Chroma Intra Prediction Using Multiple Direct Mode Candidates
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to a significant increase in transmission and storage costs due to the rise in the amount of transmitted information or bits, necessitating high-efficient image compression technology.
Innovation Solution
An image encoding/decoding method that derives a plurality of direct modes for chroma intra prediction, allowing both default modes and direct modes to be used, and eliminates overlap between them, enhancing encoding/decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple direct modes are derived and used for chroma intra prediction, then chroma intra prediction performance is improved, but device complexity increases
Solution Approach 1:
The patent segments the chroma intra prediction process by separating default modes from multiple direct modes. The encoder/decoder derives multiple direct mode candidates from luma block prediction modes and selectively applies them based on overlap detection with default modes. This segmentation allows improved prediction performance through multiple modes while managing complexity by maintaining a structured selection process.
Solution Approach 2:
The patent implements dynamic mode selection where the set of available chroma intra prediction modes is adaptively determined based on the specific video content and block characteristics. The encoder/decoder dynamically derives direct modes from luma prediction modes and adjusts the mode list by removing overlaps with default modes, creating a flexible, content-adaptive prediction system rather than a fixed mode set.
2Measurement precision
If default modes are modified to eliminate overlap with direct modes, then mode determination accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining a set of default chroma intra prediction modes before the actual prediction process. These default modes are established in advance and serve as a baseline. During encoding/decoding, the system then performs overlap detection between these pre-established default modes and the dynamically derived direct modes, removing only the necessary overlaps. This approach improves mode determination accuracy while maintaining operational simplicity by keeping the default mode set fixed and well-defined.
Data Source
AI summary
An image encoding/decoding method, a bitstream transmission method, and a computer-readable recording medium for storing a bitstream are provided. The image decoding method according to the present disclosure is an image decoding method performed by an image decoding device, and may comprise the steps of: deriving multiple direct mode (DM) candidates for a chroma block; determining one DM candidate among the multiple DM candidates on basis of first information; and performing intra prediction of the chroma block on the basis of the determined DM candidate, wherein default modes for the chroma block are modified on the basis of whether same are identical to the multiple DM candidates.