Video Decoding With Adaptive Loop Filtering After Dynamic Rescaling
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Solution Overview
Problem
Existing video encoding and decoding technologies do not effectively address the need for improved coding efficiency when dynamically re-scaling original and reconstructed pictures, leading to suboptimal performance in video codecs like VVC.
Innovation Solution
The method involves dynamically re-scaling pictures for encoding and decoding by down-sampling and up-sampling with adaptive filters, applying adaptive loop filtering (ALF) to improve picture quality and reduce coding artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic re-scaling is applied to original and reconstructed pictures for encoding, then coding efficiency is improved, but picture quality degradation occurs due to resampling artifacts
Solution Approach 1:
The patent applies adaptive loop filtering that dynamically adjusts filter coefficients based on local picture characteristics and resolution changes. The filter parameters are modified according to the specific re-scaling operation context, enabling optimization of picture quality at different resolutions while maintaining coding efficiency benefits of dynamic re-scaling.
Solution Approach 2:
The patent implements feedback mechanisms where the decoded picture buffer stores filtered pictures at different resolutions, and the filtering process uses feedback from previously processed blocks to refine current reconstruction. This feedback loop enables continuous improvement of picture quality while maintaining the efficiency gains from dynamic re-scaling.
2Manufacturing precision
If adaptive loop filtering is applied to up-sampled decoded pictures, then picture quality is improved, but processing complexity increases
Solution Approach 1:
The patent applies different filtering strategies to different regions and components of the picture based on their specific characteristics. The adaptive loop filter selectively applies different coefficient sets to luma and chroma components, and adjusts filtering strength based on local picture content, thereby improving picture quality while managing processing complexity through localized optimization.
Solution Approach 2:
The patent implements dynamic filter coefficient adjustment where the filtering parameters are not fixed but adapt based on the specific decoding context, picture resolution, and local characteristics. This dynamic adaptation enables the system to optimize picture quality for each specific re-scaling operation while controlling overall processing complexity through intelligent parameter selection.
Data Source
AI summary
Methods and apparatuses for encoding/decoding a video are provided. A picture from a video is decoded from a bitstream, the picture being encoded in the bitstream at a resolution that is lower than an original resolution of the picture. Decoding the picture further comprises up-sampling the decoded picture to the original resolution, and applying an adaptive filter to at least one component of the up-sampled decoded picture. According to some embodiments, the adaptive filter may be performed in-loop or out-of-loop of the decoding/encoding process.