Analysis of overlapped block motion compensation based on a statistical motion distribution model

Overlapped block motion compensation (OBMC) has been shown to provide reduced prediction errors as well as reduced blocking artifacts compared with the conventional non-overlapped block motion compensation (NOBMC). However, there is no satisfactory theoretical basis that clearly interprets why OBMC can reduce prediction errors. We present a theoretical analysis of OBMC based on a novel statistical motion distribution model. Our analysis proves theoretically that prediction errors increase towards block boundaries and that OBMC has an error reduction and equalization property, with the errors being more reduced at block boundaries than at block centers. The analytical results are justified by empirical experiments with typical image sequences.