The present disclosure provides a video decoding apparatus including at least a decoder configured to decode information on a size of a current block from encoded data, transform information, an inverse transformer configured to reconstruct a residual block of the current block by inversely transforming the transform coefficients in units of the size of each of the transform blocks, a predictor configured to generate a predicted block by using an inter-prediction, an adder configured to reconstruct the current block by adding the residual block to the predicted block, and a filter configured to identify transform boundaries between the transform blocks in the reconstructed current block by using the size of each of the transform blocks determined based on both the size of the current block and the information on the transform type, and then perform deblocking-filtering on at least part of the transform boundaries.