Adaptive pre-interpolation filter for high efficiency video coding

The proposed interpolation filter comprises two concatenating filters, adaptive pre-interpolation filter (APIF) and the normative interpolation filter in H.264/AVC. The former is applied only to the integer pixels in the reference frames; the latter generates all the sub-position samples, supported by the output of APIF. The convolution of APIF and the standard filter minimizes the motion prediction error on a frame basis. APIF preserves the merits of the adaptive interpolation filter (AIF) and the adaptive loop filter (ALF) in the key technical area (KTA) software and at the same time overcomes their drawbacks. The experimental results show that APIF outperforms either AIF or ALF. Compared with the joint use of AIF and ALF, APIF provides comparable performance, but has much lower complexity.

Research highlights
► The convolution of APIF and the standard filter in H.264/AVC minimizes the MCP error.
► APIF preserves the merits of AIF and ALF in KTA, and overcomes their drawbacks.
► APIF outperforms either AIF or ALF.
► APIF provides comparable performance to the joint use of AIF and ALF.
► APIF has much lower complexity than the joint use of AIF and ALF.