Apparatus for decoding motion information in merge mode

Abstract

Disclosed is an apparatus for decoding motion information in merge mode for reconstructing a moving picture signal coded at a low data rate while maintaining a high quality of an image. The apparatus for decoding motion information in merge mode discloses the position of a merge mode candidate and the configuration of a candidate in order to predict motion information in merge mode efficiently. Furthermore, a merge candidate indicated by the merge index of a current block can be efficiently reconstructed irrespective of a network environment by adaptively generating a merge candidate based on the number of valid merge candidate.

The invention claimed is: 
     
       1. An apparatus for decoding motion information in merge mode, comprising:
 a merge predictor index decoding unit configured to reconstruct a merge predictor index of a current block using a received merge codeword;   a spatial merge candidate derivation unit configured to derive spatial merge candidates of the current block;   a temporal merge candidate configuration unit configured to generate a temporal merge candidate of the current block;   a merge candidate generation unit configured to generate one or more merge candidates when a number of valid merge candidates of the current block is smaller than a predetermined number;   a merge predictor selection unit configured to generate a list of merge candidates using the merge candidates and select a merge predictor based on the merge predictor index reconstructed by the merge predictor index decoding unit; and   a motion information generation unit configured to generate a reference picture index and a motion vector of the current block,   wherein the temporal merge candidate configuration unit is configured to set a reference picture index of the temporal merge candidate as 0, and   wherein a motion vector of the temporal merge candidate is selected among a motion vector of a first merge candidate block and a motion vector of a second merge candidate block based on a position of the current block within a largest coding unit, and the motion vector of the second merge candidate block is selected as the motion vector of the temporal merge candidate if the current block is adjacent to a lower boundary of the largest coding unit.   
     
     
       2. The apparatus of  claim 1 , wherein the temporal merge candidate configuration unit determines a temporal merge candidate picture and determines a temporal merge candidate block within the temporal merge candidate picture, in order to generate the motion vector of the temporal merge candidate. 
     
     
       3. The apparatus of  claim 2 , wherein the temporal merge candidate block is a valid bock retrieved when the first candidate block and the second candidate block are searched for in due order, depending a position of the current block. 
     
     
       4. An apparatus for decoding motion information in merge mode, comprising:
 a merge predictor index decoding unit configured to reconstruct a merge predictor index of a current block using a received merge codeword;   a spatial merge candidate derivation unit configured to derive spatial merge candidates of the current block;   a temporal merge candidate configuration unit configured to generate a temporal merge candidate of the current block;   a merge candidate generation unit configured to generate one or more merge candidates when a number of valid merge candidates of the current block is smaller than a predetermined number;   a merge predictor selection unit configured to generate a list of merge candidates using the spatial merge candidates derived by the spatial merge candidate derivation unit, the temporal merge candidate generated by the temporal merge candidate configuration unit, and the one or more merge candidates generated by the merge candidate generation unit and to select a merge predictor based on the merge predictor index reconstructed by the merge predictor index decoding unit;   a motion information generation unit configured to generate a reference picture index and a motion vector of a merge candidate, selected by the merge predictor selection unit, as a reference picture index and motion vector of the current block; and   a motion vector derivation unit configured to determine a temporal merge candidate picture and determine a temporal merge candidate block within the temporal merge candidate picture in order to generate a motion vector of the temporal merge candidate,   wherein the temporal merge candidate picture is determined differently depending on a slice type, and the motion vector derivation unit determines, on a basis of the slice type, whether the temporal merge candidate picture is set in a reference picture list indicated by a flag indicative of a list for the temporal merge candidate picture in a slice header,   wherein the motion vector derivation unit is configured to set a reference picture index of the temporal merge candidate as 0, and   wherein a motion vector of the temporal merge candidate is selected among a motion vector of a first merge candidate block and a motion vector of a second merge candidate block based on a position of the current block within a largest coding unit, and the motion vector of the second merge candidate block is selected as the motion vector of the temporal merge candidate if the current block is adjacent to a lower boundary of the largest coding unit.   
     
     
       5. The apparatus of claim 4, further comprising:
 a reference picture index derivation unit configured to set a reference picture index of one of blocks neighboring the current block or 0 as a reference picture index of the temporal merge candidate.   
     
     
       6. The apparatus of claim 4, wherein the temporal merge candidate picture has a reference picture index of 0. 
     
     
       7. The apparatus of claim 4, wherein:
 the temporal merge candidate block is a first candidate block or a second candidate block,   the first candidate block is a lower left corner block of a block corresponding to a current prediction unit within the temporal merge candidate picture, and   the second candidate block is a block comprising a lower right pixel at a central position of the block corresponding to the current prediction unit within the temporal merge candidate picture.   
     
     
       8. The apparatus of claim 7, wherein the temporal merge candidate block is a valid block retrieved when the first candidate block and the second candidate block are searched for in due order or only the second candidate block is searched for depending on a position of the current block. 
     
     
       9. The apparatus of claim 4, wherein the merge candidate generation unit generates the merge candidate by combining pieces of motion information on valid merge candidates or generates the merge candidate having a motion vector of 0 and a reference picture index of 0. 
     
     
       10. The apparatus of claim 9, wherein the merge candidate generation unit generates the merge candidate whose number is equal to or smaller than the predetermined number if the merge candidate is generated by combining pieces of motion information on predetermined valid merge candidates. 
     
     
       11. The apparatus of claim 4, wherein the temporal merge candidate configuration unit determines a temporal merge candidate picture and determines a temporal merge candidate block within the temporal merge candidate picture, in order to generate the motion vector of the temporal merge candidate. 
     
     
       12. The apparatus of claim 11, wherein the temporal merge candidate block is a valid block retrieved when the first candidate block and the second candidate block are searched for in due order, depending a position of the current block.