Video Signal Decoding With Local Secondary Transforms

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Solution Overview

Problem

Existing video coding technologies face challenges in efficiently processing next-generation video content with high spatial resolution, high frame rate, and high dimensionality of scene representation, leading to increased memory storage and processing demands.

Innovation Solution

Applying an appropriate transform suitable for the current block, including primary and secondary transforms, to improve transform efficiency and reduce computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a transform technique is applied to transform spatial domain video signal into frequency domain signal, then compression performance is improved, but computational complexity increases

Engineering Contradiction:
Improvecompression performanceVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The transform process is divided into two distinct stages: primary transform and secondary transform. The primary transform processes the entire residual block, while the secondary transform selectively processes only the top-left region of the transformed coefficients. This segmentation allows the system to achieve enhanced compression performance through the secondary transform while limiting its computational impact to a small portion of the data.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The secondary transform is applied locally to only the top-left region of the transformed coefficient block, rather than processing the entire block. This local application focuses computational resources on the most significant coefficients that contribute most to compression performance, while avoiding unnecessary computation on less important regions.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If next-generation video content with high spatial resolution and high frame rate is processed, then video quality is improved, but memory storage and processing power requirements increase

Engineering Contradiction:
Improvevideo qualityVSAvoidmemory storage and processing power
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The residual block is segmented into a top-left region that receives secondary transform processing and the remaining region that does not. This segmentation strategy enables the system to handle high-resolution video content by applying enhanced transformation only where most beneficial, thereby improving video quality while controlling memory and processing requirements.

Inventive Principle:
Principle #1Segmentation

3Productivity

If transform efficiency is improved by applying appropriate transforms to current block, then compression performance increases, but device complexity increases

Engineering Contradiction:
Improvetransform efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system dynamically selects whether to apply the secondary transform based on block characteristics and configuration flags. The transform type and application region are adaptively determined, allowing the system to optimize transform efficiency for different content types while managing device complexity through conditional processing rather than always applying the most complex transform.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3723372B1Method for encoding/decoding video signal, and apparatus therefor
Publication Date: 2025.11.05 LG ELECTRONICS INC
  • EP3723372B1 patent drawingFigure 1
  • EP3723372B1 patent drawingFigure 2
  • EP3723372B1 patent drawingFigure 3

AI summary

Embodiments of the disclosure provide a method and apparatus for processing a video signal. Particularly, a method for decoding a video signal according to an embodiment of the disclosure may include: determining, among predefined secondary transform sets based on intra-prediction modes of a current block, a secondary transform set applied to the current block; obtaining a first syntax element indicating a secondary transform matrix applied to the current block in the determined secondary transform set; deriving a secondary inverse-transformed block by performing a secondary inverse transform on a left top region of the current block by using the secondary transform matrix specified by the first syntax element; and deriving a residual block of the current block by performing a primary inverse transform on the secondary inverse-transformed block using a primary transform matrix of the current block.