CABAC Context Modeling Using Multiple Spatial Neighbors

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Solution Overview

Problem

Existing video coding technologies face challenges in efficiently utilizing spatial neighboring blocks for context-based adaptive binary arithmetic coding (CABAC) context modeling, leading to suboptimal compression and decoding performance.

Innovation Solution

The method determines a CABAC context model for a current block based on decoding parameters of multiple spatially neighboring blocks, including specific conditions such as merge subblock, inter affine, and local illumination compensation flags, to enhance context modeling accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional CABAC context modeling using limited spatial neighbors is used, then device complexity is reduced, but compression efficiency deteriorates

Engineering Contradiction:
Improvecompression efficiencyVSAvoidcontext modeling complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the spatial neighborhood into multiple zones (e.g., left, above, above-right, above-left neighbors) and selectively applies different context modeling strategies to each segment. This allows the system to utilize more spatial information for improved compression while managing complexity through structured segmentation of the neighbor analysis process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically adapts the context model selection based on the actual characteristics of neighboring blocks. Instead of using a fixed context modeling approach, the system evaluates multiple candidate context models and selects the most appropriate one based on the specific spatial configuration and content of neighboring blocks, thereby improving compression efficiency adaptively.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If more spatial neighboring blocks are used for context modeling, then context modeling accuracy is improved, but processing complexity increases

Engineering Contradiction:
Improvecontext modeling accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by selectively analyzing only the most relevant neighboring blocks based on their proximity and similarity to the current block. Instead of uniformly processing all possible neighbors, the system focuses computational resources on the most informative neighbors, achieving good context modeling accuracy with reduced processing complexity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent applies different context modeling techniques to different spatial locations based on local characteristics. For example, blocks with similar content to their neighbors use simpler context models, while blocks with unique content use more sophisticated modeling approaches, thereby optimizing the balance between accuracy and complexity locally.

Inventive Principle:
Principle #3Local quality

3Productivity

If advanced context modeling with multiple flags is used, then decoding performance is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvedecoding performanceVSAvoidimplementation complexity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent performs preliminary analysis of neighboring blocks and pre-determines the appropriate context model before actual decoding. By evaluating the merge subblock flag, inter affine flag, and local illumination compensation flag in advance and selecting the context model beforehand, the system improves decoding performance while reducing the operational complexity during the actual decoding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The context modeling system automatically adapts to different block types and neighboring configurations without requiring manual intervention or complex control logic. The system self-adjusts the context model selection based on the inherent properties of the video content and spatial relationships, improving decoding performance while maintaining ease of implementation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS12526421B2CABAC context modeling with information from spatial neighbors
Publication Date: 2026.01.13 TENCENT AMERICA LLC
  • US12526421B2 patent drawing
  • US12526421B2 patent drawing
  • US12526421B2 patent drawing

AI summary

A method of video decoding performed in a video decoder is provided. In the method, coded information of a current block is received from a coded video bitstream. The coded information includes a context-coded syntax element associated with the current block. The syntax element indicates a decoding parameter of the current block. A context-based adaptive binary arithmetic coding (CABAC) context model associated with the context-coded syntax element is determined based on decoding parameters of more than two spatially neighboring blocks of the current block. The context-coded syntax element is decoded based on the determined CABAC context model associated with the context-coded syntax element. The current block is reconstructed based on the decoded syntax element.