Matrix-Based Intra Prediction for Luma and Chroma in Video Coding
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Solution Overview
Problem
Current video coding standards, such as VVC, face limitations in efficiently applying intra-prediction modes across different color components in multi-component color or video coding, particularly in the 4-4-4 single-tree case without adaptive color transform, where the combination of matrix-based intra prediction for luma and planar mode for chroma is not supported, leading to suboptimal coding efficiency.
Innovation Solution
Introduce a new value for the luma intra prediction mode that allows for the combination of matrix-based intra prediction for luma and planar mode for chroma in the 4-4-4 single-tree case, while maintaining compatibility with existing VVC specifications for other cases, enabling more flexible intra prediction mode derivation and supporting efficient coding for both luma and chroma signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If matrix-based intra prediction mode is used for luma component, then prediction accuracy for luma is improved, but the combination with planar mode for chroma component is not supported in 4-4-4 single-tree case, leading to suboptimal coding efficiency
Solution Approach 1:
The patent introduces a new syntax element `mip_chroma_direct_flag` and modifies the chroma intra prediction mode derivation process to enable the combination of matrix-based intra prediction for luma and planar mode for chroma. This parameter change allows the system to select from expanded mode combinations, resolving the contradiction by enabling previously unsupported mode pairs while maintaining backward compatibility.
Solution Approach 2:
The patent segments the intra prediction mode selection process into separate controllable components for luma and chroma. By introducing independent control mechanisms (`mip_chroma_direct_flag` and modified derivation tables), the system can independently optimize prediction modes for each color component, allowing matrix-based prediction for luma while simultaneously enabling planar mode for chroma in the 4-4-4 single-tree case.
2Productivity
If new intra prediction mode combinations are enabled, then coding efficiency is improved, but compatibility with existing VVC specifications may be compromised
Solution Approach 1:
The patent designs the new syntax element and derivation process to be universally applicable across different color formats and tree structures. The `mip_chroma_direct_flag` and modified Table 20 provide a unified mechanism that works for 4-4-4 single-tree case while maintaining compatibility with other cases, enabling the system to support multiple functionality without compromising existing VVC specification compliance.
Solution Approach 2:
The patent performs preliminary definition of the new syntax element and mode derivation rules before actual encoding/decoding operations. By pre-establishing the `mip_chroma_direct_flag` semantics and updating Table 20 with explicit mode combinations, the system ensures that both encoder and decoder can correctly interpret and process the new mode combinations, maintaining specification compatibility while enabling improved coding efficiency.
Data Source
AI summary
Concepts for applying intra-prediction in multi-component or color picture or video coding in a manner achieving a more efficient coding are described. A decoder for decoding a picture is configured to derive a color sampling format and a partitioning scheme from one more first syntax elements in a data stream. The decoder is configured to decode a first color component and a second color component. The decoder is configured to determine a second-color-component intra-prediction mode index from the data stream.