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.
Claims16
An image decoding method performed by a decoding apparatus, the method comprising:
- obtaining prediction mode information and residual information from a 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 deriving the quantized transform coefficients comprising:
- deriving the quantized transform coefficient by decoding the significant coefficient flag, the parity level flag, the first transform coefficient level flag, the second transform coefficient level flag and the remainder information,
- wherein the decoding of the first transform coefficient level flag is performed prior to the decoding of the parity level flag.
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 encoding of the residual information comprises:
- encoding the significant coefficient flag, the parity level flag, the first transform coefficient level flag, the second transform coefficient level flag and the reminder information,
- wherein the encoding of the first transform coefficient level flag is performed prior to the encoding of the parity level flag.
Dependencies are inferred from the claim text.