Decoupled Luma Chroma Transform Depths for Video Coding Efficiency

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Solution Overview

Problem

Current video coding techniques apply transforms to both luma and chroma information at the same residual quadtree depth, which can lead to inefficient coding due to differences in sampling rates and variability between luma and chroma data.

Innovation Solution

Applying transforms to luma information at a different residual quadtree depth than chroma information, allowing for decoupled transformation processes that adapt to the specific characteristics of each component, thereby improving coding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If transforms are applied to luma and chroma information at the same residual quadtree depth, then the coding process is simplified and easier to implement, but coding efficiency deteriorates due to ignoring differences in sampling rates and variability between luma and chroma data

Engineering Contradiction:
Improveease of implementationVSAvoidcoding efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent segments the transform process by applying transforms to luma and chroma information at different residual quadtree depths. Specifically, the luma information can be transformed at one depth while chroma information is transformed at another depth, allowing each component to be processed according to its specific characteristics rather than forcing a unified approach

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different transform depths to different color components (luma and chroma) based on their local characteristics. Since luma and chroma have different sampling rates and variability, the transform depth is adjusted locally for each component type to optimize the transformation process for that specific data type

Inventive Principle:
Principle #3Local quality

2Productivity

If transforms are applied at different residual quadtree depths for luma and chroma information, then coding efficiency is improved by adapting to specific characteristics of each component, but device complexity increases due to decoupled transformation processes

Engineering Contradiction:
Improvecoding efficiencyVSAvoidtransformation process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces dynamic adaptability by allowing the transform depth to vary between luma and chroma components. The system can dynamically select different depths based on the specific characteristics of each component, making the transformation process flexible rather than fixed. This dynamic approach enables optimization for each component type while maintaining a unified overall framework

Inventive Principle:
Principle #15Dynamics

3Loss of information

If transforms are applied at different residual quadtree depths for luma and chroma information, then energy compaction is improved and bit rates are reduced, but coding complexity increases due to separate depth determination processes

Engineering Contradiction:
Improvecompression efficiencyVSAvoidcoding complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent changes the parameter of transform depth separately for luma and chroma information. By adjusting this parameter independently for each color component, the system can optimize energy compaction for each type of data. The different sampling rates and variability characteristics of luma and chroma are addressed by applying appropriate transform depths, leading to better overall compression efficiency

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3013051B1Transforms in video coding
Publication Date: 2018.12.19 QUALCOMM INC
  • EP3013051B1 patent drawingFigure 1
  • EP3013051B1 patent drawingFigure 2
  • EP3013051B1 patent drawingFigure 3

AI summary

Aspects of this disclosure relate to a method of coding video data. In an example, the method includes determining a first residual quadtree (RQT) depth at which to apply a first transform to luma information associated with a block of video data, wherein the RQT represents a manner in which transforms are applied to luma information and chroma information. The method also includes determining a second RQT depth at which to apply a second transform to the chroma information associated with the block of video data, wherein the second RQT depth is different than the first RQT depth. The method also includes coding the luma information at the first RQT depth and the chroma information at the second RQT depth.