/**
 * Standard H.264 video encoding params — matches the Python encoders
 * (`-r 24 -c:v libx264 -preset fast -crf 20`). Keeping these uniform across
 * every segment is what lets the 3h stitch step concat segments cleanly.
 */
export declare const STANDARD_VIDEO_ARGS: readonly string[];
/**
 * Standard AAC audio encoding params — matches the Python encoders
 * (`-c:a aac -ar 44100 -ac 2`).
 */
export declare const STANDARD_AUDIO_ARGS: readonly string[];
/** Resolve the ffmpeg binary: explicit opt > VCLAW_FFMPEG_BIN env > `ffmpeg`. */
export declare function resolveFfmpegBin(explicit?: string): string;
/** Resolve the ffprobe binary: explicit opt > VCLAW_FFPROBE_BIN env > `ffprobe`. */
export declare function resolveFfprobeBin(explicit?: string): string;
/**
 * Per-clip cut-at-N tail trim (WS9). Returns the ffmpeg `-t <seconds>` flag pair
 * when `maxSeconds` is a positive number, else `[]` (no trim). PURE — splice the
 * result into a per-clip ffmpeg arg array just before the output path.
 */
export declare function trimTailArgs(maxSeconds?: number): string[];
/**
 * Letterbox normalization filter (WS9). Scales the source to the canvas
 * `width` (preserving aspect via `-2`) and pads it onto a `width`x`height`
 * black canvas, producing cinematic bars. Mirrors the DHUAAN TITLEFIT pattern
 * (`scale=W:-2,pad=W:H:0:(oh-ih)/2:black`). Returns '' when no `ratio` is given
 * (an empty/undefined ratio disables the filter). PURE — no ffmpeg spawned.
 *
 * `ratio` is the target aspect ratio label (e.g. '2.39:1'); the actual letterbox
 * geometry comes from the `width`/`height` canvas the caller already targets.
 */
export declare function letterboxFilter(ratio: string | undefined, width: number, height: number): string;
export interface RunFfmpegOptions {
    /** Build + return the command string without spawning ffmpeg. */
    dryRun?: boolean;
    /** Override the ffmpeg binary (falls back to VCLAW_FFMPEG_BIN, then `ffmpeg`). */
    ffmpegBin?: string;
}
export interface RunFfmpegResult {
    exitCode: number;
    stderr: string;
    /** The fully-resolved command line that was (or would be) run. */
    command: string;
}
/**
 * Run ffmpeg with the given args. The `-y` flag (overwrite output without
 * prompting) is prepended automatically, mirroring the Python wrapper, so
 * callers never block on an interactive prompt.
 *
 * On `dryRun`, returns the command string without spawning (exitCode 0,
 * empty stderr). On a non-zero exit, throws `VclawError('ffmpeg_failed', ...)`.
 *
 * NOTE: This is the real-spawn path. Unit tests must use `dryRun: true` — we do
 * NOT run ffmpeg in tests.
 */
export declare function runFfmpeg(args: string[], opts?: RunFfmpegOptions): Promise<RunFfmpegResult>;
export interface FfprobeDurationOptions {
    /** Return 0 without spawning (dry-run friendly, mirrors callers). */
    dryRun?: boolean;
    /** Override the ffprobe binary (falls back to VCLAW_FFPROBE_BIN, then `ffprobe`). */
    ffprobeBin?: string;
}
/**
 * Probe a media file's duration, returned in **milliseconds**.
 *
 * Mirrors `FFmpegWrapper.probe(entries="format=duration")` + `get_duration`:
 *   ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 <path>
 *
 * On `dryRun`, returns 0 without spawning. Throws `VclawError('ffmpeg_failed', ...)`
 * if ffprobe fails or emits an unparseable duration.
 */
export declare function ffprobeDuration(path: string, opts?: FfprobeDurationOptions): Promise<number>;
export interface IsValidMp4Options {
    /** Override the ffprobe binary (falls back to VCLAW_FFPROBE_BIN, then `ffprobe`). */
    ffprobeBin?: string;
    /** Probe timeout in ms; on expiry the probe is killed and false is returned. Default 15000. */
    timeoutMs?: number;
}
/**
 * True iff ffprobe can read a positive duration from `path`. Catches
 * truncated/no-moov MP4s that pass existence+size checks but fail at
 * stitch. Ported from parallel_video_gen._ffprobe_is_valid_mp4. Never
 * throws — returns false on any probe failure / missing file / timeout.
 *
 * Mirrors the Python guard's args exactly:
 *   ffprobe -v error -show_entries format=duration -of csv=p=0 <path>
 * returning true only when ffprobe exits 0 AND stdout trims to a finite
 * number > 0.
 */
export declare function isValidMp4(path: string, opts?: IsValidMp4Options): Promise<boolean>;
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