A deblocking filter with two separate modes in block-based video coding

This paper presents a method to remove blocking artifacts in low bit-rate b lock-based video coding. The proposed algorithm has two separate filtering modes, which are selected by pixel behavior around the block boundary, In e ach mode, proper one-dimensional filtering operations are performed across the block boundary along the horizontal and vertical directions, respective ly. In the first mode, corresponding to Bat regions, a strong filter is app lied inside the block as well as on the block boundary because the Bat regi ons are more sensitive to the human visual system (HVS) and the artifacts p ropagated from the previous frame due to motion compensation are distribute d inside the block. In the second mode, corresponding to other regions, a s ophisticated smoothing filter, which is based on the frequency information around block boundaries, is used to reduce blocking artifacts adaptively wi thout introducing undesired blur. Even though the proposed deblocking filte r is quite simple, it improves both subjective and objective image quality for various image features.