Intra Prediction Smoothing With ISP-Based Filter Selection
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Solution Overview
Problem
Existing video coding technologies face challenges in achieving efficient compression ratios with minimal sacrifice in picture quality, particularly in intra prediction processes.
Innovation Solution
The method involves determining interpolation filter coefficients based on Intra Sub-Partitions (ISP) information to select between fG and fC coefficients, and applying these coefficients to reference samples for intra prediction, thereby reducing mode dependency and enhancing encoding/decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If intra prediction is used to predict block values, then compression efficiency is improved, but artifacts appear at block boundaries causing visual degradation
Solution Approach 1:
A boundary smoothing filter is introduced as an intermediary component between the intra prediction stage and the final reconstructed image. This filter specifically targets block boundary regions and applies smoothing operations to reduce artifacts, while preserving the compression efficiency benefits of intra prediction by operating selectively on boundary areas rather than the entire block
2Device complexity
If block-based processing is used for compression, then computational complexity is reduced, but visual quality deteriorates at block boundaries
Solution Approach 1:
The smoothing filter is applied selectively only to boundary regions between blocks rather than uniformly across the entire image. This local quality approach maintains the computational efficiency of block-based processing by limiting the additional processing to specific problem areas, while improving visual quality where artifacts occur
3Object-affected harmful factors
If filter strength is increased to reduce artifacts, then visual quality is improved, but edge sharpness and detail are lost
Solution Approach 1:
The filter strength is made dynamic rather than fixed, adapting to the local characteristics of each boundary region. The filter automatically adjusts its smoothing intensity based on whether the boundary contains edges or smooth regions, applying stronger smoothing to smooth boundaries and weaker smoothing to preserve edges, thereby resolving the contradiction between artifact reduction and detail preservation
Data Source
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AI summary
Devices and methods of intra prediction of a block of a picture are provided. The method includes: obtaining information of Intra Sub-Partitions (ISP), where the information of ISP indicates whether ISP is used for splitting a current block; and selecting a set of coefficients of an interpolation filter based on the information of ISP, where the set of coefficients of the interpolation filter is fG coefficients or fC coefficients. The method further includes obtaining predicted samples of the current block by applying the set of coefficients to reference samples. When the information of ISP indicates whether ISP is used for splitting a current block (i.e., ISP is on), the method removes mode dependency during selection of interpolation filter type. This could increase encoding or decoding efficiency.