Multi-resolution motion estimation

Spatial multi-resolution video sequences provide video at multiple frame sizes, allowing extraction of only the resolution or bit rate required by the user. This paper proposes fine-to-coarse motion estimation (ME) for multi-resolution video coding. While coarse-to-fine ME, used in previously proposed coding themes, can provide a better estimate at the coarsest resolution, it is outperformed by fine-to-coarse ME at finer resolutions due to the inability of coarse-to-fine ME to accurately track motion at finer resolutions. At the finest resolution, fine-to-coarse ME provides a PSNR improvement of up to 1 dB, for the sequences tested, and better visual quality at all resolutions. In addition, fine-to-coarse ME provides more accurate and thus more compressible motion estimates