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US 2026/0313119 A1Published application
Residual coding method and device for same
AssigneeLG Electronics Inc.
InventorsJungah CHOI, Sunmi YOO, Jin HEO, Seunghwan KIM, Jangwon CHOI
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Abstract
A method for decoding a picture performed by a decoding apparatus according to the present disclosure includes receiving a bitstream including residual information, deriving a quantized transform coefficient for a current block based on the residual information included in the bitstream, deriving a transform coefficient from the quantized transform coefficient based on a dequantization process, deriving a residual sample for the current block by applying an inverse transform to the derived transform coefficient, and generating a reconstructed picture based on the residual sample for the current block.
Claims3
An image decoding method performed by a decoding apparatus, the method comprising:
- receiving a bitstream comprising prediction mode information and residual information;
- obtaining the prediction mode information and the residual information from the bitstream;
- deriving prediction samples for a current block based on the prediction mode information;
- deriving quantized transform coefficients for the current block based on the residual information;
- deriving transform coefficients based on the quantized transform coefficients;
- deriving residual samples for the current block based on the transform coefficients;
- and
- generating reconstructed samples based on the prediction samples and the residual samples for the current block,
- wherein the residual information includes a significant coefficient flag representing whether a quantized transform coefficient is a non-zero significant coefficient, a parity level flag for a parity of a transform coefficient level for the quantized transform coefficient, a first transform coefficient level flag about whether the transform coefficient level is larger than a first reference value, a second transform coefficient level flag about whether the transform coefficient level is larger than a second reference value and remainder information of the transform coefficient level,
- wherein the first reference value and the second reference value are predetermined specific values, and a predetermined specific value for the first reference value is 1 and a predetermined specific value for the second reference value is 3,
- wherein deriving the quantized transform coefficients comprising:
- deriving the quantized transform coefficient by decoding in an order of the significant coefficient flag, the first transform coefficient level flag, the parity level flag, the second transform coefficient level flag and the remainder information,
- performing a binarization process for the remainder information of the transform coefficient level based on a rice parameter;
- deriving a value of the remainder information of the transform coefficient level based on a result of the binarization process;
- and
- deriving the quantized transform coefficient based on the value of the remainder information of the transform coefficient level,
- wherein the decoding of the first transform coefficient level flag is performed prior to the decoding of the parity level flag,
- wherein the decoding of the parity level flag is performed based on a value of the first transform coefficient level flag being 1, and
- wherein the quantized transform coefficient is derived based on a calculation of (a value of the significant coefficient flag+a value of the first transform coefficient level flag+a value of the parity level flag+(2*a value of the second transform coefficient level flag)+(2*a value of the remainder information)) based on a result of the decoding.
16 more elements
An image encoding method performed by an encoding apparatus, the method comprising:
- deriving a prediction mode of a current block;
- deriving prediction samples of the current block based on the prediction mode;
- generating prediction mode information based on the derived prediction mode;
- deriving residual samples for the current block based on the prediction samples;
- deriving transform coefficients for the current block based on the residual samples;
- deriving quantized transform coefficients based on the transform coefficients;
- generating residual information for the quantized transform coefficients;
- and
- encoding image information including the prediction mode information and the residual information,
- wherein the residual information includes a significant coefficient flag representing whether a quantized transform coefficient is a non-zero significant coefficient, a parity level flag for a parity of a transform coefficient level for the quantized transform coefficient, a first transform coefficient level flag about whether the transform coefficient level is larger than a first reference value, a second transform coefficient level flag about whether the transform coefficient level is larger than a second reference value and remainder information of the transform coefficient level,
- wherein the first reference value and the second reference value are predetermined specific values, and a predetermined specific value for the first reference value is 1 and a predetermined specific value for the second reference value is 3,
- wherein the encoding of the residual information comprises:
- encoding in an order of the significant coefficient flag, the first transform coefficient level flag, the parity level flag, the second transform coefficient level flag and the remainder information,
- encoding the significant coefficient flag, the first transform coefficient level flag, the parity level flag and the second transform coefficient level flag;
- deriving a binarization value of transform coefficient level information by performing a binarization process for the transform coefficient level information based on a rice parameter;
- and
- encoding the binarization value of the transform coefficient level information,
- wherein the encoding of the first transform coefficient level flag is performed prior to the encoding of the parity level flag,
- wherein the encoding of the parity level flag is performed based on a value of the first transform coefficient level flag being 1, and
- wherein a result of the encoding for the quantized transform coefficient is derived based on a calculation of (a value of the significant coefficient flag+a value of the first transform coefficient level flag+a value of the parity level flag+(2*a value of the second transform coefficient level flag)+(2*a value of the remainder information)).
17 more elements
A method of transmitting a bitstream comprising:
- obtaining the bitstream, wherein the bitstream is generated by deriving a prediction mode of a current block, deriving prediction samples of the current block based on the prediction mode, generating prediction mode information based on the derived prediction mode, deriving residual samples for the current block based on the prediction samples, deriving transform coefficients for the current block based on the residual samples, deriving quantized transform coefficients based on the transform coefficients, generating residual information for the quantized transform coefficients, and encoding image information including the prediction mode information and the residual information;
- and
- transmitting the bitstream,
- wherein the residual information includes a significant coefficient flag representing whether a quantized transform coefficient is a non-zero significant coefficient, a parity level flag for a parity of a transform coefficient level for the quantized transform coefficient, a first transform coefficient level flag about whether the transform coefficient level is larger than a first reference value, a second transform coefficient level flag about whether the transform coefficient level is larger than a second reference value and remainder information of the transform coefficient level,
- wherein the first reference value and the second reference value are predetermined specific values, and a predetermined specific value for the first reference value is 1 and a predetermined specific value for the second reference value is 3,
- wherein the encoding of the residual information comprises:
- encoding in an order of the significant coefficient flag, the first transform coefficient level flag, the parity level flag, the second transform coefficient level flag and the remainder information,
- encoding the significant coefficient flag, the first transform coefficient level flag, the parity level flag and the second transform coefficient level flag;
- deriving a binarization value of transform coefficient level information by performing a binarization process for the transform coefficient level information based on a rice parameter;
- and
- encoding the binarization value of the transform coefficient level information,
- wherein the encoding of the first transform coefficient level flag is performed prior to the encoding of the parity level flag,
- wherein the encoding of the parity level flag is performed based on a value of the first transform coefficient level flag being 1, and
- wherein a result of the encoding for the quantized transform coefficient is derived based on a calculation of (a value of the significant coefficient flag+a value of the first transform coefficient level flag+a value of the parity level flag+(2*a value of the second transform coefficient level flag)+(2*a value of the remainder information)).
11 more elements
Dependencies are inferred from the claim text.