Adaptive Video Filter Selection for Bitrate Reduction
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Solution Overview
Problem
Existing video encoding techniques struggle to reduce bitrate without compromising video quality, often resulting in quality loss and artifacts such as blocking artifacts.
Innovation Solution
The method involves encoding a reference bitstream and applying candidate filters to an input video stream to produce filtered bitstreams. The cost value for each candidate filter is determined based on the difference in distortion and bitrate between the reference and filtered bitstreams, with the filter resulting in the lowest cost value selected for the output bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If video encoding techniques are used to reduce bitrate, then data amount is reduced, but video quality deteriorates and artifacts such as blocking artifacts are introduced
Solution Approach 1:
The patent applies a filter to the input video stream before encoding to pre-smooth the video data. This preliminary filtering action reduces high-frequency noise and minor artifacts that would otherwise require higher bitrate to maintain quality, allowing the subsequent encoding to achieve lower bitrate without significant quality loss.
Solution Approach 2:
The patent optimizes filter parameters including kernel size, sigma values for Gaussian filtering, and cutoff frequencies to balance between smoothing strength and detail preservation. By carefully tuning these parameters, the system achieves effective noise reduction while maintaining video quality at lower bitrates.
2Quantity of substance
If a filter is applied to the input video stream before encoding, then bitrate is reduced, but processing time increases due to additional filtering operations
Solution Approach 1:
The patent applies different filtering strengths and types to different regions of the video stream. Important regions with detailed content receive less aggressive filtering while smoother regions receive stronger filtering, optimizing the balance between bitrate reduction and processing time. This selective approach reduces overall computational burden compared to uniform filtering.
Solution Approach 2:
The patent uses partial filtering rather than complete filtering of the entire video stream. By applying filtering only to specific frames, specific regions, or using subsampled filtering, the system achieves sufficient bitrate reduction with acceptable processing time overhead.
3Manufacturing precision
If multiple candidate filters are evaluated to find the optimal filter, then video quality is maintained at lower bitrate, but computational complexity increases
Solution Approach 1:
The patent divides the filter selection process into segments by evaluating multiple candidate filters with different characteristics (e.g., different kernel sizes, different sigma values) and selecting the best one. This segmentation allows systematic comparison of filtering options to find the optimal balance between quality preservation and bitrate reduction.
Solution Approach 2:
The patent uses feedback from quality metrics and distortion measurements to guide the filter selection process. By evaluating candidate filters against the original video and selecting the one that minimizes distortion while achieving lowest bitrate, the system optimizes quality preservation efficiently.
Data Source
AI summary
Adaptive filtering is used video stream for bitrate reduction. A first copy of the input video stream is encoded to a reference bitstream. Each of a number of candidate filters is applied to each frame of a second copy of the input video stream to produce a filtered second copy of the input video stream. The filtered second copy is encoded to a candidate bitstream. A cost value for the candidate filter is determined based on distortion value and bitrate differences between the candidate bitstream and the reference bitstream. The candidate bitstream corresponding to the candidate filter with a lowest one of the cost values is selected as the output bitstream, which is then output or stored. Processing the input video stream using the adaptive filter and before the encoding may result in bitrate reduction, thereby improving compression, decompression, and other performance.