# US 2018/0324418 A1 · Method and apparatus for encoding and decoding video signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324418 A1 - Document ID: US20180324418A1 - Status: Published application - Kind: A1 - Application number: 15/768,326 - Filed: 2016-10-13 - Published: 2018-11-08 - Earliest claimed: 2015-10-13 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Moonmo KOO; Sehoon YEA; Kyuwoon KIM; Bumshik LEE - Web page: https://patentgrep.com/patent/US20180324418A1 ## CPC - H04N 19/11: among a plurality of spatial predictive coding modes - H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/593: involving spatial prediction techniques - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The present invention provides a method for processing a video signal, comprising generating a prediction block for a neighbor block using a reconstructed reference pixel of the neighbor block when the neighbor block adjacent to a current block is intra-coded; determining a refined intra prediction mode of the neighbor block based on the prediction block, where the refined intra prediction mode represents a mode which minimizes an error between the prediction block and a reconstructed neighbor block; generating a prediction mode candidate list for the current block based on the refined intra prediction mode; selecting an intra prediction mode for the current block from the prediction mode candidate list; and performing a prediction for the current block based on the intra prediction mode. ## Claims ### Claim 1 A method for processing a video signal, comprising: generating a prediction block for a neighbor block using a reconstructed reference pixel of the neighbor block when the neighbor block adjacent to a current block is intra-coded; determining a refined intra prediction mode of the neighbor block based on the prediction block, where the refined intra prediction mode represents a mode which minimizes an error between the prediction block and a reconstructed neighbor block; generating a prediction mode candidate list for the current block based on the refined intra prediction mode; selecting an intra prediction mode for the current block from the prediction mode candidate list; and performing a prediction for the current block based on the intra prediction mode. ### Claim 2 (depends on 1) The method of claim 1, wherein a prediction mode for the neighbor block is generated for the entire intra prediction modes, and wherein the refined intra prediction mode is a mode which minimizes an error from the reconstructed neighbor block based on prediction blocks generated for the entire intra prediction modes. ### Claim 3 (depends on 1) The method of claim 1, wherein a prediction mode for the neighbor block is generated for a specific intra prediction mode, and the specific intra prediction mode represents an intra prediction mode within a predetermined range from an intra prediction mode of the neighbor block; and the refined intra prediction mode is a mode which minimizes an error from the reconstructed neighbor block on the basis of prediction blocks generated for the specific intra prediction mode. ### Claim 4 (depends on 1) The method of claim 1, wherein, when an intra prediction mode of the neighbor block is an intra planar mode or intra DC mode, the refined intra prediction mode is determined as an intra prediction mode of the neighbor block. ### Claim 5 (depends on 1) The method of claim 1, wherein the neighbor block comprises at least one of a left neighbor block or an upper neighbor block of the current block, and wherein a reconstructed reference pixel of the neighbor block comprises at least one of a left boundary pixel, upper-left corner pixel, and upper boundary pixel adjacent to the neighbor block. ### Claim 6 (depends on 5) The method of claim 5, wherein, when an intra prediction mode of the left neighbor block is the same as that of the upper neighbor block, the refined intra prediction mode is determined as an intra prediction mode of the neighbor block. ### Claim 7 (depends on 1) The method of claim 1, further comprising obtaining a mode index from the video signal, wherein the mode index represents an index indicating a prediction mode of the current block, and wherein an intra prediction mode for the current block is selected based on the mode index. ### Claim 8 An apparatus for processing a video signal, comprising: an intra prediction unit configured to, when a neighbor block adjacent to a current block is intra-coded, generate a prediction block for the neighbor block by using a reconstructed reference pixel of the neighbor block, determine a refined intra prediction mode of the neighbor block based on the prediction block, generate a prediction mode candidate list for the current block based on the refined intra prediction mode, select an intra prediction mode for the current block from the prediction mode candidate list, and perform a prediction for the current block based on the intra prediction mode; and a reconstruction unit configured to reconstruct the video signal based on the prediction result, wherein the refined intra prediction mode is a mode which minimizes an error between the prediction block and the reconstructed neighbor block. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein a prediction mode for the neighbor block is generated for the entire intra prediction modes, and wherein the refined intra prediction mode is a mode which minimizes an error from the reconstructed neighbor block based on prediction blocks generated for the entire intra prediction modes. ### Claim 10 (depends on 8) The apparatus of claim 8, wherein a prediction mode for the neighbor block is generated for a specific intra prediction mode, and the specific intra prediction mode represents an intra prediction mode within a predetermined range from an intra prediction mode of the neighbor block; and wherein the refined intra prediction mode is a mode which minimizes an error from the reconstructed neighbor block on the basis of prediction blocks generated for the specific intra prediction mode. ### Claim 11 (depends on 8) The apparatus of claim 8, wherein, when an intra prediction mode of the neighbor block is intra planar mode or intra DC mode, the refined intra prediction mode is determined as an intra prediction mode of the neighbor block. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein the neighbor block comprises at least one of a left neighbor block or an upper neighbor block of the current block, and wherein a reconstructed reference pixel of the neighbor block comprises at least one of a left boundary pixel, upper-left corner pixel, and upper boundary pixel adjacent to the neighbor block. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein, when an intra prediction mode of the left neighbor block is the same as that of the upper neighbor block, the refined intra prediction mode is determined as an intra prediction mode of the neighbor block. ### Claim 14 (depends on 8) The apparatus of claim 8, further comprising a parsing unit configured to obtain a mode index from the video signal, wherein the mode index represents an index indicating the prediction mode of the current block, and wherein an intra prediction mode for the current block is selected based on the mode index.