Merge Candidate List Construction for Video Coding

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Solution Overview

Problem

Existing video compression methods, such as H.264/MPEG-4 AVC, face inefficiencies in encoding motion information when varying block sizes are used for inter prediction, as they fail to effectively utilize spatial and temporal redundancy between neighboring blocks, leading to suboptimal coding efficiency.

Innovation Solution

A method is introduced to construct a merge candidate list by checking availability of spatial and temporal merge candidates, including motion information from neighboring blocks, and adaptively adjusting quantization parameters to improve coding efficiency, particularly by setting certain spatial merge candidates as unavailable based on asymmetric partitioning and block positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If motion information is predictively encoded using neighboring motion vectors, then coding efficiency is improved, but the complexity of determining available candidates increases

Engineering Contradiction:
Improvecoding efficiencyVSAvoidcomplexity of determining available candidates
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of candidate availability determination by introducing specific conditions based on asymmetric partitioning and block size relationships. Instead of uniformly checking all neighboring blocks, the patent modifies the availability parameters based on partition type (first vs second prediction unit) and size comparisons, thereby improving coding efficiency while managing complexity through parameter-based differentiation.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If various sizes are used for inter prediction, then adaptability is improved, but the correlation between motion information of current block and neighboring blocks increases leading to encoding inefficiency

Engineering Contradiction:
Improveadaptability of block sizesVSAvoidencoding efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies local quality by treating different spatial regions and block configurations differently. Specifically, it determines availability of merge candidates based on local conditions such as whether a neighboring block is a first or second prediction unit, and whether size conditions are met. This localized approach allows the system to maintain high adaptability across various block sizes while improving encoding efficiency by selectively utilizing motion information only from appropriate neighboring blocks.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4224855A1Method of constructing merge list
Publication Date: 2023.08.09 GENSQUARE LLC
  • EP4224855A1 patent drawingFigure 1
  • EP4224855A1 patent drawingFigure 2
  • EP4224855A1 patent drawingFigure 3

AI summary

Provided is a method checks availability of spatial merge candidates and a temporal merge candidate, constructs a merge candidate list using available spatial and temporal merge candidates, and adds one or more candidates if the number of available spatial and temporal merge candidates is smaller than a predetermined number. The spatial merge candidate is motion information of a spatial merge candidate block, the spatial merge candidate block is a left block, an above block, an above-right block, a left-below block or an above-left block of the current block, and if the current block is a second prediction unit partitioned by asymmetric partitioning, the spatial merge candidate corresponding to a first prediction unit partitioned by the asymmetric partitioning is set as unavailable. Therefore, the coding efficiency of motion information is improved by removing unavailable merge candidates and adding new merge candidates from the merge list.