Content Adaptive Interpolation Filters for Lossless Video Coding

Focused on the issue that the fixed interpolation filters cannot adapt to the video content in high efficiency video coding (HEVC) motion compensation, which may compromise inter-prediction accuracy, an adaptive interpolation filter scheme was proposed for HEVC lossless coding. Adaptive interpolation filters were derived for each frame by minimizing the inter prediction difference, which reduced the inter prediction difference adaptively by generating the sub-pixels with the derived filters for all inter coding blocks resulting in better coding efficiency. The proposed scheme was implemented into the HM (HEVC test model) 12.1 software. Experimental results show that the proposed scheme can achieve 1.32% and 0.69% bit rate saving on average compared with HEVC under the "low delay P" and the "low delay B" configurations, respectively, which barely sacrifices the encoding and decoding time.