Overview

Multichannel smooth mute

Discussion

Smoothly mutes all input channels. Muting/unmuting is controlled by the isMuted parameter The isMuted parameter is automatically converted to a value for the internal gain variable. isMuted = 1 --> gain = 0. isMuted = 0 --> gain = 1. gain serves as a target gain for the module. Changes to the gain variable are exponentially smoothed (first order IIR) at the sample rate, with the time constant determined by the smoothingTime parameter. The internal variable currentGain represents the instantaneous smoothed gain that is applied to the data stream. currentGain exponentially approaches gain with a time constant equal to smoothingTime.

currentGain also serves as the starting gain of the module. If currentGain = gain, then the module starts up in a converged state. If currentGain != gain, then the module will smoothly vary the gain at startup.

Type Definition

typedef struct _ModuleMuteSmoothedFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 isMuted;                                // Target gain factor decider
    FLOAT32 smoothingTime;                        // Time constant of the smoothing process
    fract32 currentGain;                          // Instantaneous gain applied by the module. This is also the starting gain of the module.
    fract32 smoothingCoeffFract32;                // Smoothing coefficient
    fract32 target_gainFract32;                   // Target gain
} ModuleMuteSmoothedFract32Class;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
isMuted	int	parameter	0	0	0:1
smoothingTime	float	parameter	0	10	0:1000	msec
currentGain	fract32	state	1	0	0:0.9999	linear
smoothingCoeffFract32	fract32	derived	1	0.002081	Unrestricted
target_gainFract32	fract32	derived	1	0.9999	Unrestricted

Pins

Input Pins

Name: in

Description: audio input

Data type: fract32

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: audio output

Data type: fract32

MATLAB Usage

File Name: mute_smoothed_fract32_module.m

 M=mute_smoothed_fract32_module(NAME)
 Creates a smoothly varying scalersmoothed object for use in the
 Audio Weaver.  Arguments:
    NAME - name of the module.