Chroma QP Offset Derivation for Video Decoding Efficiency
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Solution Overview
Problem
High-resolution and high-quality image data requires efficient compression techniques to reduce transmission and storage costs, as conventional methods incur increased costs due to higher information amounts.
Innovation Solution
An image decoding method that derives a chroma Quantization Parameter (QP) offset without signaling it in the PPS syntax, using chroma QP offset index information and length information of the QP offset list to improve coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chroma QP offset information is signaled in PPS syntax, then decoding accuracy is improved, but bit rate increases
Solution Approach 1:
The patent extracts the chroma QP offset information from the PPS syntax and removes it, instead deriving it through calculation from other available parameters (luma QP offset and chroma QP offset index). This eliminates the need to transmit the chroma QP offset explicitly, reducing bit rate while maintaining decoding accuracy through mathematical derivation.
Solution Approach 2:
The system enables the chroma QP offset to be self-derived through calculation rather than requiring external signaling. By using the relationship between luma QP offset, chroma QP offset index, and chroma QP offset, the decoder can autonomously compute the required value without additional bitstream information.
2Measurement precision
If high-resolution and high-quality image data is transmitted, then image quality is improved, but transmission cost increases
Solution Approach 1:
The patent changes the parameter representation method by introducing the chroma QP offset index and establishing mathematical relationships between QP parameters. This allows the system to maintain high image quality through precise chroma QP derivation while reducing the transmission cost by eliminating redundant chroma QP offset signaling in the bitstream.
Data Source
AI summary
A video decoding method performed by a decoding device according to the present document is characterized by comprising: a step for acquiring information for a chroma quantization parameter (QP) offset for the current picture; and a step for acquiring chroma QP offset index information for a current chroma block in the current picture, wherein the information for the chroma QP offset includes chroma QP offset list length information, information for a chroma QP offset list is acquired on the basis of the chroma QP offset list length information, and the chroma QP offset index information is acquired on the basis of the chroma QP offset list length information.