Color Remapping SEI Signaling for HDR Display Adaptation
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Solution Overview
Problem
Current video coding standards, particularly HEVC, face challenges in efficiently encoding and decoding video data with High Dynamic Range (HDR) and Wide Color Gamut (WCG) representations due to limitations in the signaling of Colour Remapping Information (CRI) SEI messages, which can lead to inconsistent decoding results across different displays with varying characteristics.
Innovation Solution
The proposed solution involves enhancing the signaling of CRI SEI messages to include peak brightness values and applying colour remapping messages based on display characteristics, such as peak brightness, colour gamut, and supported transfer functions, to ensure tailored colour remapping for specific displays, thereby improving display adaptation and consistency across different devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If colour remapping information SEI messages are signaled without peak brightness values, then the signaling process is simpler, but decoding results become inconsistent across different displays with varying characteristics
Solution Approach 1:
The patent applies parameter changes by extending the CRI SEI message syntax to include peak brightness values (maxCLL and maxFALL parameters) and transfer function information. This modification allows the signaling to convey complete display adaptation information, ensuring consistent decoding results across different displays while maintaining a structured and standardized approach to the extended syntax.
2Manufacturing precision
If generic colour remapping is applied without considering display characteristics, then the processing is faster and simpler, but video quality and consistency across different displays deteriorates
Solution Approach 1:
The patent implements local quality by applying colour remapping tailored to specific display characteristics. The decoder selects and applies appropriate colour remapping information based on the target display's peak brightness, colour gamut, and transfer function. This ensures that each display receives optimized colour remapping parameters matched to its specific capabilities, improving video quality consistency across different display devices.
3Measurement precision
If comprehensive display adaptation information is signaled, then colour remapping accuracy improves, but the bit stream size and processing complexity increase
Solution Approach 1:
The patent applies universality by designing the extended CRI SEI message syntax to serve multiple functions simultaneously. The same message structure conveys peak brightness values, transfer function information, and colour remapping parameters in a unified format. This multi-functional approach enables comprehensive display adaptation while avoiding redundant signaling, thus controlling bit stream size growth.
Data Source
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AI summary
In one example, a method includes determining, by a video decoding unit, a peak brightness value of a current display; obtaining, by the video decoding unit and for a picture of video data, one or more colour remapping messages that each correspond to a respective peak brightness value of a set of peak brightness values; selecting, by the video decoding unit and based on the peak brightness value of the current display, a colour remapping message of the one or more colour remapping messages; colour remapping, by the video decoding unit and based on the selected colour remapping message, samples of the picture of video data; and outputting, by the video decoding unit and for display at the current display, the colour remapped samples of the picture of video data.