# US 12,192,443 B2 · Merge candidate list for gradual decoding refresh > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,192,443 B2 - Document ID: US12192443B2 - Status: Granted - Kind: B2 - Application number: 17/995,201 - Filed: 2021-03-18 - Published: 2023-05-11 - Granted: 2025-01-07 - Earliest claimed: 2020-03-31 - Assignees: Nokia Technologies Oy - Applicants: Nokia Technologies Oy - Inventors: Limin Wang; Seungwook Hong; Krit Panusopone - Web page: https://patentgrep.com/patent/US12192443B2 ## CPC - 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 19/52: by predictive encoding - H04N 19/134: characterised by the element, parameter or criterion affecting or controlling the adaptive coding - H04N 19/154: Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion (use of rate-distortion criteria H04N19/147) - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/167: Position within a video image, e.g. region of interest [ROI] - H04N 19/172: the region being a picture, frame or field - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/507: using conditional replenishment - H04N 19/513: Processing of motion vectors - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method, apparatus, and computer program product provide for solving merge candidate list mismatches. In the context of a method, the method accesses a current coding unit of a picture. The method can also generate a merge candidate list comprising a plurality of coding unit representations in a predefined order. The method also determines whether a particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture and prevents the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit. ## Claims ### Claim 1 An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: determine whether a picture comprises a gradual decoding refresh picture; and in an instance in which the picture comprises a gradual decoding refresh picture: access a current coding unit of a picture; generate a merge candidate list comprising a plurality of coding unit representations in a predefined order; determine whether a particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture; and in accordance with a determination that the particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture: prevent the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit. ### Claim 2 A method comprising: determine whether a picture comprises a gradual decoding refresh picture; and in an instance in which the picture comprises a gradual decoding refresh picture: accessing a current coding unit of a picture; generating a merge candidate list comprising a plurality of coding unit representations in a predefined order; determining whether a particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture; and in accordance with a determination that the particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture: preventing the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit. ### Claim 3 A computer program product comprising a non-transitory computer readable storage medium having program code portions stored thereon, the program code portions configured, upon execution, to: determine whether a picture comprises a gradual decoding refresh picture; and in an instance in which the picture comprises a gradual decoding refresh picture: access a current coding unit of a picture; generate a merge candidate list comprising a plurality of coding unit representations in a predefined order; determine whether a particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture; and in accordance with a determination that the particular coding unit representation within the merge candidate list is representative of a coding unit within a dirty area of the picture: prevent the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit. ### Claim 4 An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: determine whether a picture comprises a gradual decoding refresh picture; and in an instance in which the picture comprises a gradual decoding refresh picture: access a current coding unit of a picture; analyze a plurality of coding units associated with the current coding unit to determine whether one or more coding units of the plurality of coding units are within a dirty area of the picture; in accordance with a determination that one or more coding units of the plurality of coding units are within a dirty area of the picture, prevent the one or more coding units within the dirty area of the picture from being included in a merge candidate list; and generate a merge candidate list comprising only one or more coding unit representations representative of one or more coding units not within the dirty area of the picture. ### Claim 5 A method comprising: determine whether a picture comprises a gradual decoding refresh picture; and in an instance in which the picture comprises a gradual decoding refresh picture: accessing a current coding unit of a picture; analyzing a plurality of coding units associated with the current coding unit to determine whether one or more coding units of the plurality of coding units are within a dirty area of the picture; in accordance with a determination that one or more coding units of the plurality of coding units are within a dirty area of the picture, preventing the one or more coding units within the dirty area of the picture from being included in a merge candidate list; and generating a merge candidate list comprising only one or more coding unit representations representative of one or more coding units not within the dirty area of the picture. ### Claim 6 A computer program product comprising a non-transitory computer readable storage medium having program code portions stored thereon, the program code portions configured, upon execution, to: determine whether a picture comprises a gradual decoding refresh picture; and in an instance in which the picture comprises a gradual decoding refresh picture: access a current coding unit of a picture; analyze a plurality of coding units associated with the current coding unit to determine whether one or more coding units of the plurality of coding units are within a dirty area of the picture; in accordance with a determination that one or more coding units of the plurality of coding units are within a dirty area of the picture, prevent the one or more coding units within the dirty area of the picture from being included in a merge candidate list; and generate a merge candidate list comprising only one or more coding unit representations representative of one or more coding units not within the dirty area of the picture. ### Claim 7 (depends on 1) An apparatus according to claim 1 wherein the apparatus is caused to prevent the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit by not signaling the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order. ### Claim 8 (depends on 2) A method according to claim 2 wherein preventing the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit comprises preventing signaling of the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order. ### Claim 9 (depends on 3) A computer program product according to claim 3 wherein the program code portions configured to prevent the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order from being selected as a merge candidate for the current coding unit comprise program code portions configured to prevent signaling of the particular coding unit representation and one or more coding unit representations following the particular coding unit in the predefined order. ### Claim 10 (depends on 4) An apparatus according to claim 4 wherein the apparatus is caused to prevent the one or more coding units within the dirty area of the picture from being included in a merge candidate list by treating the one or more coding units within the dirty area of the picture as being unavailable. ### Claim 11 (depends on 5) A method according to claim 5 wherein preventing the one or more coding units within the dirty area of the picture from being included in a merge candidate list comprises treating the one or more coding units within the dirty area of the picture as being unavailable. ### Claim 12 (depends on 6) A computer program product according to claim 6 wherein the program code portions configured to prevent the one or more coding units within the dirty area of the picture from being included in a merge candidate list comprise program code portions configured to treat the one or more coding units within the dirty area of the picture as being unavailable.