Intra Block Copy Chroma Vector Inheritance Decoupled Partition Trees
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Solution Overview
Problem
In video coding, when luma and chroma components are partitioned differently, it becomes challenging to determine the block vector for chroma blocks, leading to poor correspondence and increased signaling bandwidth, as chroma blocks are shaped differently than luma blocks.
Innovation Solution
A video coder partitions chroma blocks into sub-blocks based on the luma component's partition tree, allowing each sub-block to inherit block vectors from corresponding luma blocks, thereby reducing the need for explicit signaling of chroma block vectors and maintaining a one-to-one correspondence between luma and chroma blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If chroma components are partitioned differently than luma components (decoupled partition trees), then chroma block shape flexibility is improved, but correspondence between chroma blocks and luma blocks deteriorates
Solution Approach 1:
The chroma block is segmented into multiple sub-blocks based on the luma partition tree structure. Each chroma sub-block corresponds to a specific luma block, enabling the chroma component to inherit block vectors from the luma component while maintaining the benefits of decoupled partitioning. This segmentation allows the chroma block to be divided in a way that preserves correspondence with luma blocks even when the overall partition trees are different.
2Measurement precision
If block vectors for chroma blocks are explicitly signaled, then chroma block vector accuracy is improved, but signaling bandwidth increases
Solution Approach 1:
Instead of explicitly signaling block vectors for chroma blocks, the patent copies block vectors from corresponding luma blocks. The chroma sub-blocks inherit their block vectors from the luma blocks they correspond to, eliminating the need for separate chroma block vector signaling. This copying approach maintains vector accuracy while significantly reducing signaling bandwidth requirements.
3Quantity of substance
If chroma blocks inherit block vectors from luma blocks through partitioning, then signaling bandwidth is reduced, but partition tree complexity increases
Solution Approach 1:
The luma partition tree is established first as the reference structure. The chroma partitioning is then performed based on this pre-established luma partition tree, allowing chroma blocks to inherit block vectors without requiring a completely independent chroma partition tree. This preliminary action of setting up the luma partition structure first simplifies the overall process compared to managing two fully independent partition trees.
Data Source
AI summary
This disclosure describes example techniques that a video coder (e.g., video encoder or video decoder) may utilize to determine a block vector for a chroma block where the partition trees for the chroma component and the luma component are different (e.g., decoupled partition trees).