/// <reference types="node" />
import { Duplex, PassThrough, Readable } from 'stream';
import { Logger } from 'pino';
import { Channels, FFmpegArgs, FrameSize, OpusInfo, SamplingRate, StreamGetter } from './types';
import * as Api from './api';
export declare const FRAME_SIZE_MAP: number[];
export declare type OpusReader = {
    opusInfo: OpusInfo;
    opusStream: PassThrough;
};
export declare type OpusOptions = {
    bitrateKbps?: number | null;
    channels?: Channels;
    samplingRate?: SamplingRate;
    frameSize?: FrameSize;
};
export declare function getOpusReader(parentLogger: Logger, options?: OpusOptions | null): Promise<OpusReader>;
export declare type FFmpegDuration = string;
export declare type FFmpegTempo = number;
export declare type FFmpegVolume = number;
export declare type FFmpegNormalizer = {
    integratedLoudness: number;
    loudnessRange: number;
    maximumPeak: number;
};
export declare type FFmpegCompressor = {
    threshold: number;
    ratio: number;
    attack: number;
    release: number;
};
export declare type FileStreamOptions = {
    samplingRate?: SamplingRate;
    volumeFactor?: FFmpegVolume | null | boolean;
    tempoFactor?: FFmpegTempo | null | boolean;
    normalizer?: FFmpegNormalizer | null | boolean;
    compressor?: FFmpegCompressor | null | boolean;
    startAt?: FFmpegDuration | null;
    endAt?: FFmpegDuration | null;
    ffmpegArgs?: FFmpegArgs;
};
export declare function initAudioStream(event: Api.EventStreamStart, opusInfo: OpusInfo, opusStream: Readable, logger: Logger): StreamGetter;
export declare function getAutoDecodeStream(parentLogger: Logger, options?: FileStreamOptions): Duplex;