Adaptive Interpolation Filter with Flexible Symmetry for Coding High Resolution High Quality Video

In this work, a novel sub-pixel interpolation algorithm is proposed for video coders targeted towards high resolution and high fidelity use cases. Proposed scheme is based on adapting the interpolation filter´s symmetry assumptions in a rate-distortion-optimized fashion, taking into account the coding rate and the statistical properties of each image of the video sequence. Experimental results show that, using the proposed algorithm a gain of up-to 1.1 dB is achieved compared to non-adaptive sub-pixel interpolation of H.264/AVC. Compared to other state-of-the-art adaptive sub-pixel interpolation methods, a gain of up-to 0.5 dB is achieved. Proposed scheme outperforms H.264/AVC for all test cases; however, improvement is more significant at high bitrates and at high resolutions. This is especially important for future video coding solutions targeting high fidelity video applications.