Video Encoding Quantization Matrix Control for Joint Chrominance Modes
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Solution Overview
Problem
Existing video encoding technologies, such as HEVC and VVC, face challenges in controlling quantization effectively for chrominance components, especially when the joint encoding mode is applied, leading to potential visual deterioration.
Innovation Solution
The proposed solution involves an encoding device and a decoding device that dynamically select and apply appropriate quantization matrices based on whether the joint encoding mode is applied, ensuring optimal quantization for both individual and joint encoding modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If joint encoding mode is applied to chrominance components, then encoding efficiency is improved, but quantization control becomes insufficient leading to visual deterioration
Solution Approach 1:
The patent segments the quantization control by introducing separate QP offset parameters for joint encoding mode (pps_joint_cbcr_qp_offset) distinct from individual component offsets (pps_cb_qp_offset, pps_cr_qp_offset). This allows independent optimization of quantization parameters for joint-encoded chrominance components, resolving the contradiction by maintaining encoding efficiency while restoring quantization control precision through dedicated parameters.
Solution Approach 2:
The patent changes the parameter structure by adding a new QP offset parameter specifically for joint encoding mode. This parameter change enables flexible adjustment of quantization strength for joint-encoded chroma components without affecting luminance or individually-encoded chroma components, thus improving quantization control precision while preserving the encoding efficiency benefits of joint encoding.
2Adaptability or versatility
If separate QP offsets are set for each chrominance component, then independent quantization control is achieved, but device complexity increases
Solution Approach 1:
The patent implements a universal parameter management approach where the new pps_joint_cbcr_qp_offset parameter serves both Cb and Cr components simultaneously in joint encoding mode. This multi-functionality reduces device complexity compared to managing separate parameters for each chroma component, while still achieving independent quantization control for joint-encoded chrominance components through a single unified parameter.
3Device complexity
If quantization matrix is not optimized for joint encoding mode, then device complexity is reduced, but image quality deteriorates
Solution Approach 1:
The patent applies local quality optimization by enabling separate QP offset control specifically for joint-encoded chrominance components through the pps_joint_cbcr_qp_offset parameter. This allows the quantization matrix to be locally optimized for joint encoding mode where it is most needed, without requiring complex global quantization matrix management changes, thus improving image quality while keeping device complexity manageable.
Data Source
AI summary
The encoding device includes: a predictor configured to generate, for each component, a prediction block corresponding to an encoding-target block; a residual generator configured to generate, for each component, a prediction residual representing a difference between the encoding-target block and the prediction block; a mode selector configured to select one mode either an individual encoding mode performing a transform process and a quantization process on a prediction residual of the first component and a prediction residual of the second component for each single component, or a joint encoding mode performing a transform process and a quantization process on a joint prediction residual generated from the prediction residual of the first component and the prediction residual of the second component; a quantization controller configured to determine a quantization matrix to be applied in the quantization process based on the mode selected by the mode selector.