Adaptive Loop Filtering Composite Filter Design
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Solution Overview
Problem
Current video coding technologies face limitations in compression efficiency due to restricted direction and activity values for adaptive loop filtering (ALF), which can lead to decreased video quality and increased hardware complexity.
Innovation Solution
Applying a combination of multiple filters to video blocks instead of a single filter, using a linear function of these filters to generate a new filter for each block, allowing for more flexible filtering without increasing the number of filter sets to be transmitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter is applied to each video block, then the hardware complexity is reduced, but the video quality and compression efficiency deteriorate due to restricted direction and activity values
Solution Approach 1:
The patent combines multiple filters (first filter and second filter) to form a composite filter that is applied to video blocks. This merging approach allows the system to achieve better filtering performance and video quality without requiring a large number of separate filter sets to be transmitted, thus resolving the contradiction between hardware complexity and video quality.
Solution Approach 2:
The patent creates a universal filtering mechanism where a composite filter formed from multiple filters can adapt to different video block characteristics (different directions and activities). This multi-functional approach allows a single composite filter structure to handle various filtering scenarios, improving video quality without proportionally increasing hardware complexity.
2Manufacturing precision
If multiple filter sets are transmitted to achieve better filtering, then the video quality improves, but the compression efficiency deteriorates due to increased data transmission
Solution Approach 1:
Instead of transmitting multiple separate filter sets, the patent transmits parameters for forming a composite filter from multiple base filters. This merging approach reduces the total number of filter sets that need to be transmitted while achieving comparable or better filtering performance, thus improving compression efficiency without sacrificing video quality.
Solution Approach 2:
The patent changes the parameter representation from transmitting complete filter sets to transmitting parameters that define how to form composite filters from base filters. This parameter transformation reduces the bitrate required for filter transmission while maintaining the ability to achieve high-quality filtering, resolving the contradiction between video quality and compression efficiency.
3Device complexity
If restricted direction and activity values are used for ALF, then the hardware complexity is reduced, but the compression efficiency deteriorates
Solution Approach 1:
The patent creates a universal composite filter structure that can adapt to different direction and activity values without requiring separate hardware for each case. The composite filter formed from multiple base filters can handle various video block characteristics, improving compression efficiency while maintaining manageable hardware complexity through a unified filtering mechanism.
Data Source
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AI summary
An apparatus for encoding or decoding video data reconstructs one or more blocks of a current picture of the video data. The one or more blocks of the current picture comprise reconstructed samples of the current picture. In addition, after reconstructing the one or more blocks of the current picture, the apparatus applies a particular function of a plurality of filters to a current block of the current picture. The current block comprising the reconstructed samples of the current picture.