Image Coding Transform Selection Based on Prediction Mode
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Solution Overview
Problem
Current video coding systems require significant memory resources to store multiple transform operations for various prediction modes, leading to inefficient memory usage and performance compromise, despite achieving some bitrate gains.
Innovation Solution
A method and device for coding and decoding images that dynamically adjust the number of transform operations based on the selected prediction mode, allowing for reduced memory usage or enhanced performance without increasing memory requirements, by storing common transforms across multiple modes and optimizing transform operations based on prediction direction and probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple transform operations are stored for various prediction modes, then coding performance is improved, but memory resources are significantly increased
Solution Approach 1:
The patent applies universality by making transform operations mode-independent, allowing the same transform operation to be used across multiple prediction modes. This eliminates the need to store separate transform operations for each mode, significantly reducing memory resources while maintaining coding performance through adaptive selection of transform types based on residual characteristics rather than prediction mode
Solution Approach 2:
The patent extracts the coupling between prediction modes and transform operations, separating the selection of transform type from the prediction mode. Only the necessary transform operations are stored and applied based on the actual needs of the residual data, removing the redundant storage of transform operations that would otherwise be required for each prediction mode
2Loss of information
If the number of transform operations is increased for each prediction mode, then bitrate gain is achieved, but device complexity is increased
Solution Approach 1:
The patent changes the parameter used for selecting transform operations from prediction mode to residual characteristics (such as variance, energy distribution, or other statistical properties of the residual data). This allows the system to achieve bitrate gains through adaptive transform selection based on actual data characteristics rather than relying on multiple transform operations per prediction mode, thereby reducing device complexity
3Productivity
If transform operations are optimized for each prediction mode, then coding efficiency is improved, but memory footprint is increased
Solution Approach 1:
The patent introduces dynamics by making transform operation selection adaptive based on residual characteristics rather than being statically tied to prediction modes. The system dynamically selects the most appropriate transform operation for each block based on its specific characteristics, achieving high coding efficiency without requiring large memory footprints to store transform operations for every possible prediction mode combination
Data Source
AI summary
A method of coding at least one image sliced into blocks. The method implements, for a current block to be coded: predicting the current block in accordance with a prediction mode selected from among predetermined prediction modes, Intra and Inter, the selected mode of prediction being Intra; calculating a residual data block representative of a difference between a predictor block obtained on completion of the prediction and the current block; applying a transform operation to the data of the residual block, the transform operation belonging to a set of transform operations previously stored in association with the selected mode of Intra prediction; and coding the data obtained from the transform operation. The number of transform operations contained in the set associated with the selected Intra mode is different from the number of transform operations contained in a set of transform operations stored in association with the mode of Inter prediction.