audioComp3

%Program 11.1 Audio codec
%input: vector x of input signal
%output: vector out of output signal
%Example usage: out=simplecodec(cos((1:2^(12))*2*pi*256/2^(13)));
%               example signal is 1/2 sec. pure tone of frequency f = 256
function out=audioComp3(x)
len=length(x);
n=32;                                 % length of window
nw=floor(len/n);                      % number of length n windows in x
x=x(1:n*nw);                          % cut x to integer number of n windows\
xshort=x(n+1: end-n);                 % cut for the original signal
xshort=0.3*xshort/max(abs(xshort));   % normalize signal to max amplitude = 0.3
Fs=2^(13);                            % Fs=sampling rate
b=4; L=0.3;                         % b = quantization bits, [-L,L] amplitude range
q=2*L/(2^b-1);                        % q used for b bits on interval [-L, L]
for i=1:n                             % form the MDCT matrix
  for j=1:2*n
    M(i,j)=cos((i-1+1/2)*(j-1+1/2+n/2)*pi/n);
  end
end
M=sqrt(2/n)*M;
N=M';                                 % inverse MDCT
for j=1:2*n                           % creates h(j), addition for windowing function
    h(j)=sqrt(2)*sin((j-.5)*pi/(2*n));
end
x=0.3*x/max(abs(x));                  % normalize signal to max amplitude = 0.3
sound(x,Fs)                             % Matlab's sound command
out = [];

for k=1:nw-1                            % loop over length 2n windows
  x0=(x(1+(k-1)*n:2*n+(k-1)*n)').*h';
  y0=M*x0;
  y1=round(y0/q);                     % transform components quantized
% Storage/transmission of file occurs here
  y2=y1*q;                            % transform components dequantized
  w(:,k)=(N*y2).*h';                  % invert the MDCT
  if(k>1)
      w2=w(n+1:2*n,k-1); w3=w(1:n,k);
      out=[out;(w2+w3)/2];            % collect the reconstructed signal
  end                                   % (of length 2n less than length of x)
end
pause(1)
sound(out,Fs)                           % play the reconstructed tone

RMSE = sqrt(mean((xshort(:) - out(:)).^2))  % Root Mean Squared Error
t=1000:1200;
plot(xshort(t),'k-'); hold on;
plot(out(t),'g-');hold off;
title('Original Audio Versus Compressed Audio')
xlabel('Number Of Data Points (1000 to 1200 in the actual audio matrix)') % x-axis label
legend('Original','Compressed')

Not enough input arguments.

Error in audioComp3 (line 7)
len=length(x);