Image Decoding Device Memory Reduction via Prediction Mode Derivation
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Solution Overview
Problem
Existing video image coding schemes require large memory due to the need for multiple tables that associate prediction modes with various processes, such as selecting filters, scan methods, and transform methods.
Innovation Solution
An image decoding device that decodes images using an intra prediction method associated with a prediction mode, where the prediction mode is associated with a prediction mode number, and the device determines whether the prediction mode number is less than or equal to a threshold to configure reference pixels and conduct a designated decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple tables associating prediction modes with processes are used, then the decoding device can accurately select filters, scan methods, and transform methods, but the memory requirement increases significantly
Solution Approach 1:
The patent extracts only the essential information needed for prediction mode selection by deriving the main direction and gradient directly from the prediction mode number, rather than storing complete lookup tables. This extraction approach retrieves only the necessary components (direction and gradient values) while discarding redundant data, thereby reducing memory requirements while maintaining accurate prediction mode selection.
Solution Approach 2:
The patent segments the prediction mode information into distinct components: the prediction mode number itself, the main direction derived from it, and the gradient derived from it. By segmenting this information, the system can process each component independently and store only the essential derived values rather than maintaining complete associative tables, thus reducing memory usage while preserving the ability to accurately select decoding processes.
2Adaptability or versatility
If complete lookup tables are stored for all prediction modes, then all decoding processes can be accurately determined, but the device complexity increases
Solution Approach 1:
The patent enables the prediction mode number to serve multiple functions: it directly identifies the prediction mode, determines the main direction, and determines the gradient. This self-service capability eliminates the need for separate lookup tables for each parameter, as the prediction mode number itself contains the information needed to derive all necessary decoding parameters through systematic processing, thereby reducing device complexity while maintaining comprehensive decoding process coverage.
Solution Approach 2:
The patent makes the prediction mode number a universal key that can determine multiple aspects of the decoding process simultaneously: the prediction direction, the main direction, and the gradient. This multi-functionality allows a single data structure (the prediction mode number) to serve multiple purposes that previously required separate tables, thereby reducing overall system complexity while maintaining full adaptability across different decoding scenarios.
Data Source
AI summary
Memory required during decoding is reduced.A video image decoding device (1) is equipped with main direction deriving means (1453A) that references a prediction mode definition DEFPM(1), and from a prediction mode number, derives a main direction of a prediction direction corresponding to a prediction mode, and a gradient deriver (1453B) that references a gradient definition table DEFANG(1), and derives a gradient of the prediction direction.