Granted Patent B2

US 12,445,618 · App. 17/844,462 · Granted Oct 14, 2025

Inventors: Edouard Francois (Bourg des Comptes, FR); Christophe Chevance (Brece, FR); Franck Hiron (Chateaubourg, FR)

Assignee: INTERDIGITAL VC HOLDINGS, INC.

H04N19/132H04N19/136H04N19/176H04N19/186

Abstract

Claims (96)

1. A method of encoding comprising:

obtaining a chroma prediction value of a chroma source value of a sample of a block of a picture;

obtaining a value representative of a luma prediction value of a luma source value of the sample;

determining a mapped chroma residual value from the chroma source value and from the value representative of the luma prediction value using a mapping function; and

encoding the mapped chroma residual value into a bitstream;

wherein determining the mapped chroma residual value comprises:

determining a chroma residual value as a difference between the chroma source value and the chroma prediction value; and

mapping the chroma residual value with the mapping function to obtain a mapped chroma residual value, wherein the mapping comprises multiplying the chroma residual value by a scaling factor depending on the value representative of the luma prediction value.

2. The method of claim 1 , further comprising:

obtaining the luma prediction value;

determining a mapped luma residual value from the luma source value and from the luma prediction value using a mapping function; and

encoding the mapped luma residual value into a bitstream;

wherein determining the mapped luma residual value comprises:

mapping the luma prediction value with the mapping function to obtain a mapped luma prediction value;

mapping the luma source value with the mapping function to obtain a mapped luma source value; and

determining the mapped luma residual value as a subtraction of the mapped luma prediction value and the mapped luma source value.

3. A method of decoding comprising:

obtaining a chroma prediction value of a chroma source value of a sample of a block of a picture;

obtaining a value representative of a luma prediction value of a luma source value of the sample;

decoding a chroma residual value for the sample; and

determining a reconstructed chroma value for the sample from the decoded chroma residual value and from the chroma prediction value using a mapping function;

wherein determining the reconstructed chroma value comprises:

mapping the chroma residual value to obtain a mapped chroma residual value, wherein the mapping comprises multiplying the chroma residual value by a scaling factor depending on the value representative of the luma prediction value; and

obtaining the reconstructed chroma value by adding the mapped chroma residual value to the chroma prediction value.

4. The method of claim 3 , further comprising:

obtaining the luma prediction value;

decoding a luma residual value for the sample; and

determining a reconstructed luma value for the sample from the decoded luma residual value and from the luma prediction value using both a mapping function and an inverse mapping function that is the inverse of the mapping function;

wherein determining the reconstructed luma value comprises:

mapping the luma prediction value with the mapping function to obtain a mapped luma prediction value;

obtaining an intermediate value representative of a sum of the mapped luma prediction value and the luma residual value; and

obtaining the reconstructed luma value by mapping the intermediate value with the inverse mapping function.

5. An encoding device comprising at least one processor configured to perform:

obtaining a chroma prediction value of a chroma source value of a sample of a block of a picture;

obtaining a value representative of a luma prediction value of a luma source value of the sample;

determining a mapped chroma residual value from the chroma source value and from the value representative of the luma prediction value using a mapping function; and

encoding the mapped chroma residual value into a bitstream;

wherein determining the mapped chroma residual value comprises:

determining a chroma residual value as a difference between the chroma source value and the chroma prediction value; and

mapping the chroma residual value with the mapping function to obtain a mapped chroma residual value, wherein the mapping comprises multiplying the chroma residual value by a scaling factor depending on the value representative of the luma prediction value.

6. The encoding device of claim 5 , wherein the at least one processor is further configured to perform:

obtaining the luma prediction value;

determining a mapped luma residual value from the luma source value and from the luma prediction value using a mapping function; and

encoding the mapped luma residual value into a bitstream;

wherein determining the mapped luma residual value comprises:

mapping the luma prediction value with the mapping function to obtain a mapped luma prediction value;

mapping the luma source value with the mapping function to obtain a mapped luma source value; and

determining the mapped luma residual value as a subtraction of the mapped luma prediction value and the mapped luma source value.

