Deblocking Filter Algorithm with Low Complexity for H.264 Video Coding

In H.264, block-based discrete cosine transform (DCT) and blockbased motion compensated prediction are used to reduce both spatial and temporal redundancies. Due to the block-based coding, discontinuities at block boundaries, referred to blocking artifacts are created. To reduce these blocking artifacts, H.264 employs a deblocking filter. However, it causes a significant amount of complexity; therefore, the deblocking filter occupies one-third of the computational complexity of the decoder. In this paper, we propose a deblocking filtering algorithm with low complexity. Using boundary strength (BS) of the first Line-of-Pixel (LOP), we determine BS of successive LOP in advance. Then, we apply deblocking filters including newly designed filters. Experimental results show that the proposed algorithm provides an average computations reduction of 73.45 % in the BS decision. In the filter implementation, it reduces an average 57.52 % of additions, 100 % of multiplications, and 5.66 % of shift operations compared to the deblocking filter in H.264 with comparable objective quality.