function out = ditherAndNoiseShape2(in)
%The in vector is a list of audio samples
%The values are assumed to be between -1 and 1
%Out is the audio samples at a reduced 4-bit
%bit depth, dithered and noise shaped.
%Out is also on a scale of -1 to 1.
N = length(in);
c1=1;
rnd = ((rand(N,1)+rand(N,1)) * 0.125) - 0.125;
%Since we're in 4 bits, we'd go from -8 to 7, so on a scale of -1 to 1, 1
%becomes .125.  
%This scales the random numbers to be between -.125 and .125.
%We handle the randomizing outside of the for loop for speed.

in = in+rnd;
%dithering outside of for loop for speed

for(i=2:N)
   in(i) = in(i) + c1*(in(i-1) - ((floor(in(i-1)*8))/8));
end
%Now we noise shape.  Done in one command so the for loop will go much more
%quickly.


out = (floor(in.*8))./8;
%And now we quantize, outside of for loop for speed.


%clip upper limit to .875; could be exceeded due to noise shaping
outoverflow = (out > (ones(size(out))*0.876));
% > gives a vector result
outoverflow = outoverflow .* (out - 0.875);
out = out - outoverflow;
%clip lower limit to -1; could be exceeded due to noise shaping
outunderflow = (out < (ones(size(out))*(-1.001)));
% < gives a vector result
outunderflow = outunderflow .* (out + 1);
out = out - outunderflow;


%transpose to get it in the right shape