MAP

function [f,t]=enframe(x,win,inc)

%ENFRAME split signal up into (overlapping) frames: one per row. [F,T]=(X,WIN,INC)

%

%	F = ENFRAME(X,LEN) splits the vector X(:) up into

%	frames. Each frame is of length LEN and occupies

%	one row of the output matrix. The last few frames of X

%	will be ignored if its length is not divisible by LEN.

%	It is an error if X is shorter than LEN.

%

%	F = ENFRAME(X,LEN,INC) has frames beginning at increments of INC

%	The centre of frame I is X((I-1)*INC+(LEN+1)/2) for I=1,2,...

%	The number of frames is fix((length(X)-LEN+INC)/INC)

%

%	F = ENFRAME(X,WINDOW) or ENFRAME(X,WINDOW,INC) multiplies

%	each frame by WINDOW(:)

%

%   The second output argument, T, gives the time in samples at the centre

%   of each frame. T=i corresponds to the time of sample X(i).

%

% Example of frame-based processing:

%          INC=20       													% set frame increment

%          NW=INC*2     													% oversample by a factor of 2 (4 is also often used)

%          S=cos((0:NW*7)*6*pi/NW);								% example input signal

%          W=sqrt(hamming(NW+1)); W(end)=[];      % sqrt hamming window of period NW

%          F=enframe(S,W,INC);               			% split into frames

%          ... process frames ...

%          X=overlapadd(F,W,INC);           			% reconstitute the time waveform (omit "X=" to plot waveform)

%	   Copyright (C) Mike Brookes 1997

%      Version: $Id: enframe.m,v 1.7 2009/11/01 21:08:21 dmb Exp $

%

%   VOICEBOX is a MATLAB toolbox for speech processing.

%   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html

%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%   This program is free software; you can redistribute it and/or modify

%   it under the terms of the GNU General Public License as published by

%   the Free Software Foundation; either version 2 of the License, or

%   (at your option) any later version.

%

%   This program is distributed in the hope that it will be useful,

%   but WITHOUT ANY WARRANTY; without even the implied warranty of

%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

%   GNU General Public License for more details.

%

%   You can obtain a copy of the GNU General Public License from

%   http://www.gnu.org/copyleft/gpl.html or by writing to

%   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

nx=length(x(:));

nwin=length(win);

if (nwin == 1)

   len = win;

else

   len = nwin;

end

if (nargin < 3)

   inc = len;

end

nf = fix((nx-len+inc)/inc);

f=zeros(nf,len);

indf= inc*(0:(nf-1)).';

inds = (1:len);

f(:) = x(indf(:,ones(1,len))+inds(ones(nf,1),:));

if (nwin > 1)

    w = win(:)';

    f = f .* w(ones(nf,1),:);

end

if nargout>1

    t=(1+len)/2+indf;

end