Audio Error Concealment Switching for Long-Interval Frame Loss
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Solution Overview
Problem
Existing audio signal error concealment methods, such as repetition and interpolation schemes in the frequency domain, fail to effectively prevent modulation noise when errors occur over long intervals, leading to degradation in sound quality.
Innovation Solution
A method and apparatus that selectively use error concealment in the frequency domain, including repetition and interpolation schemes, and switch to time domain concealment when errors span long intervals, minimizing modulation noise 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 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 from frequency domain methods to time domain replication, adapting the concealment strategy to the specific error conditions to prevent modulation noise while maintaining concealment effectiveness.
Solution Approach 2:
The patent changes the domain parameter from frequency domain to time domain based on error characteristics. By detecting whether errors occur over short or long intervals, the system adjusts the processing domain and method parameters, using frequency domain methods for short intervals and time domain methods for long intervals, thereby optimizing concealment performance and avoiding modulation noise.
2Loss of information
If frequency domain concealment methods are used, then spectral reconstruction is achieved, but sound quality degrades due to modulation noise in long interval errors
Solution Approach 1:
The patent dynamically selects between frequency domain and time domain concealment methods based on error interval detection. For long interval errors, it switches to time domain replication which avoids the modulation noise problem inherent in frequency domain methods, thereby preventing sound quality degradation while still achieving spectral information recovery through alternative means.
Solution Approach 2:
The patent converts the limitation of time domain methods (less spectral accuracy) into a benefit by using them specifically for long interval errors where frequency domain methods would generate harmful modulation noise. This transforms a potentially inferior method into the optimal choice for specific conditions, eliminating sound quality degradation.
3Duration of action of stationary object
If the same spectrum is repeated over a long interval, then error concealment is maintained, but modulation noise is caused
Solution Approach 1:
The patent implements dynamic method selection based on error duration. When errors persist over long intervals, the system transitions from frequency domain spectrum repetition to time domain replication, maintaining concealment duration while avoiding the modulation noise that results from repeating the same frequency spectrum over extended periods.
Solution Approach 2:
The patent changes the fundamental parameter of the concealment method from frequency domain to time domain when error duration exceeds a threshold. This parameter change allows the system to maintain long duration concealment without generating modulation noise, as time domain replication does not suffer from the same spectral repetition issues.
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.