1. A method of inter-view video decoding or inter-layer video decoding, the method comprising: constructing a list of candidate motion vector predictors; receiving a bitstream that includes information including an index into the list of candidate motion vector predictors for selecting a motion vector predictor from the list of candidate motion vector predictors and information for deriving a motion vector for a current block from the selected motion vector predictor, wherein the motion vector refers to a block in an inter-view reference picture or an inter-layer reference picture, wherein the bitstream is constrained such that the derived motion vector is compliant with a motion vector restriction, wherein the motion vector restriction restricts a range of the motion vector to refer to a sub-portion of the inter-view reference picture or inter-layer reference picture, wherein based on the list of candidate motion vector predictors being for merge mode, the bitstream is constrained such that the index into the list of candidate motion vector predictors selects the motion vector predictor that is equal to zero, and wherein based on the list of candidate motion vector predictors being for advanced motion vector prediction (AMVP) mode, the bitstream is constrained such that the index into the list of candidate motion vector predictors selects the motion vector predictor that added with a motion vector difference equals zero; deriving the motion vector for the current block based on the information in the bitstream; and inter-view prediction decoding or inter-layer prediction decoding the current block based on pixel values of the block referred to by the derived motion vector.