motion_vector_difference.m

function MVD = motion_vector_difference(mVect, imgsz, mbSize)

row = imgsz(1,1); col = imgsz(1,2);
nr = row/mbSize; nc = col/mbSize;
mbc = length(mVect);
MVp = zeros(2,mbc);
MVD = zeros(2,mbc);

MVD(:,1) = mVect(:,1) - MVp(:,1);

for k = 2:mbc

    if(k <= nc)
        MVp(:,k) = mVect(:,k-1); % MV of A block. MVleft.
    elseif(mod(k-1,nc)==0)
        MVp(1,k) = ceil(median([mVect(1, k - nc), mVect(1, k - nc + 1)])); %MV of B and C blocks. MVtop and MVtop-right.
        MVp(2,k) = ceil(median([mVect(2, k - nc), mVect(2, k - nc + 1)]));
    elseif(mod(k,nc)==0)
        MVp(1,k) = ceil(median([mVect(1, k - 1), mVect(1, k - nc), mVect(1, k - nc - 1)])); %MV of A, B and D blocks. MVtop and MVtop-left and MVleft.
        MVp(2,k) = ceil(median([mVect(2, k - 1), mVect(2, k - nc), mVect(2, k - nc - 1)]));
    else
        MVp(1,k) = ceil(median([mVect(1, k - 1), mVect(1, k - nc), mVect(1, k - nc + 1)])); %MV of A, B and C blocks. MVtop and MVtop-right and MVleft.
        MVp(2,k) = ceil(median([mVect(2, k - 1), mVect(2, k - nc), mVect(2, k - nc + 1)]));
    end
    MVD(:,k) = mVect(:,k) - MVp(:,k);
end
end