Periodic pan compensation for reduced complexity video compression

To reduce the complexity of a video encoder, we introduce a new approach to hybrid DPCM-transform video compression in which pan compensation is performed outside the feedback loop. While the basic idea is conceptually similar to the pan compensation algorithm proposed by Taubman and Zakhor (1994) for their 3D subband coder, our method is different in that it continually tracks and updates the image in the feedback loop in the same way as a conventional hybrid coder. Using both residual energy and reconstruction error as metrics, we show that pan compensation implemented outside the feedback loop compares very favorably to similar compensation implemented within the conventional hybrid-transform framework. Furthermore, if the spatial coder used to compress the residual images outputs an embedded bit stream, then the complete system is spatially scaleable