AudioFilter Class Reference

The AudioFilter object implements all filters in Designing Audio Effects Plugins in C++ 2nd Ed. by Will Pirkle. More...

#include <fxobjects.h>

Inheritance diagram for AudioFilter:

Public Member Functions
virtual bool	reset (double _sampleRate)
virtual bool	canProcessAudioFrame ()
virtual double	processAudioSample (double xn)
	process one sample through the audio filter
virtual void	setSampleRate (double _sampleRate)
AudioFilterParameters	getParameters ()
void	setParameters (const AudioFilterParameters &parameters)
double	getG_value ()
double	getS_value ()
Public Member Functions inherited from IAudioSignalProcessor
virtual bool	reset (double _sampleRate)=0
virtual double	processAudioSample (double xn)=0
virtual bool	canProcessAudioFrame ()=0
virtual void	setSampleRate (double _sampleRate)
virtual void	enableAuxInput (bool enableAuxInput)
virtual double	processAuxInputAudioSample (double xn)
virtual bool	processAudioFrame (const float *inputFrame, float *outputFrame, uint32_t inputChannels, uint32_t outputChannels)

Protected Member Functions
bool	calculateFilterCoeffs ()

Protected Attributes
Biquad	biquad
	the biquad object
double	coeffArray [numCoeffs] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 }
	our local copy of biquad coeffs
AudioFilterParameters	audioFilterParameters
	parameters
double	sampleRate = 44100.0
	current sample rate

Detailed Description

The AudioFilter object implements all filters in Designing Audio Effects Plugins in C++ 2nd Ed. by Will Pirkle.

Audio I/O:

• Processes mono input to mono output.

Control I/F:

• Use AudioFilterParameters structure to get/set object params.

Author

Will Pirkle http://www.willpirkle.com

Remarks

This object is included in Designing Audio Effects Plugins in C++ 2nd Ed. by Will Pirkle

Version

Revision : 1.0

Date

Date : 2018 / 09 / 7

Member Function Documentation

calculateFilterCoeffs()

bool AudioFilter::calculateFilterCoeffs ( )

protected

— function to recalculate coefficients due to a change in filter parameters

canProcessAudioFrame()

virtual bool AudioFilter::canProcessAudioFrame ( )

inlinevirtual

return false: this object only processes samples

Implements IAudioSignalProcessor.

getG_value()

double AudioFilter::getG_value ( )

inline

— helper for Harma filters (phaser)

getParameters()

AudioFilterParameters AudioFilter::getParameters ( )

inline

— get parameters

getS_value()

double AudioFilter::getS_value ( )

inline

— helper for Harma filters (phaser)

processAudioSample()

double AudioFilter::processAudioSample ( double  xn )

virtual

process one sample through the audio filter

process input x(n) through the filter to produce return value y(n)

Parameters

xn

input

Returns

the processed sample

• NOTES:
  Uses the modified biquaqd structure that includes the wet and dry signal coefficients c and d.
  Here the biquad object does all of the work and we simply combine the wet and dry signals.
  return (dry) + (processed): x(n)*d0 + y(n)*c0
  

  Parameters

  xn	the input sample x(n)

  Returns

  the biquad processed output y(n)

Implements IAudioSignalProcessor.

reset()

virtual bool AudioFilter::reset ( double  _sampleRate )

inlinevirtual

— set sample rate, then update coeffs

Implements IAudioSignalProcessor.

setParameters()

void AudioFilter::setParameters ( const AudioFilterParameters &  parameters )

inline

— set parameters

setSampleRate()

virtual void AudioFilter::setSampleRate ( double  _sampleRate )

inlinevirtual

— sample rate change necessarily requires recalculation

Reimplemented from IAudioSignalProcessor.

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The documentation for this class was generated from the following files:

• C:/RackAFX_v7/ASPIK_Doxygen/PluginObjects/fxobjects.h
• C:/RackAFX_v7/ASPIK_Doxygen/PluginObjects/fxobjects.cpp