Video Block Partition Constraints for VPDU-Aware Pipeline Coding
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Solution Overview
Problem
The increasing size of Virtual Pipeline Data Units (VPDUs) in next-generation video coding standards, such as VVC, leads to a significant increase in buffer size requirements, posing a critical design issue for hardware decoders, as existing partitioning methods do not adequately restrict splitting types to manage these larger units efficiently.
Innovation Solution
Implementing partition constraints that restrict certain splitting types based on the relationship between the current block and pipeline units, ensuring that each sub-block is completely contained within a pipeline unit and adhering to constraints such as the first and second constraints, which require all samples to be within a pipeline unit, and the re-visit constraint, which prohibits re-entering a pipeline unit after leaving it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional video coding techniques are used, then coding flexibility is maintained, but coding efficiency deteriorates due to unnecessary partitioning of small blocks
Solution Approach 1:
The patent applies segmentation by dividing the coding process into two distinct stages: CTU-level decision making for whether to apply partition constraints, and subsequent Ctb-level partitioning only where needed. This segmentation allows the system to avoid unnecessary fine-grained partitioning operations on small blocks, improving coding efficiency while maintaining flexibility only where beneficial.
Solution Approach 2:
The patent implements preliminary action by determining at the CTU level whether partition constraints should be applied before actual Ctb-level partitioning occurs. This preliminary decision prevents wasteful partitioning operations on small blocks that would not improve quality, thereby improving coding efficiency without sacrificing necessary coding flexibility.
2Productivity
If partition constraints are applied at Ctb level, then coding efficiency improves, but computational complexity increases
Solution Approach 1:
The patent segments the complexity by separating CTU-level constraint decisions from Ctb-level partitioning operations. This segmentation ensures that computationally intensive partitioning is only performed on blocks where constraints are actually applied, reducing overall computational complexity while maintaining coding efficiency improvements.
Solution Approach 2:
The preliminary determination of partition constraints at the CTU level acts as a filter, identifying which Ctb blocks will undergo partitioning. This preliminary action reduces computational complexity by avoiding unnecessary partitioning operations on blocks where constraints would not be beneficial, while still achieving coding efficiency gains on appropriate blocks.
3Manufacturing precision
If small blocks are partitioned into smaller units, then rate-distortion performance deteriorates, but partitioning granularity increases
Solution Approach 1:
The patent applies local quality by allowing partition constraints to be applied selectively at the CTU level based on local block characteristics. This ensures that fine-grained partitioning is only applied where it improves rate-distortion performance, while avoiding it on small blocks where it would deteriorate performance, thus achieving local optimization rather than uniform application.
Solution Approach 2:
The preliminary CTU-level assessment determines whether small blocks should undergo further partitioning. This preliminary action prevents unnecessary fine-grained partitioning of small blocks that would harm rate-distortion performance, while still enabling appropriate partitioning where beneficial, thus resolving the contradiction through selective application.
Data Source
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AI summary
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 video encoding or decoding system encodes or decodes the current block.