CRI Messaging Luminance Specification via Colour Remap ID
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing H.265 CRI syntax lacks support for specifying the minimum and maximum luminance values of a targeted display, limiting its ability to accurately remap color volume information for high dynamic range (HDR) content.
Innovation Solution
The proposed solution extends the use of the colour_remap_id parameter in CRI messaging to include bits 7:0 for specifying minimum and maximum luminance values, using a lookup table or encoding luminance values according to the inverse EOTF of SMPTE ST 2084, allowing for communication of luminance and color primaries information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the existing H.265 CRI syntax is used without extension, then the syntax structure remains simple and compatible, but it cannot specify minimum and maximum luminance values for targeted display
Solution Approach 1:
The patent embeds luminance value specifications (minimum and maximum luminance) within the existing colour_remap_id parameter structure. By nesting additional information inside the existing parameter framework, the solution transmits complete color volume information without creating a separate syntax structure, thus avoiding increased complexity while preventing information loss.
Solution Approach 2:
The colour_remap_id parameter is extended to serve multiple functions: it continues to identify color remapping operations while simultaneously encoding luminance range information. This multi-functionality allows the single parameter to convey both color transformation identity and display-specific luminance characteristics, eliminating the need for additional dedicated parameters.
2Productivity
If luminance values are encoded using lookup table with bits 7:0, then communication efficiency is improved, but precision in specifying luminance values may be reduced
Solution Approach 1:
The patent transforms luminance value representation by encoding them as indices (bits 7:0) into a lookup table rather than storing raw luminance values directly. This parameter change enables compact encoding that fits within the existing syntax while maintaining the ability to represent precise luminance values through the lookup table mapping, thus balancing communication efficiency with precision.
Data Source
AI summary
Given existing color remapping information (CRI) messaging variables, methods are described to communicate color volume information for a targeted display to a downstream receiver. Bits 7:0 of the 32-bit colour_remap_id are used to extract a first value. If the first value is not a reserved value, then the first value is used as an index to a look-up table to generate a first luminance value for a targeted display, otherwise a second value is generated based on bits 31:9 in the colour_remap_id messaging variable and the first luminance value for a targeted display is generated based on the second value. The methods may be applied to communicate via CRI messaging a minimum luminance value, a maximum luminance value, and color primaries information of the targeted display.