Affine Motion Vector Precision Selection for Video Coding Efficiency
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Solution Overview
Problem
Existing video coding standards like HEVC and VVC face challenges in achieving superior coding efficiency due to limitations in motion vector precision and modeling complex motion patterns, leading to suboptimal compression performance.
Innovation Solution
Adaptive motion vector precision is introduced for affine motion models, allowing for block-by-block selection of motion vector precisions such as ¼-pel, 1/16-pel, and 1-pel, and employing four- or six-parameter motion models to enhance prediction accuracy and reduce signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed motion vector precision is used in existing video coding standards, then implementation is simpler, but coding efficiency is limited
Solution Approach 1:
The patent implements dynamic motion vector precision by allowing the precision of motion vectors to vary adaptively across different blocks and prediction modes. The system selects from multiple precision levels (e.g., 1/4-pel, 1/8-pel, 1/16-pel) based on local motion characteristics, transforming the static precision approach into a dynamic one that optimizes coding efficiency while managing complexity through adaptive selection mechanisms.
Solution Approach 2:
The patent applies different motion vector precisions to different spatial regions and block types within the video frame. By analyzing local motion complexity and characteristics, the system assigns higher precision to regions with complex motion patterns and lower precision to regions with simple motion, thereby improving overall coding efficiency without uniformly increasing complexity across the entire video stream.
2Measurement precision
If higher motion vector precision is used, then prediction accuracy improves, but signaling overhead increases
Solution Approach 1:
The patent changes the precision parameter of motion vectors adaptively based on local motion characteristics. By adjusting the precision parameter (e.g., selecting between 1/4-pel, 1/8-pel, 1/16-pel) according to motion complexity, the system achieves higher prediction accuracy where needed while minimizing signaling overhead in regions where high precision is not necessary, thus optimizing the trade-off between accuracy and overhead.
Solution Approach 2:
The patent applies high motion vector precision only partially to specific blocks or regions where it is most beneficial, rather than uniformly across the entire video frame. This selective application of high precision reduces the overall signaling overhead while maintaining prediction accuracy in critical areas with complex motion patterns.
3Productivity
If adaptive motion vector precision is implemented, then compression performance improves, but computational complexity increases
Solution Approach 1:
The patent performs preliminary analysis of motion characteristics before final motion vector encoding. By pre-assessing motion complexity and predicting the appropriate precision level for each block, the system avoids unnecessary computational operations, thereby improving compression performance while controlling computational complexity through early decision-making about precision requirements.
Data Source
AI summary
Systems and methods are described for video coding using affine motion models with adaptive precision. In an example, a block of video is encoded in a bitstream using an affine motion model, where the affine motion model is characterized by at least two motion vectors. A precision is selected for each of the motion vectors, and the selected precisions are signaled in the bitstream. In some embodiments, the precisions are signaled by including in the bitstream information that identifies one of a plurality of elements in a selected predetermined precision set. The identified element indicates the precision of each of the motion vectors that characterize the affine motion model. In some embodiments, the precision set to be used is signaled expressly in the bitstream; in other embodiments, the precision set may be inferred, e.g., from the block size, block shape or temporal layer.