# US 2021/0243429 A1 · Method for encoding/decoding video signal and apparatus therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243429 A1 - Document ID: US20210243429A1 - Status: Published application - Kind: A1 - Application number: 17/049,289 - Filed: 2019-11-27 - Published: 2021-08-05 - Earliest claimed: 2018-11-27 - Assignees: Xris Corporation - Applicants: Xris Corporation - Inventors: Bae Keun LEE - Web page: https://patentgrep.com/patent/US20210243429A1 ## 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 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter - H04N 19/107: between spatial and temporal predictive coding, e.g. picture refresh - H04N 19/11: among a plurality of spatial predictive coding modes - H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/463: by compressing encoding parameters before transmission - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A video decoding method according to the present disclosure includes determining a reference sample line for a current block, deriving an intra prediction mode for the current block, and performing intra prediction of the current block based on the reference sample line and the intra prediction mode. ## Claims ### Claim 1 A video decoding method comprising: determining a reference sample line for a current block; deriving an intra prediction mode for the current block; and performing intra prediction of the current block, based on the reference sample line and the intra prediction mode, wherein the intra prediction mode is derived based on at least one of a default mode or a most probable mode (MPM) list, wherein whether it is allowed to set the default mode as the intra prediction mode is determined based on an index of the reference sample line. ### Claim 2 (depends on 1) The method of claim 1, wherein when the index of the reference sample line indicates an adjacent reference sample line, the intra prediction mode is derived by parsing a flag indicating whether the intra prediction mode is identical with the default mode, and wherein when the index of the reference sample line indicates a non-adjacent reference sample line, the intra prediction mode is derived without parsing the flag indicating whether the intra prediction mode is identical with the default mode. ### Claim 3 (depends on 1) The method of claim 1, wherein deriving the intra prediction mode further includes parsing an MPM flag, wherein when the MPM flag indicates that an MPM identical with the intra prediction mode is present in the MPM list, a number of intra prediction mode candidates which can be set as the intra prediction mode varies based on the index of the reference sample line. ### Claim 4 (depends on 1) The method of claim 1, wherein when a first intra prediction mode for a top neighboring block adjacent to a top of the current block and a second intra prediction mode for a left neighboring block adjacent to a left of the current block are different from each other, and each of the first intra prediction mode and the second intra prediction mode is a directional intra prediction mode, the MPM list includes an intra prediction mode candidate derived by adding or subtracting 2 to or from a maximum value of the first intra prediction mode and the second intra prediction mode. ### Claim 5 (depends on 1) The method of claim 1, wherein the default mode is a planar mode. ### Claim 6 A video encoding method comprising: determining a reference sample line for a current block; deriving an intra prediction mode for the current block; and performing intra prediction of the current block, based on the reference sample line and the intra prediction mode, wherein the intra prediction mode is derived based on at least one of a default mode or a most probable mode (MPM) list, wherein whether it is allowed to set the default mode as the intra prediction mode is determined based on an index of the reference sample line. ### Claim 7 (depends on 6) The method of claim 6, wherein when the index of the reference sample line indicates an adjacent reference sample line, a flag indicating whether the intra prediction mode is identical with the default mode is encoded, and wherein when the index of the reference sample line indicates a non-adjacent reference sample line, encoding of the flag indicating whether the intra prediction mode is identical with the default mode is omitted. ### Claim 8 (depends on 6) The method of claim 6, wherein deriving the intra prediction mode further includes encoding an MPM flag, wherein when the MPM flag indicates that an MPM identical with the intra prediction mode is present in the MPM list, a number of intra prediction mode candidates which can be set as the intra prediction mode varies based on the index of the reference sample line. ### Claim 9 (depends on 6) The method of claim 6, wherein when a first intra prediction mode for a top neighboring block adjacent to a top of the current block and a second intra prediction mode for a left neighboring block adjacent to a left of the current block are different from each other, and each of the first intra prediction mode and the second intra prediction mode is a directional intra prediction mode, the MPM list includes an intra prediction mode candidate derived by adding or subtracting 2 to or from a maximum value of the first intra prediction mode and the second intra prediction mode. ### Claim 10 (depends on 6) The method of claim 6, wherein the default mode is a planar mode. ### Claim 11 A video decoding device comprising an intra prediction unit configured to: determine a reference sample line for a current block; derive an intra prediction mode for the current block; and perform intra prediction of the current block, based on the reference sample line and the intra prediction mode, wherein the intra prediction mode is derived based on at least one of a default mode or a most probable mode (MPM) list, wherein whether it is allowed to set the default mode as the intra prediction mode is determined based on an index of the reference sample line.