Patent ID: 8743960

Claim:
A method of decoding a bi-predictive image block, the method performed by a moving picture coding system and comprising: determining, by the moving picture coding system, a first reference picture of the bi-predictive image block, the first reference picture having a co-located image block with respect to the bi-predictive image block; determining, by the moving picture coding system, a second reference picture; determining, by the moving picture coding system, at least one motion vector of the bi-predictive image block according to the motion vector of the co-located image block and the reference picture type of at least one of the first reference picture and the second reference picture, the reference picture type being one of long term type and short term type, the reference picture type characterizing a temporal distance of the at least one of the first reference picture and the second reference picture with respect to the bi-predictive image block, the determining step determining the at least one motion vector according to a first set of expressions if the reference picture type is the short term type, the determining step determining the at least one motion vector according to a second set of expressions if the reference picture type is the long term type, the second set of expressions being different than the first set of expressions; and decoding, by the moving picture coding system, the bi-predictive image block based on the at least one motion vector of the bi-predictive image block.