A method for extracting direct mode motion vectors

摘要

A method for extracting direct mode motion vectors of a current macroblock in a B-picture in moving picture processing is disclosed, comprising: determining a co-located block for the current macroblock in a list 1 reference picture; selecting a motion vector from a list 0 motion vector and a list 1 motion vector of the co-located block in the list 1 reference picture; deriving the motion vectors of the current macroblock in the B-picture from the selected motion vector; and scaling the selected motion vector of the co-located block in the list 1 reference picture for direct mode to derive a list 0 motion vector (MV F ) and a list 1 motion vector (MV B ); wherein the list 1 motion vector of the co-located block in the list 1 reference picture for direct mode is selected as the motion vector for derivation of said direct mode motion vectors only if the co-located block in the list 1 reference picture has only the list 1 motion vector and else the list 0 motion vector of the co-located block in the list 1 reference picture for direct mode is selected as the motion vector for derivation of said direct mode motion vectors; and wherein the step of deriving the motion vectors of the current macroblock in the B-picture from the selected motion vector comprises applying a bit operation to the motion vector of the current macroblock.