In-loop Filtering for Chrominance Components in Video Encoding
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Solution Overview
Problem
Current video encoding technologies suffer from compression distortions such as the block effect and ringing effect due to quantization, which affect encoding quality and compression efficiency, and existing in-loop filtering methods like deblocking, sample adaptive offset, and adaptive loop filtering have room for improvement.
Innovation Solution
An in-loop filtering method that determines a target filter for the chrominance component of an image block from multiple cross-component adaptive loop filtering (ALF) filters, calculates target filter coefficients based on the chrominance and luminance components, filters the chrominance component, and encodes the filtered result, with the total number of ALF filters represented as a single syntax element in the image stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If in-loop filtering is applied to reduce compression distortion, then image quality is improved, but computational complexity increases
Solution Approach 1:
The patent segments the filtering process by dividing the image into blocks and applying different filtering strategies to different blocks. It also segments the filter coefficients into a limited set of predefined filters, selecting from these segments rather than computing custom filters, thereby reducing computational complexity while maintaining image quality improvement.
Solution Approach 2:
The patent changes the parameter approach by using a limited set of predefined filter coefficients instead of computing arbitrary filter coefficients. This parameter discretization reduces the search space and computational burden while still allowing quality improvement through the selected filter coefficients.
2Manufacturing precision
If multiple cross-component ALF filters are used, then filtering performance is improved, but syntax element quantity increases
Solution Approach 1:
The patent merges multiple cross-component ALF filters into a unified set of predefined filters. Instead of treating each filter as a separate syntax element, the patent combines them into a single syntax element that indicates the total number of filters, with individual filter selection handled through indexing mechanisms.
Solution Approach 2:
The patent creates a universal filtering framework where a single syntax element can indicate multiple different filter configurations. The same syntax element structure serves multiple purposes by allowing flexible interpretation based on the indicated number of filters, reducing redundancy in the bitstream.
Data Source
AI summary
A video processing method including determining a target CC-ALF filter for a chrominance component of a current block of an image from a plurality of CC-ALF filters, determining target CC-ALF filter coefficients for the chrominance component according to the chrominance component after ALF and a luminance component of the current block without ALF, filtering the chrominance component after ALF according to the target CC-ALF filter and the target CC-ALF filter coefficients, determining a filtered chrominance component of the current block according to the chrominance component after being filtered with the target CC-ALF filter coefficients and the chrominance component after the ALF, and encoding the filtered chrominance component, including encoding using a total number of the plurality of CC-ALF filters, an index of the target CC-ALF filter, and the target CC-ALF filter coefficients as syntax elements.