Namespace for audio signal handling and processing classes. More...

Classes
class	hilbert_fftw_t

class	spectrum_t
	a signal processing class for spectral data (based on mha_spec_t) More...

class	waveform_t
	signal processing class for waveform data (based on mha_wave_t) More...

class	doublebuffer_t
	Double-buffering class. More...

class	ringbuffer_t
	A ringbuffer class for time domain audio signal, which makes no assumptions with respect to fragment size. More...

class	hilbert_t
	Hilbert transformation of a waveform segment. More...

class	minphase_t
	Minimal phase function. More...

class	stat_t

class	delay_wave_t
	Delayline containing wave fragments. More...

class	delay_spec_t

class	async_rmslevel_t
	Class for asynchronous level metering. More...

class	uint_vector_t
	Vector of unsigned values, used for size and index description of n-dimensional matrixes. More...

class	matrix_t
	n-dimensional matrix with real or complex floating point values. More...

class	schroeder_t
	Schroeder tone complex class. More...

class	quantizer_t
	Simple simulation of fixpoint quantization. More...

class	loop_wavefragment_t
	Copy a fixed waveform fragment to a series of waveform fragments of other size. More...

class	delay_t
	Class to realize a simple delay of waveform streams. More...

class	subsample_delay_t
	implements subsample delay in spectral domain. More...

class	fft_t

Functions
void	for_each (mha_wave_t s, mha_real_t(fun)(mha_real_t))
	Apply a function to each element of a mha_wave_t. More...

mha_real_t	lin2db (mha_real_t x, mha_real_t eps)
	Conversion from linear scale to dB (no SPL reference) More...

mha_real_t	lin2db (mha_real_t x)
	Conversion from linear scale to dB (no SPL reference) More...

mha_real_t	db2lin (mha_real_t x)
	Conversion from dB scale to linear (no SPL reference) More...

mha_real_t	sq2db (mha_real_t x, mha_real_t eps=0.0f)
	conversion from squared values to dB (no SPL reference) More...

mha_real_t	db2sq (mha_real_t x)
	conversion from dB to squared values (no SPL reference) More...

mha_real_t	pa2dbspl (mha_real_t x, mha_real_t eps)
	Conversion from linear Pascal scale to dB SPL. More...

mha_real_t	pa2dbspl (mha_real_t x)
	Conversion from linear Pascal scale to dB SPL. More...

mha_real_t	dbspl2pa (mha_real_t x)
	Conversion from dB SPL to linear Pascal scale. More...

mha_real_t	pa22dbspl (mha_real_t x, mha_real_t eps=0.0f)
	Conversion from squared Pascal scale to dB SPL. More...

mha_real_t	dbspl2pa2 (mha_real_t x)
	conversion from dB SPL to squared Pascal scale More...

mha_real_t	smp2sec (mha_real_t n, mha_real_t srate)
	conversion from samples to seconds More...

mha_real_t	sec2smp (mha_real_t sec, mha_real_t srate)
	conversion from seconds to samples More...

mha_real_t	bin2freq (mha_real_t bin, unsigned fftlen, mha_real_t srate)
	conversion from fft bin index to frequency More...

mha_real_t	freq2bin (mha_real_t freq, unsigned fftlen, mha_real_t srate)
	conversion from frequency to fft bin index More...

mha_real_t	smp2rad (mha_real_t samples, unsigned bin, unsigned fftlen)
	conversion from delay in samples to phase shift More...

mha_real_t	rad2smp (mha_real_t phase_shift, unsigned bin, unsigned fftlen)
	conversion from phase shift to delay in samples More...

template<class elem_type >
std::vector< elem_type >	dupvec (std::vector< elem_type > vec, unsigned n)
	Duplicate last vector element to match desired size. More...

template<class elem_type >
std::vector< elem_type >	dupvec_chk (std::vector< elem_type > vec, unsigned n)
	Duplicate last vector element to match desired size, check for dimension. More...

