Integer Sequence Encoding for Fractional Bit Allocation

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Solution Overview

Problem

Existing techniques for encoding sample sequences, particularly in audio or acoustic signals, face reduced compression efficiency at low bit rates due to the assignment of bits per sample, leading to increased distortion in decoded sequences.

Innovation Solution

An encoder and decoder system that selects and converts integer values within input sequences to encode and decode them, allowing for the assignment of bits similar to decimal fractions, thereby improving compression efficiency and reducing distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If variable-length reversible encoding is used to reduce bit length, then compression performance is improved, but decoding complexity increases due to code configuration constraints

Engineering Contradiction:
Improvebit lengthVSAvoiddecoding complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent changes the parameter of code assignment by introducing a statistical model that predicts integer value frequencies. Instead of using fixed or simple variable-length codes, the system dynamically assigns code lengths based on predicted frequency probabilities, achieving better compression while maintaining decodability through the statistical framework

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary statistical analysis and frequency prediction before the actual encoding process. By pre-calculating the expected frequency of each integer value and determining optimal code assignments in advance, the system simplifies the decoding process while maximizing compression efficiency

Inventive Principle:
Principle #10Preliminary action

2Loss of substance

If code assignment is optimized for high appearance probability values, then compression performance is improved, but the system becomes less adaptable to different value distributions

Engineering Contradiction:
Improvecompression efficiencyVSAvoidadaptability to value distribution
Core Design Contradiction:
Loss of substanceVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic code assignment system that adapts to different value distributions. The statistical model continuously predicts frequency probabilities based on the actual data characteristics, allowing the encoding scheme to dynamically adjust to various integer value distributions rather than being fixed for a specific distribution pattern

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the encoding parameters based on the statistical characteristics of the input data. By using frequency prediction to determine optimal code lengths for each integer value, the system adapts its parameters to match the actual value distribution, achieving high compression efficiency across different distribution types

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If bit assignment is fixed per sample, then decoding is simplified, but compression efficiency decreases at low bit rates due to increased distortion

Engineering Contradiction:
Improvedecoding simplicityVSAvoidcompression efficiency
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The patent changes from fixed bit assignment to variable bit assignment based on predicted frequency probabilities. The system dynamically determines the optimal number of bits to allocate for each sample based on the statistical model's frequency predictions, achieving better compression efficiency while maintaining manageable decoding complexity through the statistical framework

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3780396B1Encoding device, decoding device, encoding method, decoding method, program, and recording medium
Publication Date: 2023.05.31 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP3780396B1 patent drawingFigure 1~2
  • EP3780396B1 patent drawingFigure 3~4
  • EP3780396B1 patent drawingFigure 5~6

AI summary

The present invention aims to encode and decode a sequence of integer values by substantially assigning the number of bits of a decimal fraction value per sample. An integer converter 11 selects M selected integer values from L input integer values for a set of the L input integer values and obtains J-value selection information that specifies which of the L input integer values the M selected integer values are. Furthermore, the integer converter 11 obtains one converted integer value by reversibly converting the M selected integer value and an integer value corresponding to the J-value selection information. An integer encoder 12 encodes the converted integer value to obtain a code.