Granted Patent B2

US 12,238,317 · App. 18/215,704 · Granted Feb 25, 2025

Inventors: Liang Zhao (Sunnyvale, CA); Xin Zhao (Santa Clara, CA); Han Gao (San Diego, CA); Shan Liu (San Jose, CA)

Assignee: Tencent America LLC

H04N19/44H04N19/105H04N19/137H04N19/176

Abstract

Claims (81)

1. A method of video decoding in a video coder, the method comprising:

receiving a bitstream including a frame, coding information for a block in the frame indicating that the block is coded with a joint motion vector difference (JMVD) coding mode and a compound weighted prediction mode, the coding information further including scaling factor information of the JMVD coding mode;

in response to the scaling factor information indicating that each of scaling factors of components of at least one MVD associated with at least one respective reference frame of the block is a pre-defined scaling factor, determining a weighting factor of the compound weighted prediction mode based on a list of weighting factors, the list being signaled in the bitstream;

in response to the scaling factor information indicating that at least one of the scaling factors is different from the pre-defined scaling factor, determining the weighting factor of the compound weighted prediction mode based on a subset of the list of weighting factors, only the subset of the list being signaled in the bitstream;

determining, using the JMVD coding mode, motion information associated with respective reference frames of the block based on the scaling factors of the components of the at least one MVD associated with the at least one respective reference frame of the block, the reference frames of the block including the at least one respective reference frame; and

reconstructing, using the compound weighted prediction mode, the block based on the motion information associated with the respective reference frames of the block and the determined weighting factor.

2. The method of claim 1 , wherein

the scaling factor information indicates that the at least one of the scaling factors is different from the pre-defined scaling factor,

the subset of the list of weighting factors includes only one weighting factor, and

the determined weighting factor is the one weighting factor and is not signaled.

3. The method of claim 2 , wherein

the one weighting factor is an equal weighting factor, and

the reconstructing includes

obtaining a prediction block of the block by averaging reference blocks in the respective reference frames with the equal weighting factor for each reference block; and

reconstructing the block based on the prediction block.

4. The method of claim 2 , wherein

the determining the weighting factor includes determining the weighting factor based on the scaling factors of the components of the at least one MVD.

5. The method of claim 4 , wherein

the determining the weighting factor includes determining the weighting factor based on a pre-defined relationship between the weighting factor and scaling factors of components of one of the at least one MVD.

6. The method of claim 4 , wherein

the reference frames include a first reference frame with a first weighting factor and a second reference frame with a second weighting factor and a sum of the first weighting factor and the second weighting factor is a constant,

in response to the constant being 8,

the weighting factor is 3 or 5, and

the first weighting factor and the second weighting factor include 3 and 5, in response to the constant being 16,

the weighting factor is 6 or 10, and

the first weighting factor and the second weighting factor include 6 and 10, and the reconstructing includes

obtaining a prediction block of the block by averaging the first reference frame with the first weighting factor and the second reference frame with the second weighting factor, and

reconstructing the block based on the prediction block.

7. The method of claim 1 , wherein

the subset of the list of weighting factors includes only unequal weighting factors;

the determining the weighting factor includes determining the weighting factor as one of the unequal weighting factors; and

the reconstructing includes

obtaining a prediction block of the block by averaging reference blocks in the respective reference frames with respective unequal weighting factors that are determined based on the one of the unequal weighting factors; and

reconstructing the block based on the prediction block.

8. The method of claim 7 , wherein

the unequal weighting factors are two unequal weighting factors including the weighting factor,

the reference blocks include a first reference block and a second reference block, and

the obtaining the prediction block includes averaging the first reference block and the second reference block with the two unequal weighting factors, respectively.

9. The method of claim 8 , wherein the two unequal weighting factors include (i) 3 and 5 or (ii) 6 and 10.

10. The method of claim 1 , wherein

a context for signaling a weighting factor index depends on the scaling factor information;

the determining the weighting factor of the compound weighted prediction mode based on the list of weighting factors includes determining the weighting factor based on the weighting factor index and the list of weighting factors; and

the determining the weighting factor of the compound weighted prediction mode based on the subset of the list of weighting factors includes determining the weighting factor based on the weighting factor index and the subset of the list of weighting factors.

