Spiral scan in video compression

The paper describes a proposal to replace the raster (linear) scan of macroblocks by a new spiral scan. Implications of such a scan for coding efficiency and implementation complexity are considered. The considerations are verified by some experiments. The conclusion is that both coding efficiency and implementation complexity are nearly the same for both raster and spiral scan of macroblocks. The spiral scan is considered as a tool for low-complexity SNR (quality) scalability as well as for coding of regions of interest. In particular, good subjective quality may be obtained when the spiral scan is used for fine-grain quality scalability.