Audio Error Concealment Switching to Limit Modulation Noise
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Solution Overview
Problem
Existing audio signal transmission technologies face challenges in concealing errors over long intervals, leading to modulation noise and degradation of sound quality, as conventional repetition and interpolation schemes in the frequency domain are inadequate in preventing such noise.
Innovation Solution
An error concealment method and apparatus that selectively uses repetition and interpolation schemes in the frequency domain, and resorts to time domain concealment when necessary, to minimize modulation noise and maintain sound quality by reconstructing error frames based on error occurrence conditions and window types of preceding and following frames.
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 for short intervals, but modulation noise is generated when errors occur over long intervals
Solution Approach 1:
The patent dynamically switches between frequency domain concealment (repetition/interpolation schemes) and time domain concealment based on the error interval length. When errors occur over long intervals, the system transitions to time domain concealment to avoid modulation noise, making the concealment approach adaptive rather than static.
Solution Approach 2:
The patent changes the domain of operation from frequency domain to time domain based on error characteristics. By detecting the error interval length, the system alters the fundamental parameter of the concealment approach (domain type) to prevent modulation noise while maintaining concealment effectiveness.
2Loss of information
If frequency domain concealment schemes are used, then spectral reconstruction is achieved, but sound quality degrades due to modulation noise in long-interval errors
Solution Approach 1:
The system dynamically selects between frequency domain and time domain concealment based on error interval detection. For long-interval errors, it switches to time domain concealment to avoid modulation noise while still achieving spectral information recovery through alternative means.
Solution Approach 2:
The patent introduces an error interval detection mechanism as an intermediary that determines the appropriate concealment strategy. This mediator assesses the error characteristics and directs the system to use either frequency domain or time domain concealment, preventing modulation noise while recovering spectral information.
3Reliability
If the same spectrum is repeated over a long interval, then error concealment is maintained, but modulation noise is generated causing sound quality degradation
Solution Approach 1:
The patent makes the concealment strategy dynamic by detecting error interval length. When long intervals are detected, the system switches from repeating the same spectrum (frequency domain) to using time domain concealment, thereby maintaining reconstruction reliability while preserving sound quality.
Solution Approach 2:
The system changes the fundamental parameter of the concealment approach from frequency domain spectrum repetition to time domain signal processing when long errors are detected. This parameter change eliminates modulation noise while maintaining effective error frame reconstruction.
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.