Cross-Channel Chroma-from-Luma Prediction for Video Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding technologies face inefficiencies in intra prediction, particularly in handling chroma from luma (CfL) prediction, leading to suboptimal compression ratios and increased bandwidth requirements.
Innovation Solution
Implement cross-channel prediction by deriving a predictor for the chroma channel based on reconstructed samples from the luma channel, using weighted sums or averages of AC and DC contributions, and applying intra-prediction modes such as SMOOTH, SMOOTH-H, SMOOTH-V, PAETH, directional, or offset-based refinement modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional intra prediction is used for chroma channel, then prediction simplicity is maintained, but prediction accuracy and compression efficiency deteriorate
Solution Approach 1:
The patent introduces luma channel as an intermediary to improve chroma channel prediction. Instead of directly predicting chroma from surrounding chroma samples, the method uses luma channel information as a mediator to derive better predictions, achieving higher accuracy without excessive complexity in the prediction process itself
Solution Approach 2:
The patent changes the prediction parameters by introducing multiple prediction modes (first prediction mode using luma-based cross-channel prediction, second prediction mode using traditional chroma-based prediction) and allows flexible selection based on block characteristics, optimizing the balance between accuracy and complexity
2Measurement precision
If cross-channel prediction mode is applied, then prediction accuracy improves, but computational complexity increases
Solution Approach 1:
The patent applies dynamics by making the prediction mode selection adaptive rather than fixed. The encoder dynamically selects between first prediction mode (luma-based) and second prediction mode (chroma-based) based on block characteristics, and the decoder adaptively applies the appropriate mode, optimizing computational complexity for each specific case
Solution Approach 2:
The patent applies partial action by not always using the more complex luma-based cross-channel prediction. Instead, it uses the simpler chroma-based prediction when sufficient, and only applies the more complex cross-channel prediction when necessary to achieve better accuracy, thus avoiding excessive computational complexity in all cases
3Productivity
If multiple prediction modes are implemented, then compression efficiency improves, but encoding complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the prediction process into distinct modes (first prediction mode for luma-based cross-channel prediction, second prediction mode for traditional chroma prediction) that can be independently selected and applied to different blocks, allowing efficient compression through optimal mode selection without overwhelming complexity
Data Source
AI summary
This disclosure describes a set of advanced video coding technologies. More specifically, the disclosed technology involves cross-channel prediction and particularly chroma from luma (CfL) prediction. In some example implementations, a sample in a chroma channel is predicted based on a weighted sum or average of an alternate current prediction contribution derived based on reconstructed samples of a luma channel and a direct current prediction contribution generated based on an intra-prediction of the sample in the chroma channel based on reconstructed samples of the chroma channel, the intra-prediction being performed based on an intra-prediction mode other than a DC mode.