(8.D.2.7) MuteSymmetric
- Sam Stuart
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 | Â |
timeToMute | int | parameter | 0 | 10 | 0:1000 | msec |
blockOrSample | int | const | 0 | 0 | Unrestricted | Â |
targetGain | float | derived | 1 | 1 | 0:1 | linear |
muteThreshold | float | derived | 1 | 1e-10 | Unrestricted | Â |
gradient | float | derived | 1 | 1 | Unrestricted | Â |
currentGain | float | state | 1 | 1 | 0:1 | linear |
numSamples | int | state | 1 | 480 | Unrestricted | Â |
muteThreshold_dB | float | const | 1 | -200 | Unrestricted | Â |
pinID | uint | const | 1 | 1 | Unrestricted | Â |
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