Chroma Intra Prediction Mode Determination Using Luma Samples
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Solution Overview
Problem
Current video encoding and decoding methods face inefficiencies in handling high-resolution or high-definition image content, particularly in chroma prediction, where existing techniques do not effectively utilize the relationship between luma and chroma samples for improved coding efficiency.
Innovation Solution
A method and apparatus that determine a luma block corresponding to a chroma sample at a lower-right location within a current chroma block, and based on the intra prediction mode of this luma block, determine and apply a chroma intra prediction mode to the chroma block, enabling improved intra prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chroma prediction uses a direct mode with one luma block corresponding to one chroma block, then the coding process is simple, but the coding efficiency is insufficient for high-resolution content
Solution Approach 1:
The patent divides the chroma block into multiple regions (first chroma block and second chroma block) and applies different prediction modes to each region. The first chroma block uses direct mode prediction while the second chroma block uses offset mode prediction, allowing the system to improve overall coding efficiency by selectively applying more complex prediction techniques only where needed rather than uniformly across the entire chroma block.
Solution Approach 2:
The patent applies different prediction strategies to different spatial regions of the chroma block based on local characteristics. By identifying specific chroma samples that benefit from offset prediction and applying the offset mode only to the second chroma block containing these samples, the system optimizes prediction quality locally while maintaining overall simplicity.
2Loss of information
If chroma prediction uses a direct mode with one luma block corresponding to one chroma block, then the implementation is straightforward, but the utilization of luma-chroma relationship is insufficient
Solution Approach 1:
The patent introduces an intermediary mechanism where chroma samples are used to identify regions that benefit from offset prediction. By using chroma sample characteristics as a mediator to determine prediction mode selection, the system better utilizes the luma-chroma relationship without requiring complex joint processing of both components.
Solution Approach 2:
The patent performs preliminary identification of chroma samples and determination of the second chroma block before applying offset prediction. This preliminary action allows the system to prepare the prediction structure in advance, efficiently utilizing the luma-chroma relationship while maintaining implementation simplicity through a clear sequential process.
Data Source
AI summary
Provided are a method and apparatus, which, during video encoding and decoding processes, obtain chroma intra prediction mode information about a current chroma block, when the chroma intra prediction mode information indicates a direct mode (DM), determine a luma block including a luma sample corresponding to a chroma sample at a lower-right location with respect to a center of the current chroma block, determine a chroma intra prediction mode of the current chroma block based on an intra prediction mode of the determined luma block, and perform intra prediction on the current chroma block, based on the determined chroma intra prediction mode.