Chroma Mode List Construction from Co-Located Luma Blocks
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Solution Overview
Problem
Existing video coding techniques face challenges in efficiently determining intra chroma modes for chroma blocks, leading to suboptimal compression and increased bandwidth utilization.
Innovation Solution
Constructing a list of intra-prediction modes for chroma blocks that excludes cross-component linear model (CCLM) modes, incorporating intra-prediction modes from co-located and neighboring luma and chroma blocks, allowing for flexible selection of intra-prediction modes without significantly increasing decoding complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional intra-prediction mode selection is used for chroma blocks, then the decoding process is simpler, but compression efficiency is suboptimal and bandwidth utilization increases
Solution Approach 1:
The patent segments the intra-prediction mode list into two distinct lists: a first list containing CCLM modes and a second list containing non-CCLM modes. This segmentation allows the encoder to selectively construct and signal different mode lists based on chroma block characteristics, enabling more efficient compression by choosing the appropriate mode list without overwhelming complexity
Solution Approach 2:
The patent introduces dynamic construction of mode lists where the encoder can adaptively create different intra-prediction mode lists based on the specific chroma block properties and surrounding context. This dynamic approach allows optimization of compression efficiency for each block while maintaining manageable complexity through structured construction rules
2Measurement precision
If a limited set of intra-prediction modes is used for chroma blocks, then the bandwidth for signaling is reduced, but prediction accuracy decreases leading to larger residual values
Solution Approach 1:
The patent applies local quality by constructing different intra-prediction mode lists tailored to specific chroma block characteristics and positions within the picture. The encoder analyzes local context and constructs appropriate mode lists for each chroma block, enabling high prediction accuracy locally while controlling overall bandwidth through selective mode list signaling
Solution Approach 2:
The patent changes the parameter of mode list composition by dynamically adjusting which intra-prediction modes are included in the signaled list based on chroma block properties. This allows optimization of the balance between prediction accuracy and bandwidth usage by selecting the most relevant modes for each specific block rather than using a fixed comprehensive list
Data Source
AI summary
A method of encoding or decoding video data includes constructing a list of chroma intra-prediction modes for a chroma block of a current block of the video data, wherein constructing includes adding intra-prediction modes of a first group to the list of chroma intra-prediction modes, the first group comprising two or more intra-prediction modes derived from intra-prediction modes of two or more co-located luma blocks of the current block that are co-located with the chroma block; determining an intra-prediction mode for the chroma block from the list of chroma intra-prediction modes; and encoding or decoding the chroma block based on the intra-prediction mode.