Video Coding Motion Vector Difference Derivation
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Solution Overview
Problem
Current video coding techniques, such as VVC, face challenges in efficiently transmitting and deriving motion vector differences during bi-directional inter-prediction, which affects video quality and coding efficiency as image sizes, resolutions, and frame rates increase.
Innovation Solution
A video coding method and apparatus that parse one motion vector difference to derive the remaining motion vector difference or refine the remaining motion vector during bi-directional inter-prediction, enhancing video quality and coding efficiency by utilizing the decoded LX motion vector difference to calculate the L1-X motion vector difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both LX motion vector difference and L1-X motion vector difference are transmitted separately in the bitstream, then the decoding accuracy is improved, but the bitstream length increases and coding efficiency decreases
Solution Approach 1:
The patent extracts only the LX motion vector difference from the bitstream and derives the L1-X motion vector difference through symmetry relationships, removing the redundant transmission of L1-X motion vector difference while maintaining decoding accuracy
Solution Approach 2:
The transmitted LX motion vector difference serves multiple purposes: it is used directly for LX motion vector compensation and also serves as the basis for deriving the L1-X motion vector difference through symmetry relationships, reducing overall bitstream requirements
2Productivity
If the SMVD technique is applied with symmetric reference pictures, then the coding efficiency is improved, but the complexity of motion vector difference derivation increases
Solution Approach 1:
The patent applies asymmetry by treating the LX and L1-X motion vector differences differently in the bitstream - only LX is transmitted explicitly while L1-X is derived through symmetry relationships, simplifying the overall derivation process while maintaining coding efficiency
Data Source
AI summary
A method and an apparatus for video coding using a motion vector difference derivation includes parsing one motion vector difference when a motion vector pair is derived during bi-directional inter-prediction of the current block. The video coding method and the apparatus use the parsed one motion vector difference to derive the remaining motion vector difference or to refine the remaining motion vector.