HDR to SDR Conversion Using Embedded Color Mapping Parameters
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Solution Overview
Problem
Existing methods for converting High-Dynamic-Range (HDR) pictures to Standard-Dynamic-Range (SDR) pictures fail to preserve the artistic intent of color grading, as they rely on default color mapping that does not accurately represent the intended color gamut and dynamic range, leading to loss of specific colors like flesh tones, sky shades, and grass tones when played on legacy TV sets without HDR capability.
Innovation Solution
Incorporating specific color mapping parameters on Blu-Ray discs and devices to ensure that HDR content is converted to SDR while maintaining the artistic intent, using indicators to determine if color mapping parameters are present and should be applied, thereby preventing 'blind' conversions that lose artistic intent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If default color mapping is used for HDR to SDR conversion, then conversion compatibility is improved, but color accuracy and artistic intent are lost
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal color mapping parameters during HDR content production. These parameters are embedded in the HDR bitstream, so when conversion to SDR is needed, the pre-computed parameters are used directly rather than performing default conversion, thus preserving artistic intent while ensuring compatibility
Solution Approach 2:
The patent introduces color mapping parameters as an intermediary element between HDR content and SDR display. These parameters act as a bridge that translates HDR color information into SDR-compatible format while maintaining the original artistic intent, rather than directly converting without preservation of color grading information
2Device complexity
If HDR content is converted to SDR without color mapping parameters, then device complexity is reduced, but color grading information is lost
Solution Approach 1:
The patent extracts color mapping parameters from the complex HDR processing pipeline and separates them as independent data elements that can be stored and transmitted separately. This extraction allows the parameters to be preserved and applied during conversion without requiring complex real-time processing, thus reducing device complexity while preventing information loss
Solution Approach 2:
The patent creates a copy of the artistic intent information in the form of color mapping parameters that can be stored and reused. Instead of requiring the original HDR processing system to be present during SDR conversion, a copy of the essential color grading information is preserved and applied during conversion, preventing loss of artistic intent
3Measurement precision
If explicit color mapping parameters are implemented, then color accuracy is improved, but data storage requirements increase
Solution Approach 1:
The patent applies parameter changes by representing color mapping information in a compressed parametric form rather than storing complete lookup tables or full color grading data. The color mapping parameters use efficient mathematical representations that capture essential color transformation information with minimal data, thus improving color accuracy while limiting storage increase
Data Source
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AI summary
The present disclosure generally relates to a method and device of converting a high-dynamic-range (HDR) version of a picture to a standard-dynamic-range (SDR) version of this picture. The method is characterized in that it converts the high-dynamic-range version to the standard-dynamic-range version of the picture according to: a first indicator (I1) that indicates the presence of color mapping parameters; a second indicator (I2) that indicates whether a device is configured to convert the high-dynamic-range version to the standard-dynamic-range version of the picture by taking into account said color mapping parameters; and a third indicator (I3) that indicates whether converting without taking into account said color mapping parameters is inhibited.