/// <reference types="node" />
import { Transform, TransformCallback } from 'stream';
import { Smp } from '../global';
/**
 *  Transform stream for converting a pre-windowed AudioBuffer object-stream to spectral data.
 *  @returns SpectralBuffer object-stream
 */
declare class FFT extends Transform {
    windowSize: Smp;
    frameSize: Smp;
    fftFunction: any;
    constructor(windowSize?: number);
    _transform(audio: AudioBuffer, encoding: string, callback: TransformCallback): void;
}
export { FFT };