Splitting criterion for hierarchical motion estimationbased on perceptual coding

Perceptual feedback in multigrid motion estimation using an improved DCT quantization

“…Two kinds of splitting criteria have already been used: 1) the magnitude of the prediction error, e.g., energy, mean-square error or mean-absolute error [6], [29], [32], [33], and 2) the complexity of the prediction error. In this case, the zeroth-order spatial entropy [7], [8] and the entropy of the encoded DFD [9]- [12] have been reported. While the magnitude-based criteria were proposed without a specific relation to the encoding of the DFD, the entropy-based criteria make explicit use of the trade off between DVF and DFD.…”

“…The splitting criterion has effects on the relative volumes of DVF and DFD [7]- [12], and may give rise to unstable motion estimates due to an excesive refinement of the quadtree structure [12], [29]. The usefulness of the motion information for higher-level purposes (as in model-based video coding [5], [30], [31]) highly depends on its robustness (absence of false alarms) and hence on the splitting criterion.…”

“…Since the first entropy-constrained approach was introduced [7], [8], great effort has been devoted to obtaining analytical [9]- [11] or numerical [12] optimal entropy-constrained quadtree DVF decompositions. These approaches criticize the (faster) entropy measure of the DFD in the spatial domain of Dufaux et al because it does not take into account the effect of the selective DCT quantizer.…”

“…Most of the recent work on motion estimation for video coding has been focused on the adaptation of the motion estimate to a given quantizer to obtain an good balance between these elements. Since the introduction of the intuitive (suboptimal) entropy-constrained motion estimation of Dufaux et al [7], [8] several optimal, variable-size BMAs have been proposed [9]- [12]. These approaches put forward their intrinsic optimality, but the corresponding visual effect and the relative importance of the motion improvements versus the quantizer improvements have not been deeply explored, mainly because of their subjective nature.…”

“…In this paper, a novel subjective redundancy removal procedure [13], [14] and a novel perceptually weighted motion estimation algorithm [12] are jointly considered to present a fully perceptual motion compensated video coder. The aim of the paper is to assess the relative relevance of optimal variable-size BMAs and quantizer improvements.…”