Global Motion Compensation Signaling in Video Coding
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Solution Overview
Problem
Current video coding standards face inefficiencies in utilizing global motion compensation, particularly in determining and signaling the appropriate motion models and parameters across different regions and blocks, which affects coding efficiency and complexity.
Innovation Solution
The method involves signaling a GMC indication to enable global motion compensation, allowing for the selection and use of multiple global motion models, with parameters signaled at a high-level syntax, and combining GMC with local motion compensation for improved efficiency and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple global motion models are used to improve prediction accuracy, then coding efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the global motion model selection adaptive rather than static. The system dynamically selects from multiple global motion models (translational, scaling, affine, perspective) based on the actual motion characteristics of the video content, allowing the complexity to adjust to the requirements of each specific scenario, thus improving coding efficiency without unnecessarily increasing overall device complexity.
Solution Approach 2:
The patent changes parameters by introducing multiple global motion models with different numbers of parameters (2 parameters for translational, 4 for scaling, 6 for affine, 8 for perspective). The system selects the appropriate model based on motion complexity, thereby optimizing the balance between prediction accuracy and computational complexity for different video scenarios.
2Measurement precision
If global motion compensation is enabled for all regions, then prediction accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent applies local quality by enabling global motion compensation selectively for specific regions or coding units rather than uniformly across the entire picture. The system determines whether to apply GMC at the slice, tile, or coding unit level based on local motion characteristics, thus improving prediction accuracy for regions that benefit from it while avoiding unnecessary computational complexity in regions where it is not needed.
Solution Approach 2:
The patent segments the video picture into different regions (slices, tiles, or coding units) and applies global motion compensation independently to each segment. This allows the system to apply GMC only where beneficial, reducing overall computational complexity while maintaining prediction accuracy in regions that require it.
3Adaptability or versatility
If multiple global motion models are signaled in the bitstream, then adaptability is improved, but loss of information increases due to additional signaling overhead
Solution Approach 1:
The patent applies dynamics by making the global motion model selection adaptive rather than static. The system dynamically selects from multiple global motion models (translational, scaling, affine, perspective) based on the actual motion characteristics of the video content, allowing the complexity to adjust to the requirements of each specific scenario, thus improving coding efficiency without unnecessarily increasing overall device complexity.
Solution Approach 2:
The patent changes parameters by introducing multiple global motion models with different numbers of parameters (2 parameters for translational, 4 for scaling, 6 for affine, 8 for perspective). The system selects the appropriate model based on motion complexity, thereby optimizing the balance between prediction accuracy and computational complexity for different video scenarios.
Data Source
AI summary
A method and apparatus of Inter prediction for video coding performed in a video encoder or a video decoder are disclosed. In one method, a GMC (global motion compensation) indication indicating whether global motion compensation is enabled is signalled at the video encoder side or parsed from the video bitstream at the video decoder side. The current processing unit is encoded or decoded using one or more coding modes including a GMC mode if the GMC indication is indicates GMC is enabled. According to another method, if a GMC mode is enabled for a region, a number representing the total number of multiple global motion models allowed is determined for encoding or decoding the processing units in the region using multiple global motion models. In yet another method the GMC and local motion compensation are applied selectively or in a combined fashion.