Video Chroma Inloop Filtering With Luma-Guided Upsampling
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Solution Overview
Problem
Existing video coding techniques face challenges in efficiently utilizing upsampling or super-resolution techniques to enhance video encoding efficiency and quality, particularly in the inloop filtering of chroma components.
Innovation Solution
Implementing a cross-component resampling inloop filter (CC-RIF) that upsamples chroma components using luma samples to improve video quality and efficiency, replacing or interposing between existing filters such as the deblocking filter, sample adaptive offset filter, and adaptive loop filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional inloop filtering is used for chroma components, then device complexity is reduced, but video quality and coding efficiency deteriorate
Solution Approach 1:
The patent combines luma and chroma filtering processes into a unified cross-component inloop filter. The filter uses luma samples to guide chroma filtering decisions, merging what were previously separate filtering operations. This integration improves chroma quality by leveraging correlated information from luma while maintaining operational efficiency through a consolidated filtering architecture.
Solution Approach 2:
The cross-component inloop filter serves multiple functions simultaneously: it performs deblocking, sample adaptive offset, and adaptive loop filtering for both luma and chroma components using a unified structure. The filter adapts its behavior based on the component type and local image characteristics, providing versatile chroma enhancement without requiring separate dedicated filters for each function.
2Productivity
If chroma resolution is reduced for compression, then data transmission efficiency improves, but video quality deteriorates
Solution Approach 1:
The patent introduces luma samples as an intermediary to guide chroma filtering operations. The luma component, which maintains full resolution, serves as a reference that mediates the reconstruction of chroma details. The cross-component filter uses luma gradients and edge information to infer where chroma details should be preserved or smoothed, effectively using the higher-quality luma data to compensate for chroma downsampling artifacts.
Solution Approach 2:
The filter dynamically changes its filtering parameters based on local image characteristics and component type. For chroma components, the filter strength, kernel size, and adaptation thresholds are adjusted according to luma activity levels and chroma frequency content. This parameter adaptation allows the system to maintain chroma quality in regions requiring detail while applying stronger compression in less critical areas.
Data Source
AI summary
A method and an apparatus are disclosed for video coding using an improved inloop filter for chroma components. In the disclosed embodiments, a video decoding device performs obtaining a reconstructed frame that includes luma samples and chroma samples, subsequently obtaining a scale value representing a resolution difference between the reconstructed frame and an original frame. Responsive to the reconstructed frame having a resolution that is based on the scale value and is less than a resolution of the original frame, the video decoding device generates an upsampled chroma frame by inputting the luma samples and the chroma samples into a cross component resampling inloop filter (CC-RIF).