Frame-Rate-Conversion Metadata for HDR Video

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Solution Overview

Problem

Current display systems, including consumer TVs and monitors, struggle to accurately render High Dynamic Range (HDR) content due to differences in dynamic range and frame rates between studio displays and consumer devices, leading to artifacts like judder and a loss of cinematic quality.

Innovation Solution

The method involves generating and transmitting frame-rate conversion metadata to adjust the playback frame rate of HDR video signals based on the target display's maximum brightness, allowing for down-conversion from high frame rates to lower frame rates that match the display's capabilities, thereby reducing artifacts and maintaining the intended cinematic look.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If HDR video is displayed on consumer displays with lower luminance capabilities, then the dynamic range rendering is compromised, but display compatibility is improved

Engineering Contradiction:
Improvedynamic range rendering accuracyVSAvoiddisplay compatibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by modifying the luminance mapping parameters based on the target display's capabilities. The tone mapping process adjusts the transfer function parameters to match the display's maximum luminance, transforming the HDR content to be optimally rendered on displays with varying luminance characteristics while preserving the cinematic intent.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements dynamics by making the tone mapping process adaptive to the specific display device. The system dynamically adjusts the mapping parameters based on the target display's luminance capabilities, allowing the same HDR content to be optimally rendered across different display types from studio monitors to consumer TVs.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If frame rate is reduced to match consumer display capabilities, then playback compatibility is improved, but motion smoothness is degraded

Engineering Contradiction:
Improveplayback compatibilityVSAvoidmotion smoothness
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent changes the frame rate parameter dynamically based on the target display's capabilities. The system selects appropriate frame rate conversions (e.g., from 48fps to 24fps, or 60fps to 30fps) to match the display's refresh rate while applying corresponding tone mapping to maintain visual quality and reduce artifacts.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention makes the frame rate selection dynamic and adaptive to the specific display device. Rather than using a fixed frame rate conversion, the system dynamically determines the optimal frame rate based on the target display's capabilities and the source content characteristics, balancing compatibility and motion smoothness.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If frame rate down-conversion is applied to match display capabilities, then playback compatibility is improved, but judder and artifacts increase

Engineering Contradiction:
Improveplayback compatibilityVSAvoidjudder and artifacts
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by performing tone mapping and frame rate conversion in a coordinated manner before playback. The system pre-processes the HDR content by applying appropriate tone mapping curves and frame rate conversions that are specifically tailored to reduce judder and artifacts, rather than applying simple downsampling after the fact.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes multiple parameters simultaneously - both the tone mapping parameters and frame rate conversion factors - to work together in reducing artifacts. The system selects specific combinations of mapping curves and frame rate ratios that have been determined to minimize judder and other playback artifacts on consumer displays.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3688978B1Frame-rate-conversion metadata
Publication Date: 2021.07.07 DOLBY LABORATORIES LICENSING CORP
  • EP3688978B1 patent drawingFigure 1
  • EP3688978B1 patent drawingFigure 2A~2B
  • EP3688978B1 patent drawingFigure 3A~3B

AI summary

Methods for encoding and decoding high-dynamic range signals are presented. The signals are encoded in a high frame rate and are accompanied by frame-rate conversion metadata defining a preferred set of frame-rate down-conversion parameters, which are determined according to the maximum luminance of a target display, display playback priority modes, or judder control modes. A decoder uses the frame-rate conversion metadata to apply frame-rate down-conversion to the input high-frame-rate signal according to at least the maximum luminance of the target display and/or the characteristics of the signal itself. Frame-based and pixel-based frame-rate conversions, and judder models for judder control via metadata are also discussed.