Intra Prediction Normalization Using Multiplier and Shift
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Solution Overview
Problem
Current video coding technologies face challenges in reducing processor load during intra prediction processing, particularly due to the computational expense of division operations in DC, BI, and horizontal intra prediction modes, which hinder efficient compression and decompression of video data.
Innovation Solution
The method involves replacing division operations with normalization techniques using a multiplier and shift operations for intra prediction, where the multiplier is obtained from a lookup table based on block dimensions, and a fixed shift value is used, specifically for INTRA_DC, INTRA_BI, and INTRA_HOR modes, to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If division operations are used for intra prediction in DC, BI, and horizontal modes, then prediction accuracy is maintained, but processor load increases and computational efficiency decreases
Solution Approach 1:
The patent changes the mathematical parameters of the prediction operation by replacing division with multiplication and bit-shifting operations. Specifically, it uses pre-calculated multiplier values stored in lookup tables combined with right-shift operations to achieve the same normalization effect as division, thereby maintaining prediction accuracy while significantly reducing computational complexity and processor load
Solution Approach 2:
The patent substitutes the mechanical division operation with a combination of multiplication and bit-shifting operations. This substitution leverages the fact that bit-shifting is a much cheaper operation than division in both software and hardware implementations, effectively replacing a complex computational mechanism with simpler, more efficient operations while preserving the functional outcome
2Reliability
If division operations are used for intra prediction, then prediction results are obtained, but hardware implementation complexity and software processing time increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating the multiplier values and storing them in lookup tables before the actual prediction process. This allows the runtime operation to simply fetch the pre-computed multiplier and perform a multiplication followed by a bit-shift, eliminating the need for complex division logic in both hardware and software implementations
Data Source
AI summary
Devices and methods of intra prediction of a block of a picture are provided. The method includes obtaining reference samples of a block, and determining a value of a predicted sample based on the reference samples and an intra prediction mode. The method further includes obtaining a value of a multiplier based on at least one dimension of the block, and normalizing the value of the predicted sample based on the value of the multiplier and a value of a shift. The intra prediction mode is INTRA_DC, or INTRA_BI, or horizontal intra prediction mode. By normalizing the value of the predicted sample based on the value of the multiplier and a value of a shift without division operation, the method could increase intra prediction efficiency.