# US 12,604,022 B2 · Encoding/decoding apparatus for processing video signals using reduced transform, and transmission apparatus for same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,604,022 B2 - Document ID: US12604022B2 - Status: Granted - Kind: B2 - Application number: 18/819,109 - Filed: 2024-08-29 - Published: 2025-02-20 - Granted: 2026-04-14 - Earliest claimed: 2018-06-03 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Seunghwan Kim; Mehdi Salehifar; Moonmo Koo; Jaehyun Lim - Web page: https://patentgrep.com/patent/US12604022B2 ## 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 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder - 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 19/11: among a plurality of spatial predictive coding modes - H04N 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks - H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) - 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 19/60: using transform coding - H04N 19/625: using discrete cosine transform [DCT] - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - 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 19/18: the unit being a set of transform coefficients - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Provided is a method for decoding a video signal based on a reduced transform, which includes: checking whether a transform skip is applied to a current block; obtaining a transform index indicating a transform kernel of the current block from the video signal when the transform skip is not applied to the current block; determining a region where a primary transform is applied to the current block based on the transform kernel indicated by the transform index and a size of the current block; and performing an inverse primary transform on the region to which the primary transform is applied by using the transform kernel indicated by the transform index. ## Claims ### Claim 1 A decoding apparatus for image decoding, the decoding apparatus comprising: a memory; and at least one processor connected to the memory, the at least one processor being configured to: obtain transform index information indicating transform kernels of a current block from a video signal, determine a size of a non-zero region for an inverse primary transform based on the transform kernels indicated by the transform index information and a size of the current block, wherein the non-zero region has a predetermined width and height and includes a top-left sample position within the current block, and non-zero coefficients are located within the non-zero region, and perform the inverse primary transform on the non-zero region based on the transform kernels indicated by the transform index information, wherein the transform kernels indicated by the transform index information include a pair of a horizontal transform kernel and a vertical transform kernel, wherein based on the size of the current block being 32×32 and the transform kernels applied to the current block belonging to a first transform group, the size of the non-zero region is determined as 32×32, wherein based on the size of the current block being 32×32 and the transform kernels applied to the current block belonging to a second transform group, the size of the non-zero region is determined as 16×16, and wherein the first transform group includes a DCT2 kernel, and the second transform group does not include the DCT2 kernel. ### Claim 2 An encoding apparatus for image encoding, the encoding apparatus comprising: a memory; and at least one processor connected to the memory, the at least one processor being configured to: derive transform kernels being applied to a current block, perform a primary transform on the current block based on the transform kernels, generate transform index information indicating the transform kernels applied to the current block, and encode a video signal including the transform index information, wherein a size of a non-zero region for the primary transform is determined based on the transform kernels and a size of the current block, wherein the non-zero region has a predetermined width and height and includes a top-left sample position within the current block, and non-zero coefficients are located within the non-zero region, wherein the transform kernels indicated by the transform index information include a pair of a horizontal transform kernel and a vertical transform kernel, wherein based on the size of the current block being 32×32 and the transform kernels applied to the current block belonging to a first transform group, the size of the non-zero region is determined as 32×32, wherein based on the size of the current block being 32×32 and the transform kernels applied to the current block belonging to a second transform group, the size of the non-zero region is determined as 16×16, and wherein the first transform group includes a DCT2 kernel, and the second transform group does not include the DCT2 kernel. ### Claim 3 A transmission apparatus of transmitting data including a bitstream for an image, comprising: at least one processor configured to obtain the bitstream for the image, wherein the bitstream is generated based on deriving transform kernels being applied to a current block, performing a primary transform on the current block based on the transform kernels, generating transform index information indicating the transform kernels applied to the current block, and encoding a video signal including the transform index information; and a transmitter configured to transmit the data including the bitstream, wherein a size of a non-zero region for the primary transform is determined based on the transform kernels and a size of the current block, wherein the non-zero region has a predetermined width and height and includes a top-left sample position within the current block, and non-zero coefficients are located within the non-zero region, wherein the transform kernels indicated by the transform index information include a pair of a horizontal transform kernel and a vertical transform kernel, wherein based on the size of the current block being 32×32 and the transform kernels applied to the current block belonging to a first transform group, the size of the non-zero region is determined as 32×32, wherein based on the size of the current block being 32×32 and the transform kernels applied to the current block belonging to a second transform group, the size of the non-zero region is determined as 16×16, and wherein the first transform group includes a DCT2 kernel, and the second transform group does not include the DCT2 kernel.