/**
 * Video Processor
 *
 * Handles downloading, validating, and processing video files for AI consumption.
 * Since LLMs cannot process raw video, this processor extracts:
 * - Structured metadata (duration, resolution, codecs, etc.)
 * - Keyframes at configurable intervals (resized to 768px JPEG)
 * - Embedded subtitle tracks (if present)
 *
 * The extracted content is formatted as text + images that can be sent to any
 * AI provider for analysis.
 *
 * Uses mediabunny (pure TypeScript) for metadata extraction, with fluent-ffmpeg
 * as a fallback for unsupported formats. Requires ffmpeg for keyframe/subtitle
 * extraction (via ffmpeg-static or system PATH).
 *
 * Key features:
 * - Adaptive keyframe extraction intervals based on video duration
 * - Frame count capping (max 20 frames) to control token usage
 * - JPEG quality optimization for AI vision models
 * - Embedded subtitle extraction (SRT format)
 * - Graceful degradation on corrupt files or missing codecs
 * - Temp file cleanup with finally blocks
 * - Configurable timeouts for ffmpeg and ffprobe operations
 *
 * @module processors/media/VideoProcessor
 *
 * @example
 * ```typescript
 * import { videoProcessor, processVideo, isVideoFile } from "./VideoProcessor.js";
 *
 * // Check if a file is a video file
 * if (isVideoFile(fileInfo.mimetype, fileInfo.name)) {
 *   const result = await processVideo(fileInfo, {
 *     authHeaders: { Authorization: "Bearer token" },
 *   });
 *
 *   if (result.success) {
 *     console.log(`Duration: ${result.data.metadata.durationFormatted}`);
 *     console.log(`Keyframes: ${result.data.frameCount}`);
 *     console.log(`Text for LLM:\n${result.data.textContent}`);
 *   }
 * }
 * ```
 */
import { BaseFileProcessor } from "../base/BaseFileProcessor.js";
import type { FileInfo, ProcessedVideo, ProcessorFileProcessingResult, ProcessOptions } from "../../types/index.js";
/**
 * Video Processor - extracts metadata, keyframes, and subtitles from video files.
 *
 * Since LLMs cannot process raw video, this processor converts videos into
 * a structured representation consisting of:
 * 1. Text metadata block (duration, resolution, codecs, etc.)
 * 2. Keyframe images (JPEG, resized to 768px max dimension)
 * 3. Subtitle text (if embedded in the video)
 *
 * The processor uses a temp file approach because ffmpeg requires file paths
 * for most operations. Temp files are always cleaned up in finally blocks.
 *
 * @example
 * ```typescript
 * const processor = new VideoProcessor();
 * const result = await processor.processFile({
 *   id: "video-1",
 *   name: "presentation.mp4",
 *   mimetype: "video/mp4",
 *   size: 15_000_000,
 *   buffer: videoBuffer,
 * });
 *
 * if (result.success) {
 *   // result.data.textContent - text description for LLM
 *   // result.data.keyframes   - array of JPEG buffers
 *   // result.data.subtitleText - extracted subtitles (if any)
 * }
 * ```
 */
export declare class VideoProcessor extends BaseFileProcessor<ProcessedVideo> {
    constructor();
    /**
     * Build processed result stub.
     * This is a synchronous placeholder - actual processing happens in the
     * overridden processFile method since ffmpeg operations are asynchronous
     * and require temp file I/O.
     *
     * @param buffer - Downloaded file content
     * @param fileInfo - Original file information
     * @returns Empty ProcessedVideo structure
     */
    protected buildProcessedResult(buffer: Buffer, fileInfo: FileInfo): ProcessedVideo;
    /**
     * Override processFile for async video processing with ffmpeg.
     *
     * Processing pipeline:
     * 1. Validate file type and size
     * 2. Get buffer (from fileInfo.buffer or download from URL)
     * 3. Write buffer to temp file (ffmpeg requires file paths)
     * 4. Extract metadata using ffprobe
     * 5. Extract keyframes at calculated intervals, resize with sharp
     * 6. Extract subtitle tracks if embedded
     * 7. Build textContent summary for LLM
     * 8. Clean up temp files
     *
     * @param fileInfo - File information with URL or buffer
     * @param options - Optional processing options
     * @returns Processing result with extracted video data or error
     */
    processFile(fileInfo: FileInfo, options?: ProcessOptions): Promise<ProcessorFileProcessingResult<ProcessedVideo>>;
    /**
     * Probe a video file to extract metadata using ffprobe.
     *
     * @param filePath - Path to the video file
     * @returns Success result with probe data or error message
     */
    private probeVideo;
    /**
     * Probe a video file using mediabunny (pure TypeScript, no native binary).
     * Falls back to ffprobe if mediabunny fails or doesn't support the format.
     */
    private probeVideoWithMediabunny;
    /**
     * Build a structured metadata object from ffprobe data.
     *
     * @param probeData - Raw ffprobe output
     * @param fileSize - Original file size in bytes
     * @returns Structured video metadata
     */
    private buildMetadata;
    /**
     * Extract keyframes from a video at calculated intervals.
     *
     * The interval between frames is determined by the video duration:
     * - <= 10s:   every 1s  (very short clips — dense coverage)
     * - <= 30s:   every 2s  (short bug clips)
     * - <= 120s:  every 5s  (standard screen recordings)
     * - <= 600s:  every 15s (longer demos)
     * - <= 1800s: every 60s (meeting recordings)
     * - > 1800s:  every 180s (full meetings)
     *
     * Results are capped at MAX_FRAMES (100) and each frame is resized
     * to fit within 768x768px while maintaining aspect ratio.
