pitch.h File Reference

Pitch detection object. More...

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Typedefs
typedef struct _aubio_pitch_t	aubio_pitch_t
	pitch detection object

Functions
void	aubio_pitch_do (aubio_pitch_t *o, const fvec_t *in, fvec_t *out)
	execute pitch detection on an input signal frame
uint_t	aubio_pitch_set_tolerance (aubio_pitch_t *o, smpl_t tol)
	change yin or yinfft tolerance threshold
smpl_t	aubio_pitch_get_tolerance (aubio_pitch_t *o)
	get yin or yinfft tolerance threshold
void	del_aubio_pitch (aubio_pitch_t *o)
	deletion of the pitch detection object
aubio_pitch_t *	new_aubio_pitch (const char_t *method, uint_t buf_size, uint_t hop_size, uint_t samplerate)
	creation of the pitch detection object
uint_t	aubio_pitch_set_unit (aubio_pitch_t *o, const char_t *mode)
	set the output unit of the pitch detection object
uint_t	aubio_pitch_set_silence (aubio_pitch_t *o, smpl_t silence)
	set the silence threshold of the pitch detection object
smpl_t	aubio_pitch_get_silence (aubio_pitch_t *o)
	set the silence threshold of the pitch detection object
smpl_t	aubio_pitch_get_confidence (aubio_pitch_t *o)
	get the current confidence

Detailed Description

Pitch detection object.

This file creates the objects required for the computation of the selected pitch detection algorithm and output the results, in midi note or Hz.

Pitch detection methods

A list of the pitch detection methods currently available follows.

default : use the default method

Currently, the default method is set to yinfft .

schmitt : Schmitt trigger

This pitch extraction method implements a Schmitt trigger to estimate the period of a signal.

This file was derived from the tuneit project, written by Mario Lang to detect the fundamental frequency of a sound.

See http://delysid.org/tuneit.html

fcomb : a fast harmonic comb filter

This pitch extraction method implements a fast harmonic comb filter to determine the fundamental frequency of a harmonic sound.

This file was derived from the tuneit project, written by Mario Lang to detect the fundamental frequency of a sound.

See http://delysid.org/tuneit.html

mcomb : multiple-comb filter

This fundamental frequency estimation algorithm implements spectral flattening, multi-comb filtering and peak histogramming.

This method was designed by Juan P. Bello and described in:

Juan-Pablo Bello. `‘Towards the Automated Analysis of Simple Polyphonic Music’'. PhD thesis, Centre for Digital Music, Queen Mary University of London, London, UK, 2003.

yin : YIN algorithm

This algorithm was developed by A. de Cheveigne and H. Kawahara and published in:

De Cheveigné, A., Kawahara, H. (2002) "YIN, a fundamental frequency estimator for speech and music", J. Acoust. Soc. Am. 111, 1917-1930.

see http://recherche.ircam.fr/equipes/pcm/pub/people/cheveign.html

yinfast : Yinfast algorithm

This algorithm is equivalent to the YIN algorithm, but computed in the spectral domain for efficiency. See also python/demos/demo_yin_compare.py.

yinfft : Yinfft algorithm

This algorithm was derived from the YIN algorithm. In this implementation, a Fourier transform is used to compute a tapered square difference function, which allows spectral weighting. Because the difference function is tapered, the selection of the period is simplified.

Paul Brossier, Automatic annotation of musical audio for interactive systems, Chapter 3, Pitch Analysis, PhD thesis, Centre for Digital music, Queen Mary University of London, London, UK, 2006.

Definition in file pitch.h.

Typedef Documentation

aubio_pitch_t

typedef struct _aubio_pitch_t aubio_pitch_t

pitch detection object

Definition at line 106 of file pitch.h.

Function Documentation

aubio_pitch_do()

void aubio_pitch_do	(	aubio_pitch_t *	o,
		const fvec_t *	in,
		fvec_t *	out )

execute pitch detection on an input signal frame

Parameters

o	pitch detection object as returned by new_aubio_pitch()
in	input signal of size [hop_size]
out	output pitch candidates of size [1]

Examples

examples/aubiopitch.c, and pitch/test-pitch.c.

aubio_pitch_get_confidence()

smpl_t aubio_pitch_get_confidence

(

aubio_pitch_t *

o

)

get the current confidence

Parameters

o	pitch detection object as returned by new_aubio_pitch()

Returns

the current confidence of the pitch algorithm

aubio_pitch_get_silence()

smpl_t aubio_pitch_get_silence

(

aubio_pitch_t *

o

)

set the silence threshold of the pitch detection object

Parameters

o	pitch detection object as returned by new_aubio_pitch()

Returns

level threshold under which pitch should be ignored, in dB

aubio_pitch_get_tolerance()

smpl_t aubio_pitch_get_tolerance

(

aubio_pitch_t *

o

)

get yin or yinfft tolerance threshold

Parameters

o	pitch detection object as returned by new_aubio_pitch()

Returns

tolerance (default is 0.15 for yin and 0.85 for yinfft)

aubio_pitch_set_silence()

uint_t aubio_pitch_set_silence	(	aubio_pitch_t *	o,
		smpl_t	silence )

set the silence threshold of the pitch detection object

Parameters

o	pitch detection object as returned by new_aubio_pitch()
silence	level threshold under which pitch should be ignored, in dB

Returns

0 if successfull, non-zero otherwise

Examples

examples/aubiopitch.c, and pitch/test-pitch.c.

aubio_pitch_set_tolerance()

uint_t aubio_pitch_set_tolerance	(	aubio_pitch_t *	o,
		smpl_t	tol )

change yin or yinfft tolerance threshold

Parameters

o	pitch detection object as returned by new_aubio_pitch()
tol	tolerance default is 0.15 for yin and 0.85 for yinfft

Examples

examples/aubiopitch.c, and pitch/test-pitch.c.

aubio_pitch_set_unit()

uint_t aubio_pitch_set_unit	(	aubio_pitch_t *	o,
		const char_t *	mode )

set the output unit of the pitch detection object

Parameters

o	pitch detection object as returned by new_aubio_pitch()
mode	set pitch units for output

mode can be one of "Hz", "midi", "cent", or "bin". Defaults to "Hz".

Returns

0 if successfull, non-zero otherwise

Examples

examples/aubiopitch.c, and pitch/test-pitch.c.

del_aubio_pitch()

void del_aubio_pitch

(

aubio_pitch_t *

o

)

deletion of the pitch detection object

Parameters

o	pitch detection object as returned by new_aubio_pitch()

Examples

examples/aubiopitch.c, and pitch/test-pitch.c.

new_aubio_pitch()

aubio_pitch_t * new_aubio_pitch	(	const char_t *	method,
		uint_t	buf_size,
		uint_t	hop_size,
		uint_t	samplerate )

creation of the pitch detection object

Parameters

method	set pitch detection algorithm
buf_size	size of the input buffer to analyse
hop_size	step size between two consecutive analysis instant
samplerate	sampling rate of the signal

Returns

newly created aubio_pitch_t

Examples

examples/aubiopitch.c, and pitch/test-pitch.c.