Granular Synthesis Delay

Overview

Synchronous Granular Synthesis Module Delay

Discussion

This module implements (synchronous) granular synthesis functionality. It uses a delay line to store samples from a real-time input stream. Each grain reads sound from the delay line with a potentially different delay time and playback rate. At instantiation time, you must specify the maximum delay time in milliseconds, max grain size in milliseconds. These values determine the sizes of each internal state buffers to hold audio samples and intermediate results.

The input pin fRatio is a floating-point number and specifies the step size between samples as they are played back. Internally, fRatio is smoothed on a block by block basis using the .smoothingTime variable.

If "playDir" parameter has been selected to "backward" or, if fRatio has a negative value [range 0..-1] and "playDir" parameter has been selected to "auto", the delayline buffer is played back in backward direction,

The module has input pin named delayPos that specifies the starting position of the grains at audio rate. Values in the input pin ranges between 0 and 1, and the actual offset in the file is determined be multiplying it with the delayline length. The starting offset of each grain is determined internally and the value at that offset is read from delayPos.

The module has input pin named panMod that specifies the panning coefficients of the grains at audio rate. Values in the input pin ranges between 0 and 1, the specified value is considered as panning coefficient for left channel. 1-coeff is considered as the panning for right channel.

Module Pack

awe-mod-dspc-snd

ClassID

classID = 41816

Type Definition

typedef struct _ModuleGranularSynthesisDelay
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
INT32 grainSize;                              // Sets the length of each grain, denoted in milliseconds
INT32 grainDensity;                           // Sets the number of grain samples per second
INT32 playDir;                                // Playback direction, 0=Forward, 1=Backward, 2=Auto (derived from fRatio input pin)
FLOAT32 gain;                                 // The peak level of the window
INT32 smoothingTime;                          // Time constant of the pitch smoothing process
INT32 maxDelayTime;                           // Maximum delay, in milliseconds.
INT32 windowLength;                           // Number of coefficients for current window
INT32 maxDelaySamples;                        // Maximum delay in samples.
INT32 writeIndex;                             // Write offset in the delay buffer
INT32 maxGrainSize;                           // Maximum grain size in ms
INT32 maxDensity;                             // Max density in grains per sec
FLOAT32 maxRate;                              // Highest allowed rate of playback that can be specified
UINT32 pinID;                                 // Specifies which control pins are available
INT32 stateHeap;                              // Heap in which to allocate state buffer memory.
INT32 maxOverlapGrains;                       // Number of max. overlapping grains per maxGrainSize
INT32 grainSizeSamples;                       // Length of each grain in samples
INT32 interonsetTime;                         // Time between temporally adjacent grain onsets
FLOAT32 windowRatio;                          // Sample ratio of the window coefficients
FLOAT32 smoothingCoeff;                       // Smoothing (pitch) coefficient
INT32 grainIndex;                             // Current used vector index
INT32 interonsetCnt;                          // Current interonset counter
FLOAT32 smoothedFRatio;                       // Current (smoothed) rate at which audio is read from the input buffer
FLOAT32* window;                              // Window coefficients
FLOAT32* window_coeffs;                       // Window coefficients
FLOAT32* delayBuffer;                         // State variable array.
INT32* GrainDelayIndex;                       // Curr delayline index of the intermediate vector element
FLOAT32* GrainDelayIndexF;                    // Curr delayline index fract of the intermediate vector element
FLOAT32* GrainDelayFStep;                     // Curr delayline step size of the intermediate vector element
INT32* GrainEnvIndex;                         // Curr envelope index of the intermediate vector element
FLOAT32* GrainEnvIndexF;                      // Curr envelope index fract of the intermediate vector element
FLOAT32* GrainEnvFStep;                       // Curr envelope step size of the intermediate vector element
INT32* GrainOffset;                           // Curr grain offset of the intermediate vector element
FLOAT32* GrainPanCoeff;                       // Curr panning coefficient of the intermediate vector element
INT32* GrainStatus;                           // Curr status ("active"/"inactive") of the intermediate vector element
} ModuleGranularSynthesisDelayClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range	Units
grainSize	int	parameter	0	100	1:100	msec
grainDensity	int	parameter	0	10	1:100
playDir	int	parameter	0	0	0:2
gain	float	parameter	0	1	0:1
smoothingTime	int	parameter	0	100	0:1000	msec
maxDelayTime	int	const	0	500	0:500	msec
windowLength	int	const	0	32	Unrestricted
maxDelaySamples	int	derived	0	24000	Unrestricted	samples
writeIndex	int	state	0	0	Unrestricted
maxGrainSize	int	const	1	100	0:100	msec
maxDensity	int	const	1	100	0:100	grains per sec
maxRate	float	const	1	5	Unrestricted
pinID	uint	const	1	1	Unrestricted
stateHeap	int	const	1	561	Unrestricted
maxOverlapGrains	int	const	1	10	Unrestricted
grainSizeSamples	int	derived	1	4800	Unrestricted
interonsetTime	int	derived	1	4800	Unrestricted
windowRatio	float	derived	1	1	Unrestricted
smoothingCoeff	float	derived	1	0.006644	Unrestricted
grainIndex	int	state	1	0	Unrestricted
interonsetCnt	int	state	1	0	Unrestricted
smoothedFRatio	float	state	1	1	Unrestricted
window	float*	parameter	1	[35 x 1]	Unrestricted
window_coeffs	float*	parameter	0	[32 x 1]	Unrestricted
delayBuffer	float*	state	1	[1 x 24003]	Unrestricted
GrainDelayIndex	int*	state	1	[1 x 10]	Unrestricted
GrainDelayIndexF	float*	state	1	[1 x 10]	Unrestricted
GrainDelayFStep	float*	state	1	[1 x 10]	Unrestricted
GrainEnvIndex	int*	state	1	[1 x 10]	Unrestricted
GrainEnvIndexF	float*	state	1	[1 x 10]	Unrestricted
GrainEnvFStep	float*	state	1	[1 x 10]	Unrestricted
GrainOffset	int*	state	1	[1 x 10]	Unrestricted
GrainPanCoeff	float*	state	1	[1 x 10]	Unrestricted
GrainStatus	int*	state	1	[1 x 10]	Unrestricted

Pins

Input Pins


Name	in
Description	Input audio
Data type	float
Channel range	1
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real


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


Name	delayPos
Description	Start point of the grain, located relative within the delayline between 0..1(maxDelay)
Data type	float
Channel range	1
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real


Name	panMod
Description	Controls panning for each grain; relative distribution between 0(max left)..1(max right)
Data type	float
Channel range	1
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real

Output Pins


Name	audio
Description	Output data
Data Type	float

Scratch Pins


Channel Count	1
Block size	32
Sample rate	48000


Channel Count	1
Block size	32
Sample rate	48000


Channel Count	1
Block size	32
Sample rate	48000

Matlab Usage

File Name: granular_synthesis_delay_module.m