Chroma Intra Prediction Using Luma Samples and Mapping Tables
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image encoding and decoding methods face inefficiencies in handling high-resolution and high-quality image data, leading to increased data transfer and storage costs due to the large amount of data required for HD and UHD images.
Innovation Solution
An intra chroma block prediction method using a luma sample is employed, where the image decoding method derives an intra prediction mode for a chroma block based on an LM (Luma Estimated Mode) mapping table, and generates a predicted block accordingly, while also utilizing a non-LM mapping table and codeword mapping to optimize prediction modes and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution and high-quality image data is used, then image quality is improved, but data amount increases leading to higher transfer and storage costs
Solution Approach 1:
The patent uses luma sample values to predict chroma block values, creating a copy-based prediction approach where the luma component serves as a reference to generate chroma predictions. This reduces the need to store and transmit full chroma data at high resolution, thereby maintaining image quality while reducing data amount.
Solution Approach 2:
The patent introduces an intermediate prediction process where luma sample values act as mediators to derive chroma block values. Instead of directly storing high-resolution chroma data, the system uses luma values as intermediaries to reconstruct chroma information, reducing the overall data requirement while preserving image quality.
2Measurement precision
If LM mapping table is used for chroma block prediction, then prediction accuracy is improved, but decoding complexity increases
Solution Approach 1:
The patent pre-establishes mapping tables that define the relationship between luma sample values and chroma block prediction modes. By preparing these mappings in advance, the decoding process can directly lookup prediction modes without performing complex real-time calculations, thus improving prediction accuracy while managing decoding complexity through pre-computation.
Solution Approach 2:
The patent changes the parameter representation by using compact mapping tables that encode prediction mode information efficiently. Instead of storing full prediction algorithms, the system transforms the prediction logic into parameter-based lookup tables, improving prediction accuracy while reducing the computational complexity during decoding.
3Adaptability or versatility
If multiple mapping tables (LM and non-LM) are used for different prediction modes, then prediction flexibility is improved, but system complexity increases
Solution Approach 1:
The patent segments the prediction system into distinct mapping tables for different prediction scenarios (LM-based and non-LM-based). By dividing the prediction logic into separate, specialized tables, the system achieves flexibility in handling different prediction modes while managing complexity through modular organization of prediction pathways.
Solution Approach 2:
The patent implements dynamic selection between different mapping tables based on the prediction mode and available luma samples. The system can adaptively choose between LM-based and non-LM-based prediction tables, providing flexibility in prediction approaches while managing system complexity through conditional logic that activates only the necessary prediction pathway.
Data Source
AI summary
Disclosed are an intra prediction method of a chrominance block using a luminance sample and an apparatus using the same. An image decoding method comprises the steps of: calculating an intra prediction mode of a chrominance block on the basis of an LM mapping table when the chrominance block uses an LM; and generating a prediction block for the chrominance block on the basis of the calculated intra prediction mode of the chrominance block. When intra prediction mode information of chrominance blocks are decoded, mutually different tables are used depending on whether or not an LM is used, so that encoding and decoding can be performed without an unnecessary waste of bits.