Multiple sub-pixel interpolation filters with adaptive symmetry for high-resolution video coding

In order to further improve video coding efficiency, a novel adaptive sub-pixel interpolation filter is presented in this paper. Considering the local image characteristics, the proposed method designs interpolation Alters for sub-pixels in low-frequent and high-frequent areas separately. And in order to reduce the header information, flexible symmetry is assumed for each filter. Experimental results show that this method achieves up to 0.39 dB coding gain which equals to a 11.39% average bit-rate reduction for high-resolution video materials compared to the standard non-adaptive interpolation method of H.264. Compared to the state-of-art 2D non-separable adaptive interpolation scheme, an average bit-rate saving of 0.83% is achieved for high-definition video coding.