An edge filter includes an input unit and a shared edge filter module. The input unit receives first original pixels of a first decoded block and second original pixels of a second decoded block. The shared edge filter module includes a shared intermediate value generator and a filtering unit. The shared intermediate value generator generates shared intermediate values by making use of original pixels selected from the first original pixels and the second original pixels according to a coefficient rule of coefficients of the first and second original pixels under a designated video standard. The filtering unit filters the first original pixels and the second original pixels to generate a plurality of first filtered pixels and a plurality of second filtered pixels by reference to the coefficient rule. At least two of the first filtered pixels and the second filtered pixels are derived from the shared intermediate value.