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US 11,539,967 B2Granted
Luma mapping and chroma scaling-based video or image coding
AssigneeLG Electronics Inc.
InventorsJie Zhao, Seunghwan Kim
Life of this patent
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Abstract
According to the disclosure of the present document, a chroma residual scaling factor is derived on the basis of information relating to an absolute value of a chroma residual scaling delta value and information relating to a sign of the chroma residual scaling delta value, and an LMCS procedure can be efficiently performed by applying explicit signaling to information relating to a value(s) of the chroma residual scaling factor.
Claims15
An image decoding method performed by a decoding apparatus, the method comprising:
- obtaining, by the decoding apparatus, image information including prediction related information and residual information from a bitstream;
- deriving, by the decoding apparatus, a prediction mode for a current block in a current picture based on the prediction related information;
- generating, by the decoding apparatus, prediction luma samples and prediction chroma samples based on the prediction mode;
- generating, by the decoding apparatus, mapped prediction luma samples based on mapping process for the prediction luma samples;
- generating, by the decoding apparatus, residual luma samples and residual chroma samples based on the residual information;
- generating, by the decoding apparatus, reconstructed luma samples based on the mapped prediction luma samples and the residual luma samples;
- deriving, by the decoding apparatus, a chroma residual scaling factor based on the reconstructed luma samples;
- and
- generating, by the decoding apparatus, reconstructed chroma samples based on the prediction chroma samples, the residual chroma samples, and the chroma residual scaling factor,
- wherein the image information includes information on an absolute value of a chroma residual scaling delta value and information on a sign of the chroma residual scaling delta value,
- wherein an inverse scaling index is derived based on the reconstructed luma samples,
- wherein the chroma residual scaling factor is derived based on the inverse scaling index, the information on the absolute value of the chroma residual scaling delta value and the information on the sign of the chroma residual scaling delta value,
- wherein scaled residual chroma samples are generated based on the residual chroma samples and the chroma residual scaling factor, and
- wherein the reconstructed chroma samples are generated based on the prediction chroma samples and the scaled residual chroma samples.
11 more elements
An image encoding method performed by an encoding apparatus, the method comprising:
- deriving, by the encoding apparatus, a prediction mode for a current block for a current picture;
- generating, by the encoding apparatus, prediction luma samples and prediction chroma samples based on the prediction mode;
- generating, by the encoding apparatus, prediction related information based on the prediction mode;
- generating, by the encoding apparatus, mapped prediction luma samples based on mapping process for the prediction luma samples;
- generating, by the encoding apparatus, residual luma samples based on the mapped prediction luma samples;
- generating, by the encoding apparatus, reconstructed luma samples based on the mapped prediction luma samples and the residual luma samples;
- deriving, by the encoding apparatus, a chroma residual scaling factor based on the residual luma samples;
- generating, by the encoding apparatus, residual chroma samples based on the prediction chroma samples;
- generating, by the encoding apparatus, scaled residual chroma samples based on the residual chroma samples and the chroma residual scaling factor;
- generating, by the encoding apparatus, residual information based on the residual luma samples and the scaled residual chroma samples;
- encoding, by the encoding apparatus, image information including the prediction related information and the residual information,
- wherein the image information includes information on am absolute value of a chroma residual scaling delta value and information on a sign of a chroma residual scaling delta value,
- wherein an inverse scaling index is derived based on the reconstructed luma samples, and
- wherein the inverse scaling index, the information on the absolute value of the chroma residual scaling delta value and the information on the sign of the chroma residual scaling delta value are for deriving the chroma residual scaling factor.
11 more elements
A transmission method of data for an image, the method comprising:
- obtaining a bitstream for the image, wherein the bitstream is generated based on deriving a prediction mode for a current block for a current picture, generating prediction luma samples and prediction chroma samples based on the prediction mode, generating prediction related information based on the prediction mode, generating mapped prediction luma samples based on mapping process for the prediction luma samples, generating residual luma samples based on the mapped prediction luma samples, generating reconstructed luma samples based on the mapped prediction luma samples and the residual luma samples, deriving a chroma residual scaling factor based on the residual luma samples, generating residual chroma samples based on the prediction chroma samples, generating scaled residual chroma samples based on the residual chroma samples and the chroma residual scaling factor, generating residual information based on the residual luma samples and the scaled residual chroma samples, and encoding image information including the prediction related information and the residual information, and
- transmitting the data comprising the bitstream,
- wherein the image information includes information on an absolute value of a chroma residual scaling delta value and information on a sign of a chroma residual scaling delta value,
- wherein an inverse scaling index is derived based on the reconstructed luma samples, and
- wherein the inverse scaling index, the information on the absolute value of the chroma residual scaling delta value and the information on the sign of the chroma residual scaling delta value are for deriving the chroma residual scaling factor.
2 more elements
Dependencies are inferred from the claim text.