import { StreamTrackType } from '../interface/index';
import type Bridge from '../bridge';
/**
 * responsibility:
 * 从 MediaStreamTrack 上抽帧音视频
 *
 */
export default class Capture {
    _bridge: Bridge;
    _videoFirstframeCaptured: boolean;
    _audioFirstframeCaptured: boolean;
    _videoProcessorReader: ReadableStreamDefaultReader | null;
    _audioProcessorReader: ReadableStreamDefaultReader | null;
    get audioTrack(): MediaStreamTrack | null;
    get videoTrack(): MediaStreamTrack | null;
    constructor(core: Bridge);
    start(): void;
    /**
     * 采集源发生变化, 摄像头 -> 麦克风等需要重新对新的track抽帧
     * 需要先停止正在采集的老track, 开始新track抽帧
     * @param kind
     * @param mst
     */
    restartCapture(kind: StreamTrackType): void;
    _startVideoCapture(): Promise<void>;
    _startAudioCapture(): Promise<void>;
    destroy(): void;
}