Patent ID: 11962798
Assignee: SK TELECOM CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A video decoding apparatus for decoding a sequence of one or more pictures in the unit of blocks which are split from each picture, the apparatus comprising at least one processor configured to:
extract, from a header of the sequence in the bitstream, first identification information indicating whether adaptive motion vector difference resolution is allowed in the unit of blocks which belong to the sequence of one or more pictures;
extract, from the header of the sequence, size information for restricting block splitting in a tree structure which includes a quad-tree and a binary-tree rooted from a leaf node of the quad-tree, the size information including a first syntax element for representing minimum block size allowed for a leaf node of the quad-tree and a second syntax element for representing maximum block size allowed for a root node of the binary-tree;
split a coding tree block in the tree structure by extracting split information under block size restriction defined by the size information, and thereby determine a current block to be decoded;
reconstruct, from a bitstream, a current motion vector difference of the current block among the blocks which belong to the sequence of one or more pictures;
when the first identification information indicates that the adaptive motion vector difference resolution is allowed and the current motion vector difference of the current block is non-zero, extract information on motion vector resolution dedicated to the current block among the blocks which belong to the sequence from the bitstream, and set a resolution of the current motion vector difference of the current block based on the information on motion vector resolution among three or more motion vector resolutions including a ¼ pixel precision;
generate a motion vector of the current block by using the current motion vector difference, the resolution of the current motion vector difference, and a motion vector corresponding to a neighboring block which has been already decoded prior to the current block and is adjacent to the current block; and
predict and decode the current block using the motion vector of the current block,
wherein the processor is configured to extract the information on motion vector resolution dedicated to the current block by
extracting a motion vector (mv) resolution flag dedicated to the current block from the bitstream, the mv resolution flag indicating whether the resolution of the current motion vector difference of the current block is equal to a ¼ pixel precision, and
extracting, from the bitstream, alternative motion vector resolution information for representing a motion vector resolution which is dedicated to the current block among motion vector resolutions other than the ¼ pixel precision, only when the mv resolution flag indicates that the resolution of the current motion vector difference of the current block is not the ¼ pixel precision,

wherein the alternative motion vector resolution information extracted from the bitstream is a log scale value of a ratio between the resolution of the current motion vector difference of the current block and a resolution of a motion vector difference of a block decoded prior to the current block,
wherein, when the current motion vector difference of the current block is zero, the resolution of the current motion vector difference of the current block is set to the ¼ pixel precision without the information on the motion vector resolution extracted, and
wherein, the first identification information indicates that the adaptive motion vector difference resolution is not allowed, the resolution of the current motion vector difference of the current block is set to the ¼ pixel precision without the information on motion vector resolution extracted.