Page 282 - Video Coding for Mobile Communications Efficiency, Complexity, and Resilience

Appendix

Fast Block-Matching Algorithms

A.1 Notation and Assumptions

• BDM: a block distortion measure, like the SSD or SAD.

• d m : maximum allowed motion displacement.
• N : total number of steps in the search. It is an integer number greater
than 0.

• s: current search step size.
• (c x ;c y ): current search center.

• (m x ;m y ): current location of minimum distortion.
• (d x ;d y ): #nal motion vector.

• · : %oor operator. It rounds its argument to the nearest integer toward
−∞.

• · : ceil operator. It rounds its argument to the nearest integer toward
+∞.
• min: minimize operator. It returns the minimum of a given function.

• max: maximize operator. It returns the maximum of a given function.
• arg: argument operator. It returns the argument of a given function.

• All algorithms presented in this appendix assume full-pel accuracy. Sub-
pel accuracy can easily be achieved using very minor modi#cations.

• If the search procedure attempts to search a location outside the search
window, the corresponding BDM is set to a maximum value.

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