Universal Motion Prediction

This paper investigates the motion prediction techniques used in hybrid video coding. We first present a unified interpretation of motion prediction in terms of the prediction of motion threads. It is demonstrated that most current motion prediction techniques can be regarded as linear predictors of motion threads. Based on this new interpretation of motion prediction, we discuss the optimal motion predictor in the framework of Markov universal prediction. We define Markov predictability in a way that it upper bounds the optimal prediction performance in perfect reconstruction scenario. Since most current video applications use lossy coding, this results in imperfect reconstructions of the motion threads used in prediction. However, the optimality with the above perfect reconstruction scenario still holds in this case in an almost sure sense.