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US 2026/0075243 A1Published application
Image decoding method and device thereof
AssigneeLG Electronics Inc.
InventorsSunmi YOO, Junghak NAM, Jungah CHOI
Life of this patent
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Abstract
An image decoding method performed by a decoding device according to the present document comprises the steps of: acquiring a block-based delta pulse code modulation (BDPCM) flag for a current block; on the basis of the BDPCM flag indicating that BDPCM is applied to the current block, acquiring a BDPCM direction flag for the current block; and storing, as an intra-prediction mode of the current block, an intra-prediction mode of a prediction direction derived on the basis of the BDPCM direction flag.
Claims11
An image decoding method performed by an image decoding apparatus, the method comprising:
- obtaining a Block-based Delta Pulse Code Modulation (BDPCM) flag for a current block;
- obtaining a BDPCM direction flag for the current block based on the BDPCM flag representing that BDPCM is applied to the current block;
- deriving a prediction sample of a target sample of the current block based on a prediction direction derived based on the BDPCM direction flag;
- deriving a residual sample of the target sample of the current block;
- and
- reconstructing the current block based on the prediction sample and the residual sample,
- wherein an intra prediction mode of the prediction direction is derived based on the BDPCM direction flag as an intra prediction mode of the current block,
- wherein the BDPCM direction flag represents a horizontal direction or a vertical direction as the prediction direction,
- wherein based on the BDPCM being applied to the current block and the prediction direction for the current block being the vertical direction, residual information includes syntax elements for the target sample of the current block, and
- wherein the syntax elements for the target sample represent a difference between a residual coefficient value of the target sample and a top residual coefficient value of the target sample.
7 more elements
An image encoding method performed by an image encoding apparatus, the method comprising:
- deriving a prediction direction for a current block based on Block-based Delta Pulse Code Modulation (BDPCM);
- deriving a prediction sample of a target sample of the current block based on the derived prediction direction;
- deriving a residual sample of the target sample of the current block based on the prediction sample;
- encoding residual information of the current block based on the residual sample;
- and
- encoding a BDPCM flag representing that the BDPCM is applied to the current block and a BDPCM direction flag representing the prediction direction for the current block,
- wherein an intra prediction mode of the prediction direction as an intra prediction mode of the current block is derived based on the BDPCM,
- wherein the BDPCM direction flag represents a horizontal direction or a vertical direction as the prediction direction,
- wherein based on the prediction direction for the current block being the vertical direction, the residual information includes syntax elements for the target sample of the current block, and
- wherein the syntax elements for the target sample represent a difference between a residual coefficient value of the target sample and a top residual coefficient value of the target sample.
7 more elements
A transmitting method of a bitstream for an image, the method comprising:
- deriving a prediction direction for a current block based on Block-based Delta Pulse Code Modulation (BDPCM);
- deriving a prediction sample of a target sample of the current block based on the derived prediction direction;
- deriving a residual sample of the target sample of the current block based on the prediction sample;
- encoding, into the bitstream, residual information of the current block based on the residual sample;
- encoding, into the bitstream, a BDPCM flag representing that the BDPCM is applied to the current block and a BDPCM direction flag representing the prediction direction for the current block;
- and
- transmitting the bitstream,
- wherein an intra prediction mode of the prediction direction as an intra prediction mode of the current block is derived based on the BDPCM,
- wherein the BDPCM direction flag represents a horizontal direction or a vertical direction as the prediction direction,
- wherein based on the prediction direction for the current block being the vertical direction, the residual information includes syntax elements for the target sample of the current block, and
- wherein the syntax elements for the target sample represent a difference between a residual coefficient value of the target sample and a top residual coefficient value of the target sample.
8 more elements
Dependencies are inferred from the claim text.