Bilateral Filtering Signaling in Video Coding
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Solution Overview
Problem
Existing video coding technologies face limitations in efficiently signaling and applying bilateral filtering, which can lead to suboptimal coding efficiency due to assumptions about reconstruction blocks and dependencies on zero coefficients, particularly in intra-coded blocks.
Innovation Solution
The implementation of explicit and implicit signaling mechanisms for bilateral filtering, using flags within the video bitstream to determine which blocks to apply filtering, based on parameters such as slice type, motion precision, transform coefficients, and deblock filter parameters, allowing for flexible and context-dependent application of bilateral filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If bilateral filtering is applied to all reconstructed blocks, then video quality is improved, but bitstream overhead increases due to explicit signaling requirements
Solution Approach 1:
The patent applies bilateral filtering selectively to specific blocks rather than uniformly to all blocks. The filter is applied based on local characteristics such as block type (intra-coded vs inter-coded), presence of non-zero transform coefficients, and deblocking filter application. This local quality approach improves video quality where needed while avoiding unnecessary filtering and signaling overhead in blocks where it would not benefit quality.
Solution Approach 2:
The patent implements partial action by applying bilateral filtering to only a subset of reconstructed blocks that meet specific criteria. Instead of applying the filter excessively to all blocks, the method uses conditional logic to determine which blocks require filtering based on their characteristics, thereby reducing bitstream overhead while maintaining adequate video quality.
2Stability of the object's composition
If bilateral filtering is applied to intra-coded blocks with zero coefficients, then filtering consistency is improved, but computational complexity increases unnecessarily
Solution Approach 1:
The patent applies partial action by conditionally applying bilateral filtering only to intra-coded blocks that contain non-zero transform coefficients. Blocks with all zero coefficients are excluded from filtering, eliminating unnecessary computational complexity while maintaining filtering consistency for blocks that actually contain visual information.
Solution Approach 2:
The filtering decision is made based on self-service principles where the block's own characteristics (presence of non-zero coefficients) determine whether filtering is applied. This eliminates the need for external signaling or complex decision logic, reducing device complexity while ensuring consistent filtering behavior for relevant blocks.
3Measurement precision
If explicit signaling is used for bilateral filtering application, then filtering control precision is improved, but bitstream data volume increases
Solution Approach 1:
The patent uses self-service signaling where the decision to apply bilateral filtering is derived from existing bitstream data (block type, transform coefficients, deblocking filter parameters) without requiring additional explicit signaling flags. The filtering control precision is maintained by using these existing parameters to make accurate filtering decisions, while avoiding increases in bitstream data volume.
Solution Approach 2:
The patent makes existing bitstream parameters serve multiple functions: they are used for both standard video coding operations and for determining bilateral filtering application. This multi-functionality allows precise filtering control without requiring dedicated signaling elements, thereby maintaining compact bitstream representation.
4Loss of information
If bilateral filtering is applied based on zero coefficient assumptions, then signaling overhead is reduced, but coding efficiency deteriorates in intra-coded blocks
Solution Approach 1:
The patent uses self-service mechanisms where the filtering decision is automatically determined by examining the block's own transform coefficients. This eliminates the need for separate signaling overhead while ensuring that filtering is applied appropriately to intra-coded blocks based on their actual content, thereby maintaining coding efficiency without relying on zero coefficient assumptions.
Data Source
AI summary
Embodiments include use of a bilateral filter applied to reconstructed blocks as an in-loop filter by both the encoder and decoder. In particular, embodiments include systems and methods of explicitly and implicitly signaling for which blocks to apply bilateral filtering.