# US 2021/0344932 A1 · Method for processing image on basis of inter-prediction mode and device therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344932 A1 - Document ID: US20210344932A1 - Status: Published application - Kind: A1 - Application number: 17/360,734 - Filed: 2021-06-28 - Published: 2021-11-04 - Earliest claimed: 2018-06-27 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Hyeongmoon JANG - Web page: https://patentgrep.com/patent/US20210344932A1 ## CPC - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/513: Processing of motion vectors - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference - H04N 19/172: the region being a picture, frame or field - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/52: by predictive encoding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Disclosed herein are a method for decoding a video signal and a device therefor. Specifically, a method for decoding an image based on an inter prediction mode may include: if a merge mode is applied to a current block, generating a merge candidate list by using a spatial neighboring block and a temporal neighboring block of the current block; obtaining a merge index indicating a candidate to be used for an inter prediction of the current block in the merge candidate list; deriving a motion vector of each of subblocks included in the current block based on a motion vector of the candidate used for the inter prediction of the current block; and generating a prediction sample of the current block by using the motion vector of each of subblocks. ## Claims ### Claim 1 An apparatus for decoding a video signal based on an inter prediction mode, comprising: a memory configured to store the video signal; and a processor coupled with the memory, wherein the processor is configured to: generate a merge candidate list by using a spatial neighboring block and a temporal neighboring block of a current block, based on that a merge mode is applied to the current block; obtain a merge index indicating a candidate to be used for an inter prediction of the current block in the merge candidate list; derive a motion vector of each subblock included in the current block based on a motion vector of the candidate indicated by the merge index; generate a prediction block of the current block based on the motion vector of each subblock; perform inverse-transform on transformed coefficients of the current block to generate a residual block of the current block; and generate a reconstructed block of the current block based on the prediction block and the residual block, wherein the processor is further configured to add a block which is located in a collocated picture of the current block and specified by a motion vector of the spatial neighboring block to the merge candidate list as the temporal neighboring block, based on that a width and a height of the current block is greater than or equal to a pre-defined size. ### Claim 2 (depends on 1) The apparatus of claim 1, the processor is further configured to add a block in the collocated picture specified by a motion vector of a first spatial neighboring block to the merge candidate list as the temporal neighboring block, the first spatial neighboring block being determined based on a pre-defined order among two or more spatial neighboring blocks of the current block. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein a width of the subblock is set to 8 and a height of the subblock is set to 8. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein the pre-defined size is set to 8. ### Claim 5 An apparatus for encoding a video signal based on an inter prediction mode, comprising: a memory configured to store the video signal; and a processor coupled with the memory, wherein the processor is configured to: generate a merge candidate list by using a spatial neighboring block and a temporal neighboring block of a current block, based on that a merge mode is applied to the current block; generate a merge index indicating a candidate to be used for an inter prediction of the current block in the merge candidate list; derive a motion vector of each subblocks included in the current block based on a motion vector of the candidate indicated by the merge index; generate a prediction block of the current block based on the motion vector of each subblocks; generate a residual block of the current block based on the prediction block; and perform transform on the residual block, wherein the processor is further configured to add a block which is located in a collocated picture of the current block and specified by a motion vector of the spatial neighboring block to the merge candidate list as the temporal neighboring block, based on that a width and a height of the current block is greater than or equal to a pre-defined size. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the processor is further configured to add a block in the collocated picture specified by a motion vector of a first spatial neighboring block to the merge candidate list as the temporal neighboring block, the first spatial neighboring block being determined based on a pre-defined order among two or more spatial neighboring blocks of the current block. ### Claim 7 (depends on 5) The apparatus of claim 5, wherein a width of the subblock is set to 8 and a height of the subblock is set to 8. ### Claim 8 (depends on 7) The method of claim 7, wherein the pre-defined size is set to 8. ### Claim 9 A non-transitory decoder-readable storage medium storing encoded picture information generated by performing the steps of: generating a merge candidate list by using a spatial neighboring block and a temporal neighboring block of a current block, based on that a merge mode is applied to the current block; generating a merge index indicating a candidate to be used for an inter prediction of the current block in the merge candidate list; deriving a motion vector of each subblocks included in the current block based on a motion vector of the candidate indicated by the merge index; generating a prediction block of the current block based on the motion vector of each subblocks; generating a residual block of the current block based on the prediction block; and performing transform on the residual block, wherein a block which is located in a collocated picture of the current block and specified by a motion vector of the spatial neighboring block is added to the merge candidate list as the temporal neighboring block, based on that a width and a height of the current block is greater than or equal to a pre-defined size. ### Claim 10 (depends on 9) The non-transitory decoder-readable medium of claim 9, wherein a block in the collocated picture specified by a motion vector of a first spatial neighboring block is added to the merge candidate list as the temporal neighboring block, the first spatial neighboring block being determined based on a pre-defined order among two or more spatial neighboring blocks of the current block. ### Claim 11 (depends on 9) The non-transitory decoder-readable medium of claim 9, wherein a width of the subblock is set to 8 and a height of the subblock is set to 8. ### Claim 12 (depends on 11) The non-transitory decoder-readable medium of claim 11, wherein the pre-defined size is set to 8.