     * The interval is adaptive: if the tier interval would exceed MAX_FRAMES,
     * the interval widens to duration/MAX_FRAMES for full-video coverage.
     *
     * @param videoPath - Path to the video file
     * @param tempDir - Temp directory for frame output
     * @param durationSec - Video duration in seconds
     * @returns Array of JPEG frame buffers
     */
    private extractKeyframes;
    /**
     * Run ffmpeg to extract frames at specified timestamps.
     *
     * Uses the `-vf select` filter to pick frames at exact timestamps,
     * which is more efficient than seeking for each frame individually.
     *
     * @param videoPath - Path to the video file
     * @param outputDir - Directory to write frame files
     * @param timestamps - Array of timestamps in seconds
     */
    private runFfmpegFrameExtraction;
    /**
     * Determine the frame extraction interval based on video duration.
     *
     * @param durationSec - Video duration in seconds
     * @returns Interval in seconds between extracted frames
     */
    private getFrameInterval;
    /**
     * Extract embedded subtitle text from the first subtitle track.
     *
     * Uses ffmpeg to convert the first subtitle stream to SRT format,
     * then strips SRT formatting (timestamps, sequence numbers) to produce
     * plain text.
     *
     * @param videoPath - Path to the video file
     * @param tempDir - Temp directory for subtitle output
     * @returns Extracted subtitle text, or undefined if extraction fails
     */
    private extractSubtitles;
    /**
     * Parse SRT subtitle content into plain text.
     * Strips sequence numbers, timestamps, and blank lines.
     *
     * @param srt - Raw SRT content
     * @returns Plain text from subtitles
     */
    private parseSrtToPlainText;
    /**
     * Build a structured text description of the video for LLM consumption.
     *
     * The output includes:
     * - File name and basic info
     * - Technical metadata (resolution, codec, duration, etc.)
     * - Frame extraction summary
     * - Subtitle text (if available)
     *
     * @param metadata - Extracted video metadata
     * @param frameCount - Number of keyframes extracted
     * @param subtitleText - Extracted subtitle text (if any)
     * @param filename - Original filename
     * @returns Formatted text content for the LLM
     */
    private buildTextContent;
    /**
     * Format a duration in seconds to a human-readable string.
     *
     * @param seconds - Duration in seconds
     * @returns Formatted string (e.g., "1h 23m 45s")
     */
    private formatDuration;
    /**
     * Get a file extension from FileInfo, falling back to ".mp4".
     *
     * @param fileInfo - File information
     * @returns File extension with leading dot
     */
    private getExtensionFromFileInfo;
    /**
     * Write a buffer to a file using streaming to handle large files efficiently.
     *
     * @param buffer - Buffer to write
     * @param filePath - Destination file path
     */
    private writeBufferToFile;
    /**
     * Extract frames from a specific time range in a video.
     *
     * This is the on-demand extraction method called by the `extract_file_content`
     * tool. Unlike initial keyframe extraction (which covers the full video),
     * this targets a specific time window with configurable frame count.
     *
     * @param buffer - Video file buffer
     * @param filename - Original filename (for extension detection)
     * @param startSec - Start time in seconds
     * @param endSec - End time in seconds
     * @param frameCount - Number of frames to extract in the range (default: 5)
     * @returns Array of JPEG frame buffers
     */
    extractFrameRange(buffer: Buffer, filename: string, startSec: number, endSec: number, frameCount?: number): Promise<Buffer[]>;
    /**
     * Guess file extension from filename, with fallback to .mp4.
     */
    private guessExtensionFromName;
}
/**
 * Singleton Video processor instance.
 * Use this for standard video processing operations.
 *
 * @example
 * ```typescript
 * import { videoProcessor } from "./VideoProcessor.js";
 *
 * const result = await videoProcessor.processFile(fileInfo);
 * ```
 */
export declare const videoProcessor: VideoProcessor;
/**
 * Check if a file is a video file.
 * Matches by MIME type or file extension.
 *
 * @param mimetype - MIME type of the file
 * @param filename - Filename (for extension-based detection)
 * @returns true if the file is a supported video file
 *
 * @example
 * ```typescript
 * if (isVideoFile("video/mp4", "recording.mp4")) {
 *   const result = await processVideo(fileInfo);
 * }
 *
 * if (isVideoFile("", "clip.mkv")) {
 *   // Also matches by extension
 * }
 * ```
 */
export declare function isVideoFile(mimetype: string, filename: string): boolean;
/**
 * Process a single video file.
 * Convenience function that uses the singleton processor.
 *
 * @param fileInfo - File information (can include URL or buffer)
 * @param options - Optional processing options (auth headers, timeout, retry config)
 * @returns Processing result with extracted video data or error
 *
 * @example
 * ```typescript
 * import { processVideo } from "./VideoProcessor.js";
 *
 * const result = await processVideo({
 *   id: "vid-123",
 *   name: "demo.mp4",
 *   mimetype: "video/mp4",
 *   size: 15_000_000,
 *   buffer: videoBuffer,
 * });
 *
 * if (result.success) {
 *   console.log(`Duration: ${result.data.metadata.durationFormatted}`);
 *   console.log(`Extracted ${result.data.frameCount} keyframes`);
 *   console.log(`Text content:\n${result.data.textContent}`);
 *
 *   if (result.data.subtitleText) {
 *     console.log(`Subtitles:\n${result.data.subtitleText}`);
 *   }
 * } else {
 *   console.error(`Processing failed: ${result.error?.userMessage}`);
 * }
 * ```
 */
export declare function processVideo(fileInfo: FileInfo, options?: ProcessOptions): Promise<ProcessorFileProcessingResult<ProcessedVideo>>;