Audio Signal Decoding Device for Balance Adjustment
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Solution Overview
Problem
In monaural-stereo scalable encoding, stereo encoded data loss or errors during transmission lead to fluctuation in audio signal localization and deterioration of stereo audio quality due to the inability to utilize the balance parameter (panning gain factor) in the decoding apparatus.
Innovation Solution
An audio signal decoding apparatus that includes a peak detecting section to match peak frequency components between channels, a peak balance factor calculating section to calculate a balance parameter, and a multiplying section to perform stereo conversion using this parameter, thereby stabilizing signal localization and maintaining stereo perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stereo encoded data is transmitted through a transmission channel, then stereo audio quality can be achieved, but data loss or errors occur leading to localization fluctuation
Solution Approach 1:
The patent performs preliminary action by detecting peak frequency components in advance and preparing balance parameters before stereo conversion. When data loss occurs, the system can utilize previously detected peak information and calculated balance parameters to maintain stereo localization, preventing the harmful effect of data loss on audio quality
Solution Approach 2:
The patent introduces an intermediary mechanism by using peak frequency component detection and balance parameter calculation as a bridge between the transmitted stereo encoded data and the final decoded audio. When stereo encoded data is lost, this intermediary process can generate balance parameters independently, acting as a mediator to maintain stereo perception without relying on the lost data
2Adaptability or versatility
If balance parameter is used for stereo conversion, then stereo perception is achieved, but localization fluctuates when data is lost
Solution Approach 1:
The patent implements feedback by continuously monitoring peak frequency components in the decoded signal and using this information to adjust balance parameters. When data loss causes localization fluctuation, the feedback mechanism detects the fluctuation through peak frequency analysis and compensates by adjusting balance parameters to maintain stable stereo perception
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting balance parameters based on detected peak frequency components. When stereo encoded data is lost, the system changes the balance parameter values calculated from peak frequencies rather than using the original parameters, adapting to the data loss condition while maintaining localization stability
Data Source
AI summary
Disclosed is an audio signal decoding device and a method of balance adjustment that reduces a fluctuation of a decoded signal orientation and maintains a stereo perception. An interchannel correlation computation unit (224) computes a correlation between a left channel decoded stereo signal and a right channel decoded stereo signal, and if the interchannel correlation is low, a peak detection unit (225) uses a peak component of a decoded monaural signal of the current frame and a peak component of either a left or a right channel of the preceding frame to detect a peak component with a high temporal correlation. The peak detection unit (225) combines and outputs, from among the frequencies of the detected peak components, a peak frequency of a frame n−1 and a peak frequency of a frame n. A peak balance coefficient computation unit (226) computes, from the peak frequency of the frame n−1, a balance parameter that is used in converting a peak frequency component of the monaural signal to stereo.