Video encoding/decoding method and apparatus in temporal direct mode in hierarchical structure

Abstract

A video encoding/decoding method and apparatus in a temporal direct mode in a hierarchical structure. The video encoding method in the temporal direct mode in the hierarchical structure includes calculating a temporal position of a forward reference frame or a backward reference frame of a high-pass frame; searching for frames that exist at the temporal position and have motion vector information; if there is a plurality of frames searched for, selecting as a co-located frame a frame, among the plurality of frames, having a motion vector of which an interval is closest to a difference in interval between the forward reference frame and the backward reference frame of the high-pass frame, and extracting the motion vector of the selected frame; and encoding information on the selected frame so that the high-pass frame can use the extracted motion vector.

1 . A video decoding method in a temporal direct mode in a hierarchical structure, comprising:
 decoding temporal direct mode information on a high-pass frame in a received video signal;   extracting information on a co-located frame and a co-located block in the co-located frame using the decoded temporal direct mode information;   transforming a motion vector of the co-located block in the co-located frame by comparing a temporal position of the motion vector with a temporal position of the high-pass frame; and   restoring the high-pass frame using the transformed motion vector.   
     
     
         2 . The video decoding method of  claim 1 , wherein the co-located frame is a first frame existing at a forward-referencing position of the high-pass frame. 
     
     
         3 . The video decoding method of  claim 2 , wherein the first frame is a first element of a zeroth reference frame list (refPic list 0 ) or a first reference frame list (refPic list 1 ). 
     
     
         4 . The video decoding method of  claim 1 , wherein the transforming of the motion vector of the co-located block comprises transforming the motion vector into two motion vectors according to a temporal position of the high-pass frame. 
     
     
         5 . The video decoding method of  claim 1 ,
 wherein the high-pass frame does not contain a frame having the same temporal position in a lower layer of the frame,   wherein the decoding step includes decoding residual data, and   wherein after extracting the information on the co-located frame and a co-located block, the method further comprises:   transforming the motion vector into two motion vectors according to a temporal position of the high-pass frame;   generating predicted data and residual data using the two transformed motion vectors; and   restoring the high-pass frame by adding the residual data to the predicted data.   
     
     
         6 . The video decoding method of  claim 1 , wherein the co-located frame is a frame existing at a forward-referencing position based on a temporal position of the high-pass frame. 
     
     
         7 . The video decoding method of  claim 1 , wherein the co-located frame is a frame of an enhancement layer existing at a forward or backward-referencing position based on a temporal position of the high-pass frame. 
     
     
         8 . A video decoder comprising:
 a decoding unit which decodes temporal direct mode information on a high-pass frame of a received video signal;   a motion vector extraction unit which extracts information on a co-located frame and a co-located block in the co-located frame using the decoded temporal direct mode information; and   a restoration unit which transforms a motion vector of the co-located block in the co-located frame by comparing a temporal position of the motion vector with a temporal position of the high-pass frame, and restores the high-pass frame using the transformed motion vector.   
     
     
         9 . The video decoder of  claim 8 , wherein the co-located frame is a first frame existing at a forward-referencing position of the high-pass frame. 
     
     
         10 . The video decoder of  claim 9 , wherein the first frame is a first element of a zeroth reference frame list (refPic list 0 ) or a first reference frame list (refPic list 1 ). 
     
     
         11 . The video decoder of  claim 8 , wherein the restoration unit transforms the motion vector into two motion vectors according to a temporal position of the high-pass frame. 
     
     
         12 . The video decoder of  claim 8 ,
 wherein the high-pass frame does not have a frame having the same temporal position in a lower layer of the frame,   wherein the decoding unit decodes residual data, and   wherein the restoration unit transforms the motion vector into two motion vectors according to a temporal position of the high-pass frame, generates predicted data and residual data using the two transformed motion vectors, and restores the high-pass frame by adding the residual data to the predicted data.   
     
     
         13 . The video decoder of  claim 8 , wherein the co-located frame is a frame existing at a forward-referencing position based on a temporal position of the high-pass frame. 
     
     
         14 . The video decoder of  claim 8 , wherein the co-located frame is a frame of an enhancement layer existing at a forward or backward-referencing position based on a temporal position of the high-pass frame.