# US 11,451,782 B2 · Calculation in matrix-based intra prediction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,782 B2 - Document ID: US11451782B2 - Status: Granted - Kind: B2 - Application number: 17/342,996 - Filed: 2021-06-09 - Published: 2021-09-23 - Granted: 2022-09-20 - Earliest claimed: 2019-04-12 - Assignees: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Applicants: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Inventors: Zhipin Deng; Kai Zhang; Li Zhang; Hongbin Liu; Jizheng Xu - Web page: https://patentgrep.com/patent/US11451782B2 ## 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 - 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 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) - H04N 19/12: Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264 - 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 19/186: the unit being a colour or a chrominance component - H04N 19/593: involving spatial prediction techniques - H04N 19/60: using transform coding - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N 19/82: involving filtering within a prediction loop - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Devices, systems and methods for digital video coding, which includes matrix-based intra prediction methods for video coding, are described. In a representative aspect, a method for video processing includes performing a conversion between a current video block of a video and a bitstream representation of the current video block using a matrix based intra prediction (MIP) mode in which a prediction block of the current video block is determined by performing, on previously coded samples of the video, a boundary downsampling operation, followed by a matrix vector multiplication operation, and selectively followed by an upsampling operation, where the performing the conversion includes deriving, according to a rule, boundary samples by applying a left bit shift operation or a right bit shift operation on a sum of at least one reference boundary sample, and where the rule determines whether to apply the left bit shift or the right bit shift operation. ## Claims ### Claim 1 A method of video processing, comprising: performing a conversion between a current video block of a video and a bitstream of the current video block using a matrix based intra prediction (MIP) mode in which prediction samples of the current video block is determined by performing, on reference samples of the current video block, a boundary downsampling operation based on a size of the current video block, followed by a matrix vector multiplication operation, and selectively followed by an upsampling operation; wherein the prediction samples are determined according to following formulas in the upsampling operation: predSamples[xHor+dX][yHor]=((upHor−dX)*predSamples[xHor][yHor]+dX*predSamples[xHor+upHor][yHor]+offsetHor)/upHor, and predSamples[xVer][yVer+dY]=((upVer−dY)*predSamples[xVer][yVer]+dY*predSamples[xVer][yVer+upVer]+offsetVer)/upVer, wherein offsetHor and offsetVer are integers, wherein upHor is a function of the current video block width and a pre-defined value based on the current video block size, wherein upVer is a function of the current video block height and the pre-defined value based on the current video block size; wherein dX is 1 . . . upHor−1, wherein dY is 1 . . . upVer−1, and wherein xHor are positions based on the upHor and yHor are positions based on the upVer. ### Claim 2 (depends on 1) The method of claim 1, wherein offsetHor=upHor/2, and offsetVer=upVer/2. ### Claim 3 (depends on 1) The method of claim 1, wherein the boundary downsampling operation includes deriving, according to a rule, boundary samples by applying a left bit shift operation or a right bit shift operation on a sum of at least one reference boundary sample, and wherein the rule determines whether to apply the left bit shift operation or the right bit shift operation. ### Claim 4 (depends on 3) The method of claim 3, wherein the rule defines that the right bit shift operation is applied in response to a number of shifted bits being greater than zero. ### Claim 5 (depends on 4) The method of claim 4, wherein the boundary samples redBdryS[x] are calculated using one of following equations: redBdryS[x]=(Σi=0bDwn−1refS[x*bDwn+i]+(1<<(Log 2(bDwn)−1)))>>Log 2(bDwn), if bDwn>1, or redBdryS[x]=refS[x] if bDwn=1, wherein bDwn is equal to a function of the current video block size and a boundary size, wherein refS [x] indicates a number of reference samples x, wherein >> indicates the right bit shift operation, and wherein <>Log 2(bDwn), if bDwn>1, or redBdryS[x]=refS[x] if bDwn=1, wherein bDwn is equal to a function of the current video block size and a boundary size, wherein refS [x] indicates a number of reference samples x, wherein >> indicates the right bit shift operation, and wherein <