Method and apparatus for encoding/decoding images using adaptive motion vector resolution
The present disclosure relates to a method and apparatus for improving the encoding efficiency by adaptively changing the resolution of the motion vector in the inter prediction encoding and inter prediction decoding of a video. The apparatus includes: a predicted motion vector calculator for calculating a predicted motion vector of a current block to be encoded using motion vectors of one or more surrounding blocks; and a skip mode encoder for encoding a result of performing a prediction of the current block and information indicating that the current block is a skip block when the predicted motion vector satisfies a skip condition, wherein at least one motion vector among the motion vectors of the surrounding blocks and the motion vector of the current block has a resolution different from resolutions of the other motion vectors.
1. A video decoding apparatus for decoding a motion vector by adaptively determining a motion vector resolution in the unit of blocks which are split from a picture to be decoded, the apparatus comprising:
a decoder configured to decode, from a bitstream, a differential motion vector, and motion vector resolution identification information dedicated to a current block to be decoded among the blocks split from the picture, wherein the differential motion vector is a difference between a current motion vector of the current block and a predicted motion vector for the current motion vector, and the motion vector resolution identification information is used for determining a motion vector resolution of the differential motion vector among a plurality of motion vector resolutions; and
an inter predictor configured to
derive one or more predicted motion vector candidates from motion vectors of one or more neighboring blocks of the current block,
convert the predicted motion vector candidates such that the converted predicted motion vector candidates have the same motion vector resolution as the motion vector resolution determined by the motion vector resolution identification information,
derive the predicted motion vector for the current motion vector from the converted predicted motion vector candidates, and
reconstruct the current motion vector of the current block, by adding the differential motion vector to the predicted motion vector.
2. The apparatus of claim 1 ,
wherein the decoder is configured to decode resolution change information from the bitstream,
wherein the motion vector resolution identification information is decoded from the bitstream, when the resolution change information represents that a motion vector resolution is adaptively determined in units of blocks split from the picture.
3. The apparatus of claim 1 , wherein the resolution change information is decoded from a header of the bitstream, the header being a sequence parameter set or a picture parameter set or a slice header.