Semi-decoupled partitioning for video coding

1. A method of video coding, executable by a processor, comprising:

receiving video data comprising a luma component and a chroma component;

determining a first coding tree structure associated with the luma component and a second coding tree structure associated with the chroma component, wherein the first coding tree structure and the second coding tree structure share a same top level coding tree structure, wherein responsive to at least a portion of the first coding tree structure being different from the second coding tree structure, a set of tree partition types associated with the chroma component is a subset of tree partition types associated with the luma component; and

decoding the video data based on the first coding tree structure and the second coding tree structure.

2. The method of claim 1 , further comprising:

determining the same top level coding tree structure based on a block size, a coding tree depth, and a partition type associated with the luma component.

3. The method of claim 1 , wherein the first coding tree structure and the second coding tree structure are determined to share the same coding tree structure based on a block size associated with the luma component being greater than a first threshold value T 1 , a coding tree splitting depth associated with the luma component being less than or equal to a second threshold value T 2 , and a quad-tree split partitioning being used for the luma component.

4. The method of claim 1 , wherein the first coding tree structure and the second coding tree structure are determined to share the same coding tree structure based on a block size associated with the luma component being greater than a first threshold value T 1 or a coding tree splitting depth associated with the luma component being less than or equal to a second threshold value T 2 and based on a quad-tree split partitioning or a binary split partitioning being used for the luma component.

5. The method of claim 1 , wherein the first coding tree structure and the second coding tree structure does not share any coding tree structure based on L-type partitioning or T-type partitioning being used for the luma component.

6. The method of claim 1 , wherein L-type partitioning or T-type partitioning are disallowed for the chroma component.

7. The method of claim 1 , wherein only quad-tree split partitioning or binary split partitioning are allowed for the chroma component.

8. The method of claim 1 , wherein L-type partitioning is disallowed from being further partitioned for the chroma component.

9. The method of claim 1 , responsive to at least a portion of the first coding tree structure being different from the second coding tree structure, a tree depth of the chroma component is disallowed from exceeding a maximum tree depth associated with the luma component.

10. The method of claim 9 , wherein area sizes of blocks associated with the chroma component are disallowed from being smaller than a minimum area size of blocks associated with the luma component.

11. The method of claim 9 , wherein a tree depth of quad-tree split partitioning for the chroma component is disallowed from exceeding a maximum tree depth of quad-tree split partitioning for the luma component.

12. The method of claim 9 , wherein a tree depth of binary tree partitioning plus triple tree partitioning for the chroma component is disallowed from exceeding a maximum tree depth of binary tree partitioning plus triple tree partitioning for the luma component.

13. The method of claim 1 , wherein based on a depth of the luma component exceeding a first threshold value T 1 or a minimum block area size for the luma component being less than or equal to a second threshold value T 2 , the luma component and the chroma component share a partial coding tree structure.

14. The method of claim 1 , wherein based on a minimum a block area size for the luma component being less than or equal to a threshold value T 2 , the chroma component and the luma component share a top-level coding tree structure S, wherein T 2 and S are non-negative integers.

15. The method of claim 1 , wherein a point where the first coding tree structure and the second coding tree structure start to differ depends on partitioning information associated with the luma component.

16. The method of claim 15 , wherein the point where the first coding tree structure and the second coding tree structure start to differ is signaled in a high level syntax of a bitstream, the high level syntax comprises one or more of a sequence header, a frame header, and a slice header.

17. The method of claim 1 , wherein for each sub-partition of the chroma component and the luma component, a flag is signaled to indicate whether the first coding tree structure and the second coding tree structure are the same.

18. A computer system for decoding video data, the computer system comprising:

one or more computer-readable non-transitory storage media configured to store computer program code; and

one or more computer processors configured to access said computer program code and operate as instructed by said computer program code, said computer program code including:

receiving code configured to cause the one or more computer processors to receive video data comprising a luma component and a chroma component;

determining code configured to cause the one or more computer processors to determine a first coding tree structure associated with the luma component and a second coding tree structure associated with the chroma component, wherein the first coding tree structure and the second coding tree structure share a same top level coding tree structure, wherein responsive to at least a portion of the first coding tree structure being different from the second coding tree structure, a set of tree partition types associated with the chroma component is a subset of tree partition types associated with the luma component; and

decoding code configured to cause the one or more computer processors to decode the video data based on the first coding tree structure and the second coding tree structure.

19. A non-transitory computer readable medium having stored thereon a computer program for decoding video data, the computer program configured to cause one or more computer processors to:

receive video data comprising a luma component and a chroma component;

determine a first coding tree structure associated with the luma component and a second coding tree structure associated with the chroma component, wherein the first coding tree structure and the second coding tree structure share a same top level coding tree structure, wherein responsive to at least a portion of the first coding tree structure being different from the second coding tree structure, a set of tree partition types associated with the chroma component is a subset of tree partition types associated with the luma component; and

decode the video data based on the first coding tree structure and the second coding tree structure.