Luma-Based Chroma Intra Prediction for Video Coding
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Solution Overview
Problem
Conventional video coding techniques fail to effectively leverage similarities between luma and chroma blocks for improved pixel prediction during encoding and decoding processes, leading to suboptimal prediction accuracy due to their independent processing.
Innovation Solution
Implementing luma-based chroma intra prediction schemes in video encoder and decoder systems, where textural characteristics of luma pixel positions are analyzed to determine appropriate down-sample filters and coefficients for predicting chroma pixel values, and using bitstream headers to convey this information for synchronized processing across the encoder and decoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If luma and chroma blocks are intra predicted independently using conventional techniques, then the encoding and decoding processes are simple and computationally efficient, but the prediction accuracy is suboptimal because similarities between luma and chroma blocks are not leveraged
Solution Approach 1:
The patent uses luma block characteristics as an intermediary to improve chroma prediction. Instead of predicting chroma independently, the method derives chroma prediction values from luma neighboring blocks through a mediation process that leverages the correlation between luma and chroma components, thereby improving prediction accuracy while maintaining reasonable complexity
Solution Approach 2:
The patent merges the luma and chroma prediction processes by allowing chroma intra prediction to utilize luma block information. This combining of previously separate prediction streams enables the system to exploit the structural similarities between luma and chroma blocks, improving overall prediction accuracy without requiring completely separate encoding paths
2Measurement precision
If luma-based chroma intra prediction is implemented to leverage structural similarities between luma and chroma blocks, then prediction accuracy is improved, but the device complexity and computational requirements increase
Solution Approach 1:
The patent applies partial action by selectively using luma-based prediction only for chroma blocks where it provides benefit, rather than universally applying complex prediction methods to all blocks. This approach improves prediction accuracy for chroma while avoiding the full computational overhead of always using the most complex prediction methods
Solution Approach 2:
The patent changes the prediction parameters by deriving chroma prediction values from luma block characteristics rather than using traditional chroma-only prediction parameters. This parameter change enables leveraging the correlation between luma and chroma, improving accuracy while the changes are designed to be computationally efficient
Data Source
AI summary
Systems, devices and methods for performing luma-based chroma ultra prediction are described. Down-sample filters may be applied to luma values of luma pixel positions to generate reconstructed luma values for chroma pixel positions in a prediction unit of an intra frame. The down-sampled reconstructed luma values may then be used to predict chroma values for the chroma pixel positions. In some implementations, a reconstructed luma value of a chroma position may be used to predict that position's chroma value. In other implementations, reconstructed luma values of neighboring chroma pixel positions may be analyzed to adaptively predict a chroma value for a chroma pixel position.