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Overview

Periodic WAV playback supporting pitch shifting

Discussion

This module outputs wave data in loop mode. User has to specify the file name as an argument. Along with the above parameters, the playback functionality can be enabled from the control input pin, 1 - Enable and 0 - Disable.

The module supports multichannel such that, if the wave file has more channels than provided to the module argument then only channels up to output pin channels will be used. If the wave file has less channels than output pin channels, then the remaining output channels will be muted.

Type Definition

typedef struct _ModuleWaveLoopPlayerRAMFract32
{
    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 startDelay;                             // Starting delay value in samples
    INT32 enable;                                 // En/Disable playback. Resets sample position to startDelay value upon stop
    FLOAT32 normRate;                             // Rate of data used to compute the ratio for normalized players
    FLOAT32 maxRate;                              // Highest allowed rate of playback that can be specified
    INT32 NCOFracBits;                            // Number of least-significant bits for the *fractional* part of the NCO word (word size: 32)
    INT32 waveLength;                             // Number of samples in currently loaded file
    INT32 fIndex;                                 // Current index in the wave file
    FLOAT32 currentFStep;                         // Current (smoothed) rate at which audio is read from the input buffer
    INT32 waveSR;                                 // Actual sample rate of the wave file.
    INT32 waveNumChannels;                        // Number of channels in the wave file.
    FLOAT32 scaleFactor;                          // Scale factor for playback rate
    FLOAT32 smoothingCoeff;                       // Smoothing (pitch) coefficient
    INT32 NCOIntBits;                             // Number of most-significant bits for the *integer* part of the NCO word (word size: 32). By default: 20 bits
    FLOAT32 formatF;                              // Integer value of left-shift by NCOFracBits. Determines the precision of the linear interpolation.
    FLOAT32 formatI;                              // Integer value of left-shift by NCOIntBits. Determines the maximum playback rate and the maximum size of a wave file in samples.
    UINT32 pinID;                                 // Specifies which control pins are available.
    INT32* waveBuffer;                            // Data transferred from PC to target DSP via this buffer.
} ModuleWaveLoopPlayerRAMFract32Class;

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

startDelay

int

parameter

0

0

Unrestricted

enable

int

state

0

1

0:1

normRate

float

const

0

1

Unrestricted

maxRate

float

const

0

2

Unrestricted

NCOFracBits

int

const

0

12

Unrestricted

waveLength

int

derived

0

8976

Unrestricted

fIndex

int

state

0

0

Unrestricted

currentFStep

float

state

0

1

Unrestricted

waveSR

int

derived

1

48000

Unrestricted

waveNumChannels

int

derived

1

1

Unrestricted

scaleFactor

float

derived

1

1

Unrestricted

smoothingCoeff

float

derived

1

0.1248

Unrestricted

NCOIntBits

int

derived

1

20

Unrestricted

formatF

float

derived

1

4096

Unrestricted

formatI

float

derived

1

524300

Unrestricted

pinID

uint

const

1

3

Unrestricted

waveBuffer

int*

parameter

0

[4490 x 1]

Unrestricted

Pins

Input Pins

Name: enable

Description: Flag to enable playback

Data type: int

Channel range: 1

Block size range: 1

Sample rate range: Unrestricted

Complex support: Real

Name: fRatio

Description: Specifies sample rate ratio

Data type: float

Channel range: 1

Block size range: 1

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: audio

Description: output data

Data type: fract32

Name: isPlaying

Description: playing state

Data type: int

MATLAB Usage

File Name: wave_loop_player_ram_fract32_module.m

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