Affine Motion Derivation via Template Matching
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Solution Overview
Problem
Current video coding techniques face challenges in efficiently compressing high-quality video data, leading to increased storage and transmission requirements, and existing affine motion modeling methods have high signaling costs and complex processing requirements.
Innovation Solution
The proposed solution involves decoder-side affine motion derivation, where affine motion parameters are determined using templates without requiring affine motion information in the bitstream, allowing for template matching based affine motion derivation to estimate complex motions like rotation and zooming without signaling affine motion parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If affine motion parameters are signaled in the bitstream, then motion estimation accuracy is improved, but signaling cost and bitstream size increase
Solution Approach 1:
The decoder derives affine motion parameters independently using template matching on reconstructed neighboring blocks, without requiring the encoder to signal these parameters. This self-service approach eliminates signaling overhead while maintaining accurate motion estimation through local template analysis.
Solution Approach 2:
Template blocks serve as intermediaries between the encoded bitstream and the affine motion parameters. By using reconstructed neighboring blocks as templates and matching them against current block regions, the system indirectly derives accurate motion parameters without direct signaling.
2Adaptability or versatility
If affine motion modeling is implemented, then complex motion estimation capability is improved, but processing complexity increases
Solution Approach 1:
The current block is divided into multiple template regions (e.g., top, left, and other neighboring blocks) that are processed independently. Each template region is matched separately to derive component motion vectors, which are then combined to form the final affine motion parameters. This segmentation reduces per-template processing complexity.
Solution Approach 2:
Instead of performing full affine motion estimation across the entire block, the method uses partial action by applying template matching only to selected neighboring regions. This selective approach provides sufficient motion estimation capability for complex motions while significantly reducing overall processing complexity.
3Productivity
If template matching based affine motion derivation is used, then coding efficiency is improved, but computational load increases
Solution Approach 1:
The method uses already-reconstructed neighboring blocks as templates, which are available from previous decoding operations. This preliminary availability of template data eliminates the need for separate template generation, reducing computational load while maintaining coding efficiency through effective template matching.
Data Source
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AI summary
Techniques and systems are provided for deriving one or more sets of affine motion parameters at a decoder. For example, the decoder can obtain video data from an encoded video bitstream. The video data includes at least a current picture and a reference picture. The decoder can determine a set of affine motion parameters for a current block of the current picture. The set of affine motion parameters can be used for performing motion compensation prediction for the current block. The set of affine motion parameters can be determined using a current affine template of the current block and a reference affine template of the reference picture. In some cases, an encoder can determine a set of affine motion parameters for a current block using a current affine template of the current block and a reference affine template of the reference picture, and can generate an encoded video bitstream that includes a syntax item indicating template matching based affine motion derivation mode is to be used by a decoder for the current block. The encoded video bitstream may not include any affine motion parameters for determining the set of affine motion parameters.