Dual-OETF Video Encoding for HDR-SDR Playback Compatibility
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Solution Overview
Problem
Existing video data generation and reproduction methods lack backward compatibility, making it difficult to reproduce high dynamic range (HDR) video on standard dynamic range (SDR) devices and vice versa.
Innovation Solution
A data generation method and device that uses a second opto-electrical transfer function (OETF) for HDR video, along with supplemental enhancement information (SEI) and video usability information (VUI), to enable reproduction compatibility between HDR and SDR devices by identifying the appropriate OETF for each device type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If video data is generated using a second OETF for wider luminance dynamic range (HDR), then the luminance dynamic range coverage is improved, but compatibility with first devices supporting only narrow luminance dynamic range (SDR) deteriorates
Solution Approach 1:
The transfer function information is segmented into two separate data structures: VUI (Video Usability Information) containing first OETF for SDR compatibility, and SEI (Supplemental Enhancement Information) containing second OETF for HDR capability. This segmentation allows each device type to access the appropriate transfer function without interference, resolving the contradiction between HDR coverage and SDR compatibility.
Solution Approach 2:
The solution adds a new dimension to the data structure by introducing SEI as a supplemental information layer alongside the traditional VUI. This dimensional expansion allows HDR information to coexist with SDR information in the same video data stream, enabling both narrow and wide luminance dynamic ranges to be supported simultaneously through multi-layer information architecture.
2Ease of manufacture
If a single OETF is used for video encoding, then the encoding process is simplified, but the ability to support multiple luminance dynamic ranges deteriorates
Solution Approach 1:
The video data structure is designed with universal compatibility by incorporating both first OETF (in VUI) and second OETF (in SEI). This multi-functionality allows the same video data to be properly reproduced on both SDR-only devices (using VUI) and HDR-capable devices (using SEI), eliminating the need for separate encoded versions while maintaining encoding simplicity.
Solution Approach 2:
The SEI message acts as an intermediary layer that carries alternative transfer function information without disrupting the existing VUI structure. This intermediary mechanism allows HDR information to be injected into the standard video data stream, enabling dual OETF support while maintaining the simplicity of the original encoding process.
Data Source
AI summary
A data generation method is for generating video data that covers a second luminance dynamic range wider than a first luminance dynamic range and has reproduction compatibility with a first device that does not support reproduction of video having the second luminance dynamic range and supports reproduction of video having the first luminance dynamic range, and includes: generating a video signal to be included in the video data using a second OETF; storing, into VUI in the video data, first transfer function information for identifying a first OETF to be referred to by the first device when the first device decodes the video data; and storing, into SEI in the video data, second transfer function information for identifying a second OETF to be referred to by a second device supporting reproduction of video having the second luminance dynamic range when the second device decodes the video data.