Picture partitioning method and apparatus
A picture partitioning method and apparatus are described. The method includes determining a split mode of a current node, where the current node includes a luma block and a chroma block. The method further includes determining, based on the split mode of the current node and a size of the current node, that the chroma block of the current node is not further split. In accordance with the chroma block of the current node not being further split, the method includes splitting the luma block of the current node based on the split mode of the current node. In accordance with the chroma block of the current node not being further split, the method may be used to split only the luma block of the current node, thereby improving encoding and decoding efficiency, reducing a maximum throughput of a codec, and facilitating implementation of the codec.
1. A picture partitioning method, comprising:
determining a split mode of a current node that comprises a luma block and a chroma block;
determining, based on the split mode of the current node and a size of the current node, that the chroma block of the current node is not further split; and
splitting, based on the split mode of the current node, the luma block of the current node,
wherein the chroma block of the current node is not further split in accordance with either of the following determinations:
a product of a width and a height of the current node is equal to 64 and the split mode of the current node is a quadtree split or a ternary tree split, or
a product of a width and a height of the current node is equal to 32 and the split mode of the current node is a binary tree split.
2. The method according to claim 1 , wherein:
the chroma block of the current node is not further split in accordance with determining, based on the split mode of the current node and the size of the current node, that a child node generated by splitting the current node comprises a child chroma block whose side length is less than a threshold, and
the threshold is 4.
3. The method according to claim 1 ,
wherein the chroma block of the current node is not further split in accordance with any of the following determinations:
a width of the current node is equal to twice a threshold and the split mode of the current node is a vertical binary split,
a height of the current node is equal to twice a threshold and the split mode of the current node is a horizontal binary split,
a width of the current node is equal to four times a threshold and the split mode of the current node is a vertical ternary split,
a height of the current node is equal to four times a threshold and the split mode of the current node is a horizontal ternary split, or
a width of the current node is equal to twice a threshold and the split mode of the current node is a quad split; and
wherein the threshold is 4.
4. The method according to claim 1 , wherein the luma block of the current node is split, based on the split mode of the current node, to obtain child nodes of the current node,
wherein each child node comprises only a child luma block.
5. The method according to claim 1 , wherein in accordance with determining, based on the split mode of the current node and the size of the current node, that a child node generated by splitting the current node comprises a child chroma block whose width is less than a threshold, the chroma block of the current node is not further split,
wherein the threshold is 4.
6. The method according to claim 1 , wherein in accordance with determining, based on the split mode of the current node and the size of the current node, that the child node generated by splitting the current node comprises a child chroma block whose chroma sample quantity is less than 16, the chroma block of the current node is not further split.
7. The method according to claim 6 , wherein the chroma block of the current node is not further split in accordance with either of the following determinations:
a product of the width and the height of the current node is less than 128 and the split mode of the current node is a vertical binary split or a horizontal binary split, or
a product of the width and the height of the current node is less than 256 and the split mode of the current node is a vertical ternary split, a horizontal ternary split, or a quad split.
8. The method according to claim 1 , wherein the split mode of the current node comprises at least one of the group consisting of:
a quad split (QT),
a horizontal binary split (horizontal BT),
a horizontal ternary split (horizontal TT),
a vertical binary split (Vertical BT), and
a vertical ternary split (Vertical TT).
9. The method according to claim 1 , wherein the current node belongs to an I slice, and wherein the chroma block of the current node is not further split in accordance with any of the following determinations:
a product of a width and a height of the current node is equal to 64 and the split mode of the current node is a binary tree split, or
a product of a width and a height of the current node is equal to 128 and the split mode of the current node is a ternary tree split.
10. The method according to claim 1 , wherein whether the chroma block of the current node needs to be split is determined based on the split mode of the current node, the size of the current node, and a node prediction mode identifier (cons_pred_mode_flag).
11. The method according to claim 10 , wherein the current node belongs to a P or B slice, and wherein the chroma block of the current node is not further split in accordance with the following determinations:
the product of the width and the height of the current node is equal to 64 and the split mode of the current node is the binary tree split, or
the product of the width and the height of the current node is equal to 128 and the split mode of the current node is the ternary tree split; and
the node prediction mode identifier indicates that no inter prediction is performed on a coding block obtained by splitting the current node.
12. The method according to claim 1 , wherein determining, based on a data format of the current node, the split mode of the current node, and the size of the current node, whether the chroma block of the current node is further split, wherein the data format of the current node is YUV4:2:0 or YUV4:2:2.
13. The method according to claim 12 , intra prediction or inter prediction is performed on all coding units in a coverage area of the current node.
14. A video stream coding apparatus, comprising:
a non-transitory computer-readable storage medium storing instructions; and
one or more processors in communication with the medium and upon execution of the instructions, configured to:
determine a split mode of a current node that comprises a luma block and a chroma block;
determine, based on the split mode of the current node and a size of the current node, that the chroma block of the current node is not further split; and
split, based on the split mode of the current node, the luma block of the current node,
wherein the coding apparatus is a decoding apparatus or an encoding apparatus, and
wherein the chroma block of the current node is not further split in accordance with either of the following determinations:
a product of a width and a height of the current node is equal to 64 and the split mode of the current node is a quadtree split or a ternary tree split, or
a product of a width and a height of the current node is equal to 32 and the split mode of the current node is a binary tree split.
15. The apparatus according to claim 14 , wherein:
the chroma block of the current node is not further split in accordance with determining, based on the split mode of the current node and the size of the current node, that a child node generated by splitting the current node comprises a child chroma block whose side length is less than a threshold; and
the threshold is 4.
16. The apparatus according to claim 14 ,
wherein the chroma block of the current node is not further split in accordance with any of the following determinations:
a width of the current node is equal to twice a threshold and the split mode of the current node is a vertical binary split,
a height of the current node is equal to twice a threshold and the split mode of the current node is a horizontal binary split,
a width of the current node is equal to four times a threshold and the split mode of the current node is a vertical ternary split,
a height of the current node is equal to four times a threshold and the split mode of the current node is a horizontal ternary split, or
a width of the current node is equal to twice a threshold and the split mode of the current node is a quad split; and
wherein the threshold is 4.
17. The apparatus according to claim 14 , wherein the chroma block of the current node is not further split in accordance with determining, based on the split mode of the current node and the size of the current node, that the child node generated by splitting the current node comprises a child chroma block whose width is less than the threshold, and
wherein the threshold is 4.
18. The apparatus according to claim 14 , wherein the chroma block of the current node is not further split in accordance with determining, based on the split mode of the current node and the size of the current node, that the child node generated by splitting the current node comprises a child chroma block whose chroma sample quantity is less than 16.
19. The apparatus according to claim 18 , wherein the chroma block of the current node is not further split in accordance with either of the following determinations:
a product of the width and the height of the current node is less than 128 and the split mode of the current node is a vertical binary split or a horizontal binary split; or
a product of the width and the height of the current node is less than 256 and the split mode of the current node is a vertical ternary split, a horizontal ternary split, or a quad split.
20. A non-transitory computer-readable recording medium storing a bitstream that is generated by a video encoding method performed by a video encoding apparatus, the method comprising:
determining a split mode of a current node that comprises a luma block and a chroma block;
determining, based on the split mode of the current node and a size of the current node, that the chroma block of the current node is not further split; and
splitting, based on the split mode of the current node, the luma block of the current node,
wherein the chroma block of the current node is not further split in accordance with either of the following determinations:
a product of a width and a height of the current node is equal to 64 and the split mode of the current node is a quadtree split or a ternary tree split, or
a product of a width and a height of the current node is equal to 32 and the split mode of the current node is a binary tree split.