On using hierarchical motion history for motion estimation in H.264/AVC

The embedded multireference frames selection with variable block-size motion compensation model drastically increases the computational complexity of the H.264/AVC video coding standard. This paper proposes an adaptive hierarchical motion estimation (ME) algorithm for H.264/AVC with the objective of minimizing the complexity while maximizing the visual quality. The proposed algorithm is based on a framework that exploits the "history" of the motion intensity from a video sequence in order to control ME. The complexity and memory requirement for this meta information is low. The algorithm determines the motion intensity of a video sequence at three levels and accordingly employs different ME techniques. The results certify that the history-based hierarchical information can be very effective in improving the efficiency of ME.

I. Introduction

The H.264/AVC video coding standard [14] aims to provide significant improvement in coding efficiency through the inclusion of a number of new features and capabilities [30], compared with previous coding standards such as H.261 [8], H.263 [9] (also its “H.263+” and “H.263++” annexes), MPEG-1 [10], MPEG-2 [11], and MPEG-4 [12]. However, due to its flexibility and clean slate design, H.264/AVC is considerably more complex. The embedded multireference frames selection with variable block-size motion compensation model of H.264/AVC drastically enhances the computational complexity of motion estimation (ME).