From 60341ac292bb9ba6f1d33632f8fd8e767c6a99d4 Mon Sep 17 00:00:00 2001
From: mick grierson <mickgrierson@gmail.com>
Date: Tue, 27 Oct 2015 17:05:12 +0000
Subject: clean up

---
 openFrameworks/ofxMaxim/libs/maxiMFCC.h | 205 ++++++++++++++++++++++++++++++++
 1 file changed, 205 insertions(+)
 create mode 100644 openFrameworks/ofxMaxim/libs/maxiMFCC.h

(limited to 'openFrameworks/ofxMaxim/libs/maxiMFCC.h')

diff --git a/openFrameworks/ofxMaxim/libs/maxiMFCC.h b/openFrameworks/ofxMaxim/libs/maxiMFCC.h
new file mode 100644
index 0000000..19dd72e
--- /dev/null
+++ b/openFrameworks/ofxMaxim/libs/maxiMFCC.h
@@ -0,0 +1,205 @@
+/*
+ *  maxiMFCC.h
+ *  mfccs
+ *
+ *  Created by Chris on 08/03/2011.
+ *  Copyright 2011 Goldsmiths Creative Computing. All rights reserved.
+ *
+ 
+ Based on Matthew Yee-King's MFCCMYK java class
+ */
+
+#pragma once
+#pragma pack(16)
+
+#include "maxiFFT.h"
+#include <math.h>
+#include <iostream>
+#include <cstdlib>
+#ifdef __APPLE_CC__
+#include <Accelerate/Accelerate.h>
+#endif
+
+using namespace std;
+
+
+// implements this formula:
+// mel = 2595 log10(Hz/700 + 1)
+inline double hzToMel(double hz){
+	return 2595.0 * (log10(hz/700.0 + 1.0));
+}
+
+// implements this formula
+// Hz = 700 (10^(mel/2595) - 1)
+inline double melToHz(double mel){
+	return 700.0 * (pow(10, mel/2595.0) - 1.0);
+}
+
+template <class T>
+class maxiMFCCAnalyser {
+public:
+	T *melBands;
+	maxiMFCCAnalyser():melFilters(NULL),dctMatrix(NULL), melBands(NULL){};
+	~maxiMFCCAnalyser() {
+		if (melFilters) {
+			delete[] melFilters;
+			delete[] melBands;
+			delete[] dctMatrix;
+#ifdef __APPLE_CC__
+			delete doubleSpec;
+#endif
+		}
+	}
+	
+	void setup(unsigned int numBins, unsigned int numFilters, unsigned int numCoeffs, double minFreq, double maxFreq, unsigned int sampleRate) 
+	{
+		this->numFilters = numFilters;
+		this->numCoeffs = numCoeffs;
+		this->minFreq = minFreq;
+		this->maxFreq = maxFreq;
+		this->sampleRate = sampleRate;
+		this->numBins = numBins;
+		melFilters = NULL;
+		melBands = (T*) malloc(sizeof(T) * numFilters);
+#ifdef __APPLE_CC__
+		doubleSpec = (T*)malloc(sizeof(T) * numBins);
+#endif
+		//create new matrix
+		dctMatrix = (T*)malloc(sizeof(T) * numCoeffs * numFilters);
+		calcMelFilterBank(sampleRate, numBins);
+		createDCTCoeffs();
+	}
+	void mfcc(float* powerSpectrum, T *mfccs) {
+		melFilterAndLogSquare(powerSpectrum);
+		dct(mfccs);
+	}
+	
+private:
+	unsigned int numFilters, numCoeffs;
+	double minFreq, maxFreq;
+	unsigned int sampleRate;
+	T *melFilters;
+	unsigned int numBins;
+	T *dctMatrix;
+#ifdef __APPLE_CC__
+	T *doubleSpec;
+#endif
+	
+#ifdef __APPLE_CC__
+	void dct(T *mfccs); //define later
+#else
+	void dct(T *mfccs) {
+		for(int i=0; i < numCoeffs; i++) {
+			mfccs[i] = 0.0;
+		}
+		for(int i=0; i < numCoeffs; i++ ) {
+			for(int j=0; j < numFilters; j++) {
+				int idx = i + (j * numCoeffs);
+				mfccs[i] += (dctMatrix[idx] * melBands[j]);
+			}
+		}
+		for(int i=0; i < numCoeffs; i++) {