void	copy_channel (mha_spec_t &self, const mha_spec_t &src, unsigned sch, unsigned dch)
	Copy one channel of a source signal. More...

void	copy_channel (mha_wave_t &self, const mha_wave_t &src, unsigned src_channel, unsigned dest_channel)
	Copy one channel of a source signal. More...

mha_real_t	rmslevel (const mha_spec_t &s, unsigned int channel, unsigned int fftlen)
	Return RMS level of a spectrum channel. More...

mha_real_t	colored_intensity (const mha_spec_t &s, unsigned int channel, unsigned int fftlen, mha_real_t *sqfreq_response=nullptr)
	Colored spectrum intensity. More...

mha_real_t	maxabs (const mha_spec_t &s, unsigned int channel)
	Find maximal absolute value. More...

mha_real_t	rmslevel (const mha_wave_t &s, unsigned int channel)
	Return RMS level of a waveform channel. More...

mha_real_t	maxabs (const mha_wave_t &s, unsigned int channel)
	Find maximal absolute value. More...

mha_real_t	maxabs (const mha_wave_t &s)
	Find maximal absolute value. More...

mha_real_t	max (const mha_wave_t &s)
	Find maximal value. More...

mha_real_t	min (const mha_wave_t &s)
	Find minimal value. More...

mha_real_t	sumsqr_channel (const mha_wave_t &s, unsigned int channel)
	Calculate sum of squared values in one channel. More...

mha_real_t	sumsqr_frame (const mha_wave_t &s, unsigned int frame)
	Calculate sum over all channels of squared values. More...

void	scale (mha_spec_t dest, const mha_wave_t src)

void	limit (mha_wave_t &s, const mha_real_t &min, const mha_real_t &max)
	Limit the singal in the waveform buffer to the range [min, max]. More...

template<class elem_type >
elem_type	kth_smallest (elem_type array[], unsigned n, unsigned k)
	Fast search for the kth smallest element of an array. More...

template<class elem_type >
elem_type	median (elem_type array[], unsigned n)
	Fast median search. More...

template<class elem_type >
elem_type	mean (const std::vector< elem_type > &data, elem_type start_val)
	Calculate average of elements in a vector. More...

template<class elem_type >
std::vector< elem_type >	quantile (std::vector< elem_type > data, const std::vector< elem_type > &p)
	Calculate quantile of elements in a vector. More...

void	saveas_mat4 (const mha_spec_t &data, const std::string &varname, FILE *fh)
	Save a openMHA spectrum as a variable in a Matlab4 file. More...

void	saveas_mat4 (const mha_wave_t &data, const std::string &varname, FILE *fh)
	Save a openMHA waveform as a variable in a Matlab4 file. More...

void	saveas_mat4 (const std::vector< mha_real_t > &data, const std::string &varname, FILE *fh)
	Save a float vector as a variable in a Matlab4 file. More...

void	copy_permuted (mha_wave_t dest, const mha_wave_t src)
	Copy contents of a waveform to a permuted waveform. More...

Variables
unsigned long int	signal_counter = 0
	Signal counter to produce signal ID strings. More...

Detailed Description

Namespace for audio signal handling and processing classes.

Function Documentation

◆ for_each()

void MHASignal::for_each	(	mha_wave_t *	s,
		mha_real_t(*)(mha_real_t)	fun
	)

inline

Apply a function to each element of a mha_wave_t.

Parameters

s	Pointer to a mha_wave_t structure
fun	Function to be applied (one argument)

◆ lin2db() [1/2]

mha_real_t MHASignal::lin2db	(	mha_real_t	x,
		mha_real_t	eps
	)

inline

Conversion from linear scale to dB (no SPL reference)

Parameters

x	Linear input
eps	minimum linear value (if x < eps --> convert eps instead), eps < 0 not allowed

Returns: NaN if x < 0 (log not defined for negative)

Exceptions

MHA_Error if eps < 0

◆ lin2db() [2/2]

mha_real_t MHASignal::lin2db ( mha_real_t x )

inline

Conversion from linear scale to dB (no SPL reference)

Parameters

x	Linear input.

