Inter-prediction Motion Vector Scaling for Image Coding
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Solution Overview
Problem
High-resolution and high-quality image data requires efficient compression techniques to reduce transmission and storage costs, as existing methods struggle to accurately derive motion information for current blocks in image coding systems.
Innovation Solution
A method and apparatus for deriving a motion vector of a current block by scaling the motion vector of a corresponding block based on temporal distances and updating the corresponding block's position to improve prediction accuracy, thereby constructing a merge candidate list or MVP candidate list.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional motion vector derivation methods are used, then the coding process is simple, but the prediction accuracy is insufficient for high-resolution images
Solution Approach 1:
The patent performs preliminary actions by deriving motion vectors for corresponding blocks in reference pictures before using them to predict the current block. This includes scaling motion vectors based on temporal distances and updating corresponding block positions in advance, which improves prediction accuracy without significantly increasing overall coding complexity.
Solution Approach 2:
The patent introduces corresponding blocks as intermediary elements between the reference picture and the current block. By deriving motion vectors from these corresponding blocks and using them as mediators for prediction, the system achieves better accuracy while maintaining a manageable coding process.
2Reliability
If high-resolution and high-quality image data is transmitted using conventional methods, then the image quality is maintained, but the transmission cost and storage cost increase
Solution Approach 1:
The patent changes parameters by deriving and scaling motion vectors based on temporal distances between pictures. This allows for more efficient motion compensation that maintains high image quality while reducing the bitrate required for transmission, thereby lowering transmission and storage costs.
Solution Approach 2:
The patent replaces conventional motion vector derivation mechanisms with an improved system that uses corresponding block updates and temporal distance scaling. This substitution enables better compression efficiency while maintaining image quality, reducing the energy and cost associated with transmitting and storing high-resolution image data.
3Measurement precision
If the motion vector of the corresponding block is used directly without scaling, then the processing is faster, but the motion information accuracy decreases
Solution Approach 1:
The patent applies parameter changes by scaling the motion vector based on the ratio of temporal distances. This scaling operation adjusts the motion vector magnitude to account for different time intervals between reference pictures and the current picture, improving motion information accuracy while adding only a simple computational step that minimally impacts processing speed.
Data Source
AI summary
An image decoding method performed by a decoding apparatus includes the operations: deriving a correspondence block corresponding to the current block of the current picture, the correspondence block being located in a co-located picture; deriving a movement vector of the correspondence block; scaling the movement vector of the correspondence block based on a first temporal distance and second temporal distance, the first temporal distance being the difference between the POC values of the co-located picture and POC values of the reference picture of the correspondence block, and the second temporal distance being the difference between the POC values of the co-located picture and POC values of the current picture containing the current block; deriving the movement vector updated based on the scaled movement vector and location of the current block; and deriving a movement vector of the current block based on the updated movement vector.