%SimpleCodecCompressior


function [OutputBits,len,Windowing]=SimpleCodecCompressor(Input,Windowing)

%%% The switch loop section sets the default values for optional variables %%%

switch nargin
    case 1
        Windowing=0;
end

%%% The following if section sets the sound vector depending on the input %%%

if length(Input)==1
    x=cos((1:2^(13))*2*pi*Input/2^(13));    %Pure tone
    TitleVersion=1;
elseif length(Input)<100
    x=cos((1:2^(13))*2*pi*Input(1)/2^(13)); %Chord
    for i=2:length(Input)
        x=x+cos((1:2^(13))*2*pi*Input(i)/2^(13));
    end
    TitleVersion=2;
else 
    x=Input;                                %Input music vector
    len=length(x);
    x=x(1:floor(len/64)*64).';
    TitleVersion=3;
end

%%% The following lines set up parameters for the compression %%%

len=length(x);
n=2^5;                                % 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
Fs=2^(13);                            % Fs=sampling rate
b=2; 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]

%%% The following for loop creates the MDCT matrix %%%

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

x=0.3*x/max(abs(x));                  % normalize signal to max amplitude = 0.3



OutputBits=[];                               % Initialize output vector


%%% The following if block creates a windowing vector or an array of ones depending on the choice %%%

if Windowing == 1 
    h=1:1:2*n;
    h=sqrt(2).*sin((h+.5).*(pi/(2*n)));   % Windowing function
else
    h=ones(1,2*n);
end

h=h.';

%x=x.*h;

for k=1:nw-1                          % loop over l ength 2n windows
    x0=x(1+(k-1)*n:2*n+(k-1)*n)';
    x0=x0.*h;                           % Apply windowing vector
    y0=M*x0;
    
    y1=round(y0/q);           % transform components quantized
    
    OutputBits=[OutputBits,y1];                    
    % Storage/transmission of file occurs here  
    
end