export type FfmpegTool = 'ffmpeg' | 'ffprobe';
export declare function missingFfmpegMessage(tool?: FfmpegTool): string;
/**
 * Refuse up front when a tool is missing, before any frames are read or sparks spent. `spawnSync`
 * with `-version` is the cheapest probe that also proves the binary actually runs.
 */
export declare function ensureFfmpeg(tools?: readonly FfmpegTool[]): void;
/**
 * The first of `tools` that is not on PATH, or null when they all are — the non-throwing half of
 * {@link ensureFfmpeg}, for callers that skip a step rather than fail when ffmpeg is absent.
 */
export declare function missingFfmpegTool(tools?: readonly FfmpegTool[]): FfmpegTool | null;
export declare function runFfmpeg(args: string[]): Promise<void>;
/**
 * Run a tool and keep stdout. {@link runFfmpeg} discards it — everything in the trailer pipeline
 * writes files — so the PCM decode and every ffprobe query come through here instead.
 */
export declare function captureFfmpegTool(tool: FfmpegTool, args: string[]): Promise<Buffer>;