Chroma Intra Prediction Mode Derivation via Luma Reference
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Solution Overview
Problem
Current image/video compression techniques are inefficient for high-resolution, high-quality images/videos, leading to increased transmission and storage costs, especially with the growing demand for VR/AR content and immersive media.
Innovation Solution
An image coding method and apparatus that improves compression efficiency by deriving a chroma intra prediction mode using a luma intra prediction mode, generating a chroma candidate mode list, and pruning prediction modes to select the most effective chroma intra prediction mode, thereby enhancing precision and reducing data requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional image/video compression techniques are used for high-resolution, high-quality images/videos, then transmission and storage costs increase, but image quality and resolution requirements cannot be met
Solution Approach 1:
The patent changes the parameter of prediction mode derivation by using luma intra prediction mode to derive chroma intra prediction mode, rather than treating them independently. This parameter change in the coding methodology improves compression efficiency while maintaining high image quality, thereby reducing transmission and storage costs for high-resolution content.
2Measurement precision
If more bits are transmitted for high-resolution, high-quality image/video, then image quality improves, but transmission and storage costs increase
Solution Approach 1:
The patent uses the luma intra prediction mode as a reference (copy) to derive the chroma intra prediction mode. Instead of independently coding chroma prediction modes which would require more bits, the invention copies the luma mode information and adapts it for chroma, significantly reducing the data amount needed while maintaining image quality.
Solution Approach 2:
The luma intra prediction mode serves multiple functions: it is used directly for luma prediction and also serves as the basis for deriving chroma intra prediction mode. This multi-functionality reduces redundancy in the coding process and decreases the total bit rate required for high-quality image/video compression.
3Measurement precision
If chroma intra prediction mode is derived independently without using luma block information, then chroma prediction accuracy may be maintained, but coding efficiency decreases
Solution Approach 1:
The patent merges the luma and chroma prediction processes by using the luma intra prediction mode to derive the chroma intra prediction mode. This combining of information from both luma and chroma components improves coding efficiency while maintaining chroma prediction accuracy through the pruning check process that ensures prediction mode correctness.
Data Source
AI summary
An image decoding method according to the present document includes: a step for deriving a luma intra prediction mode; and a step for generating a chroma candidate mode list for a chroma block including a preset number of chroma intra candidates by using at least one among a DM, a planar mode, a DC mode, a vertical mode, a horizontal mode, and an up-right diagonal mode, which are derived from the luma intra prediction mode, wherein the DM is a prediction mode corresponding to a center (CR) position of the luma block, and the chroma intra candidates other than the DM can be derived through a duplicate check of the DM and a prediction mode corresponding to any one among the top left (TL), top right (TR), bottom left (BL), and bottom right (BR) of the luma block, the planar mode, the DC mode, the vertical mode, and the horizontal mode.