		}
	}

	// special routine for first bin
	// get frequency in linear bins

	float freqBinLin = outLogFreqVec[0] / (fsProc/(float)nfft);
	float binDown = floor(freqBinLin);
	float frac = freqBinLin - binDown;

	std::vector<float> filt(nfft/2, 0.0f);
	filt[((int)binDown) - 1] = 1 - frac;
	filt[((int)binDown + 1) - 1] = frac;

	outKrnl[0][((int)binDown) - 1] = filt[((int)binDown) - 1];
	outKrnl[0][((int)binDown + 1) - 1] = filt[((int)binDown + 1) - 1];

	// special routine for last bin
	// get frequency in linear bins
	freqBinLin = outLogFreqVec[outLogFreqVec.size() - 1] / (fsProc/nfft);

	// get next lower bin
	float nextBinDown = outLogFreqVec[outLogFreqVec.size() - 2] / (fsProc/nfft);

	float ceilNextBinDown = ceil(nextBinDown); //Subtract by -1 because of array
	float floorFreqBinLin = floor(freqBinLin);

	std::vector<int> filtIdx;

	for (size_t i = (size_t)ceilNextBinDown; i <= (size_t)floorFreqBinLin; i++ )
	{
		filtIdx.push_back(i);
	}

	std::vector<float> filt2;
	for (size_t i = 0; i < filtIdx.size(); i++)
	{
		filt2.push_back(1 - (freqBinLin - filtIdx[i]) / (freqBinLin - nextBinDown));
	}

	float sumfilt = 0.0f;
	for (size_t i = 0; i < filt2.size(); i++)
	{
		sumfilt += filt2[i];
	}

	for (size_t i = 0; i < filt2.size(); i++)
	{
		filt2[i] /= sumfilt;
	}

	for (size_t j = 0; j < filtIdx.size(); j++)
	{
		outKrnl[outKrnl.size() - 1][filtIdx[j] - 1] = filt2[j];
	}
}

float AudioSourceFeatureExtractor::Log2(float n)
{
	// log(n)/log(2) is log2.
	return logf( n ) / logf( 2 );
}

int AudioSourceFeatureExtractor::Sign(float x)
{
	int retValue = 0;
	if (x >= 0)
		retValue = 1;
	if (x < 0)
		retValue = -1;

	return retValue;
}

std::vector<float> AudioSourceFeatureExtractor::LinSpace(float min, float max, int n)
{
	std::vector<float> result;
	// vector iterator
	int iterator = 0;

	for (int i = 0; i <= n-2; i++)
	{
		float temp = min + i*(max-min)/(floor((float)n) - 1);
		result.insert(result.begin() + iterator, temp);
		iterator += 1;
	}

	result.insert(result.begin() + iterator, max);
	return result;
}

std::vector<float> AudioSourceFeatureExtractor::LogSpace(float min, float max, int n)
{
	float logMin = log(min);
	float logMax = log(max);
	double delta = (logMax - logMin) / n;
	double accDelta = 0;
	std::vector<float> v;

	for (int i = 0; i <= n; i++)
	{
		v.push_back((float) exp(logMin + accDelta));
		accDelta += delta;// accDelta = delta * i
	}

	return v;
}