Initial commit: media-to-text app
This commit is contained in:
Gan, Jimmy
@@ -0,0 +1,306 @@
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import { FFMessageType } from "./const.js";
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import { getMessageID } from "./utils.js";
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import { ERROR_TERMINATED, ERROR_NOT_LOADED } from "./errors.js";
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/**
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* Provides APIs to interact with ffmpeg web worker.
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*
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* @example
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* ```ts
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* const ffmpeg = new FFmpeg();
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* ```
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*/
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export class FFmpeg {
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#worker = null;
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/**
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* #resolves and #rejects tracks Promise resolves and rejects to
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* be called when we receive message from web worker.
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*/
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#resolves = {};
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#rejects = {};
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#logEventCallbacks = [];
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#progressEventCallbacks = [];
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loaded = false;
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/**
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* register worker message event handlers.
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*/
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#registerHandlers = () => {
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if (this.#worker) {
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this.#worker.onmessage = ({ data: { id, type, data }, }) => {
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switch (type) {
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case FFMessageType.LOAD:
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this.loaded = true;
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this.#resolves[id](data);
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break;
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case FFMessageType.MOUNT:
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case FFMessageType.UNMOUNT:
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case FFMessageType.EXEC:
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case FFMessageType.FFPROBE:
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case FFMessageType.WRITE_FILE:
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case FFMessageType.READ_FILE:
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case FFMessageType.DELETE_FILE:
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case FFMessageType.RENAME:
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case FFMessageType.CREATE_DIR:
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case FFMessageType.LIST_DIR:
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case FFMessageType.DELETE_DIR:
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this.#resolves[id](data);
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break;
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case FFMessageType.LOG:
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this.#logEventCallbacks.forEach((f) => f(data));
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break;
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case FFMessageType.PROGRESS:
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this.#progressEventCallbacks.forEach((f) => f(data));
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break;
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case FFMessageType.ERROR:
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this.#rejects[id](data);
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break;
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}
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delete this.#resolves[id];
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delete this.#rejects[id];
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};
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}
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};
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/**
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* Generic function to send messages to web worker.
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*/
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#send = ({ type, data }, trans = [], signal) => {
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if (!this.#worker) {
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return Promise.reject(ERROR_NOT_LOADED);
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}
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return new Promise((resolve, reject) => {
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const id = getMessageID();
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this.#worker && this.#worker.postMessage({ id, type, data }, trans);
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this.#resolves[id] = resolve;
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this.#rejects[id] = reject;
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signal?.addEventListener("abort", () => {
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reject(new DOMException(`Message # ${id} was aborted`, "AbortError"));
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}, { once: true });
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});
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};
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on(event, callback) {
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if (event === "log") {
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this.#logEventCallbacks.push(callback);
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}
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else if (event === "progress") {
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this.#progressEventCallbacks.push(callback);
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}
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}
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off(event, callback) {
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if (event === "log") {
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this.#logEventCallbacks = this.#logEventCallbacks.filter((f) => f !== callback);
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}
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else if (event === "progress") {
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this.#progressEventCallbacks = this.#progressEventCallbacks.filter((f) => f !== callback);
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}
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}
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/**
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* Loads ffmpeg-core inside web worker. It is required to call this method first
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* as it initializes WebAssembly and other essential variables.
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*
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* @category FFmpeg
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* @returns `true` if ffmpeg core is loaded for the first time.
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*/
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load = ({ classWorkerURL, ...config } = {}, { signal } = {}) => {
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if (!this.#worker) {
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this.#worker = classWorkerURL ?
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new Worker(new URL(classWorkerURL, import.meta.url), {
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type: "module",
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}) :
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// We need to duplicated the code here to enable webpack
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// to bundle worekr.js here.
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new Worker(new URL("./worker.js", import.meta.url), {
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type: "module",
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});
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this.#registerHandlers();
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}
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return this.#send({
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type: FFMessageType.LOAD,
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data: config,
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}, undefined, signal);
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};
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/**
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* Execute ffmpeg command.
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*
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* @remarks
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* To avoid common I/O issues, ["-nostdin", "-y"] are prepended to the args
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* by default.
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*
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* @example
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* ```ts
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* const ffmpeg = new FFmpeg();
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* await ffmpeg.load();
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* await ffmpeg.writeFile("video.avi", ...);
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* // ffmpeg -i video.avi video.mp4
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* await ffmpeg.exec(["-i", "video.avi", "video.mp4"]);
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* const data = ffmpeg.readFile("video.mp4");
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* ```
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*
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* @returns `0` if no error, `!= 0` if timeout (1) or error.
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* @category FFmpeg
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*/
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exec = (
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/** ffmpeg command line args */
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args,
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/**
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* milliseconds to wait before stopping the command execution.