Returns: NaN if x < 0 (log not defined for negative)

◆ db2lin()

mha_real_t MHASignal::db2lin ( mha_real_t x )

inline

Conversion from dB scale to linear (no SPL reference)

Parameters

x dB input.

◆ sq2db()

mha_real_t MHASignal::sq2db	(	mha_real_t	x,
		mha_real_t	eps = `0.0f`
	)

inline

conversion from squared values to dB (no SPL reference)

Parameters

x	squared value input
eps	minimum squared value (if x < eps --> convert eps instead), eps < 0 not allowed

Returns: NaN if x < 0 (log not defined for negative)

Exceptions

MHA_Error if eps < 0

◆ db2sq()

mha_real_t MHASignal::db2sq ( mha_real_t x )

inline

conversion from dB to squared values (no SPL reference)

Parameters

x dB input

◆ pa2dbspl() [1/2]

mha_real_t MHASignal::pa2dbspl	(	mha_real_t	x,
		mha_real_t	eps
	)

inline

Conversion from linear Pascal scale to dB SPL.

Parameters

x	Linear input
eps	minimum pascal value (if x < eps --> convert eps instead),

Precondition: eps >= 0

Returns: NaN if x < 0 (logarithm not defined for negative numbers)

Exceptions

MHA_Error if eps < 0

◆ pa2dbspl() [2/2]

mha_real_t MHASignal::pa2dbspl ( mha_real_t x )

inline

Conversion from linear Pascal scale to dB SPL.

Parameters

x	Linear input

Returns: NaN if x < 0 (log not defined for negative)

◆ dbspl2pa()

mha_real_t MHASignal::dbspl2pa ( mha_real_t x )

inline

Conversion from dB SPL to linear Pascal scale.

Parameters

x	Linear input.

◆ pa22dbspl()

mha_real_t MHASignal::pa22dbspl	(	mha_real_t	x,
		mha_real_t	eps = `0.0f`
	)

inline

Conversion from squared Pascal scale to dB SPL.

Parameters

x	squared pascal input
eps	minimum squared-pascal value (if x < eps --> convert eps instead), eps < 0 not allowed

Returns: NaN if x < 0 (log not defined for negative)

Exceptions

MHA_Error if eps < 0

◆ dbspl2pa2()

mha_real_t MHASignal::dbspl2pa2 ( mha_real_t x )

inline

conversion from dB SPL to squared Pascal scale

Parameters

x	dB SPL input

◆ smp2sec()

mha_real_t MHASignal::smp2sec	(	mha_real_t	n,
		mha_real_t	srate
	)

inline

conversion from samples to seconds

Parameters

n	number of samples
srate	sampling rate / Hz

◆ sec2smp()

mha_real_t MHASignal::sec2smp	(	mha_real_t	sec,
		mha_real_t	srate
	)

inline

conversion from seconds to samples

Parameters

sec	time in seconds
srate	sampling rate / Hz

Returns: number of samples, generally has non-zero fractional part

◆ scale()

void MHASignal::scale	(	mha_spec_t *	dest,
		const mha_wave_t *	src
	)

◆ limit()

void MHASignal::limit	(	mha_wave_t &	s,
		const mha_real_t &	min,
		const mha_real_t &	max
	)

Limit the singal in the waveform buffer to the range [min, max].

Parameters

s	The signal to limit. The signal in this wave buffer is modified.
min	lower limit
max	upper limit

◆ kth_smallest()

template<class elem_type >

elem_type MHASignal::kth_smallest	(	elem_type	array[],
		unsigned	n,
		unsigned	k
	)

Fast search for the kth smallest element of an array.

