Determining a temporal motion vector predictor to ensure diversity among a set of predictors

摘要

A temporal motion vector predictor is includable, together with one or more spatial motion vector predictors, in a set of motion vector predictors for a block to encode of a current frame. A method of determining the temporal motion vector predictor comprises selecting as the temporal predictor one motion vector from among motion vectors in a reference block of a reference frame different from the current frame. The reference block is a block of the reference frame collocated with the block to encode or a block of the reference frame neighboring the collocated block. The selection is based on a diversity criterion for achieving diversity among the predictors of the set. In some embodiment the temporal predictor is selected from the bottom right position of a block of the reference frame, or the temporal predictor selected may depend on the size of the block to be encoded. This can reduce the motion vector memory requirements with no or no significant additional coding efficiency penalty.