HDR Video Recovery Maps for LDR-Compatible Playback
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Solution Overview
Problem
Existing video formats struggle to efficiently display high dynamic range (HDR) content on both low dynamic range (LDR) and HDR display devices without loss of visual quality or the need for specialized hardware, and current HDR to LDR conversion techniques fail to preserve local tone-mapping details.
Innovation Solution
A video container format is developed that includes an LDR video and a recovery map track, where each recovery map frame encodes luminance gains between LDR and HDR frames, allowing devices to scale pixel luminances based on display capabilities to generate HDR or LDR output videos, using a range scaling factor for efficient storage and display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HDR video is stored in a specialized format, then visual quality is improved, but device compatibility deteriorates
Solution Approach 1:
The video container is designed to hold both LDR video data and HDR video data with associated recovery maps, enabling a single file format to serve both LDR and HDR display devices. The container includes flexible field structures that can be selectively processed based on display capabilities, achieving universal compatibility across different device types without requiring separate specialized formats.
Solution Approach 2:
The recovery map serves as an intermediary data structure that enables conversion between LDR and HDR representations. By storing recovery maps alongside video data, the system mediates between the compressed LDR representation and the full HDR representation, allowing LDR devices to display standard video while HDR devices can reconstruct high-quality HDR output through application of the recovery maps.
2Illumination intensity
If LDR to HDR conversion is performed, then dynamic range is improved, but local tone-mapping details are lost
Solution Approach 1:
The system performs preliminary capture and storage of HDR video data and recovery maps at the source, preserving local tone-mapping information before any LDR conversion occurs. By maintaining the original HDR representation with its associated recovery maps in the container, the system ensures that local detail information is preserved in advance and can be recovered when needed, rather than attempting to reconstruct it during playback on HDR devices.
3Manufacturing precision
If full HDR data is stored, then visual quality is improved, but storage efficiency deteriorates
Solution Approach 1:
The system extracts and stores only the essential HDR information (recovery maps) alongside a compressed LDR video representation, rather than storing complete independent HDR video data. The recovery maps contain the critical luminance gain information needed for HDR reconstruction, allowing the system to separate and store only the necessary HDR components, achieving efficient storage while maintaining the ability to reconstruct high-quality HDR video when needed.
Data Source
AI summary
Implementations relate to providing HDR video formats with low dynamic range compatibility. In some implementations, a method includes obtaining a first video including first frames having a first dynamic range and a second video including corresponding second frames having a second dynamic range that is different than the first dynamic range. A recovery map track is generated, including a recovery map frame for each first frame and corresponding second frame, the recovery map frame encoding differences in luminances between portions of the first frame and corresponding second frame. The first video and recovery map track are provided in a video container that is readable to display the first video or to display a derived video based on applying the recovery map track to the first video. The derived video includes derived frames that have a dynamic range different than the first dynamic range.