fl::audio::detector::MusicalBeat Class Reference

Detailed Description

MusicalBeat distinguishes true musical beats from random onset detection.

This class improves upon basic spectral flux onset detection by:

1. Tracking inter-beat intervals (IBI) to detect rhythmic patterns
2. Estimating BPM and validating beat candidates against the detected tempo
3. Applying confidence scoring based on tempo consistency
4. Rejecting random onsets that don't fit the detected tempo

Key insight: Basic onset detection triggers on ANY spectral change, not just musical beats. This detector uses temporal pattern recognition to distinguish true beats from random noise bursts or non-rhythmic transients.

Usage:

MusicalBeat detector;
MusicalBeatDetectorConfig config;
config.minBPM = 60.0f;
config.maxBPM = 180.0f;
detector.configure(config);
 
// Each audio frame:
bool onsetDetected = ... // From SpectralFluxDetector
float onsetStrength = ... // Onset magnitude
detector.processSample(onsetDetected, onsetStrength);
 
if (detector.isBeat()) {
    float bpm = detector.getBPM();
    float confidence = detector.getBeatConfidence();
    // Trigger beat-synchronized effect
}

Definition at line 70 of file musical_beat_detector.h.

#include <musical_beat_detector.h>

Collaboration diagram for fl::audio::detector::MusicalBeat:

Classes
struct	Stats
	Get statistics (for debugging/monitoring) More...

Public Member Functions
	MusicalBeat () FL_NOEXCEPT
	MusicalBeat (const MusicalBeatDetectorConfig &config)
	~MusicalBeat () FL_NOEXCEPT
void	configure (const MusicalBeatDetectorConfig &config)
	Configure the beat detector.
float	getAverageIBI () const
	Get inter-beat interval (IBI) statistics.
float	getBeatConfidence () const
	Get beat confidence for the last detected beat.
float	getBPM () const
	Get current BPM estimate.
const Stats &	getStats () const
bool	isBeat () const
	Check if a musical beat was detected in the last frame.
void	processSample (bool onsetDetected, float onsetStrength)
	Process one audio frame.
void	reset ()
	Reset internal state (clear history, reset BPM)

Private Member Functions
float	calculateBeatConfidence (float currentIBI)
	Calculate beat confidence based on rhythmic consistency.
float	calculateIBIStdDev () const
	Calculate standard deviation of IBI history.
bool	isValidIBI (float ibi) const
	Check if IBI is within valid BPM range.
void	updateBPMEstimate ()
	Update BPM estimate from inter-beat intervals.
bool	validateBeat (float onsetStrength)
	Validate if an onset is a true musical beat.

Private Attributes
float	mAverageIBI = 0.0f
	Average inter-beat interval (in frames)
bool	mBeatDetected = false
	Last beat was detected.
MusicalBeatDetectorConfig	mConfig
float	mCurrentBPM = 120.0f
	Current BPM estimate (smoothed)
u32	mCurrentFrame = 0
	Current frame counter.
deque< u32 >	mIBIHistory
	Inter-beat interval history (in frames)
float	mLastBeatConfidence = 0.0f
	Last beat confidence score.
u32	mLastBeatFrame = 0
	Last beat timestamp (in frames)
Stats	mStats

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

• fl/audio/detector/musical_beat_detector.h
• fl/audio/detector/musical_beat_detector.cpp.hpp