Chroma Block Vector Prediction for Higher Video Coding Compression
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in intra prediction due to the use of fixed and limited intra prediction directions, which result in increased bit usage for less likely directions, leading to suboptimal compression ratios.
Innovation Solution
The method involves dividing chroma coding units into smallest units and determining a block vector for chroma units based on co-located luma units, reconstructing chroma units using the block vector, and employing separate luma-chroma coding trees to improve intra prediction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed intra prediction directions are used, then the coding structure is simple, but the compression ratio is suboptimal due to increased bit usage for less likely directions
Solution Approach 1:
The patent applies dynamics by transitioning from fixed intra prediction directions to adaptive directional prediction. The system dynamically selects prediction directions based on the actual content characteristics of each block, allowing the coding structure to adapt to different scenarios while maintaining reasonable complexity through automated direction selection based on gradient analysis.
Solution Approach 2:
The patent changes the parameter of prediction direction from fixed to variable. By calculating gradients and determining optimal directions based on content characteristics, the system modifies the prediction direction parameter adaptively, improving compression ratio without significantly increasing overall coding complexity through efficient parameter selection.
2Productivity
If more intra prediction directions are supported, then the compression ratio improves, but the bit usage increases for less likely directions
Solution Approach 1:
The patent optimizes the parameter of prediction direction selection by using gradient-based analysis to determine the most likely directions. This approach changes the parameter selection strategy from exhaustive support of multiple directions to intelligent selection of optimal directions, improving compression while reducing bit usage for unlikely directions through efficient parameter encoding.
Solution Approach 2:
The patent applies partial action by supporting a limited set of prediction directions that are most likely to occur based on gradient analysis. Rather than implementing all possible directions, the system selectively applies the necessary subset of directions, achieving good compression ratios without the overhead of encoding and processing all potential directions.
3Ease of manufacture
If chroma units are coded independently, then the coding process is simple, but the intra prediction efficiency is suboptimal
Solution Approach 1:
The patent merges the coding processes of luma and chroma units by applying the same intra prediction methodology to both. This combination allows chroma units to benefit from the efficient prediction approach developed for luma, improving intra prediction efficiency while maintaining coding process simplicity through unified treatment of different color components.
Solution Approach 2:
The patent applies preliminary action by performing luma prediction first and then using the established methodology for chroma prediction. This sequential approach allows the coding process to benefit from the optimized luma prediction results while applying the same efficient techniques to chroma, improving overall intra prediction efficiency without significantly complicating the coding process.
Data Source
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AI summary
Aspects of the disclosure provide method and apparatus for video coding. In some examples, an apparatus includes processing circuitry for video decoding. The processing circuitry locates luma units of a luma coding unit that are co-located with chroma units of a chroma coding unit, and then determines a popularity of an intra block copy mode in the luma units. Further, the processing circuitry determines a block vector for a chroma unit in the chroma coding unit when the popularity meets a requirement, and reconstructs at least one sample of the chroma unit according to the block vector.