scalar extraction functions

Functions
int	xtract_mean (const float *data, const int N, const void *argv, float *result)
	Extract the mean of an input vector.
int	xtract_variance (const float *data, const int N, const void *argv, float *result)
	Extract the variance of an input vector.
int	xtract_standard_deviation (const float *data, const int N, const void *argv, float *result)
	Extract the deviation of an input vector.
int	xtract_average_deviation (const float *data, const int N, const void *argv, float *result)
	Extract the average deviation of an input vector.
int	xtract_skewness (const float *data, const int N, const void *argv, float *result)
	Extract the skewness of an input vector.
int	xtract_kurtosis (const float *data, const int N, const void *argv, float *result)
	Extract the kurtosis of an input vector.
int	xtract_spectral_mean (const float *data, const int N, const void *argv, float *result)
	Extract the mean of an input spectrum.
int	xtract_spectral_variance (const float *data, const int N, const void *argv, float *result)
	Extract the variance of an input spectrum.
int	xtract_spectral_standard_deviation (const float *data, const int N, const void *argv, float *result)
	Extract the deviation of an input spectrum.
int	xtract_spectral_average_deviation (const float *data, const int N, const void *argv, float *result)
	Extract the average deviation of an input spectrum.
int	xtract_spectral_skewness (const float *data, const int N, const void *argv, float *result)
	Extract the skewness of an input spectrum.
int	xtract_spectral_kurtosis (const float *data, const int N, const void *argv, float *result)
	Extract the kurtosis of an input spectrum.
int	xtract_spectral_centroid (const float *data, const int N, const void *argv, float *result)
	Extract the centroid of an input vector.
int	xtract_irregularity_k (const float *data, const int N, const void *argv, float *result)
	Calculate the Irregularity of an input vector using a method described by Krimphoff (1994).
int	xtract_irregularity_j (const float *data, const int N, const void *argv, float *result)
	Calculate the Irregularity of an input vector using a method described by Jensen (1999).
int	xtract_tristimulus_1 (const float *data, const int N, const void *argv, float *result)
	Calculate the Tristimulus of an input vector using a method described by Pollard and Jansson (1982).
int	xtract_tristimulus_2 (const float *data, const int N, const void *argv, float *result)
int	xtract_tristimulus_3 (const float *data, const int N, const void *argv, float *result)
int	xtract_smoothness (const float *data, const int N, const void *argv, float *result)
	Extract the smoothness of an input vector using a method described by McAdams (1999).
int	xtract_spread (const float *data, const int N, const void *argv, float *result)
	Extract the spectral spread of an input vector using a method described by Casagrande(2005).
int	xtract_zcr (const float *data, const int N, const void *argv, float *result)
	Extract the zero crossing rate of an input vector.
int	xtract_rolloff (const float *data, const int N, const void *argv, float *result)
	Extract the spectral rolloff of an input vector using a method described by Bee Suan Ong (2005).
int	xtract_loudness (const float *data, const int N, const void *argv, float *result)
	Extract the 'total loudness' of an input vector using a method described by Moore, Glasberg et al (2005).
int	xtract_flatness (const float *data, const int N, const void *argv, float *result)
	Extract the spectral flatness measure of an input vector using a method described by Tristan Jehan (2005).
int	xtract_tonality (const float *data, const int N, const void *argv, float *result)
	Extract the tonality factor of an input vector using a method described by Tristan Jehan (2005).
int	xtract_noisiness (const float *data, const int N, const void *argv, float *result)
	Extract the noisiness of an input vector using a method described by Tae Hong Park (2000).
int	xtract_rms_amplitude (const float *data, const int N, const void *argv, float *result)
	Extract the RMS amplitude of an input vector using a method described by Tae Hong Park (2000).
int	xtract_spectral_inharmonicity (const float *data, const int N, const void *argv, float *result)
	Extract the Inharmonicity of an input vector.
int	xtract_crest (const float *data, const int N, const void *argv, float *result)
	Extract the spectral crest of an input vector using a method described by Peeters (2003).
int	xtract_power (const float *data, const int N, const void *argv, float *result)
	Extract the Spectral Power of an input vector using a method described by Bee Suan Ong (2005).
int	xtract_odd_even_ratio (const float *data, const int N, const void *argv, float *result)
	Extract the Odd to even harmonic ratio of an input vector.
int	xtract_sharpness (const float *data, const int N, const void *argv, float *result)
	Extract the Sharpness of an input vector.
int	xtract_spectral_slope (const float *data, const int N, const void *argv, float *result)
	Extract the Slope of an input vector using a method described by Peeters(2003).
int	xtract_lowest_value (const float *data, const int N, const void *argv, float *result)
	Extract the value of the lowest value in an input vector.
int	xtract_highest_value (const float *data, const int N, const void *argv, float *result)
	Extract the value of the highest value in an input vector.
int	xtract_sum (const float *data, const int N, const void *argv, float *result)
	Extract the sum of the values in an input vector.
int	xtract_hps (const float *data, const int N, const void *argv, float *result)
	Extract the Pitch of an input vector using Harmonic Product Spectrum (HPS) analysis.
int	xtract_f0 (const float *data, const int N, const void *argv, float *result)
	Extract the fundamental frequency of an input vector.
int	xtract_failsafe_f0 (const float *data, const int N, const void *argv, float *result)
	Extract the fundamental frequency of an input vector.
int	xtract_nonzero_count (const float *data, const int N, const void *argv, float *result)
	Extract the number of non-zero elements in an input vector.

