What is a good motion estimation method, then?
A. When shopping for motion vectors, the three basic characteristics are: Search range, search pattern, and matching criteria. Search pattern has the greatest impact on finding the best vector. Hierarchical search patterns first find the best match between downsampled images of the reference and target pictures and then refine the vector through progressively higher resolutions. When compared to other fast methods, hierarchical patterns are less likely to be confused by extremely local distortion minimums as being a best match. Also note that subsampled search and hierarchical search are not synonymous.
