High-Definition Video Coding with Subblock Affine Motion Compensation
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Solution Overview
Problem
Existing video compression technologies, such as HEVC, face limitations in efficiently encoding and decoding high-definition video signals due to increased data volume, necessitating improved methods for video signal encoding and decoding.
Innovation Solution
An inter prediction method using an affine model is employed, where affine seed vectors are derived from translational motion vectors of subblocks, and the distance between neighboring blocks and current blocks is transformed into a power series of 2, enhancing encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If HEVC video compression standard is used to improve compression performance, then compression rate is improved (about twice as high as H.264/AVC), but data volume still increases significantly with high-definition video services
Solution Approach 1:
The current block is divided into multiple subblocks, and affine motion compensation is applied to each subblock independently. This segmentation allows for more precise local motion modeling, improving compression efficiency by better matching the actual motion patterns in different regions of the block.
Solution Approach 2:
The patent transforms the distance between control points into a power series of 2 (i.e., logarithmic transformation). This parameter change simplifies the calculation of affine motion vectors and enables more efficient encoding by reducing the computational complexity and memory requirements.
2Measurement precision
If affine motion compensation is applied to the entire current block, then prediction accuracy is improved, but computational complexity and encoding overhead increase
Solution Approach 1:
The current block is divided into multiple subblocks, and affine motion compensation is applied to each subblock independently. This segmentation allows for more precise local motion modeling, improving compression efficiency by better matching the actual motion patterns in different regions of the block.
Solution Approach 2:
Instead of applying full affine motion compensation to the entire block, the patent applies it selectively to subblocks where motion complexity warrants it. This partial application reduces computational overhead while maintaining prediction accuracy in regions that require it.
3Ease of operation
If distance between neighboring block and current block is used directly for affine seed vector derivation, then motion prediction is straightforward, but encoding efficiency decreases due to non-power-of-2 distances
Solution Approach 1:
The patent transforms the distance between control points into a power series of 2 (i.e., logarithmic transformation). This parameter change simplifies the calculation of affine motion vectors and enables more efficient encoding by reducing the computational complexity and memory requirements.
Data Source
AI summary
An image decoding method according to the present application includes the steps of: generating a merge candidate list in a current block; specifying one of a plurality of merge candidates included in the merge candidate list; deriving a first affine seed vector and a second affine seed vector of the current block on the basis of a first affine seed vector and a second affine seed vector of the specified merge candidate; deriving an affine vector for a subblock in the current block, using the first affine seed vector and the second affine seed vector of the current block; and performing motion compensation prediction for the subblock on the basis of the affine vector.