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Detailed Description

Defines scalar extraction functions, and their parameters.

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Function Documentation

int xtract_average_deviation	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the average deviation of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the mean of the input vector
	*result,:	the average deviation of N values from the array pointed to by *data

int xtract_crest	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the spectral crest of an input vector using a method described by Peeters (2003).

Parameters:

	*data,:	a pointer to NULL
	N,:	not used
	*argv,:	a pointer to an array containing a float representing the maximum value in a spectrum, and a float representing the mean value of a spectrum
	*result,:	the spectral crest of N values from the array pointed to by *data

int xtract_f0	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the fundamental frequency of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing an audio vector
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the audio sample rate
	*result,:	the pitch of N values from the array pointed to by *data

This algorithm is based on the AMDF, with peak and centre clipping. It would benefit from further improvements to improve noise robustness and overall efficiency

int xtract_failsafe_f0	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the fundamental frequency of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing an audio vector
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the audio sample rate
	*result,:	the pitch of N values from the array pointed to by *data

This function wraps xtract_f0, but provides the frequency of the lowest partial in the peak spectrum if f0 can't be found.

int xtract_flatness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the spectral flatness measure of an input vector using a method described by Tristan Jehan (2005).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the spectral flatness of N values from the array pointed to by *data

int xtract_highest_value	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the value of the highest value in an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL.
	*result,:	a pointer to a value representing the highest component in *data.

int xtract_hps	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the Pitch of an input vector using Harmonic Product Spectrum (HPS) analysis.

Warning:

{This function doesn't work properly}

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the pitch of N values from the array pointed to by *data

int xtract_irregularity_j	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Calculate the Irregularity of an input vector using a method described by Jensen (1999).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the irregularity of N values from the array pointed to by *data

int xtract_irregularity_k	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Calculate the Irregularity of an input vector using a method described by Krimphoff (1994).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the irregularity of N values from the array pointed to by *data

int xtract_kurtosis	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the kurtosis of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to an array of values representing the mean and standard deviation of the input vector
	*result,:	the kurtosis of N values from the array pointed to by *data

int xtract_loudness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the 'total loudness' of an input vector using a method described by Moore, Glasberg et al (2005).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing a set of BARK_BANDS bark coefficients
	N,:	the number of coefficients to be considered
	*argv,:	a pointer to NULL
	*result,:	the total loudness of N values from the array pointed to by *data

Note: if N = 1, the 'specific loudness' of the bark band pointed to by *data will be given by *result

int xtract_lowest_value	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the value of the lowest value in an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the lower limit for the search. i.e. (*result > *argv) returns 1.
	*result,:	a pointer to a value representing the lowest component in *data that falls above a given threshold.

int xtract_mean	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the mean of an input vector.

Parameters:

	*data,:	a pointer to the first element
	N,:	the number of array elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the mean of N values from the array pointed to by *data

int xtract_noisiness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the noisiness of an input vector using a method described by Tae Hong Park (2000).

Parameters:

	*data,:	a pointer to NULL
	N,:
	*argv,:	a pointer to an array containing a float represnting the number of harmonic partials in a spectrum, and a float representing the number of partials in a spectrum
	*result,:	the noisiness coefficient as calculated from argv

int xtract_nonzero_count	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the number of non-zero elements in an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	not used
	*result,:	the number of non-zero elements in the array pointed to by *data

int xtract_odd_even_ratio	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the Odd to even harmonic ratio of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the amplitudes of the harmonic spectrum of an audio vector. It is sufficient to pass in a pointer to the first half of the array pointed to by *result from xtract_harmonic_spectrum().
	N,:	the number of elements to be considered. If using the array pointed to by *result from xtract_harmonics, N should equal half the total array size i.e., just the amplitudes of the peaks.
	*argv,:	a pointer to NULL
	*result,:	the odd/even harmonic ratio of N values from the array pointed to by *data

int xtract_power	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the Spectral Power of an input vector using a method described by Bee Suan Ong (2005).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the spectral power of N values from the array pointed to by *data

int xtract_rms_amplitude	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the RMS amplitude of an input vector using a method described by Tae Hong Park (2000).

