Adaptive Chroma Downsampling for HDR Video Artifact Reduction
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Solution Overview
Problem
Conventional video coding systems face challenges in handling higher quality video content, such as High Dynamic Range (HDR) and wide color gamut, due to artifacts introduced during conversion and compression, which degrade the video quality upon decoding and display.
Innovation Solution
The implementation of improved techniques for filter selection and color space conversion, including adaptive chroma downsampling and closed-loop pixel format conversion, to optimize encoding and decoding processes, ensuring better compatibility with target devices and minimizing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chroma downsampling is performed to reduce data quantity for compression, then productivity is improved, but manufacturing precision deteriorates due to aliasing and banding artifacts
Solution Approach 1:
The patent applies adaptive chroma downsampling where the downsampling filter and mode are dynamically selected based on local image characteristics. Different regions of the image can use different downsampling strategies, allowing the system to maintain high compression efficiency while preserving video quality in critical areas and applying aggressive downsampling in less sensitive areas.
Solution Approach 2:
The patent implements region-dependent chroma downsampling where different parts of the image receive different processing. Areas with important color information use higher quality downsampling methods, while areas with less critical color data use more aggressive compression, thus balancing overall compression efficiency and quality.
2Productivity
If color space conversion is performed to optimize encoding, then productivity is improved, but object-affected harmful factors increase due to introduced artifacts
Solution Approach 1:
The patent employs closed-loop color space conversion where the encoding process feedback is used to adjust the conversion parameters. The system analyzes the encoded output and uses this information to refine the color space conversion, minimizing artifacts while maintaining encoding efficiency.
Solution Approach 2:
The patent applies preliminary filtering and optimization steps before the actual color space conversion. By pre-processing the chroma components and selecting optimal conversion parameters in advance, the system reduces the introduction of artifacts during the encoding process while maintaining high efficiency.
Data Source
AI summary
Techniques for selecting a luminance value for color space conversion are disclosed. Techniques include determining values for Cb and Cr from values for R′, G′, and B′; producing a reconstructed Cb* value and a reconstructed Cr* value by processing the Cb and Cr values; and determining a plurality of Y′ value options from the values for Cb* and Cr*. A Y′ output value may be selected based on the plurality of Y′ value options.