view aim-mat/tools/@signal/squeeze.m @ 4:537f939baef0 tip

various bug fixes and changed copyright message

% method of class @
% function newsig=squeeze(sig,factor) 
%   INPUT VALUES:
%  		sig: orginal @signal
%		factor: factor, by which the signal is squeezed
%   RETURN VALUE:
%		newsig: squeezed signal
% 
% reduces the length of the signal by scaling it in time
%
% This external file is included as part of the 'aim-mat' distribution package
% (c) 2011, University of Southampton
% Maintained by Stefan Bleeck ([e-mail])
% download of current version is on the soundsoftware site: 
% http://code.soundsoftware.ac.uk/projects/aimmat
% documentation and everything is on http://www.acousticscale.org

function newsig=squeeze(sig,factor)


%%%%%%%%%%%%%%%
% if squeezed it becomes shorter
if factor < 1
    len=getlength(sig);
    newlen=len*factor;
    sr=sig.samplerate;
    newsr=sr;   % dont change the sr
    if newlen < newsr
        newlen=newsr;
    end
    newsig=signal(newlen,newsr);
    nr_points=getnrpoints(newsig);
    new_vals=zeros(nr_points,1);
    for i=1:nr_points
        whichstart=(i-1)*newsr/factor;
        whichstop=i*newsr/factor;
        
        if whichstop>len
            whichstop=len;
        end
        new_vals(i)=average(sig,whichstart,whichstop);    
    end
    newsig=setvalues(newsig,new_vals);
    return
end

newsig=sig;