diff dsp/synth/unbuffer_nu.m @ 34:c75bb62b90a9

Imported audio synthesis tools.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dsp/synth/unbuffer_nu.m	Sun Jan 20 19:05:05 2013 +0000
@@ -0,0 +1,35 @@
+% unbuffer_nu - Non-uniform hop overlap and add
+%
+% unbuffer_nu :: 
+%    seq([[1,_]])  ~'sequence of overlapping frames',
+%    seq(natural)  ~'sequence of hop sizes'
+% -> seq([[1,_]])  ~'sequence of de-overlapped frames'.
+
+function Y=unbuffer_nu(X,hop)
+	Y=zipaccum(@olap,{hop,X},[]);
+
+	function [y,s1]=olap(hop,x,s)
+		ls=length(s);
+		lx=length(x);
+		if lx>=hop
+			if ls>=hop
+				% NB: this will fail if ls>lx, but this shouldn't happen since ls<=lx-hop
+				y=(x(1:hop)+s(1:hop))';
+				s1=[s(hop+1:ls)+x(hop+1:ls);x(ls+1:end)];
+			else
+				y=[x(1:ls)+s;x(ls+1:hop)]';
+				s1=x(hop+1:end);
+			end
+		else
+			if ls>=hop
+				y=[s(1:lx)+x;s(lx+1:hop)]';
+				s1=s(hop+1:end);
+			else
+				y=zeros(1,hop);
+				y(1:ls)=y(1:ls)+s';
+				y(1:lx)=y(1:lx)+x';
+			end
+		end
+	end
+end
+