Chroma Quantization Groups for Adaptive Deblocking in Video Coding
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Solution Overview
Problem
Current video coding standards face challenges in achieving optimal deblocking filter strength and efficiency, particularly in handling chroma components, which affect compression ratios and complexity in video codecs like HEVC and VVC.
Innovation Solution
The proposed methods involve applying deblocking filters with adaptive strength determination based on chroma quantization parameters, using chroma QP offsets at different levels, and employing chroma QP offsets in the deblocking process to improve filtering on video unit boundaries, while also considering joint coding of chroma residuals and boundary strength without motion vector comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single deblocking filter strength is used for all video blocks, then the implementation is simple, but the compression ratio and visual quality are suboptimal
Solution Approach 1:
The patent applies different deblocking filter strengths to different chroma blocks based on their position and characteristics. Specifically, stronger filtering is applied to chroma blocks at certain locations (e.g., near CU boundaries or in specific regions) while weaker or no filtering is applied to others, optimizing compression performance for each local region without requiring complex global analysis
Solution Approach 2:
The patent segments the chroma blocks into different categories based on their position relative to coding units and applies different filtering strategies to each segment. This segmentation allows the system to handle different chroma block types with appropriate filter strengths, improving overall compression efficiency
2Manufacturing precision
If chroma QP offsets are applied at multiple levels (picture/slice/tile/brick/subpicture), then the deblocking performance is optimized, but the complexity of determining filter strength increases
Solution Approach 1:
The patent pre-establishes the hierarchy of chroma QP offsets at different levels (picture, slice, tile, brick, subpicture) before the actual deblocking process. The system determines which level's QP offset to apply based on pre-defined rules and block position, avoiding the need for complex real-time calculations while still achieving optimized filtering performance
Solution Approach 2:
The patent introduces an intermediary mechanism that selects the appropriate QP offset level based on the block's position and characteristics. This intermediary layer simplifies the complexity by providing clear decision rules for choosing which QP offset to apply, rather than requiring direct complex analysis of all possible offset combinations
3Measurement precision
If motion vector comparisons are performed for boundary strength determination, then the filtering accuracy is improved, but the processing time and complexity increase
Solution Approach 1:
The patent extracts and applies chroma QP offsets at multiple hierarchical levels without requiring motion vector comparisons. By using the pre-established QP offset hierarchy and block position information, the system determines boundary strength and filter parameters without the time-consuming motion vector analysis, significantly reducing processing time while maintaining filtering accuracy
Solution Approach 2:
The patent replaces the expensive and time-consuming motion vector comparison process with a simpler, faster approach using chroma QP offsets at different levels. This substitution uses readily available QP offset data and block position information to achieve sufficient accuracy without the computational burden of motion vector analysis
Data Source
AI summary
An example method of video processing includes applying, in a conversion between a video comprising multiple components and a bitstream representation of the video, a deblocking filter to video blocks of the multiple components. A deblocking filter strength for the deblocking filter of each of the multiple components is determined according to a rule that specifies to use a different manner for determining the deblocking filter strength for the video blocks of each of the multiple components.