MuteSymmetric

Overview

Smoothly mutes with exponential symmetrical fading curves

Discussion

Smoothly mutes all input channels. Muting/unmuting is controlled by the isMuted parameter. It takes equal time to mute and unmute (logarithmic ramp), hence the name: symmetric. The isMuted parameter together with muteThreshold is automatically converted to a value for the internal targetGain variable.

This module works similarly as the existing ScalerSymmetric module. Current gain though can be updated per sample (blockOrSample=0) or per block (blockOrSample=1). It exponentially and sample exact approaches its target gain with the set timeToMute parameter.

When full mute, the module will output zeros. Unmuted the input samples are simply copied one by one

Optional argument isMutedPin can be used to output fully muted/unmuted state.

If timeToMute=0 then no smoothing is being performed.

Type Definition

typedef struct _ModuleMuteSymmetric
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 isMuted;                                // Boolean that controls muting/unmuting.
    INT32 timeToMute;                             // Time to fully mute/unmute in msec.
    INT32 blockOrSample;                          // Gain computed per block [checked] or per sample [unchecked]
    FLOAT32 targetGain;                           // Computed target gains in linear units
    FLOAT32 muteThreshold;                        // Level (lin) considered to be fully muted
    FLOAT32 gradient;                             // Precalculated delta or gradient.
    FLOAT32 currentGain;                          // Instantaneous gain applied by the module. This is also the starting gain of the module.
    INT32 numSamples;                             // Number of samples over which muting has to be applied
    FLOAT32 muteThreshold_dB;                     // Level (dB) considered to be fully muted
    UINT32 pinID;                                 // Specifies which control pins are available.

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
isMuted	int	parameter	0	0	0:1
timeToMute	int	parameter	0	10	0:1000	msec
blockOrSample	int	const	0	0	Unrestricted
targetGain	float	derived	1	1	0:1	linear
muteThreshold	float	derived	1	1e-10	Unrestricted
gradient	float	derived	1	1	Unrestricted
currentGain	float	state	1	1	0:1	linear
numSamples	int	state	1	480	Unrestricted
muteThreshold_dB	float	const	1	-200	Unrestricted
pinID	uint	const	1	1	Unrestricted

Pins

Input Pins

Name: in

Description: audio input

Data type: float

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real and Complex

Output Pins

Name: out

Description: audio output

Data type: float

Name: isMuted

Description: mute state

Data type: int

Scratch Pins

Channel count: 1

Block size: 32

Sample rate: 48000

MATLAB Usage

File Name: mute_symmetric_module.m

 M=mute_symmetric_module(NAME)
 Creates a module which smoothly mutes and unmutes using symmetric ramps, 
 meaning it takes equal time for fadeIn and fadeOut. 
 
 Arguments:
    NAME - name of the module.
    MUTETHRESHOLD - level in dB considered to be fully muted
    BLOCKORSAMPLE - gain computed per block or per sample. 
    ISMUTEDPIN    - boolean control signal that tells when the muting occurred