Dynamic Range Adjustment Signaling for Video Coding Efficiency
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Solution Overview
Problem
Current video coding techniques face inefficiencies in compressing High Dynamic Range (HDR) and Wide Color Gamut (WCG) video data, leading to distortions and increased bitrates, as they struggle to effectively manage dynamic range transformations and color volume changes during encoding and decoding processes.
Innovation Solution
The implementation of Dynamic Range Adjustment (DRA) using a piecewise linear function, where parameters describing the function are encoded and decoded to adjust the dynamic range of video data, allowing for efficient compression and conversion between different display formats, such as SDR and HDR, by dividing input values into non-overlapping ranges with varying lengths and signaling these parameters in the bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If current video coding techniques are used for HDR and WCG video data, then the video can be encoded and decoded, but compression efficiency is poor and distortions occur
Solution Approach 1:
The patent applies segmentation by dividing the input value range into multiple non-overlapping ranges with different lengths. This allows the piecewise linear function to handle different segments of the dynamic range separately, improving both compression efficiency and video quality by adapting to the specific characteristics of each segment.
Solution Approach 2:
The patent changes parameters by encoding specific parameters that describe the piecewise linear function, including the division into non-overlapping ranges with varying lengths. This parameter-based approach enables flexible adaptation to HDR and WCG video data characteristics, resolving the contradiction between compression efficiency and video quality.
2Quantity of substance
If dynamic range adjustment is performed without optimized parameter encoding, then the process is simple, but the number of bits required for encoding increases
Solution Approach 1:
The patent extracts and encodes only the necessary parameters that describe the piecewise linear function and its range divisions, rather than encoding the entire function. This selective extraction reduces the number of bits required while maintaining the ability to perform accurate dynamic range adjustment.
Solution Approach 2:
The patent performs preliminary encoding of the piecewise linear function parameters before the actual dynamic range adjustment process. By pre-defining the ranges and function characteristics, the encoding complexity during video processing is reduced, and fewer bits are needed to represent the transformation.
3Adaptability or versatility
If equal-length ranges are used for piecewise linear function, then encoding is simpler, but adaptability to different video content is reduced
Solution Approach 1:
The patent introduces asymmetry by using non-overlapping ranges with different lengths instead of uniform equal-length ranges. This asymmetric division allows the encoding to adapt to the specific distribution and characteristics of video content in different dynamic range segments, improving versatility while managing encoding complexity through parameter optimization.
Data Source
AI summary
Dynamic Range Adjustment can be used to correct distortions that can occur when the dynamic range of the colors in video are transformed. In various examples, Dynamic Range Adjustment can be performed using a piecewise linear function that takes as input a range of color values. Parameters describing the piecewise linear function can be encoded into a bitstream, and the parameters can be used by a decoding process to reconstruct the piecewise linear function. To improve encoding efficiency, techniques can be applied by which redundant values in the parameters need not be encoded when the range of input values for the piecewise linear function can be divided into portions having equal lengths. The decoding process can derive the omitted values from values that are provided, and can apply the piecewise linear function to decoded video data to perform Dynamic Range Adjustment.