In-loop Filtering Bypass for Lossless Video Coding
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Solution Overview
Problem
Current video compression techniques often sacrifice image quality to achieve higher compression ratios, particularly through in-loop filtering methods that can degrade visual quality in lossless coding modes, and fail to efficiently manage bandwidth limitations in modern telecommunications networks.
Innovation Solution
The proposed solution involves selectively bypassing in-loop filtering steps on reconstructed pixels during video coding, especially in lossless coding modes, to directly use unfiltered reconstructed pixels for prediction, thereby avoiding unnecessary distortion and improving visual quality and coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If in-loop filtering is applied to reconstructed pixels, then deblocking artifacts are reduced, but visual quality is degraded in lossless coding mode
Solution Approach 1:
The patent implements dynamic control of in-loop filtering by introducing a bypass mechanism that can selectively disable filtering based on coding mode. The filter is enabled for lossy coding to reduce artifacts, but disabled for lossless coding to preserve exact pixel values, making the filtering process adaptive to different operational requirements
Solution Approach 2:
The patent changes the filtering parameter state by introducing a bypass flag or mode indicator that controls whether filtering is applied. This parameter change allows the system to switch between filtered and unfiltered states, optimizing visual quality for lossless mode while maintaining artifact reduction for lossy mode
2Shape
If in-loop filtering is applied to reconstructed pixels, then block edges are smoothed, but coding efficiency is reduced due to additional processing
Solution Approach 1:
The patent makes the filtering process dynamic by conditionally enabling or disabling it based on the coding mode. This dynamic approach allows the system to apply filtering only when beneficial (lossy mode), thereby improving block edge smoothness without incurring the processing overhead in lossless mode where filtering would reduce coding efficiency
3Manufacturing precision
If lossless coding mode is used, then image fidelity is preserved, but compression ratio is reduced
Solution Approach 1:
The patent applies local quality control by allowing different processing treatments for different coding modes. In lossless mode, exact pixel values are preserved without filtering to maintain maximum image fidelity, while in lossy mode, filtering is applied to improve visual quality. This local differentiation optimizes the trade-off between fidelity and compression for each mode
Data Source
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AI summary
An apparatus comprising a processor configured to generate a reconstructed pixel, selectively bypass at least one in-loop filter on the reconstructed pixel, and generate a prediction pixel for a current pixel using at least the reconstructed pixel when the at least one in-loop filter is bypassed.