In one embodiment, the apparatus includes a decoder configured to obtain a block type of the second block and the third block. The second block is adjacent to the first block horizontally, and the third block is adjacent to the first block vertically. The decoder is configured to determine whether the second and third blocks have non-zero transform coefficient information if the block type of the second and third block, respectively, are not an intra-coded blocks. First and second motion vector differences between a motion vector for the first block and motion vectors for the second and third blocks, respectively, are obtained by the decoder. A horizontal filter strength value and a vertical filter strength value are determined by the decoder based on the above steps, and the blocking phenomenon in the first block is removed by the decoder according to the horizontal filter strength value and the vertical filter strength value.