type BankFilter = (freqPowers: Float32Array) => Float32Array;
interface MelConfig {
    fftSize: number;
    bankCount: number;
    lowFrequency: number;
    highFrequency: number;
    sampleRate: number;
}
interface MelFilterBank {
    filters: Array<Array<number>>;
    lowMel: number;
    highMel: number;
    deltaMel: number;
    lowFreq: number;
    highFreq: number;
    filter: BankFilter;
}
/**
 * Converts from Mel-scale to hertz. Used by constructFilterBank.
 * @param mels - mels to convert to hertz
 */
export declare function melsToHz(mels: number): number;
/**
 * Converts from hertz to the Mel-scale. Used by constructFilterBank.
 * @param hertz - hertz to convert to mels
 */
export declare function hertzToMels(hertz: number): number;
/**
 * Creates a filter bank with config.bankCount triangular filters.
 * Filters are distributed according to the mel scale.
 *
 * @param config - Object containing the config for mfccBank
 * (eg: config = {  fftSize: 32,  bankCount: 24,  lowFrequency: 1,
 *   highFrequency: 8000,  sampleRate: 16000,})
 */
export declare function constructMelFilterBank(config: MelConfig): MelFilterBank;
/**
 * Construct the mfcc
 * @param config - Object containing the config for mfccBank
 * (eg: config = {  fftSize: 32,  bankCount: 24,  lowFrequency: 1,
 *   highFrequency: 8000,  sampleRate: 16000,})
 * @param numberOfMFCCs - the number of mfcc you want as output,
 * can't be larger than config.bankCount
 *
 * @description
 * To calculate an MFCC from an audio input, we do the following steps:
 * audio input -> log of power spectrum from FFT -> Resample spectrum on Mel filter bank -> DCT -> MFCC Output
 */
export declare function constructMfcc(config: MelConfig): (fft: Float32Array) => Float32Array;
export {};