Audio Fingerprint Correlation for Multichannel Sync Offsets

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Solution Overview

Problem

Current methods for synchronizing multichannel extension data with audio signals face challenges due to time offsets, particularly in digital radio systems, where the separation of downmix audio signals and multichannel additional information can lead to quality losses and unreliable delay compensation.

Innovation Solution

A fingerprint-based approach is used to synchronize multichannel extension data with audio signals by calculating a fingerprint for the audio signal, extracting reference fingerprints, correlating them, and compensating for time offsets using a compensator, ensuring accurate synchronization and reconstruction of multichannel audio signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multichannel extension data and audio signal are transmitted through separate data paths, then reverse compatibility is maintained and flexible reception is enabled, but time offsets occur leading to synchronization errors and quality loss

Engineering Contradiction:

Improvereverse compatibilityVSAvoidsynchronization accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A fingerprint correlator is introduced as an intermediary component that receives fingerprints from both the audio signal and multichannel extension data, performs correlation analysis, and determines time offsets. This mediator enables synchronization between separately transmitted data paths without compromising reverse compatibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Fingerprints are calculated in advance for both audio signal and multichannel extension data before transmission. These pre-calculated fingerprints are embedded in the respective data streams, enabling subsequent synchronization operations to efficiently determine time offsets without requiring complex real-time analysis.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If traditional synchronization methods are used with separate data paths, then system flexibility is maintained, but unpredictable delay times cause synchronization errors

Engineering Contradiction:

Improvesystem flexibilityVSAvoidunpredictable delay

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

Traditional time-based synchronization mechanisms are replaced with a fingerprint-based correlation system. Instead of relying on timing information that is vulnerable to unpredictable delays in separate data paths, the system uses content-based fingerprint matching to determine and compensate for time offsets, making synchronization robust against variable transmission delays.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If precise synchronization is achieved through complex alignment algorithms, then time offset compensation is improved, but computational complexity and data requirements increase

Engineering Contradiction:

Improvesynchronization precisionVSAvoidalgorithm complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of analyzing and comparing entire audio signals for synchronization, the invention extracts distinctive fingerprint features from both the audio signal and multichannel extension data. This extraction approach maintains high synchronization precision while significantly reducing computational complexity and data processing requirements compared to full-signal analysis methods.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS8634946B2Apparatus and method for calculating a fingerprint of an audio signal, apparatus and method for synchronizing and apparatus and method for characterizing a test audio signal

Publication Date: 2014.01.21 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

For calculating a fingerprint of an audio signal, the audio signal is divided into subsequent blocks of samples. For the subsequent blocks, one fingerprint value each is calculated, wherein fingerprint samples of subsequent blocks are compared. Based on whether the fingerprint value of a block is higher than the fingerprint value of a subsequent block or not, a binary value is assigned, wherein information about a sequence of binary values is output as fingerprint for the audio signal.