Sinusoidal Interpolation for Audio Packet Loss Concealment

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Solution Overview

Problem

Existing packet-loss concealment methods for audio signals are inadequate, particularly for music, as they rely heavily on speech signal structures and fail to effectively restore continuity in more complex audio signals, leading to audible discontinuities and degraded audio quality.

Innovation Solution

A computer-implemented method that computes spectra of audio signal segments, determines magnitude peaks, pairs neighbor peaks based on a distance-dependent weighting criterion, and performs interpolation across missing segments using sinusoidal modeling to generate restoration data, allowing for real-time concealment of packet loss and discontinuities in audio signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If speech-based packet-loss concealment methods are used, then speech signal restoration is improved, but general audio signal restoration deteriorates

Engineering Contradiction:
Improvespeech signal restorationVSAvoidgeneral audio signal restoration
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by developing a packet-loss concealment method that works for both speech and music signals. The sinusoidal modeling approach with spectral peak pairing and phase alignment is designed to handle the different characteristics of speech and music signals, making the system versatile across general audio signals rather than speech-specific.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes parameters by adapting the interpolation method to account for different signal types. By adjusting the spectral peak pairing criteria, magnitude interpolation, and phase alignment based on the characteristics of the input signal (speech vs. music), the system optimizes restoration for each signal type while maintaining general applicability.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If zero insertion is used for missing segments, then implementation simplicity is improved, but audio quality deteriorates

Engineering Contradiction:
Improveimplementation simplicityVSAvoidaudible discontinuities
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary process between zero insertion and final output. By computing spectra, pairing spectral peaks, and performing magnitude and phase interpolation, the system creates a intermediate restoration that bridges the discontinuity caused by packet loss, eliminating audible artifacts while maintaining computational feasibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the simple mechanical approach of zero insertion with a spectral-domain processing approach. By working in the frequency domain (spectral peak pairing, magnitude interpolation, phase alignment) and transforming back to time domain, the system achieves superior audio quality without excessive complexity.

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

3Measurement precision

If spectral peak pairing with distance-dependent weighting is used, then interpolation accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improveinterpolation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by using distance-dependent weighting in spectral peak pairing. Peaks that are closer in frequency receive higher weighting, allowing the algorithm to focus computational effort on the most relevant peak pairings while reducing processing for distant peaks. This localized approach improves accuracy for critical peak pairs without proportionally increasing overall complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3111444B1Sinusoidal interpolation across missing data
Publication Date: 2020.09.02 GOOGLE LLC
  • EP3111444B1 patent drawingFigure 1
  • EP3111444B1 patent drawingFigure 2
  • EP3111444B1 patent drawingFigure 3

AI summary

Provided are methods and systems for concealing missing segments and/or discontinuities in an audio signal, thereby restoring the continuity of the signal. The methods and systems are designed for and targeted at audio signals, are based on interpolation and extrapolation operations for sinusoids, and do not rely on the assumption that the sinusoids are harmonic. The methods and systems are improvements over existing audio concealment approaches in that, among other advantages, the methods and systems facilitate asynchronous interpolation, use an interpolation procedure that corresponds to time-domain waveform interpolation if the signal is harmonic, and have a peak selection procedure that is effective for audio signals.