Audio Codec Index Compression Using Reduced Multidimensional Dictionaries

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Solution Overview

Problem

Existing audio codec systems face challenges in efficiently compressing indices after vector quantization, leading to increased complexity and data requirements as sequence lengths increase.

Innovation Solution

The proposed neural audio codec system employs reduced multidimensional indices compression, using nD dictionaries and key blocks to encode and decode symbols, thereby reducing complexity and improving compression efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If traditional entropy coding with longer sequences is used to improve compression efficiency, then compression ratio improves, but database complexity and data requirements increase exponentially

Engineering Contradiction:
Improvecompression efficiencyVSAvoiddatabase complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent segments the compression process into two independent stages: first, vector quantization converts audio vectors to indices; second, a separate neural network model compresses these indices. This segmentation allows each component to be optimized independently, avoiding the exponential complexity growth that occurs when trying to model long sequences in a single entropy coding stage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a neural network model as an intermediary between the vector quantizer and the final encoded output. This neural network learns the statistical dependencies in the index sequences and performs the compression function, replacing the traditional entropy coding approach that requires large databases of statistics. The neural network acts as a mediator that captures sequence patterns without requiring exponential database growth.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If longer sequences are used for generating compression statistics, then compression efficiency improves, but the amount of data needed increases exponentially

Engineering Contradiction:
Improvecompression efficiencyVSAvoiddata requirements
Core Design Contradiction:
Loss of informationVSQuantity of substance

Solution Approach 1:

The patent replaces the mechanical/statistical approach of building large databases from long sequences with a neural network-based approach. Instead of collecting and processing exponentially growing amounts of data to build statistics databases, the neural network learns compression patterns directly from training data, achieving similar or better compression efficiency without the exponential increase in data requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of how compression statistics are obtained. Rather than using long sequences to generate statistics databases through traditional entropy coding, the system uses a neural network model trained on sequences to learn compression patterns. This parameter change from statistical database building to neural network learning breaks the exponential relationship between sequence length and data requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12308037B2Reduced multidimensional indices compression for audio codec system
Publication Date: 2025.05.20 CISCO TECHNOLOGY INC
  • US12308037B2 patent drawing
  • US12308037B2 patent drawing
  • US12308037B2 patent drawing

AI summary

A method comprises: storing n dimension (nD) dictionaries (nD dictionaries) where n decreases from a highest dimension to a lowest dimension, each nD dictionary including codewords for sequences of n symbols that are of a limited number that is less than all possible sequences of n symbols; storing key blocks for corresponding ones of the nD dictionaries, each key block configured with keys that map sequences of n−1 symbols to dictionaries of a corresponding one of the nD dictionaries that includes the codewords; receiving a sequence of symbols that represent indices of codevectors of a vector quantizer codebook that are representative of audio; determining a codeword using the key blocks and the nD dictionaries; and encoding a current symbol of the sequence of symbols using the codeword.