Picture Prediction Using Lookup Table Interpolation
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Solution Overview
Problem
Existing video encoding/decoding schemes require a large number of intermediate caches and memory operations for interpolation filtering during picture prediction, leading to increased calculation complexity.
Innovation Solution
A picture prediction method that determines motion vectors of control points in a current picture block, calculates higher-precision motion vectors for pixel units using a motion model, and performs interpolation filtering with a specific phase to obtain predicted pixel values, thereby reducing the number of interpolation filtering operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple interpolation filtering operations are performed to obtain higher-precision predicted pixel values, then the precision of predicted pixel values is improved, but the quantity of intermediate caches and memory operations increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing interpolation filter coefficients in a lookup table before the actual prediction process. The coefficients are computed based on the relation (2Q-N)/2 and stored for direct retrieval, eliminating the need for real-time computation and multiple filtering operations during picture prediction, thus reducing memory operations while maintaining precision.
Solution Approach 2:
The patent changes the parameter approach by using a single interpolation filtering operation with specifically designed filter coefficients instead of multiple operations. The coefficient calculation formula (2Q-N)/2 is derived to achieve the desired precision output directly in one step, changing the parameter strategy from iterative refinement to direct computation.
2Measurement precision
If multiple interpolation filtering operations are performed to obtain higher-precision predicted pixel values, then the precision of predicted pixel values is improved, but the calculation complexity increases
Solution Approach 1:
The patent reduces calculation complexity by performing the computationally intensive coefficient calculation in advance and storing results in a lookup table. During actual picture prediction, only simple table lookups and single filtering operations are needed, dramatically reducing the computational burden while maintaining the ability to produce high-precision results.
Solution Approach 2:
The patent uses copying by storing pre-computed interpolation filter coefficients in a lookup table that can be rapidly accessed and copied during prediction operations. This allows the system to reuse the same coefficient sets multiple times without re-computation, reducing calculation complexity while maintaining precision requirements.
Data Source
AI summary
A picture prediction method includes: determining motion vectors of W control points in a current picture block; obtaining motion vectors of P pixel units of the current picture block by using a motion model and the motion vectors of the W control points, where precision of the determined motion vectors of the W control points is 1/n of pixel precision, precision of the motion vector of each of the P pixel units is 1/N of the pixel precision, the motion vector of each of the P pixel units is used to determine a corresponding reference pixel unit in a reference picture of a corresponding pixel unit; and performing interpolation filtering on a pixel of the corresponding reference pixel unit by using an interpolation filter with a phase of Q, to obtain a predicted pixel value of each of the P pixel units.