WaveIndexVector

Overview

Common index vector for looping wave player

Discussion

This module computes the common sample index vector based on the greatest common divisor of all wave files.

The input to the module can be either .fRatio or .RPM dependent on the useRPM argument.

The argument MAXRATE specifies the maximum playback rate in the units of playbackRatio or RPM. MAXRATE is used to determine the extension size of the circular index array. The module internally clips the value at to lie within the range [0 MAXRATE]. That is, if you exceed MAXRATE then the sound no longer increases in frequency (and you will not have buffer overrun artifacts). The module computes the sample-by-sample stride internally based on gcd(NUMWAVPLAYER), .rpm and the sample rate.

Type Definition

CODE

typedef struct _ModuleWaveIndexVector
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 smoothingTime;                          // Time constant of the pitch smoothing process
    INT32 smoothingFactor;                        // Update rate for smoothing coeffs (per block)
    INT32 maxIndex;                               // Usually length of the WAV file in samples
    INT32 numWavPlayer;                           // Size of base rate array
    FLOAT32 currentFStep;                         // Current (smoothed) rate
    FLOAT32 currentIndex;                         // Current vector index
    FLOAT32 maxRate;                              // Max rate or number of rotations in units of RPM
    FLOAT32 scaleFactor;                          // Inverse of the wave file rpm
    FLOAT32 smoothingCoeff;                       // Smoothing (pitch) coefficient
    INT32 vectorLength;                           // Length of the index table
    INT32* normRate;                              // Array of normalized playback rate / number of rotations of each wave player.
} ModuleWaveIndexVectorClass;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
smoothingTime	int	parameter	0	10	0:1000	msec
smoothingFactor	int	parameter	0	4	1:512
maxIndex	int	const	0	48000	Unrestricted
numWavPlayer	int	const	0	2	Unrestricted
currentFStep	float	state	0	1	Unrestricted
currentIndex	float	state	0	0	Unrestricted
maxRate	float	const	1	1	Unrestricted
scaleFactor	float	const	1	0.01667	Unrestricted
smoothingCoeff	float	derived	1	0.1248	Unrestricted
vectorLength	int	derived	1	48000	Unrestricted
normRate	int*	parameter	0	[2 x 1]	Unrestricted

Pins

Input Pins

Name: ratio

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: index

Description: Sample index vector

Data type: float

MATLAB Usage

File Name: wave_index_vector_module.m