MuteUnmute

Overview

Mutes and unmutes to hide artifacts

Discussion

This module is used to hide pops and clicks during transitions. The module smoothly mutes, outputs silence, and then smoothly unmutes. You have full control over mute period, silence period, and unmuting period.

The .trigger variable is used to engage the entire process. Normally trigger=0 and the module passes the input unchanged. When you set trigger=1, then the module goes through the overall mute/silence/unmute cycle.

The module uses a raised cosine window for muting and unmuting. For memory efficiency the module uses a complex recursion to compute the gain profile for the raised cosine.

The constructor argument INITIALSTATE allows you to set the initial state of the trigger variable. By default, INITIALSTATE = 0 meaning that the module starts up unmuted. If you set INITIALSTATE = 1, then the module starts out muted.

Module Pack

Standard

ClassID

classID = 29

Type Definition

typedef struct _ModuleMuteUnmute
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
INT32 trigger;                                // Begins the muting and unmuting process
FLOAT32 muteTime;                             // Muting time, in msec
FLOAT32 silenceTime;                          // Duration of the silence period, in msec
FLOAT32 unmuteTime;                           // Unmuting time, in msec
INT32 muteTimeSamples;                        // Muting time, in samples
INT32 silenceTimeSamples;                     // Silence time, in samples
INT32 unmuteTimeSamples;                      // Unmuting time, in samples
FLOAT32 muteCoeffR;                           // One of two coefficients used to compute the muting profile
FLOAT32 muteCoeffI;                           // One of two coefficients used to compute the muting profile
FLOAT32 unmuteCoeffR;                         // One of two coefficients used to compute the unmuting profile
FLOAT32 unmuteCoeffI;                         // One of two coefficients used to compute the unmuting profile
FLOAT32 stateR;                               // One of two state variables which control the ramping profile
FLOAT32 stateI;                               // One of two state variables which control the ramping profile
INT32 sampleTime;                             // Counts the samples elapsed in the entire mute/silence/unmute cycle
} ModuleMuteUnmuteClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range
trigger	int	state	0	0	0:1
muteTime	float	parameter	0	5	1:1000
silenceTime	float	parameter	0	100	0:10000
unmuteTime	float	parameter	0	50	1:1000
muteTimeSamples	int	derived	1	240	Unrestricted
silenceTimeSamples	int	derived	1	4800	Unrestricted
unmuteTimeSamples	int	derived	1	2400	Unrestricted
muteCoeffR	float	derived	1	0.9999	Unrestricted
muteCoeffI	float	derived	1	0.01309	Unrestricted
unmuteCoeffR	float	derived	1	1	Unrestricted
unmuteCoeffI	float	derived	1	0.001309	Unrestricted
stateR	float	state	1	0	Unrestricted
stateI	float	state	1	0	Unrestricted
sampleTime	int	state	1	0	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

Output Pins


Name	out
Description	audio output
Data Type	float

Scratch Pins


Channel Count	1
Block size	32
Sample rate	48000

Matlab Usage

File Name: mute_unmute_module.m 
 M=mute_unmute_module(NAME, INITIALSTATE) 
 Creates a module which mutes, remains silent, and then unmutes 
 after a period of time.  This is used to hide artifacts.  The 
 module has programmable mute, unmute, and silence periods.  The 
 muting and unmuting is performed using raised cosine windows. 
 Arguments: 
    NAME - name of the module. 
    INITIALSTATE - optional argument which specifies the default state 
      of the trigger variable.  By default, INITIALSTATE = 0 meaning that 
      the module comes up unmuted.