Rate-Distortion Interpolation Filter Selection for Video Coding
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Solution Overview
Problem
Current digital video encoding and decoding techniques face challenges in accurately generating predictive data, particularly during fractional interpolation, which affects compression efficiency and video quality.
Innovation Solution
The implementation of filtering techniques that utilize multiple interpolation filters and rate-distortion analysis to select the most appropriate predictive data, including fixed and adaptive filters, and encoding syntax to indicate the selection, enhances the accuracy of predictive data and reduces data transmission requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple interpolation filters are used with rate-distortion analysis to select optimal predictive data, then video quality and compression efficiency are improved, but device complexity and computational requirements increase
Solution Approach 1:
The system dynamically selects between fixed and adaptive interpolation filters based on rate-distortion analysis of the current video content. The filtering approach changes adaptively according to the characteristics of the video sequence being processed, allowing optimal balance between quality and complexity for different content types.
Solution Approach 2:
The system changes the parameter of filter selection (fixed vs. adaptive) based on rate-distortion metrics. By analyzing the distortion-reduction potential versus bit-rate cost, the system selects the appropriate filtering mode, transforming a static filtering approach into a dynamic parameter-based selection system.
2Measurement precision
If adaptive interpolation filters are used to improve predictive data accuracy, then video quality improves, but computational complexity and processing time increase
Solution Approach 1:
The system dynamically adjusts the use of adaptive filtering based on the complexity and characteristics of the current video block. Not all blocks require adaptive filtering - the system activates it selectively when rate-distortion analysis indicates potential quality improvement, reducing overall computational power requirements.
Solution Approach 2:
Instead of applying adaptive filtering uniformly to all video blocks, the system applies it partially - only to blocks where rate-distortion analysis suggests it will provide meaningful quality improvement. This selective application reduces total computational processing power requirements while maintaining quality where it matters most.
3Device complexity
If fixed interpolation filters are used, then device complexity is reduced, but adaptability to different video content and quality deteriorates
Solution Approach 1:
The system implements a universal filtering framework that can operate in multiple modes (fixed filter only, or fixed plus adaptive filters). This multi-functional approach allows the same system to handle different video content types effectively, providing adaptability without requiring completely separate processing paths for different content.
Solution Approach 2:
The system transitions from a static fixed-filter approach to a dynamic multi-mode filtering system. Based on rate-distortion analysis of the video content, the system dynamically selects whether to use only fixed filters or to incorporate adaptive filters, providing adaptability to different video content while managing complexity.
Data Source
AI summary
This disclosure describes filtering techniques applied by an encoder and a decoder during the prediction stage of a video encoding and/or decoding process. The filtering techniques may enhance the accuracy of predictive data used during fractional interpolation, and may improve predictive data of integer blocks of pixels. There are several aspects to this disclosure, including a useful twelve-pixel filter support that may be used for interpolation, techniques that use coefficient symmetry and pixel symmetry to reduce the amount of data needed to be sent between an encoder and a decoder to configure the filter support for interpolation, and techniques for filtering data at integer pixel locations in a manner that is similar to sub-pixel interpolation. Other aspects of this disclosure concern techniques for encoding information in the bitstream to convey the type of filter used, and possibly the filter coefficients used. Predictive coding of filter coefficients is also described.