# US 12,598,301 B2 · BDPCM-based image coding method and device therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,598,301 B2 - Document ID: US12598301B2 - Status: Granted - Kind: B2 - Application number: 18/774,225 - Filed: 2024-07-16 - Published: 2024-11-07 - Granted: 2026-04-07 - Earliest claimed: 2019-04-20 - Assignees: Guangdong Oppo Mobile Telecommunications Corp., Ltd. - Applicants: Guangdong Oppo Mobile Telecommunications Corp., Ltd. - Inventors: Moonmo Koo; Jaehyun Lim; Junghak Nam; Seunghwan Kim - Web page: https://patentgrep.com/patent/US12598301B2 ## CPC - 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 19/124: Quantisation - 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 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter - H04N 19/159: 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 19/18: the unit being a set of transform coefficients - H04N 19/186: the unit being a colour or a chrominance component - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/60: using transform coding - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An image decoding method according to the present document comprises the steps of: deriving a quantized transform coefficient for a current block on the basis of BDPCM; deriving a transform coefficient by performing dequantization on the quantized transform coefficient; and deriving a residual sample on the basis of the transform coefficient, wherein, when the BDPCM is applied to the current block, inverse non-separable transform is not applied to the transform coefficient. ## Claims ### Claim 1 An image decoding method performed by a decoding apparatus, the method comprising: deriving quantized transform coefficients for a component block based on a BDPCM (Block-based Delta Pulse Code Modulation); deriving transform coefficients by performing a dequantization on the quantized transform coefficients; and deriving residual samples based on the transform coefficients; wherein based on the BDPCM being applied to the component block including one or more non-zero transform coefficients, a value of a transform index for an inverse non-separable transform is inferred to be 0. ### Claim 2 (depends on 1) The image decoding method of claim 1, wherein when the value of the transform index for the inverse non-separable transform is inferred to be 0, the inverse non-separable transform is not applied to the transform coefficients of the component block. ### Claim 3 (depends on 1) The image decoding method of claim 1, wherein when the BDPCM is applied to the component block, a value of a transform skip flag indicating whether a transform is skipped in the component block is inferred to be 1. ### Claim 4 (depends on 1) The image decoding method of claim 1, wherein when the component block is a luma block and the BDPCM is applied to the luma block, the value of the transform index for the luma block is inferred to be 0. ### Claim 5 (depends on 1) The image decoding method of claim 1, wherein when the component block is a chroma block and the BDPCM is applied to the chroma block, the value of the transform index for the chroma block is inferred to be 0. ### Claim 6 (depends on 1) The image decoding method of claim 1, wherein when a width of the component block is less than or equal to a first threshold and a height of the component block is less than or equal to a second threshold, the BDPCM is applied to the component block. ### Claim 7 (depends on 1) The image decoding method of claim 1, wherein the quantized transform coefficients are derived based on direction information on the direction in which the BDPCM is performed; wherein the method further comprises performing an intra prediction on the component block based on the direction in which the BDPCM is performed; and wherein the direction information indicates a horizontal direction or a vertical direction. ### Claim 8 An image encoding method performed by an image encoding apparatus, comprising: deriving prediction samples for a component block; deriving residual samples for the component block based on the prediction samples; performing quantization on the residual samples; deriving quantized residual information based on Block-based Delta Pulse Code Modulation (BDPCM); and encoding the quantized residual information and coding information for the component block; wherein the coding information includes BDPCM flag information indicating whether the BDPCM is applied to the component block and direction information on a direction in which the BDPCM is performed; wherein based on the BDPCM being applied to the component block including one or more non-zero transform coefficients, a transform index for a non-separable transform is not encoded. ### Claim 9 (depends on 8) The image encoding method of claim 8, wherein when the non-separable transform is not applied to the transform coefficients of the component block, the transform index for the non-separable transform is not encoded. ### Claim 10 (depends on 8) The image encoding method of claim 8, wherein when the BDPCM is applied to the component block, a transform skip flag indicating whether a transform is skipped in the component block is not encoded. ### Claim 11 (depends on 8) The image encoding method of claim 8, wherein when the component block is a luma block and the BDPCM is applied to the luma block, the transform index for the luma block is not encoded. ### Claim 12 (depends on 8) The image encoding method of claim 8, wherein when the component block is a chroma block and the BDPCM is applied to the chroma block, the transform index for the chroma block is not encoded. ### Claim 13 (depends on 8) The image encoding method of claim 8, wherein the residual samples are quantized based on direction information on the direction in which the BDPCM is performed; wherein the method further comprises performing an intra prediction on the component block based on the direction in which the BDPCM is performed; and wherein the direction information indicates a horizontal direction or a vertical direction. ### Claim 14 A non-transitory computer-readable digital storage medium storing thereon a computer program and a video bitstream, wherein when processed by one or more processors, the computer program causes the one or more processors to implement the following to generate the video bitstream: deriving prediction samples for a component block; deriving residual samples for the component block based on the prediction samples; performing quantization on the residual samples; deriving quantized residual information based on Block-based Delta Pulse Code Modulation (BDPCM); and encoding the quantized residual information and coding information for the component block; wherein the coding information includes BDPCM flag information indicating whether the BDPCM is applied to the component block and direction information on a direction in which the BDPCM is performed; wherein based on the BDPCM being applied to the component block including one or more non-zero transform coefficients, a transform index for a non-separable transform is not encoded. ### Claim 15 (depends on 14) The non-transitory computer-readable digital storage medium of claim 14, wherein when the non-separable transform is not applied to the transform coefficients of the component block, the transform index for the non-separable transform is not encoded. ### Claim 16 (depends on 14) The non-transitory computer-readable digital storage medium of claim 14, wherein when the BDPCM is applied to the component block, a transform skip flag indicating whether a transform is skipped in the component block is not encoded. ### Claim 17 (depends on 14) The non-transitory computer-readable digital storage medium of claim 14, wherein when the component block is a luma block and the BDPCM is applied to the luma block, the transform index for the luma block is not encoded. ### Claim 18 (depends on 14) The non-transitory computer-readable digital storage medium of claim 14, wherein when the component block is a chroma block and the BDPCM is applied to the chroma block, the transform index for the chroma block is not encoded. ### Claim 19 (depends on 14) The non-transitory computer-readable digital storage medium of claim 14, wherein the residual samples are quantized based on direction information on the direction in which the BDPCM is performed; the method further comprising: performing an intra prediction on the component block based on the direction in which the BDPCM is performed; and the direction information indicates a horizontal direction or a vertical direction.