1. A video encoding apparatus, comprising: a video encoder configured to: generate a prediction block corresponding to a current block, generate a residual block by subtracting the prediction block from the current block, encode the residual block by transforming and quantizing the residual block, reconstruct the residual block by inversely quantizing and inversely transforming the transformed and quantized residual block, and reconstruct the current block by adding the prediction block to the reconstructed residual block; and a deblocking filter configured to filter a boundary between subblocks within a frame including the reconstructed current block, wherein a first subblock of the subblocks and a second subblock of the subblocks that engage in the filtering are different from each other in numbers of filtered pixels, depending on one or more predetermined criterion, wherein the deblocking filter is configured to perform the filtering by applying different pixel disparity values on the first subblock or the second subblock according to pixel positions relative to the boundary between the first subblock and the second subblock, wherein the deblocking filter is configured to calculate a first pixel disparity value corresponding to a first position from the boundary using a first offset value, and calculate a second pixel disparity value corresponding to a second position from the boundary using a second offset value, and wherein the first offset value and the second offset value are decided irrelevant to pixel values of the first subblock or the second subblock.