Image Decoding Chroma QP Mapping for Content-Adaptive Compression
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to higher transmission and storage costs due to increased data volume, necessitating a more efficient image compression technique.
Innovation Solution
An image decoding method that derives a chroma quantization parameter using a chroma QP mapping table based on signaled chroma quantization parameter data, improving coding efficiency by reflecting the image's characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-resolution and high-quality images are transmitted or stored, then image quality is improved, but transmission cost and storage cost increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting chroma quantization parameters based on image characteristics. Instead of using fixed default QP values, the system derives chroma QP mapping tables that adapt to local image content, allowing for more aggressive compression in regions where chroma detail is less critical while maintaining quality where needed. This selective parameter adjustment reduces overall data volume while preserving essential image quality.
2Productivity
If chroma QP mapping table is derived based on signaled chroma quantization parameter data, then coding efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-deriving chroma QP mapping tables during the encoding process and signaling them to the decoder. The encoder performs the complex table derivation in advance based on signaled chroma quantization parameter data, then transmits the pre-computed mapping tables to the decoder. This shifts the computational burden to the encoding stage, allowing the decoder to simply lookup and apply the pre-computed values, thereby improving overall coding efficiency while managing decoding complexity.
Data Source
AI summary
An image decoding method performed by a decoding apparatus, according to the present document, comprises the steps of: acquiring image information including chroma quantization parameter data of at least one chroma QP mapping table for chroma components, and prediction information and residual information regarding the chroma components; deriving the chroma QP mapping table on the basis of the chroma quantization parameter data; deriving a chroma quantization parameter for the chroma components on the basis of the chroma QP mapping table; deriving prediction samples for the chroma components on the basis of the prediction information; deriving residual samples on the basis of the residual information and the chroma quantization parameter; and generating a reconstructed picture on the basis of the prediction samples and the residual samples.