Method and device for encoding/decoding motion vector
A motion vector encoding apparatus includes: a predictor configured to obtain motion vector predictor candidates of a plurality of predetermined motion vector resolutions by using a spatial candidate block and a temporal candidate block of a current block, and to determine motion vector predictor of the current block, a motion vector of the current block, and a motion vector resolution of the current block by using the motion vector predictor candidates; and an encoder configured to encode information representing the motion vector predictor of the current block, a residual motion vector between the motion vector of the current block and the motion vector predictor of the current block, and information representing the motion vector resolution of the current block, wherein the plurality of predetermined motion vector resolutions include a resolution of a pixel unit that is greater than a resolution of one-pel unit.
1. A method for decoding a motion vector, the method comprising:
obtaining a motion vector predictor of a current block and a residual motion vector of the current block;
obtaining a shift-value for the residual motion vector, the shift-value corresponding to a resolution of the residual motion vector of the current block;
up-scaling the residual motion vector by performing left-shift using the shift-value; and
reconstructing a motion vector of the current block based on the up-scaled residual motion vector and the motion vector predictor,
wherein the shift-value is one of integer values including a shift-value equal to 0 and at least one shift-value greater than 0, and
wherein the motion vector predictor is one among a plurality of motion vector predictor candidates.
2. A method for encoding a motion vector, the method comprising:
determining a resolution for encoding a residual motion vector of a current block;
obtaining a shift-value for the residual motion vector, the shift-value corresponding to the determined resolution;
obtaining a motion vector predictor of the current block;
obtaining the residual motion vector based on a motion vector of the current block and the motion vector predictor of the current block;
down-scaling the residual motion vector by performing right-shift using the shift-value; and
encoding the down-scaled residual motion vector,
wherein the shift-value is one of integer values including a shift-value equal to 0 and at least one shift-value greater than 0, and
wherein the motion vector predictor is one among a plurality of motion vector predictor candidates.
3. A non-transitory computer-readable medium for recording a bitstream, the bitstream comprising:
an encoded down-scaled residual motion vector,
wherein the encoded down-scaled residual motion vector is obtained by:
determining a resolution for encoding a residual motion vector of a current block;
obtaining a shift-value for the residual motion vector, the shift-value corresponding to the determined resolution;
obtaining a motion vector predictor of the current block;
obtaining the residual motion vector based on a motion vector of the current block and the motion vector predictor of the current block;
down-scaling the residual motion vector by performing right-shift using the shift-value; and
encoding the down-scaled residual motion vector,
wherein the shift-value is one of integer values including a shift-value equal to 0 and at least one shift-value greater than 0, and
wherein the motion vector predictor is one among a plurality of motion vector predictor candidates.