Adaptive Loop Filtering with Zero Offset for HEVC
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Solution Overview
Problem
High Efficiency Video Coding (HEVC) faces challenges in reducing artifacts such as blocking artifacts, quantization errors, and intensity shifts in compressed video data, which affect visual quality, and existing adaptive loop filtering methods require complex computations and signaling delays.
Innovation Solution
The implementation of adaptive loop filtering with the option to apply sample adaptive offset (SAO) filtering and using adaptive loop filtering with no offset, assuming a zero offset when SAO is applied, simplifies parameter estimation and reduces computational complexity by eliminating the need to determine an offset, thereby improving video quality and reducing signaling delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adaptive loop filtering with offset computation is applied to minimize MSE between reconstructed and original video, then video quality is improved, but computational complexity increases
Solution Approach 1:
The patent changes the offset parameter from a computed value to a fixed zero value, simplifying the adaptive loop filtering process while maintaining video quality improvement through the filtering operation itself
2Measurement precision
If adaptive loop filtering with offset computation is applied to reduce artifacts, then video quality is improved, but signaling delays increase
Solution Approach 1:
The patent extracts the offset computation step from the adaptive loop filtering process, removing it entirely by fixing the offset to zero, thereby eliminating the associated signaling delays while preserving the artifact reduction benefits
3Measurement precision
If sample adaptive offset filtering is applied to reduce intensity shift distortion, then video quality is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of SAO filtering and ALF offset computation by applying both with fixed parameters, eliminating the need for separate offset determination and reducing overall device complexity
Data Source
AI summary
A method for adaptive loop filtering of a reconstructed picture in a video encoder is provided that includes determining whether or not sample adaptive offset (SAO) filtering is applied to the reconstructed picture, and using adaptive loop filtering with no offset for the reconstructed picture when the SAO filtering is determined to be applied to the reconstructed picture.