Superpowered::BandpassFilterbank Class Reference

Efficient bandpass filter bank for real-time zero latency frequency analysis. Each band is a separated bandpass filter with custom width and center frequency. More...

#include "SuperpoweredBandpassFilterbank.h"

Public Member Functions
	BandpassFilterbank (unsigned int numBands, float *frequencies, float *widths, unsigned int samplerate, unsigned int numGroups=0)
	Constructor. More...
	~BandpassFilterbank ()
float	getAverageVolume ()
	Returns with the average volume of all audio passed to all previous process() or processNoAdd() calls. More...
float	getPeakVolume ()
	Returns with the peak volume of all audio passed to all previous process() or processNoAdd() calls. More...
float	getSumVolume ()
	Returns with the cumulated absolute value of all audio passed to all previous process() or processNoAdd() calls. Like you would add the absolute value of all audio samples together. More...
void	process (float *input, unsigned int numberOfFrames, int group=0)
	Processes the audio. More...
void	processNoAdd (float *input, unsigned int numberOfFrames, int group=0)
	Processes the audio. More...
void	resetBands ()
	Sets all values of bands to 0. More...
void	resetPeakVolume ()
	Resets the peak volume value to start measurement anew. More...
void	resetSumAndAverageVolume ()
	Resets the sum and average volume value to start measurement anew. More...

Public Attributes
float *	bands
	The magnitude of the frequency bands. Will be updated after each process() or processNoAdd() call. More...
unsigned int	samplerate
	Sample rate in Hz. More...

Private Member Functions
	BandpassFilterbank (const BandpassFilterbank &)
BandpassFilterbank &	operator= (const BandpassFilterbank &)

Private Attributes
bandpassFilterbankInternals *	internals

Detailed Description

Efficient bandpass filter bank for real-time zero latency frequency analysis. Each band is a separated bandpass filter with custom width and center frequency.

Constructor & Destructor Documentation

BandpassFilterbank() [1/2]

Superpowered::BandpassFilterbank::BandpassFilterbank	(	unsigned int	numBands,
		float *	frequencies,
		float *	widths,
		unsigned int	samplerate,
		unsigned int	numGroups = 0
	)

Constructor.

Parameters

numBands	The number of bands. Must be a multiply of 8.
frequencies	Center frequencies of each band in Hz.
widths	Widths of each band in octave (1.0f is one octave, 1.0f / 12.0f is one halfnote).
samplerate	The initial sample rate in Hz.
numGroups	For advanced use. The filter bank can be set up with multiple frequency + width groups, then process() or processNoAdd() can be performed with one specific frequency + width group. For example, set up one group with wide frequency coverage for the 20-20000 Hz range and three additional groups for 20-200 Hz, 200-2000 Hz and 2000-20000 Hz. When processing with the wide group of 20-20000 Hz and the highest magnitude can be found at 1000 Hz, use the 200-2000 Hz group for the next process() or processNoAdd() call, so the filter bank will have a "focus" on a narrower range. If numGroups > 0, then the number of frequencies and widths should be numGroups * numBands. Example: for numBands = 8 and numGroups = 2, provide 8 + 8 frequencies and 8 + 8 widths.

~BandpassFilterbank()

Superpowered::BandpassFilterbank::~BandpassFilterbank

(

)

BandpassFilterbank() [2/2]

Superpowered::BandpassFilterbank::BandpassFilterbank ( const BandpassFilterbank &  )

private

Member Function Documentation

getAverageVolume()

float Superpowered::BandpassFilterbank::getAverageVolume

(

)

Returns with the average volume of all audio passed to all previous process() or processNoAdd() calls.

getPeakVolume()

float Superpowered::BandpassFilterbank::getPeakVolume

(

)

Returns with the peak volume of all audio passed to all previous process() or processNoAdd() calls.

getSumVolume()

float Superpowered::BandpassFilterbank::getSumVolume

(

)

Returns with the cumulated absolute value of all audio passed to all previous process() or processNoAdd() calls. Like you would add the absolute value of all audio samples together.

operator=()

BandpassFilterbank& Superpowered::BandpassFilterbank::operator= ( const BandpassFilterbank &  )

private

process()

void Superpowered::BandpassFilterbank::process	(	float *	input,
		unsigned int	numberOfFrames,
		int	group = 0
	)

Processes the audio.

It will ADD to the current magnitude in bands (like bands[0] += 0.123), so you can "measure" the magnitude of each frequency for a longer period of time. To calculate a result between 0 and 1 for multiple consecutive process() calls, divide each value in bands with the total number of frames passed to the consecutive process() calls.

Parameters

input	32-bit interleaved stereo input buffer.
numberOfFrames	Number of frames to process.
group	The group index for advanced "grouped" usage.

processNoAdd()

void Superpowered::BandpassFilterbank::processNoAdd	(	float *	input,
		unsigned int	numberOfFrames,
		int	group = 0
	)

Processes the audio.

It will replace the contents of bands.

Parameters

input	32-bit interleaved stereo input buffer.
numberOfFrames	Number of frames to process.
group	The group index for advanced "grouped" usage.

resetBands()

void Superpowered::BandpassFilterbank::resetBands

(

)

Sets all values of bands to 0.

resetPeakVolume()

void Superpowered::BandpassFilterbank::resetPeakVolume

(

)

Resets the peak volume value to start measurement anew.

resetSumAndAverageVolume()

void Superpowered::BandpassFilterbank::resetSumAndAverageVolume

(

)

Resets the sum and average volume value to start measurement anew.

Member Data Documentation

bands

float* Superpowered::BandpassFilterbank::bands

The magnitude of the frequency bands. Will be updated after each process() or processNoAdd() call.

internals

bandpassFilterbankInternals* Superpowered::BandpassFilterbank::internals

private

samplerate

unsigned int Superpowered::BandpassFilterbank::samplerate

Sample rate in Hz.

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

• latest/Superpowered/SuperpoweredBandpassFilterbank.h