Fast hybrid motion estimation methods

In this paper we continue our study of fast motion estimation techniques for H.263 video coding. We experiment with a hybrid method based on two techniques, the three-step search method, and out block-based gradient descent search method. Our method is a two phase procedure. For our first phase, borrowing from the three-step method, we do a search on a sparse grid. In the second phase, the block-based gradient descent search is applied to the candidate/s yielded from the first phase. The paper reports on the various parameters we have selected to test this new method, the timings for algorithms run using these parameters, and quality measurements for the resulting compressed video.