Fast motion estimation for video resolution down-conversion using spatial-variant filter

To convert a compressed video sequence to a lower-resolution compressed video, one typically needs to decompress the original sequence, down-sample each frame, and recompress it. It involves motion estimation in the reduced sequence, which is computational intensive. In this paper, a novel fast motion estimation algorithm is proposed to predict the motion vectors of the reduced-resolution video without performing any search. The motion vectors are predicted by applying spatial-variant filters to the motion vectors of the original compressed high-resolution video. In our simulations, our method outperforms other existing fast predictive algorithms which involves no searching.