Image Coding With Affine Motion Vector Compression
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to a significant increase in the amount of information to be transmitted and stored, resulting in higher transmission and storage costs due to inefficient image compression techniques.
Innovation Solution
A method and apparatus for enhancing image coding efficiency by using motion vector compression in the inter prediction process, reducing the number of bits required to store motion vector information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vector information is stored with high precision for inter prediction, then image coding quality is improved, but the number of bits required for storage increases
Solution Approach 1:
The patent applies parameter changes by transforming the motion vector representation from full precision to compressed precision. Specifically, it uses differential encoding where only the difference between motion vectors of adjacent blocks is stored, and applies threshold-based compression where small differences are represented with fewer bits. This changes the parameter of motion vector storage from full precision to variable precision based on actual variation, resolving the contradiction between precision and bit quantity.
Solution Approach 2:
The patent extracts only the essential information needed for reconstruction by storing motion vector differences rather than complete motion vectors. It separates the motion vector into a reference component (shared among blocks) and a differential component (specific to each block), storing only the differential part. This extraction principle reduces storage requirements while maintaining sufficient coding quality.
2Quantity of substance
If motion vector compression is applied in inter prediction, then the number of bits for storage is reduced, but image coding efficiency may be affected
Solution Approach 1:
The patent applies partial action by using full precision motion vectors only when necessary (when motion vector differences exceed a threshold) and compressed precision when sufficient. This selective approach applies compression partially rather than universally, maintaining coding efficiency where full precision is needed while achieving bit reduction where compression is adequate.
Solution Approach 2:
The patent uses feedback mechanisms where the encoder evaluates the impact of motion vector compression on reconstruction quality and adjusts the compression level accordingly. The decoder reconstructs motion vectors using the compressed differential information and the transmitted reference motion vectors, with the system adapting the compression strategy based on observed performance, thus maintaining efficiency while achieving compression.
Data Source
AI summary
A picture decoding method performed by a decoding apparatus according to the present disclosure includes obtaining motion prediction information from bitstream, generating an affine MVP candidate list including affine MVP candidates for a current block, deriving CPMVPs for respective CPs of the current block based on one of the affine MVP candidates included in the affine MVP candidate list, deriving the CPMVDs for the CPs of the current block based on information on CPMVDs for each of the CPs included in the obtained motion prediction information, deriving CPMVs for the CPs of the current block based on the CPMVPs and the CPMVDs, deriving prediction samples for the current block based on the CPMVs, and generating reconstructed samples for the current block based on the derived prediction samples.