Detailed Description

Pitch - Continuous pitch tracking using autocorrelation.

Detects the fundamental frequency (pitch) of audio signals using autocorrelation analysis on the time-domain PCM data. This detector provides continuous pitch tracking with configurable confidence thresholds, smoothing, and stability.

Key Features:

Autocorrelation-based pitch detection (time-domain analysis)
Configurable pitch range (default: 80-1000 Hz)
Confidence-based filtering to reject unreliable detections
Exponential smoothing for stable pitch output
Pitch change detection with configurable sensitivity
Support for both voiced (pitched) and unvoiced (unpitched) audio

Performance:

No FFT required (uses raw PCM data)
Update time: ~0.2-0.5ms per frame
Memory: ~100 bytes + autocorrelation buffer (~2KB for 512 samples)

Definition at line 33 of file pitch.h.

#include <pitch.h>

Inheritance diagram for fl::audio::detector::Pitch:

Collaboration diagram for fl::audio::detector::Pitch:

Public Types
using	PitchCallback = void(*)(float pitch)

using	PitchConfidenceCallback = void(*)(float pitch, float confidence)

using	VoicedCallback = void(*)(u8 isVoiced)

Public Member Functions
	Pitch () FL_NOEXCEPT

	Pitch () FL_NOEXCEPT

	~Pitch () FL_NOEXCEPT

	~Pitch () FL_NOEXCEPT override

void	fireCallbacks () override

float	getConfidence () const

float	getConfidence () const

const char *	getName () const override

float	getPitch () const

float	getPitch () const

float	getSmoothedPitch () const

bool	isVoiced () const

bool	isVoiced () const

bool	needsFFT () const override

void	reset ()

void	reset () override

void	setConfidenceThreshold (float threshold)

void	setConfidenceThreshold (float threshold)

void	setMaxFrequency (float hz)

void	setMaxFrequency (float hz)

void	setMinFrequency (float hz)

void	setMinFrequency (float hz)

void	setPitchChangeSensitivity (float sensitivity)

void	setPitchChangeSensitivity (float sensitivity)

void	setSampleRate (float rate)

void	setSmoothingFactor (float factor)

void	setSmoothingFactor (float)

void	update (shared_ptr< Context > context)

void	update (shared_ptr< Context > context) override

Public Member Functions inherited from fl::audio::Detector
virtual	~Detector () FL_NOEXCEPT=default

virtual bool	needsFFTHistory () const FL_NOEXCEPT

virtual void	setSampleRate (int) FL_NOEXCEPT

Public Attributes
function_list< void(float hz)>	onPitch

PitchCallback	onPitch = nullptr

function_list< void(float hz)>	onPitchChange

PitchCallback	onPitchChange = nullptr

function_list< void(float hz, float confidence)>	onPitchWithConfidence

PitchConfidenceCallback	onPitchWithConfidence = nullptr

function_list< void(u8 voiced)>	onVoiced

VoicedCallback	onVoiced = nullptr

Private Member Functions
float	calculateAutocorrelation (const i16 *pcm, size numSamples)

float	calculateAutocorrelation (const i16 *pcm, size numSamples)

float	calculateConfidence (const fl::vector< float > &autocorr, int peakLag) const

float	calculateConfidence (const vector< float > &autocorr, int peakLag) const

int	findBestPeakLag (const fl::vector< float > &autocorr) const

int	findBestPeakLag (const vector< float > &autocorr) const

int	frequencyToPeriod (float frequency) const

int	frequencyToPeriod (float frequency) const

float	periodToFrequency (int period) const

float	periodToFrequency (int period) const

bool	shouldReportPitchChange (float newPitch) const

bool	shouldReportPitchChange (float newPitch) const

void	updatePeriodRange ()

void	updatePeriodRange ()

void	updatePitchSmoothing (float newPitch)

void	updatePitchSmoothing (float newPitch)

Private Attributes
vector< float >	mAutocorrelation

fl::vector< float >	mAutocorrelation

float	mConfidence

float	mConfidenceThreshold

float	mCurrentPitch

bool	mFirePitch = false

bool	mFirePitchChange = false

bool	mIsVoiced

float	mLastDt = 0.023f

float	mMaxFrequency

int	mMaxPeriod

float	mMinFrequency

int	mMinPeriod

float	mPitchChangeSensitivity

OneEuroFilter< float >	mPitchSmoother {1.0f, 0.5f}

float	mPreviousPitch

bool	mPreviousVoiced

float	mSampleRate

float	mSmoothedPitch

float	mSmoothingFactor

bool	mVoicedStateChanged = false

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

fl/audio/detector/pitch.h
fl/audio/detector/pitch_detector.h
fl/audio/detector/pitch.cpp.hpp

Detailed Description

Public Types

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes