import { TranscriptSegment } from './types';
/**
 * Convert transcript segments to SubRip (SRT) format.
 *
 * @param segments - Array of transcript segments from {@link fetchTranscript}.
 * @returns A string in SRT format with sequence numbers and `HH:MM:SS,mmm` timestamps.
 *
 * @example
 * ```typescript
 * import { fetchTranscript, toSRT } from 'youtube-transcript-plus';
 * const transcript = await fetchTranscript('dQw4w9WgXcQ');
 * const srt = toSRT(transcript);
 *
 * // With videoDetails enabled, use result.segments:
 * const result = await fetchTranscript('dQw4w9WgXcQ', { videoDetails: true });
 * const srt2 = toSRT(result.segments);
 * ```
 */
export declare function toSRT(segments: TranscriptSegment[]): string;
/**
 * Convert transcript segments to WebVTT (VTT) format.
 *
 * @param segments - Array of transcript segments from {@link fetchTranscript}.
 * @returns A string in VTT format with `WEBVTT` header and `HH:MM:SS.mmm` timestamps.
 *
 * @example
 * ```typescript
 * import { fetchTranscript, toVTT } from 'youtube-transcript-plus';
 * const transcript = await fetchTranscript('dQw4w9WgXcQ');
 * const vtt = toVTT(transcript);
 *
 * // With videoDetails enabled, use result.segments:
 * const result = await fetchTranscript('dQw4w9WgXcQ', { videoDetails: true });
 * const vtt2 = toVTT(result.segments);
 * ```
 */
export declare function toVTT(segments: TranscriptSegment[]): string;
/**
 * Convert transcript segments to plain text.
 *
 * @param segments - Array of transcript segments from {@link fetchTranscript}.
 * @param separator - String to join segments with. Defaults to `'\n'`.
 * @returns A plain text string with segments joined by the separator.
 *
 * @example
 * ```typescript
 * import { fetchTranscript, toPlainText } from 'youtube-transcript-plus';
 * const transcript = await fetchTranscript('dQw4w9WgXcQ');
 * const text = toPlainText(transcript);
 * const paragraph = toPlainText(transcript, ' ');
 *
 * // With videoDetails enabled, use result.segments:
 * const result = await fetchTranscript('dQw4w9WgXcQ', { videoDetails: true });
 * const text2 = toPlainText(result.segments);
 * ```
 */
export declare function toPlainText(segments: TranscriptSegment[], separator?: string): string;