Affine Motion Signaling for Efficient Video Block Prediction

Solution Overview

Problem

The existing video coding standards, such as HEVC, face challenges in efficiently handling complex motions like zoom, rotation, and perspective transformations due to the complexity and increased signal overhead associated with affine motion mode, which can hinder coding efficiency and increase processing complexity.

Innovation Solution

The method involves determining the inter prediction mode and signaling affine motion mode based on the status of a skip flag, enabling or disabling affine mode accordingly, and optimizing the encoding process by considering neighboring block configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If affine motion mode is applied to handle complex motions (zoom, rotation, perspective), then motion prediction accuracy is improved, but encoder complexity and signal overhead increase

Engineering Contradiction:

Improvemotion prediction accuracyVSAvoidencoder complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies affine motion mode selectively only to specific blocks that exhibit complex motion characteristics, rather than uniformly to all blocks. The encoder determines whether to apply affine mode based on local motion analysis, applying the complex transform only where needed to improve prediction accuracy for blocks with zoom, rotation, or perspective motion, while keeping other blocks processed with simpler methods.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces dynamic switching between different motion modes (affine and non-affine) based on the characteristics of each block. The encoder can adaptively choose whether to apply affine motion mode on a block-by-block basis, allowing the system to transition between simple and complex processing modes depending on the local motion content, thereby optimizing the balance between accuracy and complexity.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If affine motion mode is applied to handle complex motions, then motion prediction accuracy is improved, but signal overhead increases

Engineering Contradiction:

Improvemotion prediction accuracyVSAvoidsignal overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies affine motion mode selectively only to specific blocks that exhibit complex motion characteristics, rather than uniformly to all blocks. The encoder determines whether to apply affine mode based on local motion analysis, applying the complex transform only where needed to improve prediction accuracy for blocks with zoom, rotation, or perspective motion, while keeping other blocks processed with simpler methods.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If affine motion mode is applied to all blocks, then motion prediction accuracy is improved, but encoding speed decreases

Engineering Contradiction:

Improvemotion prediction accuracyVSAvoidencoding speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent applies affine motion mode to only a subset of blocks that benefit most from complex motion modeling, rather than applying it excessively to all blocks. This partial application approach ensures sufficient motion prediction accuracy for complex regions while maintaining encoding speed by avoiding unnecessary complex processing in regions where simple motion models suffice.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12634501B2Video coding and decoding

Publication Date: 2026.05.19 CANON KK

AI summary

The invention relates to signalling affine mode in an encoded video stream; in particular determining a list of merge candidates corresponding to blocks neighbouring a current block; and signalling affine mode for said current block; wherein signalling said affine mode comprises decoding a context encoded flag from the data stream, and wherein the context variable for said flag is determined based on whether or not said neighbouring blocks use affine mode. Related encoding and decoding methods and devices are also disclosed.