clear
clc
%% Uloha 1
im = rgb2ycbcr(imread('lena_color_256.tif'));
[height,width,channels] = size(im);

figure;
imshow(ycbcr2rgb(im));

QL =    [16 11 10 16 24 40 51 61
12 12 14 19 26 58 60 55
14 13 16 24 40 57 69 56
14 17 22 29 51 87 80 62
18 22 37 56 68 109 103 77
24 35 55 64 81 104 113 92
49 64 78 87 103 121 120 101
72 92 95 98 112 100 103 99];

QC =    [17 18 24 47 99 99 99 99
18 21 26 66 99 99 99 99
24 26 56 99 99 99 99 99
47 66 99 99 99 99 99 99
99 99 99 99 99 99 99 99
99 99 99 99 99 99 99 99
99 99 99 99 99 99 99 99
99 99 99 99 99 99 99 99];

q = 50;

if q < 50
    alfa = 50/q;
else
    alfa = 2 - (q/50);
end

imc = zeros(height,width,channels);

for y = 1:8:height
    for x = 1:8:width
        Y = dct2(im(y:y+7,x:x+7,1));
        Cb = dct2(im(y:y+7,x:x+7,2));
        Cr = dct2(im(y:y+7,x:x+7,3));
        Y = round(Y./(alfa*QL));
        Cb = round(Cb./(alfa*QC));
        Cr = round(Cr./(alfa*QC));

        Y = Y.*(QL/alfa);
        Cb = Cb.*(QC/alfa);
        Cr = Cr.*(QC/alfa);

        Y = idct2(Y);
        Cb = idct2(Cb);
        Cr = idct2(Cr);

        imc(y:y+7,x:x+7,1) = Y;
        imc(y:y+7,x:x+7,2) = Cb;
        imc(y:y+7,x:x+7,3) = Cr;
    end
end

% do zadania udat pocet nenulovych bodov po dct a po round ... aby sme
% znazornili pomer kompresie
imcc = uint8(imc);
figure;
imshow(ycbcr2rgb(imcc));