/**
 * onset_detect() — fast spectral flux-based onset detection
 */
export function onsetDetect(audioData: any, sampleRate: any, { hopLength, frameLength, delta, wait }?: {
    hopLength?: number;
    frameLength?: number;
    delta?: number;
    wait?: number;
}): {
    onsetTimes: number[];
    onsetStrength: Float32Array<any>;
    onsetFrames: number[];
};
/**
 * Fast STFT using our optimized FFT
 */
export function computeSTFT(audioData: any, frameLength?: number, hopLength?: number): Float32Array<ArrayBufferLike>[];
/**
 * Compute spectral flux for onset detection
 * Much more accurate than simple RMS differences
 */
export function computeSpectralFlux(stft: any): Float32Array<any>;
/**
 * onset_strength() — log-power-mel onset strength envelope.
 *
 * S = power_to_db(melspectrogram(y, sr, n_fft, hop_length, fmax=sr/2))
 * onset_env[t] = mean_f max(0, S[f, t] - ref[f, t - lag])
 * padded left by lag + n_fft // (2 * hop_length) frames (center=true),
 * then trimmed to the frame count of S.
 *
 * Accepts either positional args `(y, sr, hop_length)` or an
 * options object `(y, { sr, hop_length, ... })`.
 *
 * @param {Float32Array|Array} y - 1-D audio signal (or null if opts.S given)
 * @param {Object|number} [opts] - Options object, or sr as a number
 *   @param {number} [opts.sr=22050]         sample rate (Hz)
 *   @param {Array}  [opts.S=null]           pre-computed LOG-POWER spectrogram [freq][time]
 *   @param {number} [opts.n_fft=2048]       FFT size for the mel spectrogram
 *   @param {number} [opts.hop_length=512]   hop length
 *   @param {number} [opts.lag=1]            time lag for the difference
 *   @param {number} [opts.max_size=1]       frequency-local max filter size (1 = off)
 *   @param {Array}  [opts.ref=null]         pre-computed reference spectrum
 *   @param {boolean} [opts.detrend=false]   remove DC via lfilter([1,-1],[1,-0.99])
 *   @param {boolean} [opts.center=true]     compensate for centered STFT frames
 *   @param {number} [opts.n_mels=128]       mel bands for the default feature
 *   @param {number} [opts.fmin=0]           lowest mel frequency
 *   @param {number} [opts.fmax=sr/2]        highest mel frequency (default)
 *   @param {boolean} [opts.htk=false]       HTK mel scale
 *   @param {string} [opts.aggregate='mean'] frequency aggregation: 'mean'
 *     (default) or 'median' (used by beat_track, aggregate=np.median)
 * @param {number} [maybeHop] - hop_length when called positionally (y, sr, hop)
 * @returns {Float32Array} onset strength envelope
 */
export function onset_strength(y: Float32Array | any[], opts?: any | number, maybeHop?: number): Float32Array;
/**
 * Peak picking for onset detection
 * Peak picking algorithm
 */
export function pickPeaks(onsetStrength: any, { delta, wait }?: {
    delta?: number;
    wait?: number;
}): number[];
/**
 * Convert onset times to beat times
 * Simple version - just use onset spacing
 * Reports failure honestly: with fewer than 2 onsets there is no interval to
 * measure, so bpm is null (never a fabricated default).
 */
export function onsetsToBeats(onsetTimes: any): {
    bpm: number;
    beatTimes: any[];
    interval: number;
};
/**
 * Backtrack detected onset events to the nearest preceding local minimum of energy
 * @param {Array|Float32Array} events - Frame indices of detected onsets
 * @param {Array|Float32Array} energy - Energy envelope (e.g., RMS, onset strength)
 * @returns {Float32Array} Backtracked onset event frames
 */
export function onset_backtrack(events: any[] | Float32Array, energy: any[] | Float32Array): Float32Array;
/**
 * Compute a spectral flux onset strength envelope across multiple channels
 * Useful for multi-channel or source-separated audio
 * @param {Float32Array|null} y - Audio time series
 * @param {number} sr - Sample rate
 * @param {Array|null} S - Pre-computed spectrogram [channels x freq x time]
 * @param {number} n_fft - FFT size
 * @param {number} hop_length - Hop length
 * @param {number} lag - Lag for onset detection
 * @param {number} max_size - Max filter size
 * @param {Array|null} ref - Reference power
 * @param {boolean} detrend - Remove DC component
 * @param {boolean} center - Center frames
 * @param {Function|null} feature - Feature extraction function
 * @param {Function|null} aggregate - Aggregation function across channels
 * @param {Array|null} channels - List of channel slices
 * @param {Object} kwargs - Additional arguments
 * @returns {Array} Multi-channel onset strength [channels x time]
 */
export function onset_strength_multi(y?: Float32Array | null, sr?: number, S?: any[] | null, n_fft?: number, hop_length?: number, lag?: number, max_size?: number, ref?: any[] | null, detrend?: boolean, center?: boolean, feature?: Function | null, aggregate?: Function | null, channels?: any[] | null, kwargs?: any): any[];