Adaptive Chroma Quantization Parameter Derivation
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Solution Overview
Problem
Current video coding standards, such as HEVC and JEM, have limited flexibility in adjusting chroma quantization parameters, which can impact compression efficiency and quality trade-offs between luma and chroma components.
Innovation Solution
The method involves deriving adaptive chroma quantization parameters (QP) from luma QP using a chroma QP bias, which is calculated from an intermediate QP index, allowing for more flexible control of chroma quantization and improved compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If chroma QP is derived using fixed offset from luma QP in current standards, then implementation is simple, but flexibility in quality control between luma and chroma components is limited
Solution Approach 1:
The patent implements dynamic chroma QP derivation by introducing multiple adjustable parameters (chroma_qp_offset_cb, chroma_qp_offset_cr, chroma_qp_bias_cb, chroma_qp_bias_cr) that can be adaptively selected based on content characteristics. The system dynamically switches between different derivation modes (fixed offset, adaptive offset, bias-based) to optimize quality control flexibility while managing complexity through conditional selection.
Solution Approach 2:
The patent changes the parameters controlling chroma QP derivation from fixed values to multiple adjustable parameters including chroma_qp_offset_cb, chroma_qp_offset_cr, chroma_qp_bias_cb, and chroma_qp_bias_cr. These parameters can be modified based on content characteristics, allowing flexible quality control between luma and chroma components while maintaining manageable system complexity through structured parameter management.
2Manufacturing precision
If chroma QP is independently controlled with multiple parameters, then quality control flexibility improves, but computational complexity increases
Solution Approach 1:
The patent segments the chroma QP control into separate parameters for Cb and Cr components (chroma_qp_offset_cb, chroma_qp_offset_cr, chroma_qp_bias_cb, chroma_qp_bias_cr), allowing independent quality control for each chroma component. This segmentation enables precise quality control while managing computational complexity by organizing parameters into distinct, manageable groups that can be processed independently.
Solution Approach 2:
The patent applies local quality control by allowing different QP adjustment strategies for different chroma components (Cb and Cr) based on their specific characteristics. The system can apply different offsets and biases to Cb and Cr separately, enabling precise local quality optimization for each component while maintaining overall computational efficiency through component-wise processing.
3Productivity
If adaptive chroma QP derivation is implemented, then compression efficiency improves, but encoding complexity increases
Solution Approach 1:
The patent implements dynamic adaptive chroma QP derivation that adjusts parameters (chroma_qp_offset_cb, chroma_qp_offset_cr, chroma_qp_bias_cb, chroma_qp_bias_cr) based on content characteristics such as skin tone regions and color saturation. The system dynamically selects derivation modes and adjusts parameter values to optimize compression efficiency while managing encoding complexity through content-aware adaptive selection.
Solution Approach 2:
The patent incorporates feedback mechanisms by evaluating content characteristics (skin tone detection, color saturation analysis) and using this information to adaptively adjust chroma QP parameters. The system provides feedback loops where encoding results influence subsequent QP parameter selection, improving compression efficiency while managing encoding complexity through intelligent feedback-driven adaptation.
Data Source
AI summary
Video encoding or decoding methods and apparatuses for processing video data with color components comprise receiving video data, performing inter prediction and intra prediction, determining a luma Quantization Parameter (QP), deriving a chroma QP bias, calculating a chroma QP from the chroma QP bias and the luma QP, performing transform or inverse transform, and performing quantization or inverse quantization for the luma component utilizing the luma QP and for the chroma component utilizing the chroma QP. The chroma QP bias is derived from an intermediate QP index, and the intermediate QP index is computed by clipping a sum of the luma QP and a chroma QP offset parameter to a specified range. The bits allocated to code the luma and chroma components may be adaptively controlled by restricting the chroma QP bias.