Adaptive Video Clipping Bounds for Chroma Precision

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Solution Overview

Problem

Existing video compression systems face challenges in efficiently handling video data that exceeds the data range, leading to potential data inversion and distortion during encoding and decoding processes.

Innovation Solution

The method involves adaptive clipping, where the clipping bounds are determined from the original signal characteristics and encoded in the bitstream, using Principal Component Analysis (PCA) to transform and clip the video data, particularly for the chroma components, while maintaining the luma component within its original range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If video data is clipped to a fixed range to avoid data inversion, then data reliability is improved, but manufacturing precision deteriorates due to distortion and loss of signal characteristics

Engineering Contradiction:
Improvedata reliabilityVSAvoidsignal precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies dynamic clipping by determining clipping bounds adaptively based on local signal characteristics (standard deviation, mean value) rather than using fixed clipping bounds. The clipping bounds are dynamically adjusted according to the variance and statistical properties of the video data in different regions, allowing the system to maintain reliability by preventing data inversion while preserving signal precision through context-aware clipping thresholds

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the clipping parameters (bounds) based on local signal statistics. Instead of using constant clipping bounds, the system calculates adaptive bounds using the standard deviation and mean of the video data in specific regions. This parameter adaptation allows the clipping operation to maintain reliability across different signal conditions while minimizing distortion and preserving manufacturing precision

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If adaptive clipping bounds are determined from original signal characteristics, then manufacturing precision is improved, but device complexity increases due to additional processing steps

Engineering Contradiction:
Improveclipping precisionVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by determining clipping bounds independently for different regions or blocks of video data based on their local statistical characteristics. Each region undergoes separate analysis of its standard deviation and mean values to establish region-specific clipping bounds, rather than applying a global clipping threshold. This localized approach improves clipping precision for diverse signal regions while managing complexity through modular, region-by-region processing

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system performs self-service by automatically determining its own clipping bounds from the video data's inherent statistical properties without requiring external configuration or manual tuning. The clipping algorithm uses the video data's own standard deviation and mean values to generate adaptive bounds, making the system self-adapting and reducing the need for complex external control mechanisms

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If PCA transformation is applied to chroma components, then manufacturing precision is improved, but device complexity increases due to additional transformation steps

Engineering Contradiction:
Improvecolor space precisionVSAvoidtransformation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies PCA transformation to change the parameter representation of chroma components from standard color space to a transformed space that captures the essential variance in chroma data. This transformation reparameterizes the chroma information to improve precision in representing color variations, with the transformed coefficients enabling more efficient and accurate clipping operations in the chroma domain

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces distortion by dynamically adjusting the clipping bounds based on the video signal's characteristics, effectively minimizing the difference between the clipped and original values, thereby improving the overall compression efficiency and quality of the video signal.

Implementation Method 1

transforming the second color component and the third color component into a transformed second color component and a transformed third color component in a second color space, responsive to the parameters for transforming, wherein the transforming is based on PCA (Principal Component_analysis)

Methodology Applied
Scientific EffectPrincipal Component_analysis (PCA):

Data Source

PatentEP3513557B1Method and apparatus for video coding with adaptive clipping
Publication Date: 2025.04.02 INTERDIGITAL MADISON PATENT HLDG
  • EP3513557B1 patent drawingFigure 1
  • EP3513557B1 patent drawingFigure 2~3
  • EP3513557B1 patent drawingFigure 4A~4B

AI summary

In a particular implementation, a clipping bound may be different from the signal bound. For example, to derive the upper clipping bound, a reconstructed sample value corresponding to original sample value Y is estimated to be Y + Δy. Thus, for a candidate upper clipping bound x, the difference between the clipped value and the original value is calculated as min(Y + Δy, x) — Y. The distortions using different candidate clipping values around signal bound M may be tested. The test starts with signal bound M and moves towards smaller values. The distortion may first decrease (or maintain the same) and then increase, and the turning point is chosen as upper clipping bound M'. Similarly, the lower clipping bound m' can be chosen. For more effective clipping, the color components may be transformed such that the transformed color components may be more tightly enclosed by a box defined by the clipping bounds.