VVC Decoder Chroma Residual Scaling With Dual-Flag Control
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Solution Overview
Problem
Existing decoding technologies improperly apply chroma residual scaling, leading to reduced encoding efficiency in Versatile Video Coding (VVC) due to incorrect on-off control based on significant coefficient flags, resulting in improper distribution of energy across color components.
Innovation Solution
Implement a decoding device and method that perform chroma residual scaling based on both significant coefficient flags and a color space transform application flag, ensuring proper application of chroma residual scaling by considering the energy distribution across color components in the RGB color space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chroma residual scaling is applied based only on significant coefficient flags, then calculation amount is reduced, but encoding efficiency deteriorates due to improper application of chroma residual scaling
Solution Approach 1:
The patent changes the control parameter for chroma residual scaling from only significant coefficient flags to a combination of significant coefficient flags and color space transform application flag. This parameter change ensures that chroma residual scaling is properly applied when color space transform is used, thereby improving encoding efficiency without significantly increasing calculation complexity.
2Device complexity
If chroma residual scaling is applied without considering color space transform, then processing is simplified, but energy distribution across color components becomes improper
Solution Approach 1:
The patent introduces feedback control by checking both the significant coefficient flag and the color space transform application flag before applying chroma residual scaling. This feedback mechanism ensures that chroma residual scaling is applied only when appropriate (when color space transform is used and chroma coefficients are present), thereby achieving proper energy distribution without unnecessary processing complexity.
Data Source
AI summary
A method includes: decoding a bitstream and thereby outputting a transform coefficients for each color component of the block, a first flag indicating for each color component whether the block includes a non-zero transform coefficient, and a second flag indicating whether the block has been encoded using a color space transform that transforming a color space of a prediction residual from a color space of the original image to another color space; performing a color space inverse transform for the prediction residual restored from the transform coefficients, when the second flag indicates that the block has been encoded using the color space transform; and determining whether to perform chroma residual scaling for the prediction residual of the chrominance component, based on the first flag of a chrominance component and the second flag, the chroma residual scaling that performs scaling based on a luminance component corresponding to the chrominance component.