Image Residual Coding with Last-Coefficient Limits for Faster CABAC

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Solution Overview

Problem

The increasing demand for high-resolution, high-quality images and videos, such as 4K and 8K Ultra High Definition, along with the growth of virtual reality and immersive media, has led to a need for more efficient image compression techniques to reduce transmission and storage costs, while existing methods like CABAC face throughput issues due to high data dependency.

Innovation Solution

An image decoding method that derives the maximum number of context coded bins based on the position of the last significant coefficient of a block, optimizing the encoding and decoding processes to enhance throughput and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If CABAC is used for residual coding, then compression efficiency is improved, but throughput is reduced due to high data dependency

Engineering Contradiction:
Improvecompression efficiencyVSAvoidthroughput
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent segments the residual coding process by dividing the transform coefficients into multiple groups and applying different context modeling strategies to each group. This segmentation reduces the data dependency within each group while maintaining overall compression efficiency, thereby improving throughput without sacrificing compression performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic context adaptation where the context models are updated and adjusted based on the statistical properties of the residual data. This dynamic approach allows the system to adapt to varying data characteristics, reducing data dependency and improving processing throughput while maintaining high compression efficiency.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the number of context coded bins is increased, then coding precision is improved, but processing complexity increases

Engineering Contradiction:
Improvecoding precisionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by using different context modeling approaches for different regions or groups of transform coefficients. Instead of uniformly increasing the number of context coded bins across all coefficients, the patent selectively applies enhanced context modeling only where necessary, thereby maintaining coding precision while reducing overall processing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameters of context modeling by adjusting the number of context coded bins dynamically based on the characteristics of the residual data. This parameter adaptation allows the system to achieve high coding precision when needed while reducing complexity when the data characteristics allow for simpler modeling.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250220235A1Method and device for coding residual information in image coding system
Publication Date: 2025.07.03 LG ELECTRONICS INC
  • US20250220235A1 patent drawing
  • US20250220235A1 patent drawing
  • US20250220235A1 patent drawing

AI summary

According to the present disclosure, an image decoding method performed by a decoding device comprises the steps of: receiving a bitstream including residual information on a current block; deriving the maximum number of context coded bins related to the residual information; decoding syntax elements included in the residual information on the basis of the maximum number of context coded bins; deriving transform coefficients for the current block on the basis of the decoded syntax elements; deriving residual samples for the current block on the basis of the transform coefficients; and generating reconstruction samples for the current block on the basis of the residual samples for the current block, wherein the maximum number of context coded bins is derived on the basis of a position of a last significant coefficient of the current block.