Abstract: To generate an improved image signal when estimating motion, a motion vector is first determined with pel accuracy, and a two-step interpolation filtering is subsequently carried out with sub-pel accuracy. The interpolation coefficients are selected with a view to reducing aliasing. More neighboring pixels are used for the interpolation than in usual interpolation methods. One is able to improve the quality of the prediction signal for video images and, consequently, enhance coding efficiency.

Abstract: For the determination of motion vectors, an aliasing-reducing interpolation filtration with a sub-pel precision is used in the motion-compensated prediction of moving image sequences. More adjacent pixels are accessed in this interpolation filtration than in known bilinear interpolation. Asymmetrical filtration or reflection of pixels inside a reference image block is used to assure that maximally, a block of the reference image containing (M+1)×(M+1) pixels for interpolation filtration is accessed. However this process requires less memory bandwidth in accessing reference images.