Adaptive Quantization Scaling for Video Color-Space Switching

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Solution Overview

Problem

Existing video encoding and decoding technologies lack flexibility in handling color spaces within a single video sequence, leading to inadequate compensation for quantization errors when switching between color spaces, which affects coding efficiency.

Innovation Solution

Adaptive adjustment of quantization and scaling during encoding and inverse quantization during decoding, using per component color space adjustment factors to compensate for energy amplification when converting between color spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a video codec system uses a fixed color space for the entire video sequence, then the decoding process is simple and consistent, but the system lacks flexibility to process different kinds of video content (e.g., screen capture vs. natural video) within a single sequence

Engineering Contradiction:

Improvecolor space flexibilityVSAvoidcolor space management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic color space switching within a video sequence, allowing the encoder to select different color spaces (e.g., RGB for screen capture content, YUV for natural video) based on the characteristics of each picture or block. This dynamic adaptation resolves the contradiction by making the color space configuration flexible and content-aware rather than fixed, while maintaining manageable complexity through standardized switching mechanisms defined in the codec specification.

Inventive Principle:

Principle #15Dynamics

2Productivity

If quantization parameters are kept consistent across different color spaces, then the encoding process is simpler, but quantization error energy varies significantly between color spaces causing perceptible mismatches and reduced coding efficiency

Engineering Contradiction:

Improvecoding efficiencyVSAvoidquantization parameter adjustment

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces color space adjustment factors that modify quantization parameters based on the specific color space being used. When switching between color spaces (e.g., from RGB to YUV), the system automatically adjusts the quantization parameters using pre-defined adjustment factors to compensate for differences in energy distribution and perceptual importance across color components. This resolves the contradiction by optimizing coding efficiency through parameter adaptation while keeping the complexity manageable through systematic adjustment rules.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback mechanisms where the encoder evaluates the characteristics of the current video content and the active color space, then selects appropriate quantization parameters accordingly. This feedback-driven approach allows the system to adapt quantization strength based on both content characteristics and color space properties, resolving the contradiction between simplified encoding and optimized coding efficiency.

Inventive Principle:

Principle #23Feedback

3Productivity

If the system switches color spaces between units within a video sequence to optimize for different content types, then coding efficiency improves, but quantization error energy amplification occurs during inverse color space conversion

Engineering Contradiction:

Improvecoding efficiencyVSAvoidquantization error amplification

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by pre-calculating and applying color space adjustment factors before quantization occurs. These adjustment factors are designed to counteract the potential energy amplification that would occur during inverse color space conversion. By proactively compensating for this effect through adjusted quantization parameters, the system maintains coding efficiency while preventing the harmful amplification of quantization errors, thus resolving the contradiction.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS12375668B2Adjusting quantization/scaling and inverse quantization/scaling when switching color spaces

Publication Date: 2025.07.29 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.