Improving rate and quality in MPEG 2 sequences using global motion information

Motion compensation is fundamental in the reduction of temporal redundancies in digital video sequences. In today compression standards, the estimation of the motion vectors is performed according to local characteristics of the images. It has been shown that camera movements affect all the estimates introducing false motion. In these cases, the result is a reduction in the both the compression efficiency and in quality. Methods to extract the motion due to camera movements have been proposed in the literature. In our work, wt: selected one of these algorithm and apply it as a preprocessing step in a conventional MPEG 2 coder. Results have been assessed using three common sequences and are presented to show the improvements that can be obtained by including this step in the MPEG coder.