Matrix-Based Intra-Prediction Coding With Shared Secondary Transforms
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Solution Overview
Problem
Conventional intra prediction modes in video coding lack efficient secondary transforms for matrix-based prediction modes, leading to high memory requirements and increased bit stream costs.
Innovation Solution
Select a subset of secondary transforms from a set that includes both matrix-based and non-matrix-based intra prediction modes, allowing for efficient coding by reducing memory capacity and signaling costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate secondary transforms are defined for each conventional intra prediction mode, then prediction accuracy is improved, but memory requirements increase
Solution Approach 1:
The patent applies universality by defining a single set of secondary transforms that can be used across multiple intra prediction modes (both conventional and matrix-based). Instead of maintaining separate transform sets for each prediction mode, the invention creates a universal transform set that serves all modes, thereby reducing memory requirements while preserving prediction accuracy through flexible transform selection based on prediction mode characteristics.
2Measurement precision
If separate secondary transforms are defined for each intra prediction mode, then prediction performance is improved, but bit stream signaling costs increase
Solution Approach 1:
The invention implements universality by creating a single secondary transform set that is universally applicable to all intra prediction modes. This eliminates the need to signal separate transform information for each mode, reducing bit stream costs. The system maintains prediction performance by selecting appropriate transforms from the universal set based on the specific prediction mode used.
Solution Approach 2:
The patent merges the secondary transform definitions into a single unified set that combines transforms for both conventional and matrix-based intra prediction modes. This consolidation reduces the total number of transforms that need to be signaled, thereby reducing bit stream costs while maintaining the predictive capabilities of the system.
3Adaptability or versatility
If matrix-based intra prediction modes are added to conventional modes, then coding flexibility is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a single secondary transform set that accommodates both conventional and matrix-based intra prediction modes. This universal approach allows the system to handle multiple prediction modes without requiring separate transform processing paths, thereby reducing device complexity while maintaining coding flexibility.
Solution Approach 2:
The invention merges the processing of conventional and matrix-based prediction modes into a unified framework. By combining both modes into a single prediction processing path that uses the same secondary transform set, the system reduces complexity while preserving the enhanced coding flexibility provided by matrix-based modes.
Data Source
AI summary
An apparatus configured to select a predetermined intra prediction mode out of a plurality of intra-prediction modes which includes a first set of intra-prediction modes and a second set of matrix-based intra-prediction modes. The apparatus is configured to select a subset of one or more secondary transforms dependent on the predetermined intra prediction mode so that the subset is nonempty in case of the predetermined intra prediction mode being contained in the first set of intra-prediction modes or in the second set of matrix-based intra-prediction modes. The apparatus is configured to derive a transformed version of a prediction residual for a predetermined block, which is related to a spatial domain version of the prediction residual of the predetermined block via a transform defined by a concatenation of a primary transform and a predetermined secondary transform out of the subset of secondary transforms.