Stereo Sound Decoding Apparatus Dynamic Concealment Switching
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Solution Overview
Problem
Existing stereo speech coding technologies face challenges in maintaining high-quality speech communication during packet loss, particularly when inter-channel correlation is low, leading to degraded speech quality due to insufficient lost frame concealment.
Innovation Solution
A stereo speech decoding apparatus and method that employs a monaural-stereo scalable configuration, including a monaural decoding section, stereo decoding section, comparison section, inter-channel concealment section, intra-channel concealment section, and concealed signal selecting section, which compares inter-channel and intra-channel correlations to select the best concealment approach for improving speech quality during frame loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only inter-channel concealment using past decoded side signal is performed, then the device complexity is reduced, but the concealed signal quality degrades when inter-channel correlation is low
Solution Approach 1:
The patent dynamically switches between inter-channel concealment and intra-channel concealment methods based on the calculated inter-channel correlation value. When inter-channel correlation is high, inter-channel concealment is used; when it is low, intra-channel concealment is used. This dynamic adaptation resolves the contradiction by optimizing concealed signal quality for different correlation conditions without permanently increasing device complexity.
Solution Approach 2:
The patent changes the concealment method parameter based on the inter-channel correlation parameter. By monitoring the correlation value and switching concealment strategies accordingly, the system adapts to varying signal conditions, maintaining high concealed signal quality without requiring complex permanent architecture changes.
2Speed
If inter-channel concealment is used for all frames, then the processing speed is maintained, but the concealed signal quality degrades when inter-channel correlation is low
Solution Approach 1:
The patent introduces dynamic switching between concealment methods based on real-time correlation assessment. This allows the system to maintain processing speed by using simple inter-channel concealment when appropriate (high correlation) while switching to intra-channel concealment when needed (low correlation), thus resolving the contradiction between speed and quality.
Solution Approach 2:
The patent employs a lightweight correlation calculation mechanism that quickly determines whether to switch concealment methods. This disposable assessment approach maintains overall processing speed while enabling quality optimization when necessary, without requiring permanent complex processing architecture.
3Manufacturing precision
If intra-channel concealment is always used, then the concealed signal quality is maintained, but the device complexity increases
Solution Approach 1:
The patent uses dynamic switching to apply intra-channel concealment only when inter-channel correlation is low, rather than always using it. This selective application maintains concealed signal quality when needed while avoiding the permanent complexity increase that would result from always employing the more complex intra-channel method.
Solution Approach 2:
The patent applies different concealment methods to different situations based on local correlation characteristics. By using inter-channel concealment for high-correlation frames and intra-channel concealment for low-correlation frames, the system achieves high overall quality without the permanent complexity of always using the more sophisticated method.
4Manufacturing precision
If correlation-based switching is implemented, then the concealed signal quality is improved, but the processing time increases due to correlation calculation
Solution Approach 1:
The patent calculates correlation only for the purpose of determining concealment method selection, not for full signal processing. This partial action approach - computing correlation just enough to make the switching decision - improves concealed signal quality through intelligent switching while minimizing the time overhead compared to full correlation-based processing.
Solution Approach 2:
The patent uses the decoded signal itself to calculate the correlation metric needed for switching decisions. This self-service approach leverages already-available data without requiring additional external measurements or complex processing, thus improving concealed signal quality while keeping processing time overhead minimal.
Data Source
AI summary
A stereo sound decoding apparatus wherein lost-frame compensation performance has been improved to enhance the quality of decoded sounds. In this stereo sound decoding apparatus, a sound decoding part uses encoded monophonic signal data and encoded side signal data, which are received from a sound encoding apparatus, to generate monophonic decoded signals and stereo decoded signals; a compensation signal switching determining part that compares an inter-channel correlation and an intra-channel correlation, which have been calculated by use of the monophonic decoded signals of a previous frame and the stereo decoded signals of the previous frame, with respective comparison thresholds; a compensation signal switching part that selects, based on a result of the comparison in the compensation signal switching determining part, as compensation signals either inter-channel compensation signals generated by an inter-channel compensating part or intra-channel compensation signals generated by an intra-channel compensating part; and an output signal switching part that outputs either the stereo decoded signals or the compensation signals according to whether the encoded side signal data of the current frame has been lost.