Joint Cb/Cr Chroma Residual Encoding for HEVC Compression Limits
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Solution Overview
Problem
The increasing demand for high-quality video services with larger display panels has led to a significant increase in data volume, necessitating improved video compression rates, as existing standards like HEVC are showing limitations in performance.
Innovation Solution
A method for jointly encoding and decoding residual components of chroma components in video signals, utilizing various methods to generate a joint chroma signal and performing multiple transforms, and selectively choosing residual signal reconstruction modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If HEVC compression standard is used, then compression performance is improved compared to H.264/AVC, but compression performance gradually shows limitations with rapid development of high-definition video services
Solution Approach 1:
The patent applies parameter changes by modifying the chroma residual encoding parameters through joint encoding of Cb and Cr components. The method transforms chroma residuals using 2D DCT and performs joint encoding with combined quantization matrices, changing the encoding parameters to achieve better compression performance beyond what HEVC can achieve with its standard separate encoding approach.
2Productivity
If separate encoding of chroma residual components is used, then encoding process is simple, but encoding/decoding efficiency can be improved by joint encoding of chroma components
Solution Approach 1:
The patent merges the separate Cb and Cr chroma residual encoding processes into a unified joint encoding process. Both chroma residuals are transformed using 2D DCT, combined into a single matrix, and encoded together with a single quantization matrix, achieving better efficiency while managing complexity through systematic integration.
Solution Approach 2:
The patent implements universality by creating a unified encoding framework that handles both Cb and Cr chroma components through the same transformation and quantization processes. The joint encoding mechanism serves multiple functions: transforming both chroma residuals, combining them, quantizing them together, and reconstructing both components from the same encoded data.
3Loss of energy
If multiple transform methods are used for chroma residuals, then compression performance is improved, but encoding complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically selecting transform methods and parameters based on chroma residual characteristics. The system can choose between different transform approaches and adjust quantization parameters to optimize compression performance while adapting to the specific content being encoded.
Data Source
AI summary
A method for decoding an image according to the present invention may comprise the steps of: deriving a residual coefficient of a current block; dequantizing the residual coefficient; deriving a common residual signal by performing inverse transform of the dequantized residual coefficient; and deriving a first residual signal of a first chroma component and a second residual signal of a second chroma component on the basis of the common residual signal.