Piecewise Inter-Layer Prediction for SDR-to-EDR Video Coding
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Solution Overview
Problem
Current video compression techniques face challenges in efficiently encoding and decoding signals with enhanced dynamic range (EDR) while maintaining compatibility with legacy systems and supporting advanced UHD display technologies, particularly in inter-layer prediction methods.
Innovation Solution
A piecewise inter-layer prediction method is employed using pre-computed look-up tables based on histograms and statistics of standard dynamic range (SDR) and EDR signals, allowing for fast iterative algorithms to determine prediction coefficients for piecewise polynomials, enabling efficient encoding and decoding of EDR video signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If piecewise inter-layer prediction with pre-computed look-up tables is used, then coding efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-computing look-up tables (LUTs) containing polynomial coefficients and prediction data before the actual encoding/decoding process. These pre-computed tables are stored and reused during video compression, eliminating the need for complex real-time calculations and reducing computational complexity during actual operation while maintaining high coding efficiency.
2Measurement precision
If polynomial predictors with pre-computed look-up tables are employed, then coding precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent uses preliminary action by pre-computing polynomial coefficients and storing them in look-up tables during system initialization or offline processing. This approach achieves high coding precision through accurate polynomial predictions while simplifying the manufacturing and deployment process, as the complex mathematical computations are performed in advance rather than during device fabrication or real-time operation.
Solution Approach 2:
The patent applies copying by creating pre-computed look-up tables that contain polynomial coefficients and prediction data. These tables are copied into the decoder/encoder memory and reused multiple times during video processing, eliminating the need to recalculate complex polynomial predictions for each video frame, thereby improving precision while reducing manufacturing complexity.
3Measurement precision
If enhanced dynamic range signals are encoded with high precision, then dynamic range representation is improved, but loss of information increases
Solution Approach 1:
The patent applies parameter changes by using polynomial predictors with variable degrees and adaptive look-up tables that adjust parameters based on the specific video content and dynamic range requirements. This allows high-precision encoding of EDR signals by optimizing the polynomial order and prediction parameters for different scene characteristics, maintaining accuracy while minimizing information loss through efficient compression.
Data Source
AI summary
Pixel data of a video sequence with enhanced dynamic range (EDR) are predicted based on pixel data of a corresponding video sequence with standard dynamic range (SDR) and a piecewise inter-layer predictor. The output parameters of the piecewise predictor are computed based atleast on two sets of pre-computed values and a prediction cost criterion. The first set of pre-computed values applies to all input SDR frames and comprises a set of SDR pixel values raised to one or more integer power terms. The second set of pre-computed values is frame specific and is computed based on a histogram of an input SDR frame and pixel values of the corresponding EDR frame. The pre-computed values allow for a fast iterative algorithm to identify the best pivot points for the piecewise polynomials according to a prediction cost and to solve for the coefficients of the piecewise predictor.