/**
 * success: mp4, mov
 * failed: avi, wmv, flv,
 *
 * @param videoFile video File
 * @param currentTime setting currentTime
 * @param secLimit setting timeout secounds
 *
 * @returns base64(png)
 */
export declare const videoToPng: (videoFile: File, currentTime?: number, secLimit?: number) => Promise<string>;