fl::audio::detector::MultiBandBeat Class Reference

Detailed Description

MultiBandBeat performs frequency-specific beat detection.

This class separates beat detection into three frequency bands:

• Bass (bins 0-1): 20-80 Hz - kick drums, bass guitar
• Mid (bins 6-7): 320-640 Hz - snares, vocals, guitars
• Treble (bins 14-15): 5120-16000 Hz - hi-hats, cymbals

Features:

1. Per-band energy tracking and threshold adaptation
2. Independent beat detection for each frequency range
3. Cross-band beat correlation (e.g., kick+snare = strong beat)
4. Per-band cooldown to prevent double-triggering

Usage:

MultiBandBeat detector;
MultiBandBeatDetectorConfig config;
config.bassThreshold = 0.15f;
config.midThreshold = 0.12f;
config.trebleThreshold = 0.08f;
detector.configure(config);
 
// Each audio frame:
float frequencyBins[16] = {...};  // From FrequencyBinMapper
detector.detectBeats(frequencyBins);
 
if (detector.isBassBeat()) {
    // Trigger bass-synchronized effect (e.g., strobe on kick)
}
if (detector.isMidBeat()) {
    // Trigger mid-synchronized effect (e.g., pulse on snare)
}
if (detector.isTrebleBeat()) {
    // Trigger treble-synchronized effect (e.g., sparkle on hi-hat)
}

Definition at line 74 of file multiband_beat_detector.h.

#include <multiband_beat_detector.h>

Collaboration diagram for fl::audio::detector::MultiBandBeat:

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

Public Member Functions
	MultiBandBeat () FL_NOEXCEPT
	MultiBandBeat (const MultiBandBeatDetectorConfig &config)
	~MultiBandBeat () FL_NOEXCEPT
void	configure (const MultiBandBeatDetectorConfig &config)
	Configure the multi-band beat detector.
void	detectBeats (span< const float > frequencyBins)
	Detect beats in all frequency bands.
float	getBassEnergy () const
	Get current bass energy (0.0-1.0)
float	getMidEnergy () const
	Get current mid energy (0.0-1.0)
const Stats &	getStats () const
float	getTrebleEnergy () const
	Get current treble energy (0.0-1.0)
bool	isBassBeat () const
	Check if a bass beat was detected in the last frame.
bool	isMidBeat () const
	Check if a mid beat was detected in the last frame.
bool	isMultiBandBeat () const
	Check if multiple bands triggered simultaneously (strong beat)
bool	isTrebleBeat () const
	Check if a treble beat was detected in the last frame.
void	reset ()
	Reset internal state (clear history, reset cooldowns)

Private Member Functions
float	calculateBassEnergy (span< const float > frequencyBins) const
	Calculate energy for bass band (bins 0-1)
float	calculateMidEnergy (span< const float > frequencyBins) const
	Calculate energy for mid band (bins 6-7)
float	calculateTrebleEnergy (span< const float > frequencyBins) const
	Calculate energy for treble band (bins 14-15)
bool	detectBandBeat (float currentEnergy, float previousEnergy, float threshold, u32 &cooldownCounter)
	Detect beat in a specific frequency band.

Private Attributes
bool	mBassBeat = false
	Beat detection flags for current frame.
u32	mBassCooldown = 0
	Beat cooldown counters (prevent double-triggering)
float	mBassEnergy = 0.0f
	Current band energies.
MultiBandBeatDetectorConfig	mConfig
u32	mCurrentFrame = 0
	Current frame counter.
bool	mMidBeat = false
u32	mMidCooldown = 0
float	mMidEnergy = 0.0f
float	mPreviousBassEnergy = 0.0f
	Previous band energies (for energy increase calculation)
float	mPreviousMidEnergy = 0.0f
float	mPreviousTrebleEnergy = 0.0f
Stats	mStats
bool	mTrebleBeat = false
u32	mTrebleCooldown = 0
float	mTrebleEnergy = 0.0f

Static Private Attributes
static constexpr size	BASS_BIN_END = 2
static constexpr size	BASS_BIN_START = 0
	Frequency bin indices for each band.
static constexpr size	MID_BIN_END = 8
static constexpr size	MID_BIN_START = 6
static constexpr size	TREBLE_BIN_END = 16
static constexpr size	TREBLE_BIN_START = 14

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

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