In one embodiment, the method includes obtaining quantization information of a first block including the pixel to be filtered, and obtaining a block type of the first block and a second block. The second block is adjacent to the first block. The quantization information is compared to a threshold value, and loop-filtering is performed on the pixel to be filtered by using at least three successive pixels if the quantization information is greater than the threshold value and the type of the first and second block is an intra-coded block type. The at least three successive pixels include the pixel to be filtered.