DeQuant8x8.m

function dct_block = DeQuant8x8(quant_block, qScale,intra_mode,lum)
%  Function Name : DeQuant8x8.m
%  Input         : quant_block  (Quantized Block, 8x8x3)
%                  qScale       (Quantization Parameter, scalar)
%
%  Output        : dct_block    (Dequantized DCT coefficients, 8x8x3)
if nargin == 3
    lum = "full";
end
L = [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;18,55,37,56,68,109,103,77;24,35,55,64,81,104,113,92;49,64,78,87,103,121,120,101;...
    72,92,95,98,112,100,103,99];
c = [17,18,24,47,99,99,99,99;18,21,26,66,99,99,99,99;24,13,56,99,99,99,99,99;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];
L = qScale.*L;
c = qScale.*c;
if intra_mode == 0
    dct_block(:,:,1) = quant_block(:,:,1).*L;
    dct_block(:,:,2) = quant_block(:,:,2).*c;
    dct_block(:,:,3) = quant_block(:,:,3).*c;
    return
end
if strcmp(lum,"full")
    quant_table = [L,c,c];
elseif strcmp(lum,"luminance")
    L = [1,1,1,1,2,4,5,6;1,1,1,1,2,5,6,5;1,1,1,2,4,5,6,5;1,1,2,2,...
    5,8,8,6;1,5,3,5,6,10,10,7;2,3,5,6,8,10,11,9;4,6,7,8,10,12,12,10;...
    7,9,9,9,11,10,10,9];
    L = qScale.*L;
    quant_table = L;
else
    c = [1,1,2,4,9,9,9,9;1,2,2,6,9,9,9,9;2,1,5,9,9,9,9,9;4,6,9,9,9,9,9,9;9,9,...
    9,9,9,9,9,9;9,9,9,9,9,9,9,9;9,9,9,9,9,9,9,9;9,9,9,9,9,9,9,9];
    c = qScale*c;
    quant_table = c;
end
[~,~,k] = size(quant_block);
for i = 1:k
    dct_block(:,:,i) = quant_block(:,:,i).*quant_table(i);
    %dct_block(:,:,2) = quant_block(:,:,2).*c;
    %dct_block(:,:,3) = quant_block(:,:,3).*c;
end
end