Fractional-sample motion compensation using generalized interpolation

Typical interpolation methods in video coding perform filtering of reference picture samples using FIR filters for motion-compensated prediction. This process can be viewed as a signal decomposition using basis functions which are restricted by the interpolating constraint. Using the concept of generalized interpolation provides a greater degree of freedom for selecting basis functions. We implemented generalized interpolation using a combination of IIR and FIR filters. The complexity of the proposed scheme is comparable to that of an 8-tap FIR filter. Bit rate savings up to 20% compared to the H.264/AVC 6-tap filter are shown.