Audio Error Concealment Scheme Selection 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 repetition schemes, degrading sound quality during transmission errors in networks like T-DMB and IP networks.
Innovation Solution
An error concealment method and apparatus that selectively uses repetition and interpolation schemes in the frequency domain, and error concealment in the time domain, based on error occurrence conditions and window types of previous and next frames, to minimize modulation noise and maintain sound quality.
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 switches between repetition scheme and interpolation scheme based on error duration. When errors occur over long intervals, the system transitions from repetition to interpolation to avoid modulation noise, making the error concealment mechanism adaptive rather than static.
Solution Approach 2:
The patent changes the error concealment parameter (scheme selection) based on error occurrence conditions and frame types. By monitoring error duration and frame characteristics, the system adjusts the concealment approach to maintain audio quality while preventing modulation noise.
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 adapts the error concealment duration by switching schemes. When errors persist beyond a certain interval, the system transitions from repetition (which maintains duration but causes noise) to interpolation (which reduces noise while still providing concealment).
Solution Approach 2:
The patent converts the harmful effect of long-error-duration repetition into a beneficial scheme selection criterion. By detecting when errors occur over long intervals, the system triggers the interpolation scheme, turning the potential harm of prolonged error concealment into an opportunity to switch to a quieter concealment method.
3Object-generated harmful factors
If frequency domain error concealment is used, then modulation noise is prevented in short intervals, but it is difficult or impossible to conceal errors in certain conditions
Solution Approach 1:
The patent creates a universal error concealment system that can handle both short and long interval errors, as well as various frame types. By combining frequency domain methods (repetition and interpolation) with time domain methods, the system achieves multi-functionality and adaptability across different error conditions.
Solution Approach 2:
The patent introduces time domain error concealment as an intermediary solution when frequency domain methods are difficult or impossible to apply. This intermediary approach ensures that errors can be concealed in all conditions, bridging the gap when frequency domain techniques reach their limitations.
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.