CABAC Bypass Coding for High-Throughput Transform Coefficients

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Solution Overview

Problem

CABAC is a throughput bottleneck in video codec implementations due to feedback loops, making it difficult to achieve high throughput necessary for high resolution and frame-rate videos, especially on battery-operated devices.

Innovation Solution

Implementing a method for CABAC encoding and decoding with scalable throughput by reducing the number of context-coded bins and enabling a high throughput mode, where some or all context bins are bypass coded, allowing for increased processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If context coding mode is used for all bins, then coding efficiency is improved, but throughput is reduced due to feedback loops

Engineering Contradiction:

Improvecoding efficiencyVSAvoidthroughput

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The patent segments the bins into two categories: context bins and bypass bins. Context bins are encoded using context coding mode with feedback loops to maintain coding efficiency, while bypass bins are encoded using bypass coding mode without feedback loops to improve throughput. This segmentation allows the system to achieve both high coding efficiency and high throughput simultaneously.

Inventive Principle:

Principle #1Segmentation

2Loss of information

If CABAC is implemented with feedback loops, then compression ratio is improved, but processing speed is reduced

Engineering Contradiction:

Improvecompression ratioVSAvoidprocessing speed

Core Design Contradiction:

Loss of informationVSSpeed

Solution Approach 1:

The patent dynamically switches between context coding mode and bypass coding mode for different bins based on their characteristics. This dynamic approach allows the system to use feedback loops (context coding) only when necessary for compression efficiency, while using faster bypass coding for other bins, thereby achieving both high compression ratio and high processing speed.

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If voltage scaling is used to reduce power consumption, then battery life is improved, but throughput is reduced

Engineering Contradiction:

Improvepower consumptionVSAvoidthroughput

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent extracts and removes the feedback loop mechanism from the bypass coding path, creating a simplified coding path that requires fewer computational resources. This allows the system to achieve high throughput without requiring high voltage scaling, thereby reducing power consumption and extending battery life while maintaining high throughput capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS12519943B2Context adaptive binary arithmetic coding and bypass coding

Publication Date: 2026.01.06 TEXAS INSTRUMENTS INC

AI summary

A method for encoding a video sequence is provided that includes entropy encoding syntax elements representative of transform coefficients generated as the video sequence is processed, wherein entropy encoding syntax elements representative of a transform coefficient includes binarizing the syntax elements representative of the transform coefficient to generate a plurality of binary symbols (bins), coding a portion of the plurality of bins in context coding mode, and coding a remaining portion of the plurality of bins in bypass coding mode. The method further includes reducing the number of bins that are coded in context coding mode for each transform coefficient in a plurality of subsequent transform coefficients that are entropy encoded after a specified number of transform coefficients have been entropy encoded.