Dynamic Range Adjustment Parameter Signaling Precision
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Solution Overview
Problem
Current video coding standards, such as H.265/HEVC, face limitations in the precision and effectiveness of piece-wise polynomial function-based color remapping information (CRI) and dynamic range adjustment (DRA) due to restricted bit depth and limited precision in signaling parameters, which affects the coding efficiency of High Dynamic Range (HDR) and Wide Color Gamut (WCG) content.
Innovation Solution
Enhancing the precision of CRI and DRA parameter signaling by allowing decoupled bit depths for coded and target values, enabling negative values, and incrementing bit depth for intermediate steps, thereby improving the representation of color details in extreme brightness regions and enhancing coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piece-wise polynomial function-based color remapping information (CRI) and dynamic range adjustment (DRA) are used in current video coding standards, then color remapping capability is provided, but precision and effectiveness are limited due to restricted bit depth and limited precision in signaling parameters
Solution Approach 1:
The parameter signaling is segmented into separate components: coded values and target values can have different bit depths. This segmentation allows independent optimization of precision for each parameter type, enabling higher precision signaling without uniformly increasing complexity across all parameters.
Solution Approach 2:
The patent introduces an additional dimension to the parameter representation by allowing negative values for pivot points and slopes. This expands the signaling space from strictly non-negative values to include negative values, enabling more precise representation of color remapping functions while maintaining efficient coding structures.
2Productivity
If higher precision is used in CRI and DRA parameter signaling, then coding efficiency for HDR/WCG content is improved, but bit depth requirements and processing complexity increase
Solution Approach 1:
Different bit depths are applied locally to different parameter types based on their specific precision requirements. Coded values and target values can have different bit depths, allowing optimization of bit usage for each parameter type rather than uniformly increasing bit depth for all parameters.
Solution Approach 2:
The patent applies higher precision (excessive action) only where necessary for HDR/WCG content representation, specifically for coded and target values that directly affect color accuracy, while maintaining standard precision for other parameters. This partial application of high precision improves coding efficiency without proportionally increasing overall bit depth requirements.
Data Source
AI summary
An apparatus configured to process video data includes a memory and a processor in communication with the memory where the processor is configured to obtain an input picture including a color component having a first color characteristic, obtain a plurality of parameters associated with the color component of at least one sample of the input picture where the plurality of parameters are indicative of pivot points associated with a piece-wise linear function associated with the color component, determine that a value of at least one parameter of the plurality of parameters includes a negative value, apply, on the at least one sample of the input picture, the piece-wise linear function defined with the at least one parameter having a negative value, generate at least one output sample of an output picture including the color component having a second color characteristic based on the application of the piece-wise linear function.