The order of elements is altered, but not completely sorted. Using the algorithm from N. Wirth, published in "Algorithms + data structures = programs", Prentice-Hall, 1976

Parameters

array Element array

Postcondition: The order of elements in the array is altered. array[k] then holds the result.

Parameters

n	number of elements in array

Precondition: n >= 1

Parameters

k	The k'th smalles element is returned: k = 0 returns the minimum, k = (n-1)/2 returns the median, k=(n-1) returns the maximum

Precondition: k < n

Returns: The kth smallest array element

◆ median()

template<class elem_type >

elem_type MHASignal::median	(	elem_type	array[],
		unsigned	n
	)

inline

Fast median search.

The order of elements is altered, but not completely sorted.

Parameters

array Element array

Postcondition: The order of elements in the array is altered. array[(n-1)/2] then holds the median.

Parameters

n	number of elements in array

Precondition: n >= 1

Returns: The median of the array elements

◆ mean()

template<class elem_type >

elem_type MHASignal::mean	(	const std::vector< elem_type > &	data,
		elem_type	start_val
	)

inline

Calculate average of elements in a vector.

Parameters

data	Input vector
start_val	Value for initialization of the return value before sum.

Returns: The average of the vector elements

◆ quantile()

template<class elem_type >

std::vector<elem_type> MHASignal::quantile	(	std::vector< elem_type >	data,
		const std::vector< elem_type > &	p
	)

inline

Calculate quantile of elements in a vector.

Parameters

data	Input vector
p	Vector of probability values.

Returns: Vector of quantiles of input data, one entry for each probability value.

◆ saveas_mat4() [1/3]

void MHASignal::saveas_mat4	(	const mha_spec_t &	data,
		const std::string &	varname,
		FILE *	fh
	)

Save a openMHA spectrum as a variable in a Matlab4 file.

Parameters

data	openMHA spectrum to be saved.
varname	Matlab variable name (Matlab4 limitations on maximal length are not checked).
fh	File handle to Matlab4 file.

◆ saveas_mat4() [2/3]

void MHASignal::saveas_mat4	(	const mha_wave_t &	data,
		const std::string &	varname,
		FILE *	fh
	)

Save a openMHA waveform as a variable in a Matlab4 file.

Parameters

data	openMHA waveform to be saved.
varname	Matlab variable name (Matlab4 limitations on maximal length are not checked).
fh	File handle to Matlab4 file.

◆ saveas_mat4() [3/3]

void MHASignal::saveas_mat4	(	const std::vector< mha_real_t > &	data,
		const std::string &	varname,
		FILE *	fh
	)

Save a float vector as a variable in a Matlab4 file.

Parameters

data	Float vector to be saved.
varname	Matlab variable name (Matlab4 limitations on maximal length are not checked).
fh	File handle to Matlab4 file.

◆ copy_permuted()

void MHASignal::copy_permuted	(	mha_wave_t *	dest,
		const mha_wave_t *	src
	)

Copy contents of a waveform to a permuted waveform.

Parameters

dest	Destination waveform
src	Source waveform

The total size of src and dest must be the same, num_frames and num_channels must be exchanged in dest.

Variable Documentation

◆ signal_counter

unsigned long int MHASignal::signal_counter = 0

extern

Signal counter to produce signal ID strings.

Classes

Functions

Variables

Detailed Description

Function Documentation

◆ for_each()

◆ lin2db() [1/2]

◆ lin2db() [2/2]

◆ db2lin()

◆ sq2db()

◆ db2sq()

◆ pa2dbspl() [1/2]

◆ pa2dbspl() [2/2]

◆ dbspl2pa()

◆ pa22dbspl()

◆ dbspl2pa2()

◆ smp2sec()

◆ sec2smp()

◆ scale()

◆ limit()

◆ kth_smallest()

◆ median()

◆ mean()

◆ quantile()

◆ saveas_mat4() [1/3]

◆ saveas_mat4() [2/3]

◆ saveas_mat4() [3/3]

◆ copy_permuted()

Variable Documentation

◆ signal_counter