Granted Patent B2

US 12,262,004 · App. 17/582,950 · Granted Mar 25, 2025

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

Assignee: Panasonic Intellectual Property Corporation of America

H04N19/117H04N19/132H04N19/159H04N19/176H04N19/186H04N19/82

Abstract

Claims (88)

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) process to a first reconstructed image sample of a luma component;

determines whether the first coefficient value is less than 64;

sets the first coefficient value to zero in response to determining the first coefficient value is less than 64;

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 first coefficient value to the second coefficient value;

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

writes a first parameter into a sequence parameter set;

writes a second parameter into a picture header in response to a value of the first parameter being 1;

writes a third parameter into a slice header in response to the value of the first parameter being 1; and

writes a fourth parameter into a coding tree unit in response to a value of the third parameter being 1, the fourth parameter indicating a filter to be used in the CCALF process.

2. An encoder, comprising:

a block splitter, which, in operation, splits a first image into a plurality of blocks;

an intra predictor, which, in operation, predicts blocks included in the first image, using reference blocks included in the first image;

an inter predictor, which, in operation, predicts blocks included in the first image, using reference blocks included in a second image different from the first image;

a loop filter, which, in operation, filters blocks included in the first image;

a transformer, which, in operation, transforms a prediction error between an original signal and a prediction signal generated by the intra predictor or the inter predictor, to generate transform coefficients;

a quantizer, which, in operation, quantizes the transform coefficients to generate quantized coefficients; and

an entropy encoder, which, in operation, variably encodes the quantized coefficients to generate an encoded bitstream including the encoded quantized coefficients and control information,

wherein the loop filter performs:

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

determining whether the first coefficient value is less than 64;

setting the first coefficient value to zero in response to determining the first coefficient value is less than 64;

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 first coefficient value to the second coefficient value;

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

writing a first parameter into a sequence parameter set;

writing a second parameter into a picture header in response to a value of the first parameter being 1;

writing a third parameter into a slice header in response to the value of the first parameter being 1; and

writing a fourth parameter into a coding tree unit in response to a value of the third parameter being 1, the fourth parameter indicating a filter to be used in the CCALF process.

3. A decoder, comprising:

circuitry; and

memory coupled to the circuitry;

wherein the circuitry, in operation:

parses a first parameter from a sequence parameter set;

parses a second parameter from a picture header in response to a value of the first parameter being 1;

parses a third parameter from a slice header in response to the value of the first parameter being 1;

parses a fourth parameter from a coding tree unit in response to a value of the third parameter being 1, the fourth parameter indicating a filter to be used in a CCALF (cross component adaptive loop filtering) process;

generates a first coefficient value by applying the CCALF process to a first reconstructed image sample of a luma component;

determines whether the first coefficient value is less than 64;

sets the first coefficient value to zero in response to determining the first coefficient value is less than 64;

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 first coefficient value to the second coefficient value; and

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

4. A decoding apparatus, comprising:

a decoder, which, in operation, decodes an encoded bitstream to output quantized coefficients;

an inverse quantizer, which, in operation, inverse quantizes the quantized coefficients to output transform coefficients;

an inverse transformer, which, in operation, inverse transforms the transform coefficients to output a prediction error;

an intra predictor, which, in operation, predicts blocks included in a first image, using a reference blocks included in the first image;

an inter predictor, which, in operation, predicts blocks included in the first image, using reference blocks included in a second image different from the first image;

a loop filter, which, in operation, filters blocks included in the first image; and

an output, which, in operation, outputs a picture including the first image,

wherein the loop filter performs:

parsing a first parameter from a sequence parameter set;

parsing a second parameter from a picture header in response to a value of the first parameter being 1;

parsing a third parameter from a slice header in response to the value of the first parameter being 1;

parsing a fourth parameter from a coding tree unit in response to a value of the third parameter being 1, the fourth parameter indicating a filter to be used in a CCALF (cross component adaptive loop filtering) process;

generating a first coefficient value by applying the CCALF process to a first reconstructed image sample of a luma component;

determining whether the first coefficient value is less than 64;

setting the first coefficient value to zero in response to determining the first coefficient value is less than 64;

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 first coefficient value to the second coefficient value; and

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

5. An encoding method, comprising:

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

determining whether the first coefficient value is less than 64;

setting the first coefficient value to zero in response to determining the first coefficient value is less than 64;

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 first coefficient value to the second coefficient value;

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

writing a first parameter into a sequence parameter set;

writing a second parameter into a picture header in response to a value of the first parameter being 1;

writing a third parameter into a slice header in response to the value of the first parameter being 1; and

writing a fourth parameter into a coding tree unit in response to a value of the third parameter being 1, the fourth parameter indicating a filter to be used in the CCALF process.

6. A decoding method, comprising:

parsing a first parameter from a sequence parameter set;

parsing a second parameter from a picture header in response to a value of the first parameter being 1;

parsing a third parameter from a slice header in response to the value of the first parameter being 1;

parsing a fourth parameter from a coding tree unit in response to a value of the third parameter being 1, the fourth parameter indicating a filter to be used in a CCALF (cross component adaptive loop filtering) process;

generating a first coefficient value by applying the CCALF process to a first reconstructed image sample of a luma component;

determining whether the first coefficient value is less than 64;

setting the first coefficient value to zero in response to determining the first coefficient value is less than 64;

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 first coefficient value to the second coefficient value; and

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

Assignments (1)

Continuity (3)

References Cited (37)