Dynamic Range Converter for HDR to SDR Color Mapping

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Solution Overview

Problem

Current video processing technologies face challenges in efficiently converting High Dynamic Range (HDR) signals to Standard Dynamic Range (SDR) while maintaining accurate color transformation and artistic intent, especially when dealing with diverse display devices and limited metadata standards.

Innovation Solution

A dynamic range converter with a generic and reconfigurable architecture that includes color space converters, linearizers, delinearizers, color volume transformers, and metadata-driven processing, capable of converting HDR to SDR and vice versa, using SMPTE standards like ST 2084 and ST 2094 for dynamic color transform metadata to ensure accurate color representation across different display devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional video encoding methods are used, then bandwidth reduction and memory storage efficiency are improved, but color accuracy and artistic intent preservation deteriorate during HDR to SDR conversion

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidcolor accuracy

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The conversion process is segmented into distinct functional blocks: color space converter, linearizer, color volume transformer, delinearizer, and display encoder. Each block performs a specific transformation step, allowing precise control over color accuracy at each stage while maintaining encoding efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A color volume transformer block acts as an intermediary between HDR and SDR domains, using metadata-driven processing to mediate the conversion. This intermediary preserves artistic intent by applying tone mapping and color grading transformations before final SDR encoding.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If HDR to SDR conversion is performed with high color accuracy, then artistic intent is preserved, but processing complexity and computational requirements increase

Engineering Contradiction:

Improvecolor transformation accuracyVSAvoidprocessing architecture complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The converter uses a universal processing architecture that can handle multiple HDR standards (SMPTE ST 2084, ST 2094) and various metadata formats through configurable parameters. The same hardware blocks perform different functions depending on the selected standard, reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system achieves high color accuracy through parameter-driven processing rather than complex algorithms. By changing parameters such as transfer function exponents, color volume boundaries, and tone mapping curves based on metadata, the system maintains simplicity while preserving artistic intent.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If metadata-driven processing is implemented for accurate color transformation, then adaptability to different display devices is improved, but processing time and latency increase

Engineering Contradiction:

Improvedisplay device compatibilityVSAvoidconversion latency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

Display device characteristics and color volume parameters are pre-calculated and stored as metadata alongside the video content. During conversion, the system simply retrieves and applies these pre-computed parameters rather than performing real-time calculations, minimizing latency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses lookup tables and pre-defined transformation matrices that copy proven color mapping relationships from reference displays. This allows rapid adaptation to different display devices without extensive real-time processing.

Inventive Principle:

Principle #26Copying

4Adaptability or versatility

If support for multiple HDR standards and metadata formats is provided, then versatility and adaptability are improved, but device complexity and configuration requirements increase

Engineering Contradiction:

ImproveHDR standard compatibilityVSAvoidconfiguration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The converter implements a universal architecture where a single set of processing blocks supports multiple HDR standards (SMPTE ST 2084 Perceptual Quantizer, ST 2094 Transfer Characteristic). The same hardware performs different standard-specific transformations by loading appropriate configuration parameters and metadata formats.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10257483B2Color gamut mapper for dynamic range conversion and methods for use therewith

Publication Date: 2019.04.09 VIXS SYSTEMS INC

AI summary

In various embodiments, a color gamut mapper includes a gamut map selection generator configured to analyze color space signals and generate a gamut map selection signal in response thereto. A color gamut transformer is configured to process the color space signals via a selected one of a plurality of gamut maps to generate gamut mapped color space signals, wherein the selected one of the plurality of gamut maps is selected in response to the gamut map selection signal. Other embodiments are disclosed.