Subband video coding with smooth motion compensation

A new motion compensation scheme for subband video coding is introduced, where both motion estimation and compensation are performed directly on the subband signals. During motion estimation, a full resolution search for the best candidate displacement vector is performed on all subband signals simultaneously, with down-sampling of each block before evaluating the error criterion. Furthermore, the proposed scheme allows for the use of a motion estimation error criterion which takes the subsequent dynamic bit allocation applied in the spatial quantization into account. In particular, it is shown that using the geometric mean of the subband signal variances instead of the arithmetic mean, results in increased performance. The proposed coder results in coding gains as high as 3.7 dB and 2.9 dB over traditional DCT and SBC schemes, respectively, for the video material tested