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