# US 2021/0344923 A1 · Encoder, decoder, encoding method, and decoding method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344923 A1 - Document ID: US20210344923A1 - Status: Published application - Kind: A1 - Application number: 17/377,107 - Filed: 2021-07-15 - Published: 2021-11-04 - Earliest claimed: 2019-03-01 - Assignees: Panasonic Intellectual Property Corporation of America - Applicants: Panasonic Intellectual Property Corporation of America - Inventors: Tadamasa TOMA; Takahiro NISHI; Kiyofumi ABE; Yusuke KATO - Web page: https://patentgrep.com/patent/US20210344923A1 ## CPC - H04N 19/124: Quantisation - H04N 19/126: Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers - H04N 19/136: Incoming video signal characteristics or properties - 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 19/176: the region being a block, e.g. a macroblock - H04N 19/61: in combination with predictive coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry: performs quantization on a plurality of transform coefficients of a current block to be encoded, using a quantization matrix when orthogonal transform is performed on the current block and secondary transform is not performed on the current block; and performs quantization on the plurality of transform coefficients of the current block without using the quantization matrix when orthogonal transform is not performed on the current block and when both orthogonal transform and secondary transform are performed on the current block. ## Claims ### Claim 1 An encoder, comprising: circuitry; and memory coupled to the circuitry, wherein the circuitry, in operation: determines a transform process to be performed on prediction residuals of a current block, the transform process selectively including an orthogonal transform and selectively including a secondary transform, the orthogonal transform producing transform coefficients of the current block, the secondary transform producing secondary transform coefficients of the current block; and performs either a first quantization process or a second quantization process on the current block based on the determined transform process, wherein the first quantization process is performed on the current block in both of a first case where both the orthogonal transform and the secondary transform are skipped for the current block and a second case where both the orthogonal transform and the secondary transform are performed on the current block, the first quantization process not using a quantization matrix, and the second quantization process is performed on the current block in a case where the orthogonal transform is performed and the secondary transform is not performed on the current block, the second quantization process using a first quantization matrix, the first quantization matrix generated by performing an up-conversion and a down-conversion on a second quantization matrix. ### Claim 2 (depends on 1) The encoder according to claim 1, wherein the circuitry determines whether to perform the first quantization process or the second quantization process on the current block based on information indicating whether the orthogonal transform and the secondary transform have been performed on the current block. ### Claim 3 (depends on 1) The encoder according to claim 1, wherein the first quantization matrix has a first number of rows and a first number of columns different from the first number of rows to form a rectangular matrix, the second quantization matrix has a second number of rows and a second number of columns equal to the second number of rows to form a square matrix, in the up-conversion, the circuitry generates the first quantization matrix such that one of the first number of rows or the first number of columns is larger than the second number of rows, and in the down-conversion, the circuitry generates the first quantization matrix such that the other of the first number of rows or the first number of columns is smaller than the second number of rows. ### Claim 4 (depends on 1) The encoder according to claim 1, wherein the first quantization process quantizes respective prediction residuals and respective secondary transform coefficients using a common quantization parameter. ### Claim 5 (depends on 4) The encoder according to claim 4, wherein the common quantization parameter is a quantization width. ### Claim 6 A decoder, comprising: circuitry; and memory coupled to the circuitry, wherein the circuitry, in operation: determines an inverse transform process to be performed on prediction residuals of a current block, the inverse transform process selectively including an inverse orthogonal transform and selectively including an inverse secondary transform, the inverse orthogonal transform producing transform coefficients of the current block, the inverse secondary transform producing inverse secondary transform coefficients of the current block; and performs either a first inverse quantization process or a second inverse quantization process on the current block based on the determined inverse transform process, wherein the first inverse quantization process is performed on the current block in both of a first case where both the inverse orthogonal transform and the inverse secondary transform are skipped for the current block and a second case where both the inverse orthogonal transform and the inverse secondary transform are performed on the current block, the first inverse quantization process not using an inverse quantization matrix, and the second inverse quantization process is performed on the current block in a case where the inverse orthogonal transform is performed and the inverse secondary transform is not performed on the current block, the second inverse quantization process using a first inverse quantization matrix, the first inverse quantization matrix generated by performing an up-conversion and a down-conversion on a second inverse quantization matrix. ### Claim 7 (depends on 6) The decoder according to claim 6, wherein the circuitry determines whether to perform the first inverse quantization process or the second inverse quantization process on the current block based on information indicating whether the inverse orthogonal transform and the inverse secondary transform have been performed on the current block. ### Claim 8 (depends on 6) The decoder according to claim 6, wherein the first inverse quantization matrix has a first number of rows and a first number of columns different from the first number of rows to form a rectangular matrix, the second inverse quantization matrix has a second number of rows and a second number of columns equal to the second number of rows to form a square matrix, in the up-conversion, the circuitry generates the first inverse quantization matrix such that one of the first number of rows or the first number of columns is larger than the second number of rows, and in the down-conversion, the circuitry generates the first inverse quantization matrix such that the other of the first number of rows or the first number of columns is smaller than the second number of rows. ### Claim 9 (depends on 6) The decoder according to claim 6, wherein the first inverse quantization process inverse-quantizes respective prediction residuals and respective secondary transform coefficients using a common quantization parameter. ### Claim 10 (depends on 9) The decoder according to claim 9, wherein the common quantization parameter is a quantization width. ### Claim 11 An encoding method, comprising: determining a transform process to be performed on prediction residuals of a current block, the transform process selectively including an orthogonal transform and selectively including a secondary transform, the orthogonal transform producing transform coefficients of the current block, the secondary transform producing secondary transform coefficients of the current block; and performing either a first quantization process or a second quantization process on the current block based on the determined transform process, wherein the first quantization process is performed on the current block in both of a first case where both the orthogonal transform and the secondary transform are skipped for the current block and a second case where both the orthogonal transform and the secondary transform are performed on the current block, the first quantization process not using a quantization matrix, and the second quantization process is performed on the current block in a case where the orthogonal transform is performed and the secondary transform is not performed on the current block, the second quantization process using a first quantization matrix, the first quantization matrix generated by performing an up-conversion and a down-conversion on a second quantization matrix. ### Claim 12 A decoding method, comprising: determining an inverse transform process to be performed on prediction residuals of a current block, the inverse transform process selectively including an inverse orthogonal transform and selectively including an inverse secondary transform, the inverse orthogonal transform producing transform coefficients of the current block, the inverse secondary transform producing inverse secondary transform coefficients of the current block; and performing either a first inverse quantization process or a second inverse quantization process on the current block based on the determined inverse transform process, wherein the first inverse quantization process is performed on the current block in both of a first case where both the inverse orthogonal transform and the inverse secondary transform are skipped for the current block and a second case where both the inverse orthogonal transform and the inverse secondary transform are performed on the current block, the first inverse quantization process not using a quantization matrix, and the second inverse quantization process is performed on the current block in a case where the inverse orthogonal transform is performed and the inverse secondary transform is not performed on the current block, the second inverse quantization process using a first quantization matrix, the first quantization matrix generated by performing an up-conversion and a down-conversion on a second quantization matrix.