11. The method of claim 10 , wherein

the context for signaling the weighting factor index is a first context based on the scaling factor information indicating that each of the scaling factors of the components of the at least one MVD is the pre-defined scaling factor, and

the context for signaling the weighting factor index is a second context that is different from the first context based on the scaling factor information indicating that the at least one of the scaling factors is different from the pre-defined scaling factor.

12. A method of video decoding in a video coder, the method comprising:

receiving a bitstream including a frame, coding information for a block in the frame indicating that the block is coded with a joint motion vector difference (MVD) coding mode and a compound weighted prediction mode, the coding information further indicating weighting factor information of the compound weighted prediction mode;

in response to the weighting factor information indicating that an equal weighting factor is applied to each of reference frames of the block, determining scaling factors of components of at least one MVD associated with at least one respective reference frame in the reference frames based on a list of scaling factors;

in response to the weighting factor information indicating that unequal weighting factors are applied to the reference frames of the block, determining the scaling factors of the components of the at least one MVD based on a subset of the list of scaling factors;

determining, using the joint MVD coding mode, motion information associated with the respective reference frames of the block based on the determined scaling factors; and

reconstructing, using the compound weighted prediction mode, the block based on the motion information associated with the respective reference frames of the block and the weighting factor information.

13. The method of claim 12 , wherein

the weighting factor information indicates that the unequal weighting factors are applied to the reference frames of the block,

the subset of the list of scaling factors includes only a pre-defined scaling factor, and

the determined scaling factors are equal to the pre-defined scaling factor and are not signaled.

14. The method of claim 13 , wherein the pre-defined scaling factor is 1.

15. The method of claim 12 , wherein

the weighting factor information indicates that the unequal weighting factors are applied to the reference frames of the block, and

the subset of the list of scaling factors does not include a pre-defined scaling factor.

16. The method of claim 15 , wherein the pre-defined scaling factor is 1.

17. The method of claim 12 , wherein

a context for signaling a scaling factor index depends on the weighting factor information;

the determining the scaling factors based on the list of scaling factors includes determining the scaling factors based on the scaling factor index and the list of scaling factors; and

the determining the scaling factors based on the subset of the list of scaling factors includes determining the scaling factors based on the scaling factor index and the subset of the list of scaling factors.

18. An apparatus for video decoding, comprising

processing circuitry configured to:

receive a bitstream including a frame, coding information for a block in the frame indicating that the block is coded with a joint motion vector difference (JMVD) coding mode and a compound weighted prediction mode, the coding information further including scaling factor information of the JMVD coding mode;

in response to the scaling factor information indicating that each of scaling factors of components of at least one MVD associated with at least one respective reference frame of the block is a pre-defined scaling factor, determine a weighting factor of the compound weighted prediction mode based on a list of weighting factors, the list being signaled in the bitstream;

in response to the scaling factor information indicating that at least one of the scaling factors is different from the pre-defined scaling factor, determine the weighting factor of the compound weighted prediction mode based on a subset of the list of weighting factors, only the subset of the list being signaled in the bitstream;

determine, using the JMVD coding mode, motion information associated with respective reference frames of the block based on the scaling factors of the components of the at least one MVD associated with the at least one respective reference frame of the block, the reference frames of the block including the at least one respective reference frame; and

reconstruct, using the compound weighted prediction mode, the block based on the motion information associated with the respective reference frames of the block and the determined weighting factor.

19. The apparatus of claim 18 , wherein

the scaling factor information indicates that the at least one of the scaling factors is different from the pre-defined scaling factor,

the subset of the list of weighting factors includes only one weighting factor, and

the determined weighting factor is the one weighting factor and is not signaled.

20. The apparatus of claim 19 , wherein

the one weighting factor is an equal weighting factor, and

the processing circuitry is configured to:

obtain a prediction block of the block by averaging reference blocks in the respective reference frames with the equal weighting factor for each reference block; and

reconstruct the block based on the prediction block.

Assignments (1)

Continuity (2)

References Cited (15)