1. A motion estimation method, comprising: receiving, via a video coder, a current image frame and a reference image frame; applying, via the video coder, nonlinear scaling to the current image frame to generate at least a first current image layer; applying, via the video coder, nonlinear scaling to the reference image frame to generate at least a first reference image layer; and performing, via the video coder, hierarchical motion estimation in response, at least in part, to a source block of the first current image layer and to the firs reference image layer.