1. A method for video decoding that supports a multi-view, comprising: constructing a merge motion candidate list by deriving a default merge motion candidate with respect to a current Prediction Unit (PU); deriving an extended merge motion candidate with respect to the current PU in response to the current PU being a depth map or a dependent view; and adding the extended merge motion candidate to the merge motion candidate list in response to the extended merge motion candidate not being the same as the default merge motion candidate within the merge motion candidate list, wherein the extended merge motion candidate comprises a view synthesis prediction merge candidate that is derived according to whether a view synthesis prediction of the current PU is performed, and wherein the adding the extended merge motion candidate comprises adding the view synthesis prediction merge candidate into the merge motion candidate list in response to a sum of a number of extended merge motion candidates already added to the merge motion candidate list and a number of default merge motion candidates being smaller than a maximum number of the merge motion candidate list.