Granted Patent B2

US 12,684,165 · App. 18/883,444 · Granted Jul 14, 2026

Inventors: Ling Li (Seoul, KR); Jin Heo (Seoul, KR); Seunghwan Kim (Seoul, KR)

Assignee: NOKIA TECHNOLOGIES OY

H04N19/593H04N19/11H04N19/132H04N19/136H04N19/176H04N19/70H04N19/119H04N21/431

Abstract

Claims (37)

1 . An image decoding method performed by a decoding apparatus, the method comprising:

obtaining image information including Most Probable Mode (MPM) flag information, and residual information from a bitstream;

deriving a first intra prediction mode based on a first neighboring block which is located in a left side of a current block;

deriving a second intra prediction mode based on a second neighboring block which is located in an upper side of the current block;

configuring an MPM list for the current block based on the first intra prediction mode and the second intra prediction mode;

deriving an intra prediction mode of the current block based on the MPM flag information and the MPM list;

deriving prediction samples for the current block based on the intra prediction mode;

deriving residual samples for the current block based on the residual information; and

generating a reconstructed picture for the current block based on the prediction samples and the residual samples,

wherein the MPM list comprises MPM candidates derived based on whether at least one of the first intra prediction mode or the second intra prediction mode is non-directional intra prediction mode,

wherein the MPM candidates which are derived based on a case that the first intra prediction mode and the second intra prediction mode are both the non-directional intra prediction mode, comprise:

a DC intra prediction mode, a vertical directional intra prediction mode, a horizontal directional intra prediction mode, an intra prediction mode of which mode number is equal to a mode number of the vertical directional intra prediction mode minus 4, and an intra prediction mode of which mode number is equal to the mode number of the vertical directional intra prediction mode plus 4, and

wherein the MPM candidates which are derived based on a case that one of the first intra prediction mode and the second intra prediction mode is the non-directional intra prediction mode and the other is directional intra prediction mode, comprise:

one of the first intra prediction mode and the second intra prediction mode, an intra prediction mode of which mode number is equal to a maximum mode number of the first intra prediction mode and the second intra prediction mode minus 1, an intra prediction mode of which mode number is equal to the maximum mode number plus 1, an intra prediction mode of which mode number is equal to the maximum mode number minus 2.

2 . An image encoding method performed by an encoding apparatus, the method comprising:

deriving a first intra prediction mode based on a first neighboring block which is located in a left side of a current block;

deriving a second intra prediction mode based on a second neighboring block which is located in an upper side of the current block;

configuring a Most Probable Mode (MPM) list for the current block based on the first intra prediction mode and the second intra prediction mode;

determining an intra prediction mode of the current block;

deriving prediction samples for the current block based on the intra prediction mode;

deriving residual samples for the current block based on the prediction samples;

generating MPM flag information based on the MPM list and the intra prediction mode;

generating residual information based on the residual samples; and

encoding image information including the MPM flag information and the residual information,

wherein the MPM list comprises MPM candidates derived based on whether at least one of the first intra prediction mode or the second intra prediction mode is non-directional intra prediction mode,

wherein the MPM candidates which are derived based on a case that the first intra prediction mode and the second intra prediction mode are both the non-directional intra prediction mode, comprise:

a DC intra prediction mode, a vertical directional intra prediction mode, a horizontal directional intra prediction mode, an intra prediction mode of which mode number is equal to a mode number of the vertical directional intra prediction mode minus 4, and an intra prediction mode of which mode number is equal to the mode number of the vertical directional intra prediction mode plus 4, and

wherein the MPM candidates which are derived based on a case that one of the first intra prediction mode and the second intra prediction mode is the non-directional intra prediction mode and the other is directional intra prediction mode, comprise:

one of the first intra prediction mode and the second intra prediction mode, an intra prediction mode of which mode number is equal to a maximum mode number of the first intra prediction mode and the second intra prediction mode minus 1, an intra prediction mode of which mode number is equal to the maximum mode number plus 1, an intra prediction mode of which mode number is equal to the maximum mode number minus 2.

3 . A transmission method of data for image, the transmission method comprising:

obtaining a bitstream for the image, wherein the bitstream is generated based on deriving a first intra prediction mode based on a first neighboring block which is located in a left side of a current block, deriving a second intra prediction mode based on a second neighboring block which is located in an upper side of the current block, configuring a Most Probable Mode (MPM) list for the current block based on the first intra prediction mode and the second intra prediction mode, determining an intra prediction mode of the current block, deriving prediction samples for the current block based on the intra prediction mode, deriving residual samples for the current block based on the prediction samples, generating MPM flag information based on the MPM list and the intra prediction mode, generating residual information based on the residual samples, and generating the bitstream by encoding image information including the MPM flag information and the residual information; and

transmitting the data comprising the bitstream,

wherein the MPM list comprises MPM candidates derived based on whether at least one of the first intra prediction mode or the second intra prediction mode is non-directional intra prediction mode,

wherein the MPM candidates which are derived based on a case that the first intra prediction mode and the second intra prediction mode are both the non-directional intra prediction mode, comprise:

a DC intra prediction mode, a vertical directional intra prediction mode, a horizontal directional intra prediction mode, an intra prediction mode of which mode number is equal to a mode number of the vertical directional intra prediction mode minus 4, and an intra prediction mode of which mode number is equal to the mode number of the vertical directional intra prediction mode plus 4, and

wherein the MPM candidates which are derived based on a case that one of the first intra prediction mode and the second intra prediction mode is the non-directional intra prediction mode and the other is directional intra prediction mode, comprise:

one of the first intra prediction mode and the second intra prediction mode, an intra prediction mode of which mode number is equal to a maximum mode number of the first intra prediction mode and the second intra prediction mode minus 1, an intra prediction mode of which mode number is equal to the maximum mode number plus 1, an intra prediction mode of which mode number is equal to the maximum mode number minus 2.

Assignments (2)

Continuity (5)

References Cited (43)