7. A decoding device comprising at least one processor configured to perform:

obtaining a chroma prediction value of a chroma source value of a sample of a block of a picture;

obtaining a value representative of a luma prediction value of a luma source value of the sample;

decoding a chroma residual value for the sample; and

determining a reconstructed chroma value for the sample from the decoded chroma residual value and from the chroma prediction value using a mapping function;

wherein determining the reconstructed chroma value comprises:

mapping the chroma residual value to obtain a mapped chroma residual value, wherein the mapping comprises multiplying the chroma residual value by a scaling factor depending on the value representative of the luma prediction value; and

obtaining the reconstructed chroma value by adding the mapped chroma residual value to the chroma prediction value.

8. The decoding device of claim 7 , wherein the at least one processor is further configured to perform:

obtaining the luma prediction value;

decoding a luma residual value for the sample; and

determining a reconstructed luma value for the sample from the decoded luma residual value and from the luma prediction value using both a mapping function and an inverse mapping function that is the inverse of the mapping function;

wherein determining the reconstructed luma value comprises:

mapping the luma prediction value with the mapping function to obtain a mapped luma prediction value;

obtaining an intermediate value representative of a sum of the mapped luma prediction value and the luma residual value; and

obtaining the reconstructed luma value by mapping the intermediate value with the inverse mapping function.

9. A non-transitory computer readable storage medium having stored instructions that, when executed by a processor, cause the processor to perform a method of encoding comprising:

obtaining a chroma prediction value of a chroma source value of a sample of a block of a picture;

obtaining a value representative of a luma prediction value of a luma source value of the sample;

determining a mapped chroma residual value from the chroma source value and from the value representative of the luma prediction value using a mapping function; and

encoding the mapped chroma residual value into a bitstream;

wherein determining the mapped chroma residual value comprises:

determining a chroma residual value as a difference between the chroma source value and the chroma prediction value; and

mapping the chroma residual value with the mapping function to obtain a mapped chroma residual value, wherein the mapping comprises multiplying the chroma residual value by a scaling factor depending on the value representative of the luma prediction value.

10. The non-transitory computer readable storage medium of claim 9 , wherein the method of encoding further comprises:

obtaining the luma prediction value;

determining a mapped luma residual value from the luma source value and from the luma prediction value using a mapping function; and

encoding the mapped luma residual value into a bitstream;

wherein determining the mapped luma residual value comprises:

mapping the luma prediction value with the mapping function to obtain a mapped luma prediction value;

mapping the luma source value with the mapping function to obtain a mapped luma source value; and

determining the mapped luma residual value as a subtraction of the mapped luma prediction value and the mapped luma source value.

11. A non-transitory computer readable storage medium having stored instructions that, when executed by a processor, cause the processor to perform a method of decoding comprising:

obtaining a chroma prediction value of a chroma source value of a sample of a block of a picture;

obtaining a value representative of a luma prediction value of a luma source value of the sample;

decoding a chroma residual value for the sample; and

determining a reconstructed chroma value for the sample from the decoded chroma residual value and from the chroma prediction value using a mapping function;

wherein determining the reconstructed chroma value comprises:

mapping the chroma residual value to obtain a mapped chroma residual value, wherein the mapping comprises multiplying the chroma residual value by a scaling factor depending on the value representative of the luma prediction value; and

obtaining the reconstructed chroma value by adding the mapped chroma residual value to the chroma prediction value.

12. The non-transitory computer readable storage medium of claim 11 , wherein the method of decoding further comprises:

obtaining the luma prediction value;

decoding a luma residual value for the sample; and

determining a reconstructed luma value for the sample from the decoded luma residual value and from the luma prediction value using both a mapping function and an inverse mapping function that is the inverse of the mapping function;

wherein determining the reconstructed luma value comprises:

mapping the luma prediction value with the mapping function to obtain a mapped luma prediction value;

obtaining an intermediate value representative of a sum of the mapped luma prediction value and the luma residual value; and

obtaining the reconstructed luma value by mapping the intermediate value with the inverse mapping function.

Assignments (2)

Priority Claims (1)

Continuity (2)

References Cited (55)