Motion Compensation Access Window Padding for Faster Vector Refinement
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Solution Overview
Problem
Current motion vector refinement methods require increased on-chip memory or external memory access, which can slow down processing, especially in decoder implementations, due to the need for additional memory access during fractional interpolation.
Innovation Solution
Implement motion vector prediction by padding sample values outside a predefined memory access window with replacement values based on samples within the window, using interpolation filtering to limit the number of memory accesses and samples needed for interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vector refinement is performed using conventional methods, then prediction accuracy is improved, but memory access requirements increase and processing speed decreases
Solution Approach 1:
The patent segments the reference picture into a current block and a padding block, where the padding block contains synthesized sample values. This segmentation allows the interpolation filter to access padded samples without requiring additional external memory accesses, thus maintaining prediction accuracy while improving processing speed.
Solution Approach 2:
The patent performs preliminary action by synthesizing padding sample values before the interpolation filtering process. The padding block is prepared in advance with synthesized samples that extend the boundaries of the current block, ensuring that all required samples for interpolation are available in on-chip memory before the actual motion vector refinement occurs.
2Measurement precision
If on-chip memory size is increased to support motion vector refinement, then prediction accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a copy of the current block's sample values and places them in the padding block with appropriate offsets. This copying approach allows the interpolation filter to access synthesized samples that mimic the characteristics of actual reference samples without requiring additional physical memory resources, thereby maintaining prediction accuracy while avoiding increased device complexity.
3Measurement precision
If external memory access is used for motion vector refinement, then prediction accuracy is improved, but processing speed decreases
Solution Approach 1:
The patent performs preliminary action by synthesizing padding sample values before the interpolation filtering process. The padding block is prepared in advance with synthesized samples that extend the boundaries of the current block, ensuring that all required samples for interpolation are available in on-chip memory before the actual motion vector refinement occurs.
Solution Approach 2:
The patent introduces the padding block as an intermediary structure that mediates between the current block and the interpolation filter. The padding block contains synthesized samples that act as intermediaries, allowing the filter to access required samples without direct external memory access, thus maintaining prediction accuracy while improving processing speed.
Data Source
AI summary
The present disclosure relates to motion vector determination using template or bilateral matching and predictor generation based on the motion vector. The template or bilateral matching and/or the predictor generation use interpolation filtering. The interpolation filtering operation accesses integer sample positions within a window, and further uses padded sample values for integer sample positions outside the window, which are based on at least one sample within said window, and uses the accessed integer sample position values as well as the padded sample values to perform the template or bilateral matching and/or predictor generation.