Cross-Component Sample Offset Filtering for Chroma Reconstruction Error
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Solution Overview
Problem
Existing video coding technologies face challenges in effectively reducing reconstruction errors in video data compression, particularly in handling cross-component sample offsets between different color components, which can degrade image quality.
Innovation Solution
Implementing a cross-component offset filtering method that adjusts reconstruction values of current samples by deriving an offset value from co-located and neighboring reconstructed samples of a first color component, using a loop filter with specified filter types and shapes to improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lossy compression is used to reduce bandwidth and storage requirements, then compression ratio is improved, but reconstruction error increases
Solution Approach 1:
The patent introduces a cross-component offset filter as an intermediary processing stage between compression and reconstruction. This filter uses luma component information to generate chroma offset values that compensate for reconstruction errors in the chroma component, thereby reducing the overall reconstruction error while maintaining the benefits of lossy compression.
Solution Approach 2:
The patent dynamically adjusts the chroma sample offset values based on the luma component characteristics. By changing the offset parameters adaptively according to the luma-chroma correlation in different regions, the system achieves better reconstruction accuracy without significantly increasing the compression ratio.
2Manufacturing precision
If cross-component offset filtering is applied to reduce reconstruction error, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent applies cross-component offset filtering selectively rather than uniformly across the entire image. The filter operates on a block-by-block basis, using local luma sample values to generate chroma offsets only where needed. This localized approach improves image quality in regions with significant luma-chroma correlation while minimizing the overall processing complexity.
Solution Approach 2:
The patent implements a simplified version of cross-component offset filtering that uses only the necessary minimum information from the luma component. Rather than using all available luma data, the filter selectively uses specific neighboring luma samples to generate chroma offsets, achieving adequate image quality improvement with reduced computational complexity.
3Measurement precision
If adaptive multi-tap-filter classifiers are used to adjust sample offsets, then reconstruction accuracy is improved, but computational load increases
Solution Approach 1:
The patent divides the chroma component processing into multiple segments or blocks, applying the cross-component offset filter independently to each block. This segmentation allows the system to use adaptive multi-tap-filter classifiers on a smaller scale, improving reconstruction accuracy locally while distributing the computational load across multiple smaller processing units.
Solution Approach 2:
The patent implements dynamic filter selection where the number of taps in the classifier is adjusted based on the local image characteristics. In regions with high luma-chroma correlation, more taps are used for higher accuracy, while in regions with low correlation, fewer taps are used to reduce computational load. This dynamic adaptation balances reconstruction accuracy with computational efficiency.
Data Source
AI summary
Various implementations described herein include methods and systems for coding video. In one aspect, a video bitstream includes a current coding block of an image frame, a first syntax element for a cross-component sample offset mode, and a second syntax element for a filter type and a filter shape index of a loop filter. Based on the loop filter, an electronic device identifies one or more neighboring luma samples of a first luma sample of the current coding block. The electronic device further determines and quantizes one or more difference values between the one or more neighboring luma samples and the first luma sample. The electronic device classifies a first color sample co-located with the first luma sample based on the quantized difference values to determine a first sample offset. The current coding block is reconstructed at least by adjusting the first color sample based on the first sample offset.