HDR Picture Encoding with Adaptive In-Loop and Out-Loop Mapping
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Solution Overview
Problem
The existing video encoding and decoding technologies for HDR video suffer from poor adaptability and low encoding efficiency due to the challenges in coordinating out-loop and in-loop luma and chroma mapping transformations with other encoding and decoding processes, leading to suboptimal performance.
Innovation Solution
A method and apparatus that support a composite use of out-loop and in-loop luma and chroma mapping transformations, determining picture features to generate and embed identification information in the encoding process, and apply these transformations during and outside the encoding loop to improve efficiency and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If in-loop LMCS technology is used to map luma components and scale chroma components, then storage space is reduced and encoding efficiency is improved, but adaptability becomes poor and encoding efficiency decreases
Solution Approach 1:
The patent implements dynamic switching between in-loop LMCS and out-loop reshaper technologies based on picture characteristics. The encoder determines whether to apply in-loop mapping or out-loop mapping adaptively, allowing the system to optimize for different content types and requirements, thereby resolving the contradiction between storage efficiency and adaptability.
Solution Approach 2:
The patent changes the operational parameters of the mapping transformation by introducing a switching mechanism that adjusts which technology (in-loop or out-loop) is active based on picture features. This parameter change enables the system to achieve both storage efficiency and adaptability by selecting the appropriate technology for each specific case.
2Manufacturing precision
If out-loop reshaper technology is used to pre-process video before encoding, then luma and chroma mapping transformation is performed, but coordination with encoding tools such as blocking, intra prediction, inter prediction, transformation and quantization and loop filtering is poor, resulting in low encoding performance
Solution Approach 1:
The patent dynamically selects between in-loop and out-loop processing based on picture characteristics, ensuring that the mapping transformation is coordinated with subsequent encoding tools. By making the processing dynamic and adaptive rather than static, the system maintains high encoding performance while achieving quality mapping transformation.
Solution Approach 2:
The patent allows out-loop reshaper to perform preliminary mapping transformation when beneficial, while still coordinating with subsequent encoding tools through the adaptive switching mechanism. This preliminary action is taken selectively rather than universally, resolving the contradiction between transformation quality and overall encoding performance.
3Manufacturing precision
If HDR video with larger luma range is used to present real world more accurately, then video quality is improved, but storage space occupied increases
Solution Approach 1:
The patent changes the luma range parameter dynamically by applying mapping transformation that compresses the large HDR luma range into a smaller range suitable for efficient encoding and storage. This parameter transformation maintains the visual quality of HDR video while reducing the storage space required.
Solution Approach 2:
The patent implements dynamic mapping transformation that adapts to different HDR content characteristics, optimizing the compression of luma range while preserving video quality. The system dynamically adjusts the mapping parameters based on picture features to achieve the best balance between quality and storage efficiency.
Data Source
AI summary
Provided are a picture encoding method, a picture encoding apparatus, a picture decoding method, a picture decoding apparatus, an electronic device and a storage medium. The encoding method includes: acquiring a video picture, and determining a picture feature of the video picture; determining in-loop identification information and out-loop identification information according to the picture feature; processing the video picture according to the in-loop identification information and the out-loop identification information; and encoding the processed video picture to generate a code stream, and writing the in-loop identification information and the out-loop identification information into the code stream. Therefore, the processing of a video picture is achieved both encoding and decoding out-loop and encoding and decoding in-loop according to the picture feature during a picture transmission process, thereby effectively improving the video encoding and decoding efficiency and improving the quality of a decoded picture at the same code rate.