Irregularity-cross multi-hexagon-grid search algorithm for fastmotion estimation on H.264

The UMHexagonS algorithm has been accepted for the possible implementation of the block motion estimation process in the H.264 video coding standard due to its high accuracy and low computational requirement. And there were also many modifications coming up with it. In article, the author offered several improvements which reduce the computational complexity of the UMHexagonS algorithm with a little loss of its accuracy. And In this paper, a new algorithm is proposed, which bases on the UMHexagonS algorithm and in two aspects. Firstly, a new prediction vector is added to replace the way of median vector. Secondly, we propose an Irregular-cross template in place of the primary unsymmetrical-cross one. The simulation results show that this two proposed methods reduce the motion estimation time by from 10% to 27% than UMHexagonS according to different types of sequences with negligible coding loss.