Reference-Line Intra-Prediction Mode Derivation for Precise Chroma Coding
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Solution Overview
Problem
Existing video compression technologies, such as H.264/AVC and HEVC, face challenges in efficiently encoding and decoding videos due to increasing video sizes, resolutions, and frame rates, leading to a need for improved coding efficiency and higher image quality.
Innovation Solution
A method and apparatus for deriving an intra-prediction mode using an intra-prediction mode derivation scheme that obtains reference line information and most probable mode (MPM) information to determine planar information, thereby efficiently selecting candidate intra modes for chroma blocks and improving compression performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing video compression technologies (H.264/AVC and HEVC) are used, then video data can be compressed and transmitted, but coding efficiency and image quality are insufficient due to increasing video sizes, resolutions, and frame rates
Solution Approach 1:
The patent segments the intra-prediction mode derivation process into distinct stages: obtaining reference line information, determining MPM information, determining planar information, and deriving the final intra-prediction mode. This segmentation allows for more precise and efficient processing of chroma blocks, improving coding efficiency while handling increasing data amounts.
Solution Approach 2:
The patent performs preliminary actions by obtaining reference line information and determining MPM (most probable mode) information before deriving the final intra-prediction mode. This preliminary processing enables more efficient selection of candidate modes, reducing the computational burden and improving overall coding efficiency for high-resolution and high-frame-rate videos.
2Productivity
If an intra-prediction mode derivation scheme is applied to chroma blocks, then compression performance is improved, but the application range and precision of mode selection are limited without extended schemes
Solution Approach 1:
The patent creates a universal intra-prediction mode derivation scheme that can be applied to both luma and chroma blocks. By defining a general framework that obtains reference line information and determines MPM information applicable to different block types, the scheme extends its application range while maintaining improved compression performance across various video content.
Solution Approach 2:
The patent applies local quality by treating chroma blocks with a specialized derivation process that considers reference line information and MPM information specific to chroma characteristics. This localized approach for chroma blocks, while part of a universal framework, enhances compression performance by adapting to the specific requirements of chroma prediction.
3Device complexity
If MPM information is determined without planar mode consideration, then the MPM list is simpler, but the precision of intra-prediction mode selection is reduced
Solution Approach 1:
The patent segments the mode selection process by first determining MPM information from reference lines, then separately determining planar information based on the MPM results. This segmentation allows the MPM list to remain relatively simple while achieving high precision in final mode selection by combining MPM candidates with planar mode determination in a structured two-stage process.
Data Source
AI summary
A method and apparatus for deriving an intra-prediction mode are disclosed. At least one embodiment of the present disclosure provides a method of deriving an intra-prediction mode, including (i) obtaining, based on reference line information indicating any one of a plurality of reference lines, most probable mode (MPM) information indicating whether an intra-prediction mode of a current block is included in an MPM list lacking a planar mode, (ii) determining, based on the reference line information and the MPM information, planar information indicating whether the intra-prediction mode of the current block is the planar mode, and (iii) deriving the intra-prediction mode of the current block by using the planar information.