1. An adaptive deblocking filtering apparatus comprising: a boundary strength determiner for determining strength of boundaries between subblocks of a current block; a direction selector for selecting a number of directions preset with reference to the boundary individually and sequentially; a filtering pixel selector for selecting pixels for filtering based on selected directions; a filtering determiner for performing a determination of whether to perform the filtering for the selected directions depending on relationships between pixel values of selected pixels; and a filtering unit for performing the filtering with respect to the selected pixels in the selected directions depending on the determination of whether to perform the filtering.