HDR Video Encoding with SDR Reconstruction and Residual Mapping
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Solution Overview
Problem
Existing video encoding technologies waste processor resources due to the lack of support for scalable encoding and high data calculation requirements, leading to poor HDR display effects on devices that do not support HDR, and existing methods do not efficiently handle dynamic range mapping between HDR and SDR formats.
Innovation Solution
A method for video encoding that maps reconstructed SDR data to HDR data using a correspondence and adjusts residual values to a bit width suitable for SDR bitstreams, ensuring efficient transmission and decoding across devices with varying dynamic range capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If scalable encoding is used to process HDR video, then HDR display effect is improved, but processor resources are wasted and device compatibility deteriorates
Solution Approach 1:
The video encoding is segmented into two separate streams: an SDR bitstream for compatibility with non-HDR devices and an HDR bitstream for HDR-capable devices. This segmentation allows each stream to be optimized independently, resolving the contradiction between HDR quality and device compatibility.
Solution Approach 2:
An SDR-to-HDR conversion mechanism serves as an intermediary process. The encoder converts SDR reconstructed data to HDR data using tone mapping and residual adjustment, enabling HDR output from an SDR bitstream without requiring full scalable encoding infrastructure.
2Manufacturing precision
If scalable encoding is used for video processing, then HDR display effect is improved, but data calculation amount increases
Solution Approach 1:
The SDR bitstream is encoded first using conventional SDR encoding, establishing a baseline that is compatible with all devices. Then, HDR data is generated through conversion from the SDR reconstructed data, rather than encoding HDR separately from the beginning. This preliminary SDR encoding reduces overall computational burden.
Solution Approach 2:
The encoding process changes key parameters dynamically: it adjusts tone mapping curves, modifies residual bit widths, and transforms color space representations. These parameter changes enable HDR output while leveraging the already-computed SDR encoding results, improving efficiency.
3Adaptability or versatility
If conventional SDR encoding is used, then device compatibility is improved, but HDR display effect deteriorates
Solution Approach 1:
The encoding system provides different quality levels locally: SDR quality for non-HDR devices and HDR quality for HDR-capable devices. The same bitstream contains both SDR content and HDR enhancement data, allowing each device to receive the appropriate quality level for its capabilities.
Solution Approach 2:
The encoded bitstream serves multiple functions simultaneously: it acts as a standalone SDR bitstream for compatibility and as an HDR bitstream when combined with the SDR-to-HDR conversion data. This multi-functionality resolves the contradiction between compatibility and HDR quality.
Data Source
AI summary
Embodiments of this application provide a video encoding method, a video decoding method, and an apparatus. The video encoding apparatus may obtain source data, where the source data includes first high dynamic range HDR data and a first standard dynamic range SDR bitstream for same video data; map reconstructed data of the first SDR bitstream to second HDR data based on a correspondence between the reconstructed data of the first SDR bitstream and the first HDR data; determine a target residual value between the second HDR data and the first HDR data, where a bit width of the target residual value is less than or equal to a data bit width for encoding a first SDR video into the first SDR bitstream; encode the correspondence and the target residual value, to determine preset data; and transmit the first SDR bitstream to which the preset data is added.