Depth-Based QP Group Mapping for Accurate Video Decoding
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Solution Overview
Problem
Existing video coding technologies, such as HEVC, struggle to further compress video data without sacrificing picture quality, leading to inefficiencies in decoding processes.
Innovation Solution
A video decoding method that determines the region covered by a current quantization group based on the depth of a current node, using thresholds and split modes to accurately match quantization parameters (QPs) with coding units (CUs), thereby improving decoding efficiency and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one CU corresponds to two different QGs in existing video coding technologies, then the decoding process becomes simpler, but the QP matching accuracy deteriorates leading to reduced decoding efficiency and quality
Solution Approach 1:
The patent segments the quantization process by introducing quantization groups (QGs) as intermediate units between coding units (CUs) and transform units (TUs). Each CU is associated with a specific QG determined by depth-based calculations, ensuring one-to-one mapping between CU and QG. This segmentation resolves the ambiguity of existing technologies where one CU could correspond to two different QGs, thereby improving QP matching accuracy while maintaining decoding process clarity.
Solution Approach 2:
The patent applies local quality by allowing different QP values for different QGs based on their depth and position. Each QG can have its own QP delta (QpOffset) derived from neighboring QG values, enabling localized QP adjustments tailored to specific regions. This ensures that each CU receives the appropriate QP value for its specific location and depth, improving overall decoding quality without requiring complex global adjustments.
2Productivity
If the region coverage of QG is not accurately determined, then the decoding process is faster, but the QP application precision deteriorates resulting in reduced picture quality
Solution Approach 1:
The patent performs preliminary action by pre-determining the QG region coverage and QP values during the encoding phase. The QP deltas and QG boundaries are calculated and stored in advance based on depth information and neighboring QG values. During decoding, these pre-calculated values are directly applied without requiring complex real-time calculations, thus maintaining high decoding speed while ensuring precise QP application to the correct regions.
Solution Approach 2:
The patent replaces complex mechanical region-determination mechanisms with a simplified depth-based calculation system. Instead of using complex geometric calculations or iterative region-finding algorithms, the QG region is determined through straightforward depth comparisons and coordinate calculations. This substitution maintains computational efficiency while achieving accurate region coverage determination.
Data Source
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AI summary
The present invention discloses a video decoding method and a video decoder. The method includes: parsing coding tree split information to obtain a current node; determining, based on a depth N of the current node, a region covered by a current quantization group; obtaining a quantization parameter QP delta of a current coding unit CU in the region covered by the current quantization group; and obtaining a reconstructed picture of the current CU based on the QP delta of the current CU. By using the present invention, decoding efficiency can be improved.