Jean-Marcs spectrogram function

git-svn-id: https://svn.code.sf.net/p/freetel/code@342 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/codec2-dev/octave/spec.m b/codec2-dev/octave/spec.m
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+% spec.m
+% Jean Marc Valin
+%
+% Spectrogram function for Octave 
+%
+%   Copyright (c) John-Marc Valin 2012
+%
+%   Redistribution and use in source and binary forms, with or without
+%   modification, are permitted provided that the following conditions
+%   are met:
+%   
+%   - Redistributions of source code must retain the above copyright
+%   notice, this list of conditions and the following disclaimer.
+%   
+%   - Redistributions in binary form must reproduce the above copyright
+%   notice, this list of conditions and the following disclaimer in the
+%   documentation and/or other materials provided with the distribution.
+%   
+%   - Neither the name of Jean Marc Valin nor the names of its
+%   contributors may be used to endorse or promote products derived from
+%   this software without specific prior written permission.
+%   
+%   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+%   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+%   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+%   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+%   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+%   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+%   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+%   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+%   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+%   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+%   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function X = spec(x, Fs, framesize, start, stop)
+
+
+gr=[zeros(1024,1),[0:1023]'/1023,.68*[0:1023]'/1023];
+
+%gr=[.4*[0:1023]'/1023,[0:1023]'/1023,.68*[0:1023]'/1023];
+
+%t=[0:1023]'/1023;
+%t=(1+.25*t-cos(pi*t))/2.25;
+%gr = [zeros(1024,1),t,.68*t];
+
+
+%colormap(gr);
+
+if nargin < 2 || isempty(Fs)
+   Fs = 44100;
+end
+
+if nargin < 3 || isempty(framesize)
+   framesize = 2048;
+endif
+
+offset = framesize/4;
+
+X = 20*log10(abs(specgram(x, framesize, 48000, blackmanharris(framesize)', framesize-offset)));
+
+XM=max(max(X));
+X = max(XM-120,X);
+%size(X)
+F = -[framesize/2-1:-1:0]/framesize*Fs;
+%F = [0:127]/128*24000;
+T=[1:size(X,2)]/Fs*offset;
+%imagesc(X(end:-1:1,:));
+
+if nargin < 4 || isempty(start)
+   istart=1;
+else
+   istart = round(start*Fs/offset);
+end
+
+if nargin < 5 || isempty(stop)
+   istop = size(X,2);
+else
+   istop = round(stop*Fs/offset);
+endif
+
+istart = max(1,istart);
+istop = min(istop, size(X,2));
+
+imagesc(T(1+istart:istop), F, X(end:-1:1,1+istart:istop));
+
+X = X(:,1+istart:istop);