Fast motion estimation within the H.264 codec

Three of the main reasons why the new H.264 (MPEG-4AVC) video coding standard has a significant performance benefit versus older standards are the adoption of variable block sizes, multiple reference frames, and the consideration of rate distortion optimization as a non-normative tool within the codec. Unfortunately these features incur a considerable increase in encoder complexity, mainly with regards to motion estimation and mode decision. In this paper, we extend and adapt the concept of the well-known enhanced predictive zonal search (EPZS) motion estimation algorithms, which is effectively used within other video coding standards into H.264. Simulation results demonstrate the efficiency of these algorithms of considerable reducing encoding complexity while incurring little, if any, loss in quality.