Techniques for estimating global motion parameters based on block-based motion vectors are described. Horizontal and vertical motion parameters are estimated independently. A video processing device, in one example, generates horizontal motion parameter candidates for each row and vertical motion parameter candidates for each column, and selects the median of the horizontal motion parameter candidates as the global horizontal motion parameter and the median of the vertical motion parameter candidates as the global vertical motion parameter. The video processing device may further eliminate candidates by calculating error values for each candidate and remove those candidates with error values below an error threshold. The video processing device may also use pre-calculated values of matrices when calculating each of the candidates to further improve efficient calculation of the global motion parameters.