DMVR Inter Prediction Refinement for Lower-Complexity Video Decoding

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Solution Overview

Problem

The increasing demand for high-resolution and high-quality images and videos, along with immersive media formats, necessitates a high-efficiency image and video compression technology to reduce transmission and storage costs while maintaining quality.

Innovation Solution

Implementing decoder-side motion vector refinement (DMVR) and bi-directional optical flow (BDOF) with application conditions to enhance inter prediction efficiency, reducing calculation complexity and improving overall coding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high-resolution and high-quality images and videos are transmitted, then image and video quality is improved, but transmission costs and storage costs are increased

Engineering Contradiction:
Improveimage and video qualityVSAvoidtransmission costs and storage costs
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting motion vector refinement operations based on picture characteristics and coding conditions. The system changes parameters such as refinement precision and computational complexity based on the specific requirements of different video sequences, achieving high quality compression without excessive transmission and storage costs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements partial action by selectively applying motion vector refinement only to specific blocks or regions where it is most beneficial, rather than uniformly processing the entire image. This partial refinement approach maintains image quality while significantly reducing the overall computational burden and associated costs.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If decoder-side motion vector refinement (DMVR) is applied to enhance prediction accuracy, then inter prediction efficiency is improved, but calculation complexity is increased

Engineering Contradiction:
Improveprediction accuracyVSAvoidcalculation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the motion vector refinement process adaptive and configurable. The system dynamically adjusts the refinement strength and computational complexity based on picture characteristics, coding conditions, and available resources. This allows the system to optimize between prediction accuracy and calculation complexity in real-time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements local quality by applying different levels of motion vector refinement to different regions of the image based on their specific requirements. Areas with complex motion patterns receive more refined prediction, while regions with simple motion receive less processing, thereby optimizing the balance between accuracy and complexity.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If bi-directional optical flow (BDOF) is applied to refine motion information, then prediction performance is enhanced, but processing time is increased

Engineering Contradiction:
Improveprediction performanceVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies periodic action by implementing multi-stage motion vector refinement processes that operate in sequential phases. The BDOF algorithm is applied in periodic intervals or at specific stages of the coding process rather than continuously, maintaining prediction performance while managing processing time through staged computation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements preliminary action by performing motion information refinement in advance during encoding, so that the refined motion vectors are available for subsequent decoding operations. This preliminary processing of motion information can reduce the computational burden during actual prediction and rendering operations.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4459986B1DMVR-based inter-prediction device
Publication Date: 2026.04.01 LG ELECTRONICS INC
  • EP4459986B1 patent drawingFigure 1
  • EP4459986B1 patent drawingFigure 2
  • EP4459986B1 patent drawingFigure 3

AI summary

An image decoding method according to the present document comprises the steps of: determining whether or not an application condition of decoder-side motion vector refinement (DMVR) for applying motion vector refinement for a current block is satisfied; deriving a minimum sum of absolute differences (SAD) on the basis of L0 and L1 motion vectors of the current block if the application condition of the DMVR is satisfied; deriving refined L0 and L1 motion vectors of the current block on the basis of the minimum SAD; deriving prediction samples of the current block on the basis of the refined L0 and L1 motion vectors; and generating reconstructed samples of the current block on the basis of the prediction samples. With respect to whether or not the application condition of the DMVR is satisfied, the application condition of the DMVR is determined to be satisfied if a prediction mode, in which inter-prediction and intra-prediction are combined, is not applied to the current block.