87 lines
2.6 KiB
Matlab
87 lines
2.6 KiB
Matlab
% spec.m
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% Jean Marc Valin
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%
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% Spectrogram function for Octave
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%
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% Copyright (c) John-Marc Valin 2012
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%
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% Redistribution and use in source and binary forms, with or without
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% modification, are permitted provided that the following conditions
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% are met:
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%
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% - Redistributions of source code must retain the above copyright
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% notice, this list of conditions and the following disclaimer.
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%
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% - Redistributions in binary form must reproduce the above copyright
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% notice, this list of conditions and the following disclaimer in the
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% documentation and/or other materials provided with the distribution.
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%
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% - Neither the name of Jean Marc Valin nor the names of its
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% contributors may be used to endorse or promote products derived from
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% this software without specific prior written permission.
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%
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% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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% ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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% LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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% A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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% CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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% EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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% PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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% PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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% LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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% NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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% SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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function X = spec(x, Fs, framesize, start, stop)
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gr=[zeros(1024,1),[0:1023]'/1023,.68*[0:1023]'/1023];
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%gr=[.4*[0:1023]'/1023,[0:1023]'/1023,.68*[0:1023]'/1023];
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%t=[0:1023]'/1023;
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%t=(1+.25*t-cos(pi*t))/2.25;
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%gr = [zeros(1024,1),t,.68*t];
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%colormap(gr);
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if nargin < 2 || isempty(Fs)
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Fs = 44100;
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end
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if nargin < 3 || isempty(framesize)
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framesize = 2048;
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endif
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offset = framesize/4;
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X = 20*log10(abs(specgram(x, framesize, 48000, blackmanharris(framesize)', framesize-offset)));
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XM=max(max(X));
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X = max(XM-120,X);
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%size(X)
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F = -[framesize/2-1:-1:0]/framesize*Fs;
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%F = [0:127]/128*24000;
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T=[1:size(X,2)]/Fs*offset;
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%imagesc(X(end:-1:1,:));
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if nargin < 4 || isempty(start)
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istart=1;
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else
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istart = round(start*Fs/offset);
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end
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if nargin < 5 || isempty(stop)
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istop = size(X,2);
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else
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istop = round(stop*Fs/offset);
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endif
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istart = max(1,istart);
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istop = min(istop, size(X,2));
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imagesc(T(1+istart:istop), F, X(end:-1:1,1+istart:istop));
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X = X(:,1+istart:istop);
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