1. A non-iterative method for estimating global motions between a plurality of image frames in an input video stream, comprising: grouping a plurality of motion vectors in the input video stream into a predetermined number of groups of motion vectors; calculating a set of global motion parameters from each of the predetermined groups of the motion vector; wherein the calculating results in a group of global motion parameters {m j } j=1;J , and processing the set of global motion parameters generated from the calculation to obtain a final estimation, wherein the processing further comprises: calculating a histogram of the group of global motion parameters {m j } j=1;J with a plurality of bins; choosing a bin from the plurality of bins that includes a largest amount of m j ; and averaging over the m j of the chosen bin to obtain the final estimate.