Out-of-Loop Motion Compensation for Reduced Complexity Video Encoding+

To reduce the complexity of a video encoder, we introduce a new approach to global motion compensation related to the conventional hybrid DPCM-transform method in which the motion compensation is performed outside the feedback loop as shown in Fig. I. Within this framework, many specific implementations are possible, and we study a few of them here. While the basic idea is conceptually similar to the pan compensation proposed by Taubman and Zakhor for their 3D subband coder, our method continually tracks and updates the image in the feedback loop in the same way as a conventional hybrid system. Using both residual energy and reconstruction error as metrics, Fig. 2 shows that the new motion compensation scheme compares very favorably to the conventional one.