In one embodiment, the method includes obtaining a coded block pattern of first and second blocks. The coded block pattern may be one of a plurality of coded block patterns, the plurality of coded block patterns may include an intra-coded block, and the second block may be adjacent to the first block. Whether the first block and the second block have non-zero transform coefficient information is determined if the block type of the first block and the second block is not intra-coded block. A non-zero filter strength value is determined based on the obtained coded block pattern of the first and second block and the determination of whether the first block and second blocks have non-zero transform coefficient information, and the blocking phenomenon is removed according to the filter strength value.