Arithmetic Coding Interval Sizing With Multi-Time-Scale State Mapping
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Solution Overview
Problem
Arithmetic encoding and decoding require accurate determination of interval size information to achieve optimal coding efficiency, which is challenging due to the need for balancing computational efficiency and reliability in adapting to varying probabilities of symbols.
Innovation Solution
The use of lookup tables to map state variable values representing symbol statistics with different adaptation time constants, allowing for efficient derivation of interval size information through combined state variable values and scaling/rounding operations, thereby optimizing interval size determination for arithmetic encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If accurate determination of interval size information is used to achieve optimal coding efficiency, then coding efficiency is improved, but computational complexity increases
Solution Approach 1:
The patent divides the determination of interval size information into multiple components: a base interval size determined from current coding context, and adjustment values derived from statistics of previously encoded symbols with different adaptation time constants. This segmentation allows accurate interval sizing without requiring complex single-step calculations.
Solution Approach 2:
The patent pre-calculates and stores statistics of previously encoded symbols with different adaptation time constants in lookup tables. These pre-computed statistics are then used to adjust the base interval size, eliminating the need for complex real-time probability calculations during encoding.
2Measurement precision
If adaptation to varying probabilities of symbols is improved, then encoding accuracy is improved, but resource demand increases
Solution Approach 1:
Statistics of previously encoded symbols with different adaptation time constants are pre-computed and stored in lookup tables before encoding. This preliminary action allows the encoder to quickly retrieve and apply appropriate statistics without performing complex calculations during the encoding process, reducing real-time resource demand.
Solution Approach 2:
The patent uses multiple copies of statistical information corresponding to different adaptation time constants (short-term, medium-term, long-term statistics). These copied statistical representations allow the encoder to select and combine appropriate statistics for accurate probability estimation without requiring extensive computational resources.
3Adaptability or versatility
If multiple state variable values with different adaptation time constants are used, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent segments the probability adaptation process into multiple independent state variables, each with a different adaptation time constant. This segmentation allows each state variable to independently track symbol probabilities at different time scales, improving adaptability while keeping the management of each individual state variable relatively simple.
Solution Approach 2:
The patent introduces lookup tables as intermediary structures that store pre-computed statistics for multiple state variables. These lookup tables mediate between the multiple state variables and the interval size determination process, simplifying the management complexity by providing a standardized interface for accessing statistical information.
Data Source
AI summary
An arithmetic encoder for encoding a plurality of symbols having symbol values to derive an interval size information for an arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values representing statistics of a plurality of previously encoded symbol values with different adaptation time constants. The arithmetic encoder maps a first state variable value, or a scaled and/or rounded version thereof, using a lookup-table and maps a second state variable value, or a scaled and/or rounded version thereof using the lookup-table, 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.