# US 2020/0396459 A1 · Method and Apparatus of Matrix-Based Intra Prediction for Video Coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0396459 A1 - Document ID: US20200396459A1 - Status: Published application - Kind: A1 - Application number: 16/895,073 - Filed: 2020-06-08 - Published: 2020-12-17 - Earliest claimed: 2019-06-11 - Assignees: Mediatek Inc. - Applicants: Mediatek Inc. - Inventors: Zhi-Yi LIN; Tzu-Der CHUANG; Ching-Yeh CHEN; Chih-Wei HSU - Web page: https://patentgrep.com/patent/US20200396459A1 ## CPC - 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 - G06F 17/16: Matrix or vector computation {, e.g. matrix-matrix or matrix-vector multiplication, matrix factorization (matrix transposition G06F7/78)} - 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 19/159: 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 19/593: involving spatial prediction techniques - H04N 19/60: using transform coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Method and apparatus of video coding are disclosed. According to one method, the left reference boundary samples and the top reference boundary samples are checked jointly. According to another method, selected original left reference boundary samples and selected original top reference boundary samples at specific positions are used for predictor up-sampling. According to yet another method, the horizontal interpolation and the vertical interpolation are in a fixed order regardless of a shape of the current block, size of the current block or both. ## Claims ### Claim 1 A method of video coding using a coding mode belonging to a mode group comprising a regular Intra Prediction mode and a Matrix-based Intra Prediction (MIP) mode, the method comprising: receiving input data related to a current block in a current picture at a video encoder side or receiving a video bitstream comprising coded data of the current block at a video decoder side; when the MIP mode is applied to the current block: checking availability for a target reference boundary region comprising left reference boundary samples and top reference boundary samples, wherein the left reference boundary samples and the top reference boundary samples are checked jointly for the current block; deriving a reduced predictor, wherein said deriving the reduced predictor comprises applying matrix multiplication on a boundary vector and adding an offset, wherein the boundary vector is derived from the target reference boundary region, and wherein at least one unavailable samples is padded if there exists any unavailable sample in the target reference boundary region; and encoding or decoding the current block using a MIP predictor derived from the reduced predictor. ### Claim 2 (depends on 1) The method of claim 1, wherein the availability for the target reference boundary region is checked from a bottom sample to a top sample of the left reference boundary samples, then a top-left corner reference sample, and then from a leftmost sample to a rightmost sample of the top reference boundary samples. ### Claim 3 (depends on 1) The method of claim 1, wherein if all reference samples in the target reference boundary region are not available, the target reference boundary region is padded with a default value. ### Claim 4 (depends on 1) The method of claim 1, wherein if there exist at least one available sample and at least one unavailable sample in the target reference boundary region, any unavailable sample prior to a firstly available sample is padded using the firstly available sample. ### Claim 5 (depends on 4) The method of claim 4, wherein a target unavailable sample after the firstly available sample is padded using a last available sample checked prior to the target unavailable sample. ### Claim 6 (depends on 1) The method of claim 1, wherein the MIP predictor is derived by applying transpose, up-sampling or both to the reduced predictor. ### Claim 7 An apparatus of video coding using a coding mode belonging to a mode group comprising a regular Intra Prediction mode and a Matrix-based Intra Prediction (MIP) mode, the apparatus of video coding comprising one or more electronic circuits or processors arranged to: receive input data related to a current block in a current picture at a video encoder side or receive a video bitstream comprising coded data of the current block at a video decoder side; when the MIP mode is applied to the current block: check availability for a target reference boundary region comprising left reference boundary samples and top reference boundary samples, wherein the left reference boundary samples and the top reference boundary samples are checked jointly for the current block; derive a reduced predictor, wherein a process to derive the reduced predictor comprises to apply matrix multiplication on a boundary vector and to add an offset, wherein the boundary vector is derived from the target reference boundary region, and wherein at least one unavailable samples is padded if there exists any unavailable sample in the target reference boundary region; and encode or decode the current block using a MIP predictor derived from the reduced predictor. ### Claim 8 A method of video coding, the method comprising: receiving input data related to a current block in a current picture at a video encoder side or receiving a video bitstream comprising coded data of the current block at a video decoder side; deriving target samples from a target reference boundary region comprising left reference boundary samples and top reference boundary samples; deriving a reduced predictor, wherein said deriving the reduced predictor comprises applying matrix multiplication on a boundary vector and adding an offset, and wherein the boundary vector is derived from the target reference boundary region; and if current block size is larger than reduced predictor size: generating an up-sampled reduced predictor having the current block size by applying horizontal and vertical bi-linear interpolation to the reduced predictor and selected original left reference boundary samples and selected original top reference boundary samples at specific positions; and encoding or decoding the current block using the up-sampled reduced predictor. ### Claim 9 (depends on 8) The method of claim 8, wherein the specific positions are dependent on width and height of the current block, length of the up-sampled the reduced predictor or both. ### Claim 10 An apparatus of video coding, the apparatus of video coding comprising one or more electronic circuits or processors arranged to: receive input data related to a current block in a current picture at a video encoder side or receive a video bitstream comprising coded data of the current block at a video decoder side; derive target samples from a target reference boundary region comprising left reference boundary samples and top reference boundary samples; derive a reduced predictor, wherein a process to derive the reduced predictor comprises to apply matrix multiplication on a boundary vector and to add an offset, and wherein the boundary vector is derived from the target reference boundary region; and if current block size is larger than reduced predictor size: generate an up-sampled reduced predictor having the current block size by applying horizontal and vertical bi-linear interpolation to the reduced predictor and selected original left reference boundary samples and selected original top reference boundary samples at specific positions; and encode or decode the current block using the up-sampled reduced predictor. ### Claim 11 A method of video coding, the method comprising: receiving input data related to a current block in a current picture at a video encoder side or receiving a video bitstream comprising coded data of the current block at a video decoder side; determining a target reference boundary region comprising left reference boundary samples and top reference boundary samples; deriving a reduced predictor, wherein a process to derive the reduced predictor comprises apply matrix multiplication on a boundary vector and adding an offset, and wherein the boundary vector is derived from the target reference boundary region; up-sampling the reduced predictor to a same size as the current block using horizontal interpolation and vertical interpolation if the reduced predictor is smaller than the current block, wherein the horizontal interpolation and the vertical interpolation are in a fixed order regardless of a shape of the current block, size of the current block or both; and encoding or decoding the current block using the up-sampled reduced predictor. ### Claim 12 (depends on 11) The method of claim 11, wherein the horizontal interpolation is always applied before the vertical interpolation. ### Claim 13 (depends on 11) The method of claim 11, wherein the vertical interpolation is always applied before the horizontal interpolation. ### Claim 14 An apparatus of video coding, the apparatus of video coding comprising one or more electronic circuits or processors arranged to: receive input data related to a current block in a current picture at a video encoder side or receive a video bitstream comprising coded data of the current block at a video decoder side; determine a target reference boundary region comprising left reference boundary samples and top reference boundary samples; derive a reduced predictor, wherein a process to derive the reduced predictor comprises to apply matrix multiplication on a boundary vector and to add an offset, wherein the boundary vector is derived from the target reference boundary region; up-sample the reduced predictor to a same size as the current block using horizontal interpolation and vertical interpolation if the reduced predictor is smaller than the current block, wherein the horizontal interpolation and the vertical interpolation are in a fixed order regardless of a shape of the current block, size of the current block or both; and encode or decode the current block using the up-sampled reduced predictor.