Method for generating prediction block in amvp mode

Abstract

A method for generating a prediction block in Advanced Motion Vector Prediction (AMVP) mode to reconstruct a prediction-coded video signal using a motion vector approximate to original motion information. An AMVP candidate list is generated using effective spatial and temporal AMVP candidates for a current Prediction Unit (PU). If the number of the effective AMVP candidates is smaller than a predetermined value, a motion vector having a predetermined value as a candidate to the AMVP candidate list. Then a motion vector corresponding to an AMVP index of the current PU from among motion vectors included in the AMVP candidate list is determined to be a motion vector predictor of the current PU.

1 . A method for generating a prediction block in Advanced Motion Vector Prediction (AMVP) mode, the method comprising:
 reconstructing a reference picture index and a differential motion vector of a current Prediction Unit (PU);   searching an effective spatial AMVP candidate for the current PU;   searching an effective temporal AMVP candidate for the current PU;   generating an AMVP candidate list using the effective spatial and temporal AMVP candidates;   adding a motion vector having a predetermined value as a candidate to the AMVP candidate list, when the number of the effective AMVP candidates is smaller than a predetermined number;   determining a motion vector corresponding to an AMVP index of the current PU from among motion vectors included in the AMVP candidate list to be a motion vector predictor of the current PU;   reconstructing a motion vector of the current PU using the differential motion vector and the motion vector predictor; and   generating a prediction block corresponding to a position indicated by the reconstructed motion vector within a reference picture indicated by the reference picture index.   
     
     
         2 . The method according to  claim 1 , wherein the generating of the AMVP candidate list comprises deleting lower-ranked AMVP candidate in the AMVP candidate list when there are two or more AMVP candidates having the same motion vector. 
     
     
         3 . The method according to  claim 1 , wherein the search of an effective temporal AMVP candidate comprises:
 determining a temporal AMVP candidate picture; and   determining a temporal AMVP candidate block in the temporal AMVP candidate picture,   wherein the temporal AMVP candidate picture is determined based on a slice type.   
     
     
         4 . The method according to  claim 3 , wherein the temporal AMVP candidate picture is a picture with reference picture index  0 . 
     
     
         5 . The method according to  claim 3 , wherein the temporal AMVP candidate block is a first effective block resulting from scanning the first and second candidate blocks sequentially. 
     
     
         6 . The method according to  claim 1 , wherein a motion vector of the spatial AMVP candidate for the current PU is determined based on a size and position of the current PU. 
     
     
         7 . The method according to  claim 6 , wherein when the current PU is positioned at an upper boundary of a Largest Coding Unit (LCU), a motion vector of a spatial AMVP candidate above the current PU is a motion vector of a PU corresponding to the AMVP candidate, or a motion vector of a left or right PU adjacent to the AMVP candidate. 
     
     
         8 . The method according to  claim 1 , wherein the predetermined number is 2.