Motion Vector Refinement Using Unified Reference Picture
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Solution Overview
Problem
Existing video encoding and decoding methods face challenges in efficiently refining motion vectors, particularly in bi-directional optical flow (BIO) processing, due to high computational complexity and inconsistencies between theoretical and practical implementations.
Innovation Solution
The proposed solution involves simplifying the criteria for determining whether to perform motion vector refinement techniques like BIO by adjusting the conditions and reducing computational complexity, thereby enabling more efficient encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vector refinement techniques like BIO are performed, then motion estimation accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent changes the parameter of reference picture selection by using the same reference picture for both forward and backward motion compensation instead of selecting different reference pictures. This parameter change simplifies the BIO processing computational complexity while maintaining motion estimation accuracy, directly resolving the technical contradiction between precision and complexity.
2Measurement precision
If motion vector refinement is performed, then prediction accuracy is improved, but processing time increases
Solution Approach 1:
The patent modifies the processing parameter by using a unified reference picture for both motion compensation directions, which reduces the number of computational operations required in BIO processing. This parameter change decreases processing time while preserving prediction accuracy, effectively resolving the contradiction between these two factors.
3Measurement precision
If different reference pictures are used for forward and backward motion compensation, then motion estimation accuracy is improved, but inconsistency between theoretical and practical implementations occurs
Solution Approach 1:
The patent changes the reference picture selection parameter to use the same reference picture for both forward and backward motion compensation. This parameter change eliminates the inconsistency between theoretical BIO processing and practical implementation while maintaining adequate motion estimation accuracy, thereby resolving the contradiction between precision and reliability.
Data Source
AI summary
A method for decoding a current block in a current picture of a video bitstream includes decoding, from the video bitstream, a first motion vector for the current block relative to a first reference block of a first reference picture having a first picture order count, and decoding, from the video bitstream, a second motion vector for the current block relative to a second reference block of a second reference picture having a second picture order count. A similarity metric is generated based on a comparison of the first motion vector and the second motion vector. The method further includes determining whether to refine the first motion vector based on the similarity metric, generating a first refined motion vector from the first motion vector, and performing motion compensation to derive a first reference block from the first reference picture using the first refined motion vector.