DCT Deblocking Filter for Video Coding Efficiency
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Solution Overview
Problem
Existing video coding standards like JVET suffer from blocking artifacts and lack efficient coding techniques, particularly at low bit rates and in areas with low spatial activity, which degrade video quality.
Innovation Solution
Implement a DCT-based deblocking filter that replaces both weak and strong filtering in HEVC and JVET, using ramp-preserving filters to reduce blocking artifacts while maintaining coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block-based hybrid spatial and temporal predictive coding is used in JVET, then coding efficiency is improved, but blocking artifacts are generated that degrade video quality
Solution Approach 1:
A deblocking filter is introduced as an intermediary component between the block-based predictive coding process and the final decoded video output. This filter processes the coded blocks to smooth out discontinuities at block boundaries, thereby reducing blocking artifacts while preserving the coding efficiency benefits of the block-based approach
Solution Approach 2:
The patent converts the harmful blocking artifacts into a benefit by using them as indicators to guide the deblocking filter operation. The filter selectively applies smoothing operations based on the detected boundary strength and pixel differences, transforming the artifact problem into a controlled enhancement process that improves video quality
2Object-affected harmful factors
If existing deblocking filters are applied to reduce blocking artifacts, then video quality improves, but coding efficiency decreases and bit rate increases
Solution Approach 1:
The deblocking filter applies different filtering strengths to different regions of the video based on local characteristics. By calculating boundary strength and pixel differences locally, the filter applies strong smoothing only where blocking artifacts are present while leaving other regions unchanged, thereby maintaining coding efficiency in areas that don't require filtering
Solution Approach 2:
The patent dynamically adjusts filtering parameters based on local image characteristics such as boundary strength, pixel differences, and spatial activity. This adaptive parameter adjustment allows the filter to achieve effective artifact reduction with minimal impact on coding efficiency, as the filtering intensity is optimized for each specific region rather than applying uniform filtering across the entire video
3Object-affected harmful factors
If strong filtering is applied to reduce blocking artifacts in areas with low spatial activity, then visual quality improves, but coding complexity increases
Solution Approach 1:
The patent applies filtering selectively rather than uniformly across all video regions. By using thresholds for boundary strength and pixel differences, the filter applies strong filtering only to specific regions where blocking artifacts are present (partial action), while skipping regions where filtering would be unnecessary, thereby reducing overall computational complexity
Data Source
AI summary
A system and method of reducing blocking artifacts and providing enhanced coding efficiency based, as least in part, upon evaluation of relative smoothness of signals at a coding boundary. In some embodiments, a boundary threshold difference can be established beyond which it is determined that the difference is representative of a natural or intended boundary and filtering can be applied to those boundaries having differences below the boundary threshold difference. In some further embodiments, the ramps of the signal across the boundary can be evaluated to determine whether weak or strong filtering might be appropriate. In some further embodiments, weak filtering can be performed that reduces blocking artifacts, improves coding efficiency, but does not distort ramp signals across the boundary.