samer@3: % unbuffer - Opposite of buffer using overlap and add (for sequences)
samer@3: %
samer@3: % unbuffer :: 
samer@3: %    seq([[N]])  ~'sequence of overlapping frames',
samer@3: %    M:natural   ~'hop size'
samer@3: % -> seq([[1,M]])~'sequence of de-overlapped frames'.
samer@3: %
samer@3: % NB. what about windowing function?
samer@3: 
samer@3: function Y=unbuffer(X,hop)
samer@3: 	if isscalar(hop)
samer@3: 		N=max(size(X));
samer@3: 		ol=N-hop;
samer@3: 		if ol<=hop
samer@3: 			I=1:hop; J=1:ol; K=hop+1:N;
samer@3: 			Y=mapaccum(@olap1,X,zeros(ol,1));
samer@3: 		else
samer@3: 			I=1:hop; J=hop+1:ol; K=ol+1:N;
samer@3: 			Y=mapaccum(@olap3,X,zeros(ol,1));
samer@3: 		end
samer@3: 	else
samer@3: 		Y=zipaccum(@olap2,{windowdata(repeat(hop)),X},[]);
samer@3: 	end
samer@3: 
samer@3: 	function [y,s1]=olap1(x,s)
samer@3: 		y=x(I)';
samer@3: 		y(J)=y(J)+s';
samer@3: 		s1=x(K);
samer@3: 	end
samer@3: 
samer@3: 	function [y,s1]=olap3(x,s)
samer@3: 		y=(s(I)+x(I))';
samer@3: 		s1=[s(J)+x(J);x(K)];
samer@3: 	end
samer@3: end
samer@3: