Multi-resolution backward video coding

Hierarchical decomposition of images and their relationship with motion fields continues to be a hotly pursued topic, and the role of backward motion information in coding is beginning to capture the interest of video coding community. This paper simultaneously addresses some of the fundamental issues in multi-resolution and backward motion systems. From a coding viewpoint, a multi-resolution motion hierarchy should be coupled with an estimation system that deals with a maximally subsampled wavelet decomposition of the frames, to avoid redundancy of representation. Given the known difficulties of band-to-band motion compensated estimation in a wavelet domain, we use an alternative approach for estimation of detail bands, using lowpass bands of the anchor frames at higher resolutions. The resulting estimation errors are coded through a zerotree quantizer. Simulations show that a prototype coder of this type is very competitive, with a performance better than conventional forward (block-based) coders