Add classWorkerURL (#652)

Author: jeromewu

packages/ffmpeg/src/classes.ts

@@ -184,13 +184,19 @@ export class FFmpeg {
    * @returns `true` if ffmpeg core is loaded for the first time.
    */
   public load = (
-    config: FFMessageLoadConfig = {},
+    { classWorkerURL, ...config }: FFMessageLoadConfig = {},
     { signal }: FFMessageOptions = {}
   ): Promise<IsFirst> => {
     if (!this.#worker) {
-      this.#worker = new Worker(new URL("./worker.js", import.meta.url), {
-        type: "module",
-      });
+      this.#worker = classWorkerURL ?
+        new Worker(new URL(classWorkerURL, import.meta.url), {
+          type: "module",
+        }) :
+        // We need to duplicated the code here to enable webpack
+        // to bundle worekr.js here.
+        new Worker(new URL("./worker.js", import.meta.url), {
+          type: "module",
+        });
       this.#registerHandlers();
     }
     return this.#send(

packages/ffmpeg/src/types.ts

@@ -17,11 +17,19 @@ export interface FFMessageLoadConfig {
    */
   wasmURL?: string;
   /**
-   * `ffmpeg-core.worker.js` URL.
+   * `ffmpeg-core.worker.js` URL. This worker is spawned when using multithread version of ffmpeg-core.
    *
+   * @ref: https://ffmpegwasm.netlify.app/docs/overview#architecture
    * @defaultValue `https://unpkg.com/@ffmpeg/core-mt@${CORE_VERSION}/dist/umd/ffmpeg-core.worker.js`;
    */
   workerURL?: string;
+  /**
+   * `ffmpeg.worker.js` URL. This worker is spawned when FFmpeg.load() is called, it is an essential worker and usually you don't need to update this config.
+   *
+   * @ref: https://ffmpegwasm.netlify.app/docs/overview#architecture
+   * @defaultValue `./worker.js`
+   */
+  classWorkerURL?: string;
 }
 
 export interface FFMessageExecData {