Chroma enhancement filtering for high dynamic range video coding

1. A method comprising:

identifying a characteristic within a picture of a video signal, the characteristic comprising a color component;

determining a sample set that comprises samples in the picture that are associated with the characteristic, the sample set comprising a first sample in a first spatial region and a second sample in a second spatial region of the picture, wherein the first sample and the second sample within the picture have corresponding color component values that are within a predetermined range;

applying a cross-plane filter to a first luma plane component of the first sample in the first spatial region and a second luma plane component of the second sample in the second spatial region to determine a first offset associated with the first sample and a second offset associated with the second sample, the cross-plane filter comprising a high pass filter;

adding the first offset to a first reconstructed chroma plane component of the first sample in the first spatial region that corresponds to the first luma plane component; and

adding the second offset to a second reconstructed chroma plane component of the second sample in the second spatial region that corresponds to the second luma plane component.

2. The method of claim 1 , wherein the same cross-plane filter is applied to a respective luma plane component of each sample in the sample set in a plurality of spatial regions that comprises the first and second spatial regions.

3. The method of claim 1 , wherein identifying the characteristic is based on a received indication that identifies the characteristic.

4. The method of claim 1 , wherein the characteristic comprises an edge direction, the sample set comprising the samples within the picture having a dominant edge direction that matches the edge direction.

5. The method of claim 1 , wherein the sample set comprising the samples within the picture that match the color component.

6. The method of claim 1 , wherein the characteristic comprises a luminance, the sample set comprising the samples within the picture having a luminance value within a predetermined luminance range.

7. The method of claim 1 , wherein a plurality of characteristics is identified within the picture, and wherein the sample set is determined based on the plurality of characteristics.

8. The method of claim 1 , further comprising determining to apply the cross-plane filter based on a receipt of one or more cross-plane filter parameters via an SEI message.

9. The method of claim 1 , wherein the first luma plane component and the first reconstructed chroma plane component have different spatial dimensions.

10. The method of claim 1 , wherein the sample set comprising a third sample in a third spatial region and a fourth sample in a fourth spatial region of the picture, the cross-plane filter comprising a first cross-plane filter, the method further comprising:

applying a second cross-plane filter to a third luma plane component of the third sample in the third spatial region and a fourth luma plane component of the fourth sample in the fourth spatial region to determine a third offset associated with the third sample and a fourth offset associated with the fourth sample, the cross-plane filter comprising a high pass filter;

adding the third offset to a third reconstructed chroma plane component of third first sample that corresponds to the third luma plane component; and

adding the fourth offset to a fourth reconstructed chroma plane component of the fourth sample that corresponds to the fourth luma plane component.

11. A video coding device comprising:

a processor configured to:

identify a characteristic within a picture of a video signal, the characteristic comprising a color component;

determine a sample set that comprises samples in the picture that are associated with the characteristic, the sample set comprising a first sample in a first spatial region and a second sample in a second spatial region of the picture, wherein the first sample and the second sample within the picture have corresponding color component values that are within a predetermined range;

apply a cross-plane filter to a first luma plane component of the first sample in the first spatial region and a second luma plane component of the second sample in the second spatial region to determine a first offset associated with the first sample and a second offset associated with the second sample, the cross-plane filter comprising a high pass filter;

add the first offset to a first reconstructed chroma plane component of the first sample in the first spatial region that corresponds to the first luma plane component; and

add the second offset to a second reconstructed chroma plane component of the second sample in the second spatial region that corresponds to the second luma plane component.

12. The video coding device of claim 11 , wherein the processor is configured to apply the same cross-plane filter to a respective luma plane component of each sample in the sample set in a plurality of spatial regions that comprises the first and second spatial regions.

13. The video coding device of claim 11 , wherein the characteristic comprises an edge direction, the sample set comprising the samples within the picture having a dominant edge direction that matches the edge direction.

14. The video coding device of claim 11 , wherein the processor is configured to identify the characteristic based on a received indication that identifies the characteristic.

15. The video coding device of claim 11 , wherein the the sample set comprising the samples within the picture that match the color component.

16. The video coding device of claim 11 , wherein the characteristic comprises a luminance, the sample set comprising the samples within the picture having a luminance value within a predetermined luminance range.

17. The video coding device of claim 11 , wherein the processor is configured to identify a plurality of characteristics within the picture, and wherein the sample set is determined based on the plurality of characteristics.

18. The video coding device of claim 11 , wherein the processor is further configured to determine to apply the cross-plane filter based on a receipt of one or more cross-plane filter parameters via an SEI message.

19. The video coding device of claim 11 , wherein the first luma plane component and the first reconstructed chroma plane component have different spatial dimensions.

20. The video coding device of claim 11 , wherein the sample set comprising a third sample in a third spatial region and a fourth sample in a fourth spatial region of the picture, the cross-plane filter comprising a first cross-plane filter, wherein the processor is further configured to:

apply a second cross-plane filter to a third luma plane component of the third sample in the third spatial region and a fourth luma plane component of the fourth sample in the fourth spatial region to determine a third offset associated with the third sample and a fourth offset associated with the fourth sample, the cross-plane filter comprising a high pass filter;

add the third offset to a third reconstructed chroma plane component of the third sample that corresponds to the third luma plane component; and

add the fourth offset to a fourth reconstructed chroma plane component of the fourth sample that corresponds to the fourth luma plane component.