Cross-plane filtering for chroma signal enhancement in video coding
View Patent ↗Cross-plane filtering may be used to restore blurred edges and/or textures in one or both chroma planes using information from a corresponding luma plane. Adaptive cross-plane filters may be implemented. Cross-plane filter coefficients may be quantized and/or signaled such that overhead in a bitstream minimizes performance degradation. Cross-plane filtering may be applied to select regions of a video image (e.g., to edge areas). Cross-plane filters may be implemented in single-layer video coding systems and/or multi-layer video coding systems.
1. A method comprising:
obtaining a video signal comprising a first color component and a second color component;
obtaining a cross-plane filter indication indicating that a cross-plane filter is to be applied to the second color component at a current location associated with the video signal;
determining a cross-plane filter coefficient for the cross-plane filter that is to be applied to the second color component at the current location based on the obtained cross-plane filter indication;
applying the cross-plane filter to the second color component based on the determined cross-plane filter coefficient such that a color component offset associated with the first color component is determined; and
modifying the first color component based on the determined color component offset.
2. The method of claim 1 , wherein the first color component comprises a chroma component, and the second color component comprises a luma component.
3. The method of claim 1 , wherein the cross-plane filter indication is obtained at a slice level.
4. The method of claim 1 , wherein the cross-plane filter indication is configured to indicate whether the cross-plane filter is to be applied to the second color component at the current location of the video signal and a cross-plane filter coefficient index associated with the cross-plane filter that is to be applied to the second color component at the current location of the video signal, and
wherein the method comprises determining the cross-plane filter coefficient for the cross-plane filter based on the cross-plane filter coefficient index.
5. The method of claim 1 , comprising:
obtaining a cross-plane filter signal indication indicating that at least one cross-plane filter is signaled; and
based on the cross-plane filter signal indication indicating that the at least one cross-plane filter is signaled, obtaining the at least one cross-plane filter from the video signal.
6. The method of claim 5 , comprising:
on a condition that the cross-plane filter signal indication indicating that the at least one cross-plane filter is signaled, obtaining a cross-plane filter number indication that indicates a number of the at least one cross-plane filter that is being signaled; and
obtaining the at least one cross-plane filter based on the obtained number of the at least one cross-plane filter.
7. The method of claim 6 , wherein the cross-plane filter signal indication, the cross-plane filter number indication, and the at least one cross-plane filter are obtained at an adaptive parameter set (APS) level.
8. The method of claim 6 , wherein the cross-plane filter indication comprises a cross-plane filter index indication that indicates a cross-plane filter coefficient index associated with the cross-plane filter for the current location, and wherein the method comprises:
determining the cross-plane filter coefficient for the cross-plane filter that is to be applied to the second color component at the current location based on the cross-plane filter coefficient index associated with the cross-plane filter for the current location and the obtained at least one cross-plane filter.
9. The method of claim 6 , wherein the number of the at least one cross-plane filter that is being signaled from the cross-plane filter number indication is between 1 and 4.
10. The method of claim 1 , wherein the cross-plane filter indication is a first cross-plane filter indication, the cross-plane filter coefficient is a first cross-plane filter coefficient, the cross-plane filter is a first cross-plane filter, the color component offset is a first color component offset, the video signal further comprises a third color component, and wherein the method further comprises:
obtaining a second cross-plane filter indication indicating that a second cross-plane filter is to be applied to the third color component at the current location associated with the video signal;
determining a second cross-plane filter coefficient for the second cross-plane filter that is to be applied to the third color component at the current location based on the obtained second cross-plane filter indication;
applying the second cross-plane filter to the third color component based on the determined second cross-plane filter coefficient such that a second color component offset associated with the first color component is determined; and
modifying the first color component based on the determined second color component offset.
11. A device comprising:
a processor configured to:
obtain a video signal comprising a first color component and a second color component;
obtain a cross-plane filter indication indicating that a cross-plane filter is to be applied to the second color component at a current location associated with the video signal;
determine a cross-plane filter coefficient for the cross-plane filter that is to be applied to the second color component at the current location based on the obtained cross-plane filter indication;
apply the cross-plane filter to the second color component based on the determined cross-plane filter coefficient such that a color component offset associated with the first color component is determined; and
modify the first color component based on the determined color component offset.
12. The device of claim 11 , wherein the first color component comprises a chroma component, and the second color component comprises a luma component, and wherein to modify the first color component, the processor is configured to:
add the determined color component offset to the first color component.
13. The device of claim 11 , wherein the processor is configured to:
obtain a cross-plane filter signal indication indicating that at least one cross-plane filter is signaled; and
based on the cross-plane filter signal indication indicating that the at least one cross-plane filter is signaled, obtain the at least one cross-plane filter from the video signal.
14. The device of claim 13 , wherein the processor is configured to:
on a condition that the cross-plane filter signal indication indicating that the at least one cross-plane filter is signaled, obtain a cross-plane filter number indication that indicates a number of the at least one cross-plane filter that is being signaled; and
obtain the at least one cross-plane filter based on the obtained number of the at least one cross-plane filter.
15. The device of claim 14 , wherein the cross-plane filter signal indication, the cross-plane filter number indication, and the at least one cross-plane filter are obtained at an adaptive parameter set (APS) level.
16. The device of claim 14 , wherein the cross-plane filter indication is obtained at a slice level, and wherein the number of the at least one cross-plane filter that is being signaled from the cross-plane filter number indication is between 1 and 4.
17. A method comprising:
obtaining a video signal comprising a first color component and a second color component;
encoding the first color component and the second color component;
reconstructing the first color component based on the encoded first color component and reconstructing the second color component based on the encoded second color component;
generating a cross-plane filter indication indicating a current location associated with the video signal where a cross-plane filter is to be applied, the cross-plane filter indication being generated based on a reconstructed second color component, a reconstructed first color component, and the first color component; and
including the cross-plane filter indication and a filter coefficient indication associated with the cross-plane filter in a bitstream that is representative of the video signal.
18. The method of claim 17 , wherein the first color component comprises a chroma component, and the second color component comprises a luma component, and wherein the cross-plane filter is applied to minimize a distortion between the first color component and the reconstructed first color component.
19. A device comprising:
a processor configured to:
obtain a video signal comprising a first color component and a second color component;
encode the first color component and the second color component;
reconstruct the first color component based on the encoded first color component and reconstruct the second color component based on the encoded second color component;
generate a cross-plane filter indication indicating a current location associated with the video signal where a cross-plane filter is to be applied, the cross-plane filter indication being generated based on a reconstructed second color component, a reconstructed first color component, and the first color component; and
include the cross-plane filter indication and a filter coefficient indication associated with the cross-plane filter in a bitstream that is representative of the video signal.
20. The device of claim 19 , wherein the first color component comprises a chroma component, and the second color component comprises a luma component, and wherein the cross-plane filter is applied to minimize a distortion between the first color component and the reconstructed first color component.