clc
close
clear

X = audioread('ATrain.wav');
X = double(X);
X = floor(X * 2^15 + 0.5);
L1 = X(:,1);
P1 = X(:,2);

[x,y] = size(X);

L = zeros(x,1);
P = zeros(x,1);
L(1) = L1(1);
P(1) = P1(1);
DL = zeros(2*(2^16)-1,1);
DP = zeros(2*(2^16)-1,1);
[x1,y2] = size(DL);

for i= 2:x
    L(i) = L1(i) - L1(i-1);
    P(i) = P1(i) - P1(i-1);
end

for i = 1:x
    if L(i) < 0
        DL(L(i) + 65536 ) = DL(L(i) + 65536 ) + 1;
    else
        DL(L(i) + 65536 ) = DL(L(i) + 65536 ) + 1;
    end

    if P(i) < 0
        DP(P(i) + 65536 ) = DP(P(i) + 65536 ) + 1;
    else
        DP(P(i) + 65536 ) = DP(P(i) + 65536 ) + 1;
    end
end

PL = DL/x;
PP = DP/x;

SL = 0;
SP = 0;
for i = 1:x1
   if PL(i) ~= 0
       SL = SL + (PL(i) .* log2(PL(i)));
   end

   if PP(i) ~= 0
       SP = SP + (PP(i) .* log2(PP(i)));
   end
end
l = -SL;
p = -SP;
fprintf('Entropia lewego kanału po kodowaniu: %f\n', l)
fprintf('Entropia prawego kanału po kodowaniu: %f\n', p)
fprintf('Srednia arytmetyczna lewego i prawego kanalu: %f\n', (p+l)/2)