Method of conditional binary tree block partitioning structure for video and image coding
A method and apparatus of block partition for video encoding or decoding for a video encoder or a video decoder respectively are disclosed. Partitioning tree structure corresponding to a conditional partitioning process is determined for partitioning the current block of video data into one or more final sub-blocks. The conditional partitioning process comprises a conditional binary partitioning process that uses at least a first constraint if a given block of the partitioning tree structure is partitioned into above and below blocks, or a second constraint if the given block of the partitioning tree structure is partitioned into left and right blocks. The below block is disallowed to be split into a lower-left and a lower-right block according to the first constraint, and the right block is disallowed to be split into an upper-right block and a lower-right block according to the second constraint.
1. A method of block partitioning for video encoding or decoding for a video encoder or a video decoder respectively, the method comprising:
receiving input data associated with a current block of video data;
determining a partitioning tree structure corresponding to a conditional partitioning process for partitioning the current block of video data into one or more final sub-blocks, wherein the conditional partitioning process comprises a conditional binary partitioning process that uses at least a first constraint if a given block of the partitioning tree structure is partitioned into an above block and a below block, or a second constraint if the given block of the partitioning tree structure is partitioned into a left block and a right block, and wherein the below block is disallowed to be split into a first lower-left block and a first lower-right block according to the first constraint, and the right block is disallowed to be split into a second upper-right block and a second lower-right block according to the second constraint; and
applying an encoding or decoding process comprising prediction process, transform process or both to the current block of video data by applying the encoding or decoding process at a level corresponding to the final sub-blocks.
2. The method of claim 1 , wherein said determining the partitioning tree structure is performed by the video encoder and information associated with the partitioning tree structure is signalled from the video encoder to the video decoder.
3. The method of claim 1 , wherein said determining the partitioning tree structure is performed by the video decoder based on information associated with the partitioning tree structure signalled in a bitstream.
4. The method of claim 1 , wherein the conditional binary partitioning process is applied to the given block recursively to generate binary tree leaf nodes belonging to said one or more final sub-blocks.
5. The method of claim 1 , wherein if both quad-partition and binary partition are allowed for the given block of the partitioning tree structure, the conditional binary partitioning process uses both the first constraint and the second constraint.
6. The method of claim 1 , wherein if only binary partition is allowed for the given block of the partitioning tree structure, the conditional binary partitioning process uses only the first constraint or uses only the second constraint.
7. The method of claim 1 , wherein when the conditional binary partitioning process uses the second constraint, one flag is signalled for the left block to indicate whether the left block is split into a second upper-left block and a second lower-left block, and no flag is signalled for the right block to indicate whether the right block is split into the second upper-right block and the second lower-right block.
8. The method of claim 1 , wherein when the conditional binary partitioning process uses the first constraint, one flag is signalled for the above block to indicate whether the above block is split into a first upper-left block and a first upper-right block, and no flag is signalled for the below block to indicate whether the below block is split into the first lower-left block and the first lower-right block.
9. The method of claim 1 , wherein whether the conditional binary partitioning process uses the first constraint, the second constraint or both is based on a slice type of a current slice covering the current block of video data.
10. The method of claim 9 , wherein the conditional binary partitioning process uses the first constraint or the second constraint if the current slice is a P-slice or B-slice, and wherein the conditional binary partitioning process uses neither the first constraint nor the second constraint if the current slice is an I-slice.
11. The method of claim 9 , wherein the conditional binary partitioning process uses the first constraint or the second constraint if the current slice is an I-slice, and wherein the conditional binary partitioning process uses neither the first constraint nor the second constraint if the current slice is a P-slice or B-slice.
12. The method of claim 1 , wherein whether the conditional binary partitioning process uses the first constraint, the second constraint or both is based on a colour component type of the current block of video data.
13. The method of claim 12 , wherein the conditional binary partitioning process uses the first constraint or the second constraint if the current block of video data is a luma component, and wherein the conditional binary partitioning process uses neither the first constraint nor the second constraint if the current block of video data is a chroma component.
14. The method of claim 12 , wherein the conditional binary partitioning process uses the first constraint or the second constraint if the current block of video data is a chroma component, and wherein the conditional binary partitioning process uses neither the first constraint nor the second constraint if the current block of video data is a luma component.
15. The method of claim 1 , wherein at least one flag is signalled in VPS (video parameter set), SPS (sequence parameter set), PPS (picture parameter set), slice header, or CU (coding unit) to indicate whether the first constraint, the second constraint, or both the first and second constraints are included for the conditional binary partitioning process.
16. The method of claim 1 , wherein the conditional binary partitioning process uses the first constraint if the above block is split into a first upper-left block and a first upper-right block.
17. The method of claim 1 , wherein the conditional binary partitioning process uses the second constraint if the left block is split into a second upper-left block and a second lower-left block.
18. An apparatus for block partitioning for video encoding or decoding performed by a video encoder or a video decoder respectively, the apparatus comprising one or more electronic circuits or a processor configured to:
receive input data associated with a current block of video data;
determine a partitioning tree structure corresponding to a conditional partitioning process for partitioning the current block of video data into one or more final sub-blocks, wherein the conditional partitioning process comprises a conditional binary partitioning process that uses at least a first constraint if a given block of the partitioning tree structure is partitioned into an above block and a below block, or a second constraint if the given block of the partitioning tree structure is partitioned into a left block and a right block, and wherein the below block is disallowed to be split into a first lower-left block and a first lower-right block according to the first constraint, and the right block is disallowed to be split into a second upper-right block and a second lower-right block according to the second constraint; and
apply an encoding or decoding process comprising prediction process, transform process or both to the current block of video data by applying the encoding or decoding process at a level corresponding to the final sub-blocks.
19. The apparatus of claim 18 , wherein if both quad-partition and binary partition are allowed for the given block of the partitioning tree structure, the conditional binary partitioning process uses both the first constraint and the second constraint.
20. The apparatus of claim 18 , wherein if only binary partition is allowed for the given block of the partitioning tree structure, the conditional binary partitioning process uses only the first constraint or only the second constraint.