OneShotPlayer

Overview

One shot player with trigger pin

Discussion

WAV file player in which playback is triggered via an input pin. The input .trigger is a Boolean value which, if set, starts playback. The trigger must be an impulse of length 1 frame, or the initial frame of the WAV will be repeated while .trigger remains set. When .trigger is reset to 0, playback continues from the second frame until it stops at end of the file. If .trigger is set again while in the middle of playback then playback will restart.

The second input pin fRatio determines the playback speed. If fRatio = 1.0 then playback is at the expected rate. fRatio > 1.0 causes the speed to increase and fRatio < 1.0 causes the speed to decrease. Any negative fRatio value is replaced with a zero internally.

The module supports only mono playback and first channel of the input wave file is used if it is a multi-channel wave file. Internally the module stores wave data as float values.

Module Pack

Advanced

ClassID

classID =

Type Definition

typedef struct _ModuleOneShotPlayer
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
} ModuleOneShotPlayerClass;

Variables

Properties

Name	Type	Usage	Default Value	Range
wavLength	int	const	100415	Unrestricted
wavSR	int	const	48000	Unrestricted
nRate	float	const	1	Unrestricted
mRate	float	const	1	Unrestricted

Pins

Input Pins


Name	trigger
Description	Boolean trigger signal
Data type	int
Channel range	1
Block size range	1
Sample rate range	Unrestricted
Complex support	Real


Name	fRatio
Description	Specifies the playback speed
Data type	float
Channel range	1
Block size range	1
Sample rate range	Unrestricted
Complex support	Real

Output Pins


Name	out
Description	Output audio
Data Type	float

Scratch Pins


Channel Count	1
Block size	1
Sample rate	48000


Channel Count	1
Block size	1
Sample rate	48000

Matlab Usage

File Name: one_shot_player_module.m 
 SYS=one_shot_player_module(NAME, BLOCKSIZE, SAMPLERATE, WAVFILE, NRATE, MRATE, FPIN) 
 Creates a one shot player module which plays back a WAV file when triggered.  Arguments: 
    NAME - name of the module. 
    BLOCKSIZE - block size of the module output.  By default, 
                BLOCKSIZE = 256. 
    SAMPLERATE - sample rate of the output signal, in Hz.  By default, 
                 SAMPLERATE = 48000.  This does not have to match the sample rate of 
                 the WAVFILE. 
    WAVFILE - WAV file containing the samples to playback. 
    NRATE - normalized playback rate.  This helps to scale the playback audio 
            rate.  For example, if the WAVFILE corresponds to 1500 RPM, then set 
            NORMALIZEDRATE = 1500 and when the signal on the .fRate input pin 
            equals 1500 then the WAVFILE will be played back at the original 
            rate. 
    MRATE - Maximum playback rate (relative to NRATE).