+			mfccs[i] /= numCoeffs;
+		}
+	}
+#endif
+	
+	void melFilterAndLogSquare(float* powerSpectrum);
+	void melFilterAndLogSq_Part2(float *powerSpectrum);
+
+	
+	void calcMelFilterBank(double sampleRate, int numBins) {
+
+		double mel, dMel, maxMel, minMel, nyquist, binFreq, start, end, thisF, nextF, prevF;
+		int numValidBins;
+		
+		// ignore bins over nyquist
+		numValidBins = numBins;
+		
+		nyquist = sampleRate/2;
+		if (maxFreq > nyquist) {
+			maxFreq = nyquist;
+		}
+		
+		maxMel = hzToMel(maxFreq);
+		minMel = hzToMel(minFreq);
+		
+		dMel = (maxMel - minMel) / (numFilters + 2 - 1);
+		
+		T *filtPos = (T*) malloc(sizeof(double) * (numFilters + 2));
+		
+		// first generate an array of start and end freqs for each triangle
+		mel = minMel;
+		for (int i=0;i<numFilters + 2;i++) {
+			// start of the triangle
+			filtPos[i] = melToHz(mel);
+			//		std::cout << "[" << i << "] MFCC: centre is at " <<filtPos[i]<<"hz "<<mel<<" mels" << endl;
+			mel += dMel;
+		}
+		// now generate the coefficients for the mag spectrum
+		melFilters = (T*) malloc(sizeof(T) * numFilters * numValidBins);
+		
+		for (int filter = 1; filter < numFilters; filter++) {
+			for (int bin=0;bin<numValidBins;bin++) {
+				// frequency this bin represents
+				binFreq = (T) sampleRate / (T) numValidBins * (T) bin;
+				thisF = filtPos[filter];
+				nextF = filtPos[filter+1];
+				prevF = filtPos[filter-1];
+				int idx = filter + (bin * numFilters);
+				if (binFreq > nextF || binFreq < prevF) {
+					// outside this filter
+					melFilters[idx] = 0;
+					//cout << "MFCCMYK: filter at " <<thisF << " bin at " <<binFreq <<" coeff " <<melFilters[filter][bin] << endl;
+				}
+				else {
+					T height = 2.0 / (nextF - prevF);
+					
+					if (binFreq < thisF) {
+						// up
+						start = prevF;
+						end = thisF;
+						melFilters[idx] = (binFreq - start) * (height / (thisF - start));	  
+					}
+					else {
+						// down
+						start = thisF;
+						end = nextF;
+						melFilters[idx] = height + ((binFreq - thisF) * (-height /(nextF - thisF)));	  
+					}
+					//				cout << "MFCCMYK: filter at " <<thisF << " bin at " <<binFreq <<" coeff " <<melFilters[filter][bin] << endl;
+					//cout << "MFCCMYK: filter at " <<thisF << " bin at " <<binFreq <<" coeff " <<melFilters[idx] << endl;
+				}
+			}
+		}
+	}
+	void createDCTCoeffs() {
+		T k = 3.14159265358979323846/numFilters;
+		T w1 = 1.0/(sqrt(numFilters));
+		T w2 = sqrt(2.0/numFilters);
+		
+		
+		//generate dct matrix
+		for(int i = 0; i < numCoeffs; i++)
+		{
+			for(int j = 0; j < numFilters; j++)
+			{
+				int idx = i + (j * numCoeffs);
+				if(i == 0)
+					dctMatrix[idx]= w1 * cos(k * (i+1) * (j + 0.5));
+				else
+					dctMatrix[idx] = w2 * cos(k * (i+1) * (j + 0.5));
+			}
+		}
+		
+		
+	}
+		
+	
+	
+};
+
+
+
+typedef maxiMFCCAnalyser<double> maxiMFCC;
+//typedef maxiMFCCAnalyser<float> maxiFloatMFCC;
-- 
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