Affine Mode Signaling With Mode-Specific CABAC Contexts

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Solution Overview

Problem

Existing video compression systems, such as VVC, face inefficiencies in encoding and decoding affine flags due to the use of a single CABAC context for different inter-prediction modes, failing to capture the varying statistical behaviors of affine mode usage.

Innovation Solution

Implementing separate CABAC contexts and probability models for affine mode and other inter-prediction modes, such as AMVP and merge, to independently encode and decode affine flags, thereby adapting to the specific statistical behaviors of each mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single CABAC context is used for different inter-prediction modes, then device complexity is reduced, but compression efficiency deteriorates due to inability to capture varying statistical behaviors

Engineering Contradiction:
ImproveCABAC context structureVSAvoidStatistical behavior information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent segments the single CABAC context into multiple mode-specific contexts (affine context and non-affine context). Each context is dedicated to a specific inter-prediction mode, allowing independent probability modeling that captures the distinct statistical behaviors of affine and non-affine modes without increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the CABAC context adaptive to local mode characteristics. Each inter-prediction mode receives a customized context with probability models tailored to its specific statistical properties, improving the accuracy of probability estimation for each mode while maintaining a manageable overall structure.

Inventive Principle:
Principle #3Local quality

2Loss of information

If separate CABAC contexts are implemented for different modes, then compression efficiency is improved through accurate probability modeling, but device complexity increases

Engineering Contradiction:
ImproveProbability modeling accuracyVSAvoidCABAC context management
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent implements dynamic context selection where the CABAC context automatically adapts to the current inter-prediction mode. The system dynamically switches between affine and non-affine contexts based on the mode being used, allowing accurate probability modeling for each mode while avoiding the need for manual context management and reducing overall complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal CABAC context management structure that handles multiple inter-prediction modes through a single unified mechanism. The context selection logic serves as a multi-functional component that routes to the appropriate context based on mode, improving probability modeling accuracy without proportionally increasing device complexity.

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

3Manufacturing precision

If mode-specific probability models are used, then encoding precision is improved, but encoding complexity increases

Engineering Contradiction:
ImproveEncoding precisionVSAvoidProbability model management
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent prepares mode-specific probability models in advance, with each context pre-configured for its designated inter-prediction mode. This preliminary setup eliminates the need for complex runtime model selection and switching, achieving high encoding precision through accurate pre-adapted probability models while keeping the encoding process itself simple and efficient.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12581081B2Affine mode signaling in video encoding and decoding
Publication Date: 2026.03.17 INTERDIGITAL VC HOLDINGS INC
  • US12581081B2 patent drawing
  • US12581081B2 patent drawing
  • US12581081B2 patent drawing

AI summary

In general, encoding or decoding a picture part can involve a first CABAC probability model associated with a first flag indicating use of an affine mode and a second CABAC probability model associated with a second flag indicating use of either the affine mode or a second mode different from the affine mode, where the first and second CABAC probability models are different and are determined independently.