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the RMS amplitude of N values from the array pointed to by *data

int xtract_rolloff	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the spectral rolloff of an input vector using a method described by Bee Suan Ong (2005).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to an array containing a float representing (samplerate / N ) and a float representing the threshold for rolloff, i.e. the percentile at which the rolloff is determined, expressed as a percentage, and
	*result,:	the spectral rolloff in Hz of N values from the array pointed to by *data. This is the point in the spectrum below which argv[0] of the energy is distributed.

int xtract_sharpness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the Sharpness of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the Sharpness of N values from the array pointed to by *data

int xtract_skewness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the skewness of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to an array of floats representing the mean and standard deviation of the input vector
	*result,:	the skewness of N values from the array pointed to by *data

int xtract_smoothness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the smoothness of an input vector using a method described by McAdams (1999).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to the first element of an array of integers containing the lower bound, upper bound, and pre-scaling factor, whereby array data in the range lower < n < upper will be pre-scaled by p before processing.
	*result,:	the smoothness of N values from the array pointed to by *data

int xtract_spectral_average_deviation	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the average deviation of an input spectrum.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the size of the array pointed to by *data
	*argv,:	a pointer to a float representing the spectral mean of the input spectrum
	*result,:	the average deviation of the spectrum pointed to by *data

int xtract_spectral_centroid	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the centroid of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the centroid of the values pointed to by *data

Note: for a more 'accurate' result *result from xtract_spectral_peaks() can be passed in. This gives the interpolated peak frequency locations.

int xtract_spectral_inharmonicity	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the Inharmonicity of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats represeting a magnitude peak spectrum of size N/2, and a frequency spectrum of size N/2 (This is the output format of xtract_spectral_peaks())
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the fundamental frequency of the input vector.
	*result,:	the inharmonicity of N values from the array pointed to by *data

int xtract_spectral_kurtosis	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the kurtosis of an input spectrum.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the size of the array pointed to by *data
	*argv,:	a pointer to an array of values representing the spectral mean and spectral standard deviation of the input spectrum
	*result,:	the kurtosis of the spectrum pointed to by *data

int xtract_spectral_mean	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the mean of an input spectrum.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the size of the array pointed to by *data
	*argv,:	a pointer to NULL
	*result,:	the mean of the spectrum pointed to by *data

int xtract_spectral_skewness	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the skewness of an input spectrum.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the size of the array pointed to by *data
	*argv,:	a pointer to an array of floats representing the spectral mean and spectral standard deviation of the input spectrum
	*result,:	the skewness of the spectrum pointed to by *data

int xtract_spectral_slope	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the Slope of an input vector using a method described by Peeters(2003).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the Slope of N values from the array pointed to by *data

int xtract_spectral_standard_deviation	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the deviation of an input spectrum.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the size of the array pointed to by *data
	*argv,:	a pointer to a float representing the spectral variance of the input spectrum
	*result,:	the deviation of the spectrum pointed to by *data

int xtract_spectral_variance	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the variance of an input spectrum.

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the spectrum of an audio vector, (e.g. the array pointed to by *result from xtract_magnitude_spectrum(), xtract_spectral_peaks() or xtract_spectral_harmonics()).
	N,:	the number of elements to be considered
	N,:	the size of the array pointed to by *data
	*argv,:	a pointer to a float representing the spectral mean of the input spectrum
	*result,:	the variance of the spectrum pointed to by *data

int xtract_spread	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the spectral spread of an input vector using a method described by Casagrande(2005).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients from the spectrum of an audio vector, (e.g. the first half of the array pointed to by *result from xtract_spectrum().
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the spectral spread of N values from the array pointed to by *data

int xtract_standard_deviation	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the deviation of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the variance of the input vector
	*result,:	the deviation of N values from the array pointed to by *data

int xtract_sum	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the sum of the values in an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL.
	*result,:	a pointer to a value representing the sum of all of the values pointed to by *data.

int xtract_tonality	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the tonality factor of an input vector using a method described by Tristan Jehan (2005).

Parameters:

	*data,:	not used.
	N,:	not used
	*argv,:	a pointer to the spectral flatness measure of an audio vector (e.g. the output from xtract_flatness)
	*result,:	the tonality factor of N values from the array pointed to by *data

int xtract_tristimulus_1	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Calculate the Tristimulus of an input vector using a method described by Pollard and Jansson (1982).

Parameters:

	*data,:	a pointer to the first element in an array of floats representing the magnitude coefficients of the harmonic spectrum of an audio vector e.g. a pointer to the first half of the array pointed to by *result from xtract_harmonics(). The amplitudes of the peak spectrum (e.g. *result from xtract_spectral_peaks()) can be used if one wishes to consider all partials not just harmonics.
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the tristimulus of N values from the array pointed to by *data

These three functions provide the first, second and third order tristimulus formulae

int xtract_tristimulus_2	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

int xtract_tristimulus_3	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

int xtract_variance	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the variance of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to a float representing the mean of the input vector
	*result,:	the variance of N values from the array pointed to by *data

int xtract_zcr	(	const float *	data,
		const int	N,
		const void *	argv,
		float *	result
	)

Extract the zero crossing rate of an input vector.

Parameters:

	*data,:	a pointer to the first element in an array of floats
	N,:	the number of elements to be considered
	*argv,:	a pointer to NULL
	*result,:	the zero crossing rate of N values from the array pointed to by *data

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