/// <reference types="node" />
import { Transform, TransformCallback } from "stream";
import { EnvelopeType } from "../global";
/** Applies an envelope to AudioChunks to prepare them for FFT. */
declare class Windower extends Transform {
    windowSize: number;
    envelopeType: EnvelopeType;
    envelopeName: any;
    envelope: any;
    static envelopes: {
        [propName: string]: Float32Array;
    };
    static envelopeFunctions: {
        "hamming": (n: number, N: number) => number;
    };
    constructor(windowSize?: number, envelopeType?: EnvelopeType);
    _transform(audio: AudioBuffer, encoding: String, callback: TransformCallback): void;
    static getEnvelope(size: number, type: EnvelopeType): Float32Array;
}
export { Windower };