Intra Prediction Device CCLM Mode Implicit Selection
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Solution Overview
Problem
The application of Cross-Component Linear Model (CCLM) prediction in video encoding increases additional information transmission, leading to reduced encoding efficiency due to the need to transmit CCLM mode information for each chrominance block.
Innovation Solution
An intra prediction device that predicts luminance and chrominance blocks using a cross-component linear model predictor, where the calculation of the linear model is controlled based on the luminance intra prediction mode, eliminating the need to transmit CCLM mode information by implicitly selecting linear model calculation pixel positions based on the luminance intra prediction mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CCLM mode information is transmitted for each chrominance block, then prediction accuracy for chrominance block is improved, but additional information transmission increases and encoding efficiency is lowered
Solution Approach 1:
The patent extracts and removes the CCLM mode information transmission requirement from the encoding process. By deriving the linear model calculation pixel positions implicitly from the luminance intra prediction mode, the patent eliminates the need to transmit separate CCLM mode information, thereby resolving the contradiction between prediction accuracy and information transmission overhead
Solution Approach 2:
The luminance intra prediction mode serves a dual function: it not only predicts the luminance block but also implicitly determines the linear model calculation pixel positions for chrominance prediction. This multi-functionality approach allows the system to maintain accurate chrominance prediction without requiring additional mode information transmission
2Measurement precision
If CCLM mode information is transmitted for each chrominance block, then prediction accuracy for chrominance block is improved, but encoding efficiency is lowered
Solution Approach 1:
The patent removes the overhead of transmitting CCLM mode information by deriving pixel positions implicitly from existing luminance prediction mode data, thereby improving encoding efficiency while preserving prediction accuracy
Solution Approach 2:
The system uses the existing luminance intra prediction mode information to automatically determine the appropriate linear model calculation pixel positions for chrominance prediction, eliminating the need for separate mode signaling and improving overall encoding efficiency
Data Source
AI summary
An intra prediction device predicts, by intra prediction, a luminance block and a chrominance block obtained by dividing an image. The intra prediction device includes a cross-component linear model predictor configured to predict the chrominance block from a decoded luminance block at a position corresponding to a position of the chrominance block using a linear model calculated from respective luminance and chrominance reference pixels around the chrominance block. The cross-component linear model predictor includes a reference pixel position selector configured to select linear model calculation pixel positions that are positions of the reference pixels to be used to calculate the linear model based on a luminance intra prediction mode that is an intra prediction mode applied to the intra prediction of the decoded luminance block.