Luma and Chroma Block Partitioning in Video Coding

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Solution Overview

Problem

Existing video coding techniques face inefficiencies in compressing video data due to the use of a single coding tree for both luma and chroma samples, which can lead to sub-optimal coding efficiency and increased processing resources, as luma and chroma samples often contain different patterns.

Innovation Solution

Implementing a method where a common coding tree is used for luma and chroma samples when the block size exceeds a threshold, and splitting into separate luma and chroma coding sub-trees when the block size is below the threshold, allowing for tailored partitioning and reduced complexity and memory usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If separate coding trees are used for luma and chroma samples, then coding efficiency is improved, but processing resources and memory usage increase

Engineering Contradiction:
Improvecoding efficiencyVSAvoidprocessing resources
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the coding tree structure into two parts: a common coding tree for blocks above threshold size and separate coding sub-trees for blocks at or below threshold size. This segmentation allows the system to apply separate luma and chroma coding only where needed (smaller blocks), thereby improving coding efficiency for those specific cases while avoiding the overhead of maintaining completely separate trees for all block sizes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different coding strategies to different regions of the video data based on block size. For larger blocks (above threshold), a common coding tree is used, while for smaller blocks (at or below threshold), separate luma and chroma coding sub-trees are applied. This local differentiation optimizes coding efficiency where it matters most while controlling overall system complexity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If separate coding trees are used for luma and chroma samples, then coding efficiency is improved, but memory usage increases

Engineering Contradiction:
Improvecoding efficiencyVSAvoidmemory usage
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent segments the memory requirements by storing a single common coding tree structure that is shared between luma and chroma coding for larger blocks, while maintaining separate sub-trees only for smaller blocks. This reduces the total memory footprint compared to maintaining completely separate coding trees for all block sizes, while still capturing the benefits of separate coding where applicable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The common coding tree serves multiple functions by being used for both luma and chroma samples in larger blocks, eliminating the need to store duplicate tree structures. This multi-functionality reduces memory usage while the separate sub-trees provide specialized coding for smaller blocks when needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a common coding tree is used for luma and chroma samples, then processing resources are reduced, but coding efficiency decreases

Engineering Contradiction:
Improveprocessing resourcesVSAvoidcoding efficiency
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the coding process into two segments based on block size: common coding for larger blocks and separate coding for smaller blocks. This segmentation ensures that the simplification benefits of common coding are applied where they have the greatest impact (larger blocks), while the efficiency benefits of separate coding are applied where they are most beneficial (smaller blocks).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the coding parameter (tree structure) based on the block size parameter. When block size exceeds the threshold, common coding is applied; when block size is at or below the threshold, separate coding is applied. This dynamic parameter adjustment optimizes the trade-off between processing resources and coding efficiency.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4072146A1LUMA and chroma block partitioning
Publication Date: 2022.10.12 HUAWEI TECH CO LTD
  • EP4072146A1 patent drawingFigure 1
  • EP4072146A1 patent drawingFigure 2
  • EP4072146A1 patent drawingFigure 3

AI summary

A video coding mechanism is disclosed. The mechanism includes obtaining a coding tree unit including luma samples and chroma samples. The mechanism partitions the luma samples and the chroma samples according to a common coding tree when a size of a first coding tree node exceeds a threshold. The mechanism also partitions the luma samples with a luma coding sub-tree when a size of a second coding tree node is equal to or less than the threshold. The mechanism also chroma samples with a chroma coding sub-tree when a size of a third coding tree node is equal to or less than the threshold. The luma coding sub-tree contains a different set of split modes than the chroma coding sub-tree.