Arithmetic Coding Lookup Tables for Adaptive Probability Updates
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Solution Overview
Problem
Existing arithmetic encoding and decoding methods struggle to achieve optimal coding efficiency due to the need for accurate probability information of binary symbols, which can vary over time.
Innovation Solution
The use of a lookup table to update state variable values, which represent statistical information of previously encoded or decoded symbols, allows for efficient adaptation of interval sizes in arithmetic encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extensive computations (trigonometric, exponential, or logarithmic functions) are used to update state variable values, then the accuracy of probability adaptation is improved, but the computational complexity increases
Solution Approach 1:
The patent replaces complex computational functions with a lookup table that stores pre-computed state variable updates. This table acts as a simplified, pre-prepared resource that provides accurate probability adaptation without requiring extensive real-time computations of trigonometric, exponential, or logarithmic functions.
Solution Approach 2:
The patent pre-computes and stores state variable update values in a lookup table before actual encoding/decoding operations. By performing the computationally intensive work in advance and storing results, the system avoids repeating extensive computations during real-time operation, thus reducing computational complexity while maintaining accuracy.
2Device complexity
If lookup tables are used to update state variable values, then the computational complexity is reduced, but the memory requirements increase
Solution Approach 1:
The patent implements a scalable lookup table approach where the table size and precision can be adapted to specific application requirements. This allows optimizing the balance between memory usage and computational savings by selecting appropriate table dimensions based on the specific encoding/decoding context and available resources.
3Productivity
If interval sub-division is adjusted frequently to adapt to varying probabilities, then the coding efficiency is improved, but the computational overhead increases
Solution Approach 1:
The patent uses a lookup table to provide pre-computed interval sub-division adjustments that can be applied quickly during encoding/decoding. This allows frequent adaptation to varying symbol probabilities without incurring the full computational overhead of recalculating interval boundaries from scratch, thus maintaining high coding efficiency with reduced computational cost.
Data Source
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AI summary
An arithmetic encoder for encoding a plurality of symbols having symbol values is configured to derive an interval size information for an arithmetic encoding of one or more symbol values to be encoded on the basis of a plurality of state variable values, which represent statistics of a plurality of previously encoded symbol values with different adaptation time constants. The arithmetic encoder is configured to map a first state variable value, or a scaled and/or rounded version thereof, using a lookup-table and to map a second state variable value, or a scaled and/or rounded version thereof using the lookup-table, in order to obtain the interval size information describing an interval size for the arithmetic encoding of one or more symbols to be encoded. Further arithmetic encoders, arithmetic decoders, video encoders, video decoder, methods for encoding, methods for decoding and computer programs are also disclosed which are based on the same concept and on other concepts.