Spectrum Class Reference

Frequency-domain representation of a multi-channel audio signal. More...

#include <hart_spectrum.hpp>

Public Member Functions
template<typename SampleType >
	Spectrum (const AudioBuffer< SampleType > &buffer)
	Constructs spectrum from an audio buffer.
size_t	getNumChannels () const
	Returns number of channels.
size_t	getNumBins () const
	Returns number of frequency bins per channel.
size_t	getFFTSize () const
	Returns FFT size.
double	getSampleRateHz () const
	Returns sample rate in Hz.
double	getBinFrequencyHz (size_t binIndex) const
	Returns frequency corresponding to a bin index.
double	getBinWidthHz () const
std::complex< double >	getBinValue (size_t channel, size_t binIndex) const
	Returns complex value of a frequency bin, by bin index.
std::complex< double >	getBinValue (size_t channel, double frequencyHz) const
	Returns complex value of a frequency bin, by frequency.
double	getBinMagnitude (size_t channel, size_t binIndex) const
	Returns magnitude of a frequency bin, by bin index.
double	getBinMagnitude (size_t channel, double frequencyHz) const
	Returns magnitude of a frequency bin, by frequency.
const std::complex< double > *	operator[] (size_t channel) const
	Returns pointer to read-only magnitudes of a specific channel.
std::complex< double > *	operator[] (size_t channel)
	Returns pointer to mutable magnitudes of a specific channel.
size_t	findClosestBin (double frequencyHz) const
	Finds closest FFT bin to a given frequency.
std::pair< size_t, size_t >	getBinIndices (const Slice &slice) const
	Returns a pair of indices representing a provided slice.

Static Public Member Functions
static Spectrum	zeros (size_t numChannels, size_t signalDurationFrames, double sampleRateHz)

Detailed Description

Frequency-domain representation of a multi-channel audio signal.

Stores complex spectra for each channel independently. Spectrum is constructed by performing FFT on the entire signal, zero-padding to the next power-of-two size if necessary.

Current implementation assumptions:

• Rectangular window (no windowing)
• Real-valued input signal
• One-sided spectrum only (fftSize / 2 + 1 bins)
• Double floating-point precision, regardless of input signal value types

Definition at line 29 of file hart_spectrum.hpp.

Constructor & Destructor Documentation

Spectrum()

template<typename SampleType >

Spectrum ( const AudioBuffer< SampleType > &  buffer )

inline

Constructs spectrum from an audio buffer.

Parameters

buffer

Audio buffer to perform FFT on

Exceptions

hart::SampleRateError

if the audio buffer has no sample rate metadata

Definition at line 36 of file hart_spectrum.hpp.

Member Function Documentation

zeros()

static Spectrum zeros ( size_t  numChannels, size_t  signalDurationFrames, double  sampleRateHz  )

inlinestatic

Definition at line 69 of file hart_spectrum.hpp.

getNumChannels()

size_t getNumChannels ( ) const

inline

Returns number of channels.

Definition at line 100 of file hart_spectrum.hpp.

getNumBins()

size_t getNumBins ( ) const

inline

Returns number of frequency bins per channel.

Definition at line 106 of file hart_spectrum.hpp.

getFFTSize()

size_t getFFTSize ( ) const

inline

Returns FFT size.

Definition at line 112 of file hart_spectrum.hpp.

getSampleRateHz()

double getSampleRateHz ( ) const

inline

Returns sample rate in Hz.

Definition at line 118 of file hart_spectrum.hpp.

getBinFrequencyHz()

double getBinFrequencyHz ( size_t  binIndex ) const

inline

Returns frequency corresponding to a bin index.

Definition at line 124 of file hart_spectrum.hpp.

getBinWidthHz()

double getBinWidthHz ( ) const

inline

Definition at line 132 of file hart_spectrum.hpp.

getBinValue() [1/2]

std::complex< double > getBinValue ( size_t  channel, size_t  binIndex  ) const

inline

Returns complex value of a frequency bin, by bin index.

Definition at line 138 of file hart_spectrum.hpp.

getBinValue() [2/2]

std::complex< double > getBinValue ( size_t  channel, double  frequencyHz  ) const

inline

Returns complex value of a frequency bin, by frequency.

Definition at line 150 of file hart_spectrum.hpp.

getBinMagnitude() [1/2]

double getBinMagnitude ( size_t  channel, size_t  binIndex  ) const

inline

Returns magnitude of a frequency bin, by bin index.

Definition at line 156 of file hart_spectrum.hpp.

getBinMagnitude() [2/2]

double getBinMagnitude ( size_t  channel, double  frequencyHz  ) const

inline

Returns magnitude of a frequency bin, by frequency.

Definition at line 162 of file hart_spectrum.hpp.

operator[]() [1/2]

const std::complex< double > * operator[] ( size_t  channel ) const

inline

Returns pointer to read-only magnitudes of a specific channel.

Definition at line 168 of file hart_spectrum.hpp.

operator[]() [2/2]

std::complex< double > * operator[] ( size_t  channel )

inline

Returns pointer to mutable magnitudes of a specific channel.

Definition at line 177 of file hart_spectrum.hpp.

findClosestBin()

size_t findClosestBin ( double  frequencyHz ) const

inline

Finds closest FFT bin to a given frequency.

Definition at line 186 of file hart_spectrum.hpp.

getBinIndices()

std::pair< size_t, size_t > getBinIndices ( const Slice &  slice ) const

inline

Returns a pair of indices representing a provided slice.

Parameters

slice

A Slice instance. Valid slice types are Slice::Type::whole Slice::Type::bins and Slice::Type::freq

Return values

first	Index representing the beginning of the range, inclusive
second	Index representing the end of the range, non-inclusive

Definition at line 200 of file hart_spectrum.hpp.

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

• include/hart_spectrum.hpp