Theoretical background and improvement of a simplified half-pel motion estimation

This paper describes theoretical background of a mean absolute error (MAE) approximation method which was adopted as a half-pel motion estimation method in our real-time MPEG-2 codec VisuaLink 7000. We also propose an improved MAE approximation method which employs the horizontal and the vertical differentials of a source picture in addition to the MAEs of adjacent full-pel motion vectors. In general, any approximation method for MAE involves some loss of coding efficiency. However, the proposed method reduces loss of coding efficiency to 1/2~3/4 of other existing methods with negligible increases of necessary computations and data transfers