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*
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* @defaultValue -1
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*/
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timeout = -1, { signal } = {}) => this.#send({
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type: FFMessageType.EXEC,
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data: { args, timeout },
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}, undefined, signal);
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/**
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* Execute ffprobe command.
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*
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* @example
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* ```ts
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* const ffmpeg = new FFmpeg();
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* await ffmpeg.load();
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* await ffmpeg.writeFile("video.avi", ...);
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* // Getting duration of a video in seconds: ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 video.avi -o output.txt
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* await ffmpeg.ffprobe(["-v", "error", "-show_entries", "format=duration", "-of", "default=noprint_wrappers=1:nokey=1", "video.avi", "-o", "output.txt"]);
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* const data = ffmpeg.readFile("output.txt");
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* ```
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*
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* @returns `0` if no error, `!= 0` if timeout (1) or error.
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* @category FFmpeg
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*/
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ffprobe = (
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/** ffprobe command line args */
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args,
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/**
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* milliseconds to wait before stopping the command execution.
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*
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* @defaultValue -1
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*/
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timeout = -1, { signal } = {}) => this.#send({
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type: FFMessageType.FFPROBE,
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data: { args, timeout },
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}, undefined, signal);
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/**
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* Terminate all ongoing API calls and terminate web worker.
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* `FFmpeg.load()` must be called again before calling any other APIs.
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*
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* @category FFmpeg
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*/
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terminate = () => {
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const ids = Object.keys(this.#rejects);
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// rejects all incomplete Promises.
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for (const id of ids) {
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this.#rejects[id](ERROR_TERMINATED);
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delete this.#rejects[id];
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delete this.#resolves[id];
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}
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if (this.#worker) {
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this.#worker.terminate();
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this.#worker = null;
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this.loaded = false;
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}
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};
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/**
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* Write data to ffmpeg.wasm.
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*
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* @example
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* ```ts
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* const ffmpeg = new FFmpeg();
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* await ffmpeg.load();
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* await ffmpeg.writeFile("video.avi", await fetchFile("../video.avi"));
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* await ffmpeg.writeFile("text.txt", "hello world");
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* ```
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*
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* @category File System
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*/
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writeFile = (path, data, { signal } = {}) => {
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const trans = [];
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if (data instanceof Uint8Array) {
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trans.push(data.buffer);
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}
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return this.#send({
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type: FFMessageType.WRITE_FILE,
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data: { path, data },
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}, trans, signal);
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};
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mount = (fsType, options, mountPoint) => {
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const trans = [];
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return this.#send({
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type: FFMessageType.MOUNT,
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data: { fsType, options, mountPoint },
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}, trans);
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};
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unmount = (mountPoint) => {
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const trans = [];
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return this.#send({
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type: FFMessageType.UNMOUNT,
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data: { mountPoint },
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}, trans);
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};
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/**
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* Read data from ffmpeg.wasm.
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*
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* @example
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* ```ts
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* const ffmpeg = new FFmpeg();
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* await ffmpeg.load();
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* const data = await ffmpeg.readFile("video.mp4");
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* ```
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*
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* @category File System
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*/
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readFile = (path,
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/**
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* File content encoding, supports two encodings:
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* - utf8: read file as text file, return data in string type.
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* - binary: read file as binary file, return data in Uint8Array type.
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*
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* @defaultValue binary
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*/
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encoding = "binary", { signal } = {}) => this.#send({
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type: FFMessageType.READ_FILE,
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data: { path, encoding },
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}, undefined, signal);
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/**
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* Delete a file.
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*
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* @category File System
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*/
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deleteFile = (path, { signal } = {}) => this.#send({
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type: FFMessageType.DELETE_FILE,
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data: { path },
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}, undefined, signal);
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/**
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* Rename a file or directory.
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*
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* @category File System
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*/
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rename = (oldPath, newPath, { signal } = {}) => this.#send({
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type: FFMessageType.RENAME,
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data: { oldPath, newPath },
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}, undefined, signal);
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/**
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* Create a directory.
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*
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* @category File System
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*/
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createDir = (path, { signal } = {}) => this.#send({
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type: FFMessageType.CREATE_DIR,
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data: { path },
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}, undefined, signal);
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/**
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* List directory contents.
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*
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* @category File System
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*/
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listDir = (path, { signal } = {}) => this.#send({
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type: FFMessageType.LIST_DIR,
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data: { path },
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}, undefined, signal);
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/**
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* Delete an empty directory.
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*
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* @category File System
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*/
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deleteDir = (path, { signal } = {}) => this.#send({
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type: FFMessageType.DELETE_DIR,
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data: { path },
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}, undefined, signal);
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}
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