Adaptive Spatially Varying Transform for Residual Block Coverage

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Solution Overview

Problem

The existing Spatially Varying Transform (SVT) scheme for video coding faces challenges with heavy signaling overhead and increased encoder complexity due to the large number of candidate positions for transform block placement, and the transform blocks may not adequately cover the major residuals in larger residual blocks.

Innovation Solution

Adaptive use of SVT-V and SVT-H transform types with discrete sine transforms (DST) and discrete cosine transforms (DCT) based on block position and size, reducing the number of candidate positions and simplifying the decoding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the number of candidate positions for transform block placement is increased to improve residual coverage, then the transform block can capture more major residuals, but the signaling overhead and encoder complexity increase significantly

Engineering Contradiction:

Improveresidual coverage accuracyVSAvoidencoder complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating transform block placement strategies based on residual block characteristics. Different transform block sizes (SVT-I, SVT-II, SVT-III types) are selected adaptively according to the specific residual patterns in different regions, allowing optimized residual coverage without uniformly increasing complexity across all blocks

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the transform block configuration adaptive rather than fixed. The encoder dynamically selects from multiple SVT types and positions based on rate-distortion optimization, allowing the system to adjust transform parameters according to actual residual distributions in each block

Inventive Principle:

Principle #15Dynamics

2Productivity

If the transform block size is reduced to focus on major residuals, then coding efficiency improves, but the ability to cover larger residual blocks adequately is compromised

Engineering Contradiction:

Improvecoding efficiencyVSAvoidtransform block coverage area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The patent applies segmentation by dividing the transform block placement into multiple discrete candidate positions and types (SVT-I, SVT-II, SVT-III) with different sizes and locations. This allows the system to select appropriate segment sizes that match the residual distribution, achieving both efficiency and adequate coverage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements parameter changes by varying transform block size parameters (width and height) across different SVT types. The encoder adjusts these parameters adaptively based on the residual block characteristics, allowing smaller blocks for high-frequency residuals and larger blocks for low-frequency patterns

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12470735B2Spatially varying transform with adaptive transform type

Publication Date: 2025.11.11 HUAWEI TECH CO LTD

AI summary

A video decoding method includes determining a usage of an SVT-vertical (V) or an SVT-horizontal (H) for a residual block; determining a transform block position of a transform block of the residual block; determining a transform type of the transform block, wherein the transform type indicates a horizontal transform and a vertical transform for the transform block, wherein at least one of the horizontal transform or the vertical transform is a discrete sine transform (DST)-7; and reconstructing the residual block based on the transform type, the transform block position, and transform coefficients of the transform block.