SCALABLE CODING OF VARIABLE-SIZE MOTION VECTOR BLOCKS (TA-L5)

Author(s) : Davide Maestroni (DEI - Politecnico di Milano, Italy) Augusto Sarti (DEI - Politecnico di Milano, Italy) Marco Tagliasacchi (DEI - Politecnico di Milano, Italy) Stefano Tubaro (DEI - Politecnico di Milano, Italy)

Abstract : In this paper we propose and illustrate an algorithm that is able to provide a scalable (multi-resolution) representation of the motion field information. It has been recently proven that, for an open loop wavelet video coder, it is possible to use at the decoder side a scaled version of the original motion information and the residual coefficients computed with the full resolution/quality motion field without incurring into drift. Here we propose a fully-scalable wavelet-based video coder that performs motion estimation/compensation in the wavelet domain. In particular, the coding scheme is specifically designed for variable-size block-matching algorithms. In this scenario motion vectors are distributed across an irregular lattice according to a quadtree structure. The developed system allows a scalable representation of the motion field and a flexible allocation of the bit budget between motion and residual data. The simulations that we have carried out show, at low bit-rates, a significant gain of the proposed approach with respect to the case in which the motion information is coded lossless.

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