Adaptive Interpolation Filter Coefficients for Video Coding
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Solution Overview
Problem
Current video coding standards, such as HEVC, face challenges in efficiently encoding and decoding video frames due to the lack of effective interpolation filters that adapt to varying block sizes and availability of reference samples, leading to suboptimal prediction quality.
Innovation Solution
The method involves selecting and determining coefficients for interpolation filters, such as Lanczos or bi-linear filters, based on the projection phase and block characteristics, and incorporating filter flags in the bit stream to ensure consistent encoding and decoding, even when reference samples are unavailable, thereby improving prediction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed interpolation filter is used for all blocks, then the device complexity is reduced, but the prediction quality deteriorates due to inability to adapt to varying block sizes and reference sample availability
Solution Approach 1:
The patent implements dynamic filter selection by determining different interpolation filters based on block size categories (e.g., 4×4, 8×8, 16×16) and reference sample availability conditions. The filter type changes dynamically according to the specific coding context, allowing optimal prediction quality for each block while maintaining manageable complexity through systematic classification rules.
Solution Approach 2:
The patent changes the filter parameters (filter type, tap length, coefficients) based on block characteristics such as size and reference sample availability. Different block sizes trigger different filter configurations, and the filter parameters are adjusted according to whether reference samples are available, enabling adaptive optimization without requiring complex machine learning models.
2Manufacturing precision
If multiple interpolation filters are selected based on block characteristics, then the prediction quality is improved, but the encoding complexity increases due to additional filter determination steps
Solution Approach 1:
The patent performs preliminary classification of blocks into size categories and reference availability groups before applying specific filters. This pre-grouping allows the encoder to quickly determine the appropriate filter without complex real-time analysis, maintaining high encoding speed while achieving adaptive prediction quality through the preliminary structuring of the filtering process.
Solution Approach 2:
The patent uses simple parameter-based decision rules (block size thresholds, reference sample presence flags) to select filters, avoiding complex optimization algorithms. This approach maintains encoding efficiency by using lightweight parameter checks rather than computationally intensive filter selection methods.
3Manufacturing precision
If interpolation filters are applied to all blocks, then the video quality is improved, but the coding efficiency decreases due to increased bit rate for transmitting filter information
Solution Approach 1:
The patent applies different filtering strategies to different blocks based on their local characteristics (size, position, reference availability). Not all blocks receive the same treatment - some blocks use simple filters while others use more complex filters, and some may even skip filtering. This localized approach improves overall video quality while minimizing the bit rate overhead by only transmitting filter information when necessary.
Solution Approach 2:
The patent dynamically adjusts the filtering parameters and selection criteria based on block characteristics, allowing the system to use stronger filtering only when beneficial. This adaptive parameter adjustment reduces unnecessary bit rate overhead by avoiding transmission of filter information for blocks where simple or no filtering is sufficient.
4Reliability
If reference samples are unavailable, then the coding flexibility is reduced, but using alternative samples may degrade the prediction quality
Solution Approach 1:
The patent prepares alternative reference sample selection strategies in advance for cases where primary reference samples are unavailable. By pre-defining fallback mechanisms and alternative sampling locations, the system ensures continuous operation with reliable prediction quality even when reference samples are missing, without requiring complex runtime decision-making that would reduce coding flexibility.
Data Source
AI summary
Aspects of the disclosure provide a method for video coding. The method includes receiving input data associated with a processing block in a current picture, selecting, from a set of neighboring reconstructed samples for intra-coding pixels in the processing block, a plurality of reference samples for a pixel in the processing block based on a position of the pixel and an intra prediction mode of the processing block, determining a projection phase for the pixel based on the position of the pixel and the intra prediction mode of the processing block, determining coefficients of an interpolation filter based on the projection phase for the pixel, applying the interpolation filter with the determined coefficients on the reference samples to generate a prediction of the pixel, and encoding or decoding the pixel in the processing block using the prediction of the pixel.