Weighting Factors for Prediction Sample Filtering in Intra Modes

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Solution Overview

Problem

Current video coding technologies face challenges in efficiently handling non-square blocks and wide-angle intra prediction modes, particularly in determining weighting factors for neighboring samples in planar and DC modes, which affects prediction accuracy and bandwidth usage.

Innovation Solution

The proposed method involves deriving weighting factors for neighboring samples based on the dimensions and positions of the current video block, using a position-dependent intra prediction combination (PDPC) method that combines neighboring samples with a prediction signal to generate a refined prediction signal, specifically for planar and DC modes, and applying these factors during video encoding and decoding processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional intra prediction methods are used for non-square blocks, then the coding process is simple, but the prediction accuracy is insufficient

Engineering Contradiction:
Improveprediction accuracyVSAvoidcoding complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies different weighting factor determination methods to different prediction modes (planar/DC modes use dimension/position-based weighting, while angular modes use gradient-based weighting). This local differentiation optimizes prediction accuracy for each mode type without uniformly increasing complexity across all modes, resolving the contradiction between accuracy and complexity.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If position-dependent intra prediction combination is applied to all modes, then prediction accuracy improves, but computational complexity increases

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent segments the intra prediction modes into two categories: planar/DC modes that benefit from position-dependent weighting factors based on block dimensions, and angular modes that use gradient-based weighting. This segmentation allows selective application of computationally intensive methods only where beneficial, improving accuracy while controlling overall complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies position-dependent intra prediction combination selectively to planar and DC modes rather than all intra prediction modes. This partial application provides sufficient accuracy improvement for modes where it matters most while avoiding unnecessary computational overhead in angular modes, resolving the power-complexity tradeoff.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If weighting factors are determined from block dimensions and positions, then prediction quality improves for planar and DC modes, but the method becomes more complex

Engineering Contradiction:
Improveprediction qualityVSAvoidmethod complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameters used for weighting factor determination based on prediction mode: for planar and DC modes, it uses block dimensions and sample positions as parameters; for angular modes, it uses gradient calculations. This parameter adaptation improves prediction quality for each mode type while keeping the overall method manageable through systematic parameter selection.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11533477B2Weighting factors for prediction sample filtering in intra mode
Publication Date: 2022.12.20 BYTEDANCE INC
  • US11533477B2 patent drawing
  • US11533477B2 patent drawing
  • US11533477B2 patent drawing

AI summary

A video processing method is provided to include: deriving weighting factors for neighboring samples of samples of a current video block of a video according to a rule; and performing a conversion between the current video block and a coded representation of the video, and wherein the rule specifies that, in case that the current video block is coded using a planar mode or a DC mode, the weighting factors are determined from at least one of a dimension of the current video block or positions of the samples of the current video block, wherein the current video block uses a PDPC method that combines the neighboring samples with a prediction signal of the current video block to generate a refined prediction signal, and wherein a weighting factor of a prediction signal of a sample is determined based on weighting factors of corresponding neighboring samples of the sample.