Video Codec Color-Space Switching With Adaptive Quantization

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Solution Overview

Problem

Existing video codec systems lack flexibility in handling color space transitions during encoding and decoding, leading to inefficiencies due to amplified quantization errors when switching between color spaces.

Innovation Solution

Implementing per component color space adjustment factors to adjust quantization and scaling during encoding and inverse quantization during decoding, compensating for energy amplification in color space conversions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If color space switching is implemented during encoding/decoding to improve flexibility and coding efficiency for different video content types, then adaptability and coding efficiency are improved, but quantization errors are amplified leading to degraded video quality

Engineering Contradiction:

Improvecolor space switching flexibilityVSAvoidquantization error amplification

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by adjusting quantization parameters (QP) and scaling factors based on the target color space being used. Different color spaces (e.g., YUV, RGB, BGR) have different energy distributions and sensitivity characteristics, so the encoder dynamically modifies quantization parameters to compensate for energy amplification in specific color components during color space conversion, thereby maintaining consistent quality across different color spaces

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary mechanism in the form of color space adjustment factors that act as mediators between the color space conversion process and quantization. These adjustment factors (multipliers applied to QP values and scaling factors) serve as a buffer to control and compensate for energy amplification, allowing the system to switch color spaces flexibly while maintaining quality through the mediating effect of these adjustment parameters

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If fixed quantization parameters are used across different color spaces to simplify the encoding process, then device complexity is reduced, but coding efficiency deteriorates due to inability to optimize for specific color space characteristics

Engineering Contradiction:

Improvequantization parameter managementVSAvoidcoding efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

Rather than using fixed quantization parameters, the patent implements dynamic parameter changes where QP values and scaling factors are adjusted according to the target color space. The system calculates color space adjustment factors based on the specific color space being used and applies these to modify quantization parameters, enabling optimization for each color space's characteristics while maintaining manageable complexity through systematic parameter adjustment

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transforms the static quantization parameter approach into a dynamic system where parameters adapt to the color space being used. The encoder determines the target color space for each coding unit and dynamically adjusts quantization parameters and scaling factors accordingly, allowing the system to respond to different content requirements and color space characteristics without requiring completely separate encoding paths for each color space

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If color space switching is performed without adjusting quantization to maintain simplicity, then ease of operation is improved, but manufacturing precision of video quality deteriorates due to perceptible mismatches in quantization error levels

Engineering Contradiction:

Improvecolor space switching operationVSAvoidquantization error consistency

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent maintains ease of operation by keeping the color space switching mechanism itself simple, while addressing quality issues through automatic parameter adjustments. The system changes quantization parameters and scaling factors based on the target color space without requiring complex manual intervention, thereby maintaining both operational simplicity and quality consistency through automated parameter adaptation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the encoder evaluates the target color space characteristics and automatically adjusts quantization parameters and scaling factors accordingly. This closed-loop approach ensures that quantization error levels remain consistent across different color spaces by using feedback from the color space identification to drive parameter adjustments, maintaining precision without complicating the operation

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250324056A1Adjusting quantization/scaling and inverse quantization/scaling when switching color spaces

Publication Date: 2025.10.16 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Innovations in adaptive encoding and decoding for units of a video sequence can improve coding efficiency when switching between color spaces during encoding and decoding. For example, some of the innovations relate to adjustment of quantization or scaling when an encoder switches color spaces between units within a video sequence during encoding. Other innovations relate to adjustment of inverse quantization or scaling when a decoder switches color spaces between units within a video sequence during decoding.