Method and apparatus for predictive encoding/decoding of motion vector
A video encoding apparatus for predicting a motion vector of a current block to be encoded is to determine one or more representative blocks from neighboring blocks of the current block according to priorities of the neighboring blocks; and encode the motion vector of the current block by using, as a predicted motion vector of the current block, a first motion vector selected from motion vectors of the determined one or more representative blocks and a second motion vector of at least one block within a reference picture.
1. A video decoding method performed by a video decoding apparatus for predicting a current block to be decoded, the method comprising:
extracting an index for use in identifying a predicted motion vector of the current block and a differential motion vector from a bitstream;
determining one or more representative blocks using neighboring blocks of the current block, in consideration of priorities of block positions;
determining the predicted motion vector of the current block to be a motion vector identified by the extracted index; and
generating a predicted block of the current block by reconstructing a motion vector of the current block based on the determined predicted motion vector and the extracted differential motion vector,
wherein the determining of the one or more representative blocks comprises considering a difference between a first picture order count (POC) corresponding to a first reference picture of a neighboring block and a second picture order count (POC) corresponding to a second reference picture of the current block when a first inter prediction direction corresponding to the neighboring block and a second inter prediction direction corresponding to the current block are identical.
2. The video decoding method of claim 1 , wherein the determining of the one or more representative blocks comprises:
determining a first representative block corresponding to a left block group; and
determining a second representative block corresponding to an upper block group.
3. The video decoding method of claim 1 , wherein the one or more representative blocks are determined by comparing a picture order count corresponding to a reference picture of a neighboring block and a picture order count corresponding to a reference picture of the current block.
4. The video decoding method of claim 1 , wherein the representative blocks are determined from a left block group and an upper block group,
wherein the left block group includes two neighboring blocks located at a left side of the current block, and the upper block group includes three neighboring blocks located at an upper side of the current block and the priorities of block positions are in an order of ‘lower>upper’ for the left block group and in an order of ‘right>left’ for the upper block group.
5. The video decoding method of claim 1 , wherein the determining of the one or more representative blocks comprises:
determining one of the representative blocks corresponding to a temporal candidate block in a reference picture.
6. The video decoding method of claim 5 , wherein the temporal candidate block is located at a right lower side of a corresponding location of the current block in the reference picture.
7. The video decoding method of claim 1 , wherein a preset number of the representative blocks are determined and the index for use in identifying the predicted motion vector of the current block indicates one of the preset number of the representative blocks.