boblsturm@0: function Y = chromagram_P(d,sr,fftlen,nbin,f_ctr,f_sd)
boblsturm@0: % Y = chromagram_E(d,sr,fftlen,nbin)
boblsturm@0: %  Calculate a "chromagram" of the sound in d (at sampling rate sr)
boblsturm@0: %  Use windows of fftlen points, hopped by ffthop points
boblsturm@0: %  Divide the octave into nbin steps
boblsturm@0: %  Weight with center frequency f_ctr (in Hz) and gaussian SD f_sd (in octaves)
boblsturm@0: % 2006-09-26 dpwe@ee.columbia.edu
boblsturm@0: 
boblsturm@0: if nargin < 3;   fftlen = 2048; end
boblsturm@0: if nargin < 4;   nbin = 12; end
boblsturm@0: if nargin < 5;   f_ctr = 1000; end
boblsturm@0: if nargin < 6;   f_sd = 1; end
boblsturm@0: 
boblsturm@0: fftwin = fftlen/2;
boblsturm@0: ffthop = fftlen/4;  % always for this
boblsturm@0: 
boblsturm@0: D = abs(specgram(d,fftlen,sr,fftwin,(fftwin-ffthop)));
boblsturm@0: 
boblsturm@0: [nr,nc] = size(D);
boblsturm@0: 
boblsturm@0: A0 = 27.5; % Hz
boblsturm@0: A440 = 440; % Hz
boblsturm@0: 
boblsturm@0: f_ctr_log = log(f_ctr/A0) / log(2);
boblsturm@0: 
boblsturm@0: CM = fft2chromamx(fftlen, nbin, sr, A440, f_ctr_log, f_sd);
boblsturm@0: % Chop extra dims
boblsturm@0: CM = CM(:,1:(fftlen/2)+1);
boblsturm@0: 
boblsturm@0: % Keep only local maxes in freq
boblsturm@0: Dm = (D > D([1,[1:nr-1]],:)) & (D >= D([[2:nr],nr],:));
boblsturm@0: Y = CM*(D.*Dm);