Hash-Table Arithmetic Decoding for Low-Power Audio Coding

Solution Overview

Problem

Current audio encoding and decoding technologies face challenges in achieving a balance between bitrate efficiency and resource efficiency, particularly in portable consumer devices, where complex decoding processes consume high power and resources.

Innovation Solution

The implementation of an arithmetic decoder and encoder that utilize a hash table to efficiently map spectral values, selecting a mapping rule based on a context state described by a numeric current context value, allowing for reduced computational resources and improved coding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If complex decoding processes are used to improve bitrate efficiency, then coding performance is improved, but power consumption and resource usage increase significantly

Engineering Contradiction:

Improvebitrate efficiencyVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The hash table is divided into multiple sections or regions, each handling different ranges of context values. This segmentation allows the decoder to quickly identify which section to search without examining the entire table, reducing the computational effort and power consumption while maintaining coding performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of performing a complete linear search through the entire hash table, the method performs a partial search limited to a predetermined number of entries or a specific section. This partial action approach achieves sufficient matching accuracy without the excessive computational resources required for a complete search, thus reducing power consumption while maintaining acceptable bitrate efficiency.

Inventive Principle:

Principle #16Partial or excessive action

2Measurement precision

If a large hash table is used to improve mapping accuracy, then coding performance is improved, but memory demands and device complexity increase

Engineering Contradiction:

Improvemapping accuracyVSAvoidmemory demands

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The hash table is divided into multiple sections or regions, each handling different ranges of context values. This segmentation allows the decoder to quickly identify which section to search without examining the entire table, reducing the computational effort and power consumption while maintaining coding performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of performing a complete linear search through the entire hash table, the method performs a partial search limited to a predetermined number of entries or a specific section. This partial action approach achieves sufficient matching accuracy without the excessive computational resources required for a complete search, thus reducing power consumption while maintaining acceptable bitrate efficiency.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If linear search through hash table is used to find mapping rules, then all possible mappings are evaluated, but computational complexity and processing time increase

Engineering Contradiction:

Improvemapping rule selectionVSAvoidcomputational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The hash table is divided into multiple sections or regions, each handling different ranges of context values. This segmentation allows the decoder to quickly identify which section to search without examining the entire table, reducing the computational effort and power consumption while maintaining coding performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of performing a complete linear search through the entire hash table, the method performs a partial search limited to a predetermined number of entries or a specific section. This partial action approach achieves sufficient matching accuracy without the excessive computational resources required for a complete search, thus reducing power consumption while maintaining acceptable bitrate efficiency.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8645145B2Audio encoder, audio decoder, method for encoding and audio information, method for decoding an audio information and computer program using a hash table describing both significant state values and interval boundaries

Publication Date: 2014.02.04 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An audio decoder includes an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically encoded representation of the spectral values, and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state described by a numeric current context value. The arithmetic decoder determines the numeric current context value in dependence on a plurality of previously decoded spectral values. The arithmetic decoder evaluates a hash table, entries of which define both significant state values and boundaries of intervals of numeric context values, in order to select the mapping rule. A mapping rule index value is individually associated to a numeric context value being a significant state value.