Adaptive Loop Filtering Without Neighboring-Block Line Buffers
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Solution Overview
Problem
Existing video coding technologies require significant memory resources for line buffers to store samples from neighboring blocks for adaptive loop filtering, which increases computational complexity and resource utilization.
Innovation Solution
The proposed techniques enable adaptive loop filters by using padded samples instead of samples outside the largest coding unit rows, reducing the need for line buffers and enabling efficient filtering without storing samples from neighboring blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If samples from neighboring blocks are stored in line buffers for adaptive loop filtering, then filtering accuracy is improved, but memory requirements and computational complexity increase
Solution Approach 1:
The patent extracts only the necessary samples for filtering by using virtual padding to generate boundary samples from available neighboring samples, rather than storing all neighboring block samples in line buffers. This selective extraction reduces memory requirements while maintaining filtering accuracy for the samples that actually need filtering.
Solution Approach 2:
The patent introduces virtual padding as an intermediary mechanism that generates boundary samples through copying and shifting operations. These padded samples serve as mediators that provide the necessary boundary values for filtering without requiring physical storage of extensive neighboring block data in line buffers.
2Adaptability or versatility
If line buffers are used to store samples from neighboring blocks, then adaptive loop filtering can be performed, but device complexity increases
Solution Approach 1:
The patent uses virtual padding to create temporary boundary samples that exist only during the filtering operation. These padded samples are generated on-demand through simple copying and shifting operations, used for filtering, and then discarded, avoiding the need for complex persistent line buffer structures.
Solution Approach 2:
Instead of storing neighboring block samples in line buffers and then accessing them for filtering, the patent inverts the approach by generating boundary samples through virtual padding from available samples. This reverses the traditional flow from storage-to-access to generation-to-use, reducing device complexity.
Data Source
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AI summary
A method of coding video data, the method comprising coding a block of video data to obtaining a coded block of video data, applying an adaptive loop filter defined by a filter support to samples of the coded block of video data, including using padded samples for portions of the filter support that are outside of the block, and outputting the coded block of video data after applying adaptive loop filtering to the coded block of video data.