Audio Error Concealment Switching to Reduce Modulation Noise
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Solution Overview
Problem
Conventional error concealment methods for audio signals in long intervals generate modulation noise due to repeated spectra, degrading sound quality during transmission errors in networks like T-DMB or IP networks.
Innovation Solution
The method selectively employs a repetition scheme or interpolation scheme in the frequency domain for error concealment, and when these are not feasible, uses time-domain concealment to minimize modulation noise and maintain sound quality, by choosing the appropriate scheme based on error conditions and frame characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a repetition scheme is used to conceal errors in the frequency domain, then error concealment is achieved, but modulation noise is generated when errors occur over long intervals
Solution Approach 1:
The patent dynamically selects between repetition scheme and interpolation scheme based on the error interval length. When error interval is short, repetition scheme is used; when error interval is long, interpolation scheme is used. This dynamic adaptation prevents modulation noise while maintaining error concealment effectiveness.
Solution Approach 2:
The patent changes the error concealment parameter (scheme type) based on the error interval parameter. By monitoring the error interval length and switching between different concealment schemes, the system optimizes performance to avoid modulation noise generation.
2Duration of action of stationary object
If the same spectrum is repeated over a long interval, then error concealment is maintained, but sound quality degrades due to modulation noise
Solution Approach 1:
The system dynamically adjusts the error concealment approach based on the duration of the error interval. For short durations, repetition is applied; for long durations, interpolation is applied. This dynamic adjustment maintains error concealment effectiveness while preventing modulation noise.
Solution Approach 2:
The patent changes the concealment parameter based on the error interval length parameter. When the interval exceeds a threshold, the system switches from repetition to interpolation, thereby maintaining duration-based error concealment while avoiding the harmful modulation noise effect.
3Object-generated harmful factors
If interpolation scheme is used in the frequency domain, then modulation noise is reduced, but the method complexity increases
Solution Approach 1:
The patent applies different error concealment schemes to different local conditions (error interval lengths). Interpolation scheme is applied locally when error interval is long, while repetition scheme is applied when error interval is short. This localized approach reduces modulation noise without unnecessarily increasing complexity in all cases.
Solution Approach 2:
The system changes the concealment parameter based on the error interval parameter, applying the more complex interpolation scheme only when necessary (long error intervals). This conditional parameter change reduces overall system complexity while still addressing modulation noise when it becomes a problem.
Data Source
AI summary
An error concealment method and apparatus for an audio signal and a decoding method and apparatus for an audio signal using the error concealment method and apparatus. The error concealment method includes selecting one of an error concealment in a frequency domain and an error concealment in a time domain as an error concealment scheme for a current frame based on a predetermined criteria when an error occurs in the current frame, selecting one of a repetition scheme and an interpolation scheme in the frequency domain as the error concealment scheme for the current frame based on a predetermined criteria when the error concealment in the frequency domain is selected, and concealing the error of the current frame using the selected scheme.