Granted Patent B2

US 12,457,332 · App. 18/671,457 · Granted Oct 28, 2025

Inventors: Jing Ya Li (Singapore, SG); Chong Soon Lim (Singapore, SG); Hai Wei Sun (Singapore, SG); Han Boon Teo (Singapore, SG); Che Wei Kuo (Singapore, SG); Chu Tong Wang (Singapore, SG); Kiyofumi Abe (Osaka, JP); Takahiro Nishi (Nara, JP); Tadamasa Toma (Osaka, JP); Yusuke Kato (Osaka, JP)

Assignee: Panasonic Intellectual Property Corporation of America

H04N19/117H04N19/105H04N19/119H04N19/124H04N19/13H04N19/18H04N19/186H04N19/82

Abstract

Claims (54)

1. An encoder, comprising:

circuitry; and

memory coupled to the circuitry;

wherein the circuitry, in operation:

generates a first coefficient value by applying a CCALF (cross component adaptive loop filtering) filter to first reconstructed image samples of a luma component;

clips the first coefficient value to be within a range of −2 7 to 2 7 −1;

generates a second coefficient value by applying an ALF (adaptive loop filtering) process to a second reconstructed image sample of a chroma component;

generates a third coefficient value by adding the clipped first coefficient value to the second coefficient value, and

encodes a third reconstructed image sample of the chroma component using the third coefficient value:

wherein in applying the CCALF filter,

in response to a coordinate of the second reconstructed image sample being (x, y), coordinates of the first reconstructed image samples are (2x, 2y−1), (2x−1, 2y), (2x, 2y), (2x+1, 2y), (2x−1, 2y+1), (2x, 2y+1), (2x+1, 2y+1), and (2x, 2y+2).

2. A decoder, comprising:

circuitry; and

memory coupled to the circuitry;

wherein the circuitry, in operation:

generates a first coefficient value by applying a CCALF (cross component adaptive loop filtering) filter to first reconstructed image samples of a luma component;

clips the first coefficient value to be within a range of −2 7 to 2 7 −1;

generates a second coefficient value by applying an ALF (adaptive loop filtering) process to a second reconstructed image sample of a chroma component;

generates a third coefficient value by adding the clipped first coefficient value to the second coefficient value, and

decodes a third reconstructed image sample of the chroma component using the third coefficient value:

wherein in applying the CCALF filter,

in response to a coordinate of the second reconstructed image sample being (x, y), coordinates of the first reconstructed image samples are (2x, 2y−1), (2x−1, 2y), (2x, 2y), (2x+1, 2y), (2x−1, 2y+1), (2x, 2y+1), (2x+1, 2y+1), and (2x, 2y+2).

3. An encoding method, comprising:

generating a first coefficient value by applying a CCALF (cross component adaptive loop filtering) filter to first reconstructed image samples of a luma component;

clipping the first coefficient value to be within a range of −2 7 to 2 7 −1;

generating a second coefficient value by applying an ALF (adaptive loop filtering) process to a second reconstructed image sample of a chroma component;

generating a third coefficient value by adding the clipped first coefficient value to the second coefficient value, and

encoding a third reconstructed image sample of the chroma component using the third coefficient value:

wherein in applying the CCALF filter,

in response to a coordinate of the second reconstructed image sample being (x, y), coordinates of the first reconstructed image samples are (2x, 2y−1), (2x−1, 2y), (2x, 2y), (2x+1, 2y), (2x−1, 2y+1), (2x, 2y+1), (2x+1, 2y+1), and (2x, 2y+2).

4. A decoding method, comprising:

generating a first coefficient value by applying a CCALF (cross component adaptive loop filtering) filter to first reconstructed image samples of a luma component;

clipping the first coefficient value to be within a range of −2 7 to 2 7 −1;

generating a second coefficient value by applying an ALF (adaptive loop filtering) process to a second reconstructed image sample of a chroma component;

generating a third coefficient value by adding the clipped first coefficient value to the second coefficient value, and

decoding a third reconstructed image sample of the chroma component using the third coefficient value:

wherein in applying the CCALF filter,

in response to a coordinate of the second reconstructed image sample being (x, y), coordinates of the first reconstructed image samples are (2x, 2y−1), (2x−1, 2y), (2x, 2y), (2x+1, 2y), (2x−1, 2y+1), (2x, 2y+1), (2x+1, 2y+1), and (2x, 2y+2).

5. A non-transitory computer readable medium storing a bitstream containing information according to which an encoder performs an encoding process, wherein in the encoding process:

a first coefficient value is generated by applying a CCALF (cross component adaptive loop filtering) filter to first reconstructed image samples of a luma component;

the first coefficient value is clipped to be within a range of −2 7 to 2 7 −1;

a second coefficient value is generated by applying an ALF (adaptive loop filtering) process to a second reconstructed image sample of a chroma component;

a third coefficient value is generated by adding the clipped first coefficient value to the second coefficient value, and

a third reconstructed image sample of the chroma component is encoded using the third coefficient value:

wherein in applying the CCALF filter,

in response to a coordinate of the second reconstructed image sample being (x, y), coordinates of the first reconstructed image samples are (2x, 2y−1), (2x−1, 2y), (2x, 2y), (2x+1, 2y), (2x−1, 2y+1), (2x, 2y+1), (2x+1, 2y+1), and (2x, 2y+2).

6. A non-transitory computer readable medium storing a bitstream containing information according to which a decoder performs a decoding process, wherein in the decoding process:

a first coefficient value is generated by applying a CCALF (cross component adaptive loop filtering) filter to first reconstructed image samples of a luma component;

the first coefficient value is clipped to be within a range of −2 7 to 2 7 −1;

a second coefficient value is generated by applying an ALF (adaptive loop filtering) process to a second reconstructed image sample of a chroma component;

a third coefficient value is generated by adding the clipped first coefficient value to the second coefficient value, and

a third reconstructed image sample of the chroma component is decoded using the third coefficient value:

wherein in applying the CCALF filter,

in response to a coordinate of the second reconstructed image sample being (x, y), coordinates of the first reconstructed image samples are (2x, 2y−1), (2x−1, 2y), (2x, 2y), (2x+1, 2y), (2x−1, 2y+1), (2x, 2y+1), (2x+1, 2y+1), and (2x, 2y+2).

Continuity (5)

References Cited (50)