Chroma Intra Prediction Using Collocated Luma Angular Modes
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Solution Overview
Problem
Existing video coding technologies face challenges in accurately encoding and decoding chroma blocks due to insufficient utilization of information from collocated luma blocks, leading to suboptimal compression efficiency and video quality.
Innovation Solution
Utilize angular intra prediction modes from collocated luma blocks as references for coding chroma blocks, enabling improved accuracy and precision in video encoding and decoding by employing methods that involve block partitioning and mode signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional chroma block encoding methods are used without utilizing luma block information, then the encoding process is simpler and faster, but the compression efficiency and video quality are suboptimal
Solution Approach 1:
The patent merges the encoding processes of luma and chroma blocks by utilizing the angular intra prediction mode information from collocated luma blocks to guide chroma block encoding. This integration allows the decoder to infer chroma prediction modes from already-decoded luma data, improving compression efficiency without requiring separate, redundant mode signaling for chroma blocks.
Solution Approach 2:
The chroma block encoding process serves itself by automatically utilizing the prediction mode information from the already-decoded collocated luma block. The luma block's angular intra prediction mode becomes a reference for chroma encoding, eliminating the need for additional complex mode selection and signaling mechanisms while improving compression performance.
2Measurement precision
If angular intra prediction mode from collocated luma block is used as reference for chroma block, then the accuracy and precision of video encoding is improved, but the processing complexity increases
Solution Approach 1:
The luma block is decoded and its angular intra prediction mode is determined before the chroma block encoding process. This preliminary action allows the chroma encoding to directly utilize the already-analyzed luma prediction mode information, improving encoding accuracy while avoiding the need to perform separate, redundant analysis during chroma processing.
Solution Approach 2:
The angular intra prediction mode of the collocated luma block serves as an intermediary that bridges the encoding processes of luma and chroma components. This intermediary information is naturally available from luma decoding and provides a useful reference for chroma prediction, improving precision without requiring direct complex interactions between luma and chroma processing pipelines.
3Reliability
If chroma blocks are encoded independently without using luma block information, then the encoding process is more straightforward, but the video quality and compression efficiency are reduced
Solution Approach 1:
The patent applies local quality enhancement by utilizing spatially collocated luma block information specifically for the corresponding chroma block encoding. This localized approach improves video quality at each chroma block position by leveraging nearby luma data, while maintaining encoding simplicity through a straightforward reference relationship rather than requiring global or complex multi-block analysis.
Data Source
AI summary
An example method of video coding includes receiving a video bitstream including a plurality of blocks; identifying, based on a first indicator in the video bitstream, a coding region that includes two or more blocks of the plurality of blocks, where each block in the coding region is encoded in an intra prediction mode. The method further includes identifying, for a chroma block in the coding region, an angular intra prediction mode of a collocated luma block; and reconstructing the two or more blocks of the coding region using the angular intra prediction mode of the collocated luma block as a reference for the chroma block.