A single-pass based adaptive interpolation filtering algorithm for video coding

An adaptive interpolation filtering (AIF) algorithm has been proposed to improve the conventional hybrid video coding scheme recently. Although such an algorithm does improve coding efficiency significantly, its encoding complexity, in terms of computational complexity and memory access, increases dramatically due to its inherent two-pass encoding structure. In this paper, we propose a novel single-pass based algorithm which can reduce the complexity of AIF significantly. In our method, a competitive filter set which includes optimal filters trained from several previous frames and the fixed H.264 filters is considered for the current coding frame. A rate-distortion optimization (RDO) criterion is then used to select the best one at macro-block (MB) level. In order to reduce overhead, a predictive coding method is used to compress the filter type for each MB. Experimental results show that, by using the proposed algorithm, the encoding complexity can be significantly reduced without sacrifice of coding gain.