/**
 * A class which wraps a FFmpeg process.
 *
 * @example
 *
 * ```js
 * import { Converter } from "ffmpeg-stream"
 *
 * const converter = new Converter()
 *
 * converter.createInputFromFile("input.mp4")
 * converter.createOutputToFile("output.webm")
 *
 * await converter.run()
 * ```
 */
export class Converter {
    /**
     * Initializes the converter.
     *
     * Remember to call {@link Converter.run} to actually start the FFmpeg process.
     *
     * @param {string} [ffmpegPath] Path to the FFmpeg executable. (default: `"ffmpeg"`)
     */
    constructor(ffmpegPath?: string | undefined);
    /**
     * @private
     */
    private fdCount;
    /**
     * @private
     * @readonly
     * @type {ConverterPipe[]}
     */
    private readonly pipes;
    /**
     * @private
     * @type {import("node:child_process").ChildProcess | undefined}
     */
    private process;
    /**
     * @private
     */
    private killed;
    /** @private */
    private ffmpegPath;
    /**
     * Defines an FFmpeg input file.
     *
     * This builds a command like the one you would normally use in the terminal.
     *
     * @param {string} file Path to the input file.
     * @param {ConverterPipeOptions} [options] FFmpeg options for this input.
     *
     * @example
     *
     * ```js
     * import { Converter } from "ffmpeg-stream"
     *
     * const converter = new Converter()
     *
     * converter.createInputFromFile("input.mp4", { r: 30 })
     * // ffmpeg -r 30 -i input.mp4 ...
     *
     * await converter.run()
     * ```
     */
    createInputFromFile(file: string, options?: ConverterPipeOptions | undefined): void;
    /**
     * Defines an FFmpeg output file.
     *
     * This builds a command like the one you would normally use in the terminal.
     *
     * @param {string} file Path to the output file.
     * @param {ConverterPipeOptions} [options] FFmpeg options for this output.
     *
     * @example
     *
     * ```js
     * import { Converter } from "ffmpeg-stream"
     *
     * const converter = new Converter()
     *
     * converter.createOutputToFile("output.mp4", { vcodec: "libx264" })
     * // ffmpeg ... -vcodec libx264 output.mp4
     *
     * await converter.run()
     * ```
     */
    createOutputToFile(file: string, options?: ConverterPipeOptions | undefined): void;
    /**
     * Defines an FFmpeg input stream.
     *
     * Internally, it adds a special `pipe:<number>` input argument to the FFmpeg command.
     *
     * Remember to specify the [`f` option](https://ffmpeg.org/ffmpeg.html#Main-options),
     * which specifies the format of the input data.
     *
     * @param {ConverterPipeOptions} options FFmpeg options for this input.
     * @returns {import("node:stream").Writable} A stream which will be written to the FFmpeg process' stdio.
     *
     * @example
     *
     * ```js
     * import { createReadStream } from "node:fs"
     * import { Converter } from "ffmpeg-stream"
     *
     * const converter = new Converter()
     *
     * createReadStream("input.mp4").pipe(
     *   converter.createInputStream({ f: "mp4" }),
     * )
     *
     * await converter.run()
     * ```
     */
    createInputStream(options: ConverterPipeOptions): import("node:stream").Writable;
    /**
     * Defines an FFmpeg output stream.
     *
     * Internally, it adds a special `pipe:<number>` output argument to the FFmpeg command.
     *
     * Remember to specify the [`f` option](https://ffmpeg.org/ffmpeg.html#Main-options),
     * which specifies the format of the output data.
     *
     * @param {ConverterPipeOptions} options FFmpeg options for this output.
     * @returns {import("node:stream").Readable} A stream which will be read from the FFmpeg process' stdio.
     *
     * @example
     *
     * ```js
     * import { createWriteStream } from "node:fs"
     * import { Converter } from "ffmpeg-stream"
     *
     * const converter = new Converter()
     *
     * converter.createOutputStream({ f: "mp4" })
     *   .pipe(createWriteStream("output.mp4"))
     *
     * await converter.run()
     * ```
     */
    createOutputStream(options: ConverterPipeOptions): import("node:stream").Readable;
    /**
     * Defines an FFmpeg input stream from a temporary file.
     *
     * Creates a temporary file that you can write to and instructs FFmpeg to read from it.
     * Note that the actual conversion process will not start until the file is fully written.
     *
     * Use this method if the format you want to read doesn't support non-seekable input.
     *
     * @param {ConverterPipeOptions} options FFmpeg options for this input.
     * @returns {import("node:stream").Writable} A stream which will be written to the temporary file.
     */
    createBufferedInputStream(options: ConverterPipeOptions): import("node:stream").Writable;
    /**
     * Defines an FFmpeg output stream to a temporary file.
     *
     * Creates a temporary file that you can read from and instructs FFmpeg to write to it.
     * Note that you will be able to read from the file only after the conversion process is finished.
     *
     * Use this method if the format you want to write doesn't support non-seekable output.
     *
     * @param {ConverterPipeOptions} options FFmpeg options for this output.
     * @returns {import("node:stream").Readable} A stream which will be read from the temporary file.
     */
    createBufferedOutputStream(options: ConverterPipeOptions): import("node:stream").Readable;
    /**
     * Starts the conversion process.
     *
     * You can use {@link Converter.kill} to cancel the conversion.
     *
     * @returns {Promise<void>} Promise which resolves on normal exit or kill, but rejects on ffmpeg error.
     */
    run(): Promise<void>;
    /**
     * Stops the conversion process.
     */
    kill(): void;
    /**
     * @private
     * @returns {number}
     */
    private getUniqueFd;
    /**
     * Returns stdio pipes which can be passed to {@link spawn}.
     * @private
     * @returns {Array<"ignore" | "pipe">}
     */
    private getStdioArg;
    /**
     * Returns arguments which can be passed to {@link spawn}.
     * @private
     * @returns {string[]}
     */
    private getSpawnArgs;
    /**
     * @private
     */
    private handleProcess;
}
/**
 * Options object for a single input or output of a {@link Converter}.
 *
 * These are the same options that you normally pass to the ffmpeg command in the terminal.
 * Documentation for individual options can be found in the [ffmpeg docs](https://ffmpeg.org/ffmpeg.html#Main-options).
 *
 * To specify a boolean option, set it to `true`.
 * To specify an option multiple times, use an array.
 * Options with nullish or `false` values are ignored.
 */
export type ConverterPipeOptions = Record<string, string | number | boolean | Array<string | null | undefined> | null | undefined>;
/**
 * Data about a single input or output of a {@link Converter}.
 */
export type ConverterPipe = {
    type: "input" | "output";
    options: ConverterPipeOptions;
    file: string;
    onBegin?: (() => Promise<void>) | undefined;
    onSpawn?: ((process: import("node:child_process").ChildProcess) => void) | undefined;
    onFinish?: (() => Promise<void>) | undefined;
};