Provided are a filtering method and apparatus for removing blocking artifacts and/or ringing noise. The filtering apparatus includes (a) performing one-dimensional discrete cosine transform (1D DCT) on video data on a block-by-block basis in a horizontal or vertical direction; (b) performing 1D DCT in the other direction of (a) and quantization on at least one of 1D DCT coefficients for a pixel obtained by performing 1D-DCT on the video data, the pixel being selected according to pixel position; and (c) generating filtering information based on the quantized pixel coefficient obtained from (b). According to the filtering method and apparatus, it is possible to reduce the amount of calculation when obtaining filtering information to remove the blocking artifacts and/or ringing noise.