Hybrid OETF Signaling for SDR-HDR Video Compatibility
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Solution Overview
Problem
Existing video data generation methods lack backward compatibility, making it difficult for devices supporting standard dynamic range (SDR) to reproduce high dynamic range (HDR) video data, and vice versa.
Innovation Solution
A data generation method that includes storing first and second opto-electrical transfer function (OETF) information in video usability information and supplemental enhancement information, respectively, allowing devices to switch between SDR and HDR reproduction schemes based on hybrid information, ensuring backward compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If video data is generated using a second OETF for wider luminance dynamic range (HDR), then HDR reproduction quality is improved, but compatibility with first devices supporting only standard luminance dynamic range (SDR) deteriorates
Solution Approach 1:
The patent embeds multiple layers of transfer function information within the video data structure. The VUI parameters store first OETF information accessible to all devices, while SEI messages contain second OETF information for HDR-capable devices. This nested structure allows SDR devices to use the VUI information while HDR devices can access the more advanced SEI information, enabling both to reproduce video appropriately from the same encoded stream
Solution Approach 2:
The patent changes the parameter representation by storing transfer function information in two different formats and locations within the video data structure. By encoding transfer_characteristics values in VUI and alternative_transfer_characteristics in SEI messages, the system allows devices to select appropriate parameters based on their capabilities, transforming a single-parameter limitation into a multi-parameter solution
2Adaptability or versatility
If separate transfer function information is stored for both SDR and HDR devices, then reproduction compatibility is improved, but device complexity increases
Solution Approach 1:
The patent segments transfer function information into two distinct components stored in separate locations within the video bitstream. VUI parameters contain transfer_characteristics for SDR compatibility, while SEI messages contain alternative_transfer_characteristics for HDR enhancement. This segmentation allows devices to selectively process only the relevant portion based on their capabilities, reducing the effective complexity each device must handle while maintaining overall system compatibility
3Measurement precision
If video signal is encoded using second OETF for HDR, then HDR video quality is improved, but processing complexity for maintaining SDR compatibility increases
Solution Approach 1:
The patent performs preliminary encoding of the video signal using the second OETF for HDR while simultaneously embedding both first and second transfer function information in the VUI and SEI structures during the encoding phase. This preliminary action ensures that all necessary information for both SDR and HDR reproduction is prepared in advance, eliminating the need for complex real-time processing or conversion during playback, as devices can directly use the pre-prepared transfer function information appropriate to their capabilities
Data Source
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AI summary
A data generation device comprises: a generating circuit configured to generate video data according to an Advanced Video Coding (AVC) standard and a second opto-electrical transfer function (OETF); and a storage to store: video usability information (VUI) including a first value indicating a first OETF; and supplemental enhancement information (SEI) including a second value indicating the second OETF, wherein the first OETF and the second OETF support a standard dynamic range (SDR) and a high dynamic range (HDR), respectively, the first value is to be referred to by a decoding device that does not support HDR, the second OETF is a combination of a square root function and a logarithmic function, the SEI is provided in a multiplexing layer other than a video coding layer, and the second OETF has compatibility with the first OETF.