# US 2021/0344946 A1 · Motion information prediction method and apparatus for distortion due to projection formation conversion > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344946 A1 - Document ID: US20210344946A1 - Status: Published application - Kind: A1 - Application number: 17/378,075 - Filed: 2021-07-16 - Published: 2021-11-04 - Earliest claimed: 2019-01-07 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Electronics and Telecommunications Research Institute - Inventors: Gun BANG; Hui Yong KIM; Gwang Hoon PARK; Woo Woen GWUN; Tae Hyun KIM; Won Jun LEE - Web page: https://patentgrep.com/patent/US20210344946A1 ## CPC - H04N 19/517: by encoding - H04N 19/52: by predictive encoding - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/182: the unit being a pixel - H04N 19/184: the unit being bits, e.g. of the compressed video stream - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract There is provided a method of decoding an image, the method comprising: decoding information for motion information prediction of a current block from a bitstream, predicting motion information of the current block based on the information, refining motion information of the current block by using the decoded information and the predicted motion information of the current block and reconstructing the current block based on the refined motion information of the current block. ## Claims ### Claim 1 A method of decoding an image, the method comprising: decoding, from a bitstream, motion vector refinement information indicating whether to refine motion vectors of blocks in a current sequence; decoding, from the bitstream, motion vector prediction information of a current block in the current sequence; determining a motion vector of the current block based on the motion vector prediction information of the current block; refining the motion vector of the current block based on the motion vector refinement information; and reconstructing the current block based on the refined motion vector of the current block, wherein the motion vector is refined according to a size of the current block. ### Claim 2 (depends on 1) The method of claim 1, wherein the refining of the motion vector of a current block comprises refining the motion vector of the current block based on a pixel value in L0 reference picture and L1 reference picture for the current block. ### Claim 3 (depends on 2) The method of claim 2, wherein the motion vector refinement information comprises information indicating whether the L0 reference picture and the L1 reference picture are available. ### Claim 4 (depends on 1) The method of claim 1, wherein the determining of motion vector of a current block comprises: determining the motion vector of the current block based on motion vector of a neighboring block of the current block, and the neighboring block comprises at least one among temporally neighboring blocks and spatially neighboring blocks the current block. ### Claim 5 (depends on 4) The method of claim 4, wherein the motion vector of the neighboring block is at least one of motion information before motion information refinement is performed and motion information after motion information refinement is performed. ### Claim 6 (depends on 1) The method of claim 1, wherein the refining of the motion vector of the current block comprises refining the motion vector of the current block based on projection format conversion information indicating an original projection format and a current projection format. ### Claim 7 (depends on 6) The method of claim 6, wherein the refining of the motion vector of the current block based on projection format conversion information comprises: generating an intermediate motion vector by refining the motion vector according to projection format conversion from the current projection format to the original projection format based on a position of a neighboring block that is referenced by the current block; and generating the refined motion vector by refining the intermediate motion vector according to projection format conversion from the original projection format to the current projection format based on a position of the current block. ### Claim 8 (depends on 7) The method of claim 7, wherein the current projection format is an HEC (Hybrid Equi-Angular Cube Map) format and the original projection format is CMP (Cube MaP) format. ### Claim 9 A method of encoding an image, the method comprising: determining whether to refine motion vectors of blocks in a current sequence; determining a motion vector of a current block in the current sequence; refining the motion vector of the current block in response to that the motion vectors of the blocks in the current sequence are determined to be refined; and encoding motion vector refinement information of the current sequence, the motion vector refinement information indicating whether to refine the motion vectors of the blocks in the current sequence, wherein the motion vector is refined according to a size of the current block. ### Claim 10 (depends on 9) The method of claim 9, wherein the determining of the motion vector of a current block comprises: determining the motion vector of the current block based on a pixel value in L0 reference picture and L1 reference picture for the current block. ### Claim 11 (depends on 10) The method of claim 10, wherein the motion vector refinement information comprises information indicating whether or not the L0 reference picture and the L1 reference picture are available. ### Claim 12 (depends on 9) The method of claim 9, wherein the determining of motion vector of a current block comprises: determining the motion vector of the current block based on motion vector of a neighboring block of the current block, and the neighboring block comprises at least one among temporally neighboring blocks and spatially neighboring the current block. ### Claim 13 (depends on 12) The method of claim 12, wherein the motion vector of the neighboring block is at least one of motion information before motion information refinement is performed and motion information after motion information refinement is performed. ### Claim 14 (depends on 9) The method of claim 9, wherein the refining of the motion vector of the current block comprises refining the motion vector of the current block based on projection format conversion information indicating an original projection format and a current projection format. ### Claim 15 (depends on 14) The method of claim 14, wherein the refining of the motion vector of the current block based on projection format conversion information comprises: generating an intermediate motion vector by refining the motion vector according to projection format conversion from the current projection format to the original projection format based on a position of a neighboring block that is referenced by the current block; and generating the refined motion vector by refining the intermediate motion vector according to projection format conversion from the original projection format to the current projection format based on a position of the current block. ### Claim 16 (depends on 15) The method of claim 15, wherein the current projection format is an HEC (Hybrid Equi-Angular Cube Map) format and the original projection format is CMP (Cube MaP) format. ### Claim 17 A non-transitory computer readable recording medium storing a bitstream that is received and decoded by an image decoding method and is used to reconstruct an image, wherein the bitstream comprises motion vector prediction information of a current sequence, the motion vector prediction information of the current sequence indicates whether to refine motion vectors of blocks in a current sequence, the motion vector of the current block is refined based on the motion vector refinement information of the current sequence, and the refined motion vector of the current block is used to reconstruct the current block, wherein the motion vector is refined according to a size of the current block.