Adaptive Rice Parameter Initialization for Coefficient Level Coding
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Solution Overview
Problem
Existing video coding techniques, such as those in the HEVC standard, face inefficiencies in initializing the Rice parameter for coding transform coefficients, particularly in handling large coefficient values and screen content, leading to suboptimal compression performance.
Innovation Solution
The proposed solution involves dynamically determining the initial value of the Rice parameter based on statistics of previously coded coefficient levels, allowing for adaptive adjustment within each coefficient group to better accommodate large coefficient values and content types, such as screen content, rather than resetting it to zero for all cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the Rice parameter is initialized to zero for all cases, then the coding process is simple and consistent, but the compression performance deteriorates for large coefficient values and screen content
Solution Approach 1:
The patent changes the Rice parameter initialization value dynamically based on the content type. Instead of always initializing to zero, the system selects different initial values (e.g., 0, 1, 2, or 3) based on statistics from previously coded coefficients and the current coefficient group characteristics. This parameter adaptation resolves the contradiction by maintaining simplicity through automated selection while improving compression performance for diverse content types.
Solution Approach 2:
The patent introduces dynamic adaptation of the Rice parameter initialization based on content analysis. The system continuously updates statistics from previously coded coefficients and uses these to determine the optimal initial value for the current coefficient group. This dynamic approach allows the coding process to adapt to different content types (natural video vs. screen content) while maintaining operational simplicity through automated decision-making.
2Productivity
If the Rice parameter is dynamically adjusted based on statistics, then the compression performance improves, but the computational complexity increases
Solution Approach 1:
The patent performs preliminary statistical analysis during the coding process by maintaining running statistics of previously coded coefficients. These statistics are updated incrementally as coefficients are coded, and the accumulated information is used to determine the optimal Rice parameter initialization for subsequent coefficient groups. This preliminary action enables dynamic adaptation without requiring complex real-time computations.
Solution Approach 2:
The system implements feedback mechanisms where the statistics from previously coded coefficients continuously inform the Rice parameter initialization decisions. The encoder monitors the distribution of previously coded coefficient values and uses this feedback to select appropriate initial values for the Rice parameter, creating a closed-loop system that adapts to content characteristics while maintaining computational efficiency through iterative refinement.
3Productivity
If the Rice parameter initialization is optimized for specific content types, then the compression performance for that content improves, but the adaptability to other content types deteriorates
Solution Approach 1:
The patent applies local quality optimization by selecting different Rice parameter initialization values tailored to specific content types and coefficient group characteristics. Instead of using a universal initialization value, the system analyzes local statistics from previously coded coefficients and chooses the most appropriate initial value for each specific coefficient group. This localized optimization improves compression performance for each content type while maintaining overall system versatility through adaptive selection.
Solution Approach 2:
The system maintains adaptability across different content types through dynamic parameter selection. By continuously updating statistics and selecting Rice parameter initial values based on current content characteristics, the system can adapt to various content types (natural video, screen content, mixed content) without requiring separate optimization for each type. The dynamic nature of the approach ensures both specialized performance and broad adaptability.
Data Source
AI summary
Techniques are described for initializing a Rice parameter used to define codes for coefficient level coding. According to the techniques, the initial value of the Rice parameter is determined for a coefficient group (CG) in a transform block of video data based on statistics of coefficient levels that are gathered for previously coded coefficients of the video data. The statistics may be statistics of absolute values of coefficient levels or remaining absolute values of coefficient levels of previously coded coefficients. A value of the statistics may be initialized to zero at a beginning of a video slice and updated based on coefficient levels coded in each CG of the slice. The statistics may be updated once per CG. In some cases, statistics may be gathered separately for each of a plurality of different categories of CGs that are defined based on characteristics of transform blocks that include the CGs.