Nested Entropy Encoding Using VLC Tables for Motion Vectors

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Solution Overview

Problem

Existing video compression systems face challenges in achieving efficient data compression while maintaining image quality, particularly due to high bit rates required for motion vector signaling, which can lead to decoding errors and inefficiencies.

Innovation Solution

A nested entropy encoding structure is employed to signal motion vectors using a plurality of VLC tables based on syntax elements, optimizing coding efficiency by preserving spatial and temporal independence, and reducing overhead through intelligent selection of candidate sets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If motion vectors are signaled using conventional encoding methods, then motion information can be transmitted, but the bit rate becomes excessively high leading to decoding errors and inefficiencies

Engineering Contradiction:

Improvedecoding reliabilityVSAvoidbit rate

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments motion vector signaling into multiple independent VLC tables (first VLC table for motion vector difference, second VLC table for motion vector predictor index). This segmentation allows each component to be encoded with appropriate entropy coding parameters, reducing overall bit rate while maintaining decoding reliability through independent error resilience.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs nested entropy encoding where one VLC table is used to encode indices that select from candidate motion vectors stored in another structure. This nested approach compresses the motion vector information by referencing pre-computed candidates, significantly reducing bit rate while preserving the ability to reconstruct accurate motion vectors for reliable decoding.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If compression techniques discard more frame data to reduce bit rate, then data transmission becomes more efficient, but image quality deteriorates

Engineering Contradiction:

Improvecompression efficiencyVSAvoidimage quality

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent changes the parameter representation by using motion vector predictors and difference encoding instead of transmitting full motion vectors. This parameter transformation achieves higher compression efficiency by exploiting temporal redundancy, while the use of multiple VLC tables with syntax-element-based selection ensures that critical motion information is preserved, maintaining image quality.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single VLC table is used for encoding motion vectors, then the encoding process is simpler, but coding efficiency is reduced

Engineering Contradiction:

Improveencoding complexityVSAvoidcoding efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent introduces dynamic selection of VLC tables based on syntax elements and candidate set conditions. The encoder dynamically chooses between first and second VLC tables depending on the motion vector predictor index and other syntax elements, optimizing coding efficiency for different scene conditions while maintaining manageable encoding complexity through systematic decision rules.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12519969B2System for nested entropy encoding

Publication Date: 2026.01.06 DOLBY INTERNATIONAL AB

AI summary

Methods and systems for improving coding efficiency of video.