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US 2022/0191478 A1Published application
Image decoding method and device and image encoding method and device in image coding system
AssigneeLG Electronics Inc.
InventorsJangwon CHOI, Jin HEO, Seunghwan KIM, Jaehyun LIM, Ling LI
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Abstract
According to embodiments of the present document, an intra-prediction mode candidate list of a current block can be constructed by means of a process of constructing a common intra-prediction mode list with respect to intra-prediction types. Therefore, the dependency of the intra-prediction types in the process of constructing the intra-prediction mode list is reduced, and thus the coding efficiency of an intra-prediction can be enhanced.
Claims15
An image decoding method performed by a decoding apparatus, comprising:
- receiving image information including prediction related information for a current block;
- and
- generating a reconstructed sample of the current block based on the image information,
- wherein the generating of the reconstructed sample comprises:
- deriving an intra prediction type for the current block as Multi Reference Line intra prediction (MRL) based on the prediction related information wherein the MRL is an intra prediction type based on an intra prediction reference line not adjacent to the current block;
- constructing an intra prediction mode candidate list including a DC intra prediction mode based on intra prediction modes of neighboring blocks of the current block;
- deriving an intra prediction mode of the current block based on the intra prediction mode candidate list;
- and
- deriving a prediction sample of the current block based the intra prediction mode,
- wherein, based on the intra prediction mode of the current block being derived as the DC intra prediction mode and a width of the current block being equal to a height of the current block, a DC value is derived based on a reference sample of (0, −refIdx−1) coordinates to a reference sample of (W−1, −refIdx−1) coordinates in the intra prediction reference line indicated by a reference line index of the current block and a reference sample of (−refIdx−1, 0) coordinates to a reference sample of (−refIdx−1, H−1) coordinates in the intra prediction reference line, and the prediction sample is derived as the DC value,
- wherein the refIdx is a value of the reference line index, and the prediction related information includes the reference line index.
8 more elements
(canceled)
An image encoding method performed by an encoding apparatus, comprising:
- generating a reconstructed sample of a current block;
- generating prediction related information for the current block;
- and
- encoding image information including the prediction related information,
- wherein the generating of the reconstructed sample of the current block comprises:
- determining an intra prediction type for the current block as Multi Reference Line intra prediction (MRL), wherein the MRL is an intra prediction type based on an intra prediction reference line not adjacent to the current block;
- constructing an intra prediction mode candidate list including a DC intra prediction mode based on intra prediction modes of neighboring blocks of the current block;
- deriving an intra prediction mode of the current block based on the intra prediction mode candidate list;
- and
- deriving a prediction sample of the current block based the intra prediction mode,
- wherein, based on the intra prediction mode of the current block being derived as the DC intra prediction mode and a width of the current block being equal to a height of the current block, a DC value is derived based on a reference sample of (0, −refIdx−1) coordinates to a reference sample of (W−1, −refIdx−1) coordinates in the intra prediction reference line indicated by a reference line index of the current block and a reference sample of (−refIdx−1, 0) coordinates to a reference sample of (−refIdx−1, H−1) coordinates in the intra prediction reference line, and the prediction sample is derived as the DC value,
- wherein the refIdx is a value of the reference line index, and the prediction related information includes the reference line index.
9 more elements
A non-transitory computer-readable storage medium storing a bitstream generated by a method, the method comprising:
- generating a reconstructed sample of a current block;
- generating prediction related information for the current block;
- encoding image information including the prediction related information;
- and
- generating the bitstream including the image information,
- wherein the generating of the reconstructed sample of the current block comprises:
- determining an intra prediction type for the current block as Multi Reference Line intra prediction (MRL), wherein the MRL is an intra prediction type based on an intra prediction reference line not adjacent to the current block;
- constructing an intra prediction mode candidate list including a DC intra prediction mode based on intra prediction modes of neighboring blocks of the current block;
- deriving an intra prediction mode of the current block based on the intra prediction mode candidate list;
- and
- deriving a prediction sample of the current block based the intra prediction mode,
- wherein, based on the intra prediction mode of the current block being derived as the DC intra prediction mode and a width of the current block being equal to a height of the current block, a DC value is derived based on a reference sample of (0, −refIdx−1) coordinates to a reference sample of (W−1, −refIdx−1) coordinates in the intra prediction reference line indicated by a reference line index of the current block and a reference sample of (−refIdx−1, 0) coordinates to a reference sample of (−refIdx−1, H−1) coordinates in the intra prediction reference line, and the prediction sample is derived as the DC value,
- wherein the refIdx is a value of the reference line index, and the prediction related information includes the reference line index.
10 more elements
Dependencies are inferred from the claim text.