comparison Source/initMFCCVariables.m @ 0:25bf17994ef1

First commit. VS2013, Codeblocks and Mac OSX configuration

+function [mfccFilterWeights mfccDCTMatrix] = initMFCCVariables(sampleRate, FFTsize)
+
+Fs   = sampleRate;
+Nfft = FFTsize;
+    
+%Filter bank parameters
+lowestFrequency = 133.3333;
+linearFilters = 13;
+linearSpacing = 66.66666666;
+logFilters = 27;
+logSpacing = 1.0711703;
+cepstralCoefficients = 13;
+
+% Keep this around for later....
+totalFilters = linearFilters + logFilters;
+
+% Now figure the band edges.  Interesting frequencies are spaced
+% by linearSpacing for a while, then go logarithmic.  First figure0
+% all the interesting frequencies.  Lower, center, and upper band
+% edges are all consecutive interesting frequencies. 
+freqs = lowestFrequency + (0:linearFilters-1)*linearSpacing;
+freqs(linearFilters+1:totalFilters+2) = freqs(linearFilters) * logSpacing.^(1:logFilters+2);
+lower  = freqs(1:totalFilters);
+center = freqs(2:totalFilters+1);
+upper  = freqs(3:totalFilters+2);
+
+% each filter has unit weight, assuming a triangular weighting function
+mfccFilterWeights = zeros(totalFilters,Nfft/2);
+triangleHeight = 2./(upper-lower);
+fftFreqs = (0:Nfft/2-1)/(Nfft)*Fs;
+for chan=1:totalFilters
+	mfccFilterWeights(chan,:) = (fftFreqs > lower(chan) & fftFreqs <= center(chan)).* triangleHeight(chan).*(fftFreqs-lower(chan))/(center(chan)-lower(chan)) + ...
+                                (fftFreqs > center(chan) & fftFreqs < upper(chan)) .* triangleHeight(chan).*(upper(chan)-fftFreqs)/(upper(chan)-center(chan));
+end
+
+% Figure out Discrete Cosine Transform.  We want a matrix
+% dct(i,j) which is totalFilters x cepstralCoefficients in size.
+% The i,j component is given by cos( i * (j+0.5)/totalFilters pi )
+% where we have assumed that i and j start at 0.
+mfccDCTMatrix      = 1/sqrt(totalFilters/2)*cos((0:(cepstralCoefficients-1))' * (2*(0:(totalFilters-1))+1) * pi/2/totalFilters);
+mfccDCTMatrix(1,:) = mfccDCTMatrix(1,:) * sqrt(2)/2;
+