Methods and apparatuses of processing video pictures with partition constraints in a video coding system
Video processing methods and apparatuses in a video encoding or decoding system for processing a video picture partitioned into blocks with one or more partition constraints. The video encoding or decoding system receives input data of a current block and checks whether a predefined splitting type is allowed to partition the current block according to first and second constraints. The first constraint restricts each sub-block partitioned from the current block to be completely contained in one pipeline unit, and the second constraint restricts each sub-block partitioned from the current block to contain one or more complete pipeline units. The pipeline units are non-overlapping units in the video picture designed for pipeline processing. The current block is not partitioned by the predefined splitting type if any sub-block partitioned by the predefined splitting type violates both the first and second constraints. The system encodes or decodes the current block.
1. A method of video processing in a video coding system for encoding or decoding video pictures with a partition constraint, the method comprising:
receiving input data associated with a current block in a current video picture;
determining two positive integers W and H as a pipeline unit size of pipeline units or a maximum transform size in a video compression standard, wherein the pipeline units are non-overlapping units in the current video picture and configured for pipeline processing;
determining whether a predefined splitting type is allowed for partitioning the current block into multiple sub-blocks according to a partition constraint, wherein the partition constraint corresponds to a comparing result of a width of the current block, a height of the current block, or both the width and height of the current block with one or both W and H;
based on the width of the current block being larger than W and the height of the current block being less than or equal to H, horizontal binary-tree splitting is not allowed, and
based on the width of the current block being less than or equal to W and the height of the current block being larger than H, vertical binary-tree splitting is not allowed,
partitioning the current block with one allowed splitting type, wherein the predefined splitting type is not used to partition the current block if the comparing result indicates the predefined splitting type is not allowed; and
encoding or decoding the current block according to a block partitioning structure of the current block.
2. The method of claim 1 , wherein W and H are predefined or implicitly defined based on a profile or level according to a video compression standard.
3. The method of claim 1 , wherein ternary-tree splitting is not allowed if the width of the current block is larger than W, or the height of the current block is larger than H.
4. The method of claim 1 , wherein horizontal ternary-tree splitting is not allowed if the width of the current block is larger than or equal to W and the height of the current block divide by 4 is smaller than H, and vertical ternary-tree splitting is not allowed if the height of the current block is larger than or equal to H and the width of the current block divide by 4 is smaller than W.
5. The method of claim 1 , wherein horizontal ternary-tree splitting is not allowed if the width of the current block is larger than W and the height of the current block is larger than H but the height divide by 4 is smaller than H, and vertical ternary-tree splitting is not allowed if the height of the current block is larger than H and the width of the current block is larger than W but the width divide by 4 is smaller than W.
6. The method of claim 1 , wherein horizontal ternary-tree splitting is not allowed if the width of the current block is larger than or equal to W and the height of the current block is larger than H but the height divide by 4 is smaller than H, and vertical ternary-tree splitting is not allowed if the height of the current block is larger than or equal to H and the width of the current block is larger than W but the width divide by 4 is smaller than W.
7. The method of claim 1 , wherein horizontal ternary-tree splitting is not allowed if the width of the current block is larger than W and the height of the current block is larger than H and the height divide by 4 is not a multiple of H, and vertical ternary-tree splitting is not allowed if the height of the current block is larger than H and the width of the current block is larger than W but the width divide by 4 is not a multiple of W.
8. The method of claim 1 , wherein at least a partition syntax is inferred according to the comparing result, and the partition syntax is not signaled in a video bitstream.
9. The method of claim 1 , wherein a pipeline unit is defined to have a width equal to W and a height equal to H, a pipeline unit size is a product of W and H, the predefined splitting type is ternary-tree splitting, and the predefined splitting type is not allowed if a size of the current block is twice as large as the pipeline unit size.
10. The method of claim 1 , wherein a pipeline unit is defined to have a width equal to W and a height equal to H, a pipeline unit size is a product of W and H, a size of the current block is twice as large as the pipeline unit size, and ternary-tree splitting is not allowed unless all further splitting directions are the same and a center sub-block of the current block is partitioned by binary-tree splitting.
11. The method of claim 1 , wherein a pipeline unit is defined to have a width equal to W and a height equal to H, a pipeline unit size is a product of W and H, and the predefined splitting type is allowed if a size of the current block is four times as large as the pipeline unit size or if the size of the current block is smaller than the pipeline unit size, wherein the predefined splitting type is selected from quadtree, binary-tree, and ternary-tree splitting.
12. The method of claim 1 , wherein a pipeline unit is defined to have a width equal to W and a height equal to H, determining whether a predefined splitting type is allowed for partitioning the current block further by considering a re-visit constraint, and the predefined splitting type is not allowed if the re-visit constraint is violated, wherein the re-visit constraint prohibits re-visiting any pipeline unit in the current block after leaving the pipeline unit when processing the sub-blocks partitioned from the current block.
13. An apparatus of video processing in a video coding system for encoding or decoding video pictures with a partition constraint, the apparatus comprising one or more electronic circuits configured to:
receive input data associated with a current block in a current video picture;
determine in a video compression standard a pipeline unit size of pipeline units or a maximum transform size in a video compression standard, wherein the pipeline units are non-overlapping units in the current video picture and configured for pipeline processing;
determine whether a predefined splitting type is allowed for partitioning the current block into multiple sub-blocks according to a partition constraint, wherein the partition constraint corresponds to a comparing result of a width of the current block, a height of the current block, or both the width and height of the current block with one or both W and H;
based on the width of the current block being larger than W and the height of the current block being less than or equal to H, horizontal binary-tree splitting is not allowed, and
based on the width of the current block being less than or equal to W and the height of the current block being larger than H, vertical binary-tree splitting is not allowed,
wherein the pipeline unit size W by H is set corresponding to a maximum transform block size in a video compression standard;
partition the current block with one allowed splitting type, wherein the predefined splitting type is not used to partition the current block if the comparing result indicates the predefined splitting type is not allowed; and
encode or decode the current block according to a block partitioning structure of the current block.
14. A non-transitory computer readable medium storing program instructions causing a processing circuit of an apparatus to encode or decode video pictures with a partition constraint, the instructions causing the processing circuit to:
receive input data associated with a current block in a current video picture;
determine two positive integers W and H as a pipeline unit size of pipeline units or a maximum transform size in a video compresson standard, wherein the pipeline units are non-overlapping units in the current video picture and configured for pipeline processing;
determine whether a predefined splitting type is allowed for partitioning the current block into multiple sub-blocks according to a partition constraint, wherein the partition constraint corresponds to a comparing result of a width of the current block, a height of the current block, or both the width and height of the current block with one or both W and H;
based on the width of the current block being larger than W and the height of the current block being less than or equal to H, horizontal binary-tree splitting is not allowed, and
based on the width of the current block being less than or equal to W and the height of the current block being larger than H, vertical binary-tree splitting is not allowed,
partition the current block with one allowed splitting type, wherein the predefined splitting type is not used to partition the current block if the comparing result indicates the predefined splitting type is not allowed; and
encode or decode the current block according to a block partitioning structure of the current block.