Audio Dynamics Reset Using Stored State for Channel Change Stability
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Solution Overview
Problem
Audio dynamics processors with large time constants take a long time to adapt to abrupt changes in audio content, leading to perceived volume fluctuations during channel changes or content discontinuities, resulting in user intervention to adjust volume levels.
Innovation Solution
Incorporating a reset mechanism that detects changes in the audio signal or external triggers to rapidly adjust time constants and modification parameters, allowing for faster adaptation to new audio levels by setting time constants to shorter values or using stored state indicators for smoother transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large time constants are used in the dynamics processor, then the short-term dynamics of the audio signal are preserved, but the adaptation time to abrupt content changes becomes excessively long
Solution Approach 1:
The patent applies the Dynamics principle by making the time constants adaptive rather than fixed. The system automatically adjusts time constants based on signal characteristics: using large time constants during steady-state to preserve short-term dynamics, and switching to small time constants during transient periods or when abrupt changes are detected to enable rapid adaptation. This dynamic adjustment resolves the contradiction between preserving dynamics and enabling fast adaptation.
Solution Approach 2:
The patent implements Parameter changes by modifying the time constant values based on signal analysis. The system monitors the audio signal and dynamically changes the time constant parameter from large values (for dynamics preservation) to small values (for fast adaptation) when abrupt changes are detected, thereby resolving the trade-off between stability and adaptation speed.
2Speed
If time constants are reduced to speed up adaptation, then the response to content changes improves, but the short-term dynamics of the audio signal are distorted
Solution Approach 1:
The system dynamically adjusts time constants based on the operational context: using small time constants during transient periods or abrupt changes to achieve fast response, and switching to large time constants during steady-state to preserve short-term dynamics. This dynamic behavior allows the system to achieve both fast response and dynamics preservation at different times.
Solution Approach 2:
The patent employs periodic monitoring of the audio signal to detect abrupt changes and trigger time constant adjustments. The system continuously analyzes the signal and periodically switches between different time constant settings based on the detected signal characteristics, enabling fast adaptation when needed while preserving dynamics during normal operation.
3Ease of operation
If manual volume adjustment is allowed during adaptation, then user control is provided, but the perceived audio experience is degraded due to fighting the AGC convergence
Solution Approach 1:
The patent applies Preliminary action by detecting abrupt content changes before the AGC would normally take a long time to adapt. When such changes are detected, the system proactively switches to fast adaptation mode with small time constants, anticipating the user's need for quick volume stabilization and preventing the harmful effect of prolonged volume fluctuations that would require manual adjustment.
Solution Approach 2:
The system uses feedback by continuously monitoring the audio signal for abrupt changes and using this information to automatically adjust time constants. This closed-loop control enables the system to respond to content changes without requiring user intervention, thereby eliminating the harmful effect of perceived volume fluctuations while maintaining ease of operation.
Data Source
AI summary
An audio dynamics processor or processing method that uses a reset mechanism or process in order to adapt quickly to content changes in the audio signal. A reset signal may be generated by analyzing the audio signal itself or the reset may be triggered from an external event such as a channel change on a television set or an input selection change on an audio/visual receiver. In the case of an external trigger, one or more indicators of the state of the dynamics processor for a current audio source may be saved and associated with that audio source before switching to a new audio source. Then, if the system switches back to the first audio source, the dynamics processor may be reset to the state previously stored or an approximation thereof.