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.
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 | Units |
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.