Fix worker script origin issue

Author: jeromewu

README.md

@@ -66,7 +66,7 @@ $ node --experimental-wasm-threads --experimental-wasm-bulk-memory transcode.js
 Or, using a script tag in the browser (only works in Chrome):
 
 ```html
-<script src="https://unpkg.com/@ffmpeg/ffmpeg@0.8.0/dist/ffmpeg.min.js"></script>
+<script src="https://unpkg.com/@ffmpeg/ffmpeg@0.8.1/dist/ffmpeg.min.js"></script>
 <script>
   const { createFFmpeg } = FFmpeg;
   ...

src/browser/getModule.js

@@ -1,23 +1,28 @@
 const { log } = require('../utils/log');
 
-module.exports = ({ corePath }) => new Promise((resolve) => {
+module.exports = async ({ corePath }) => {
   if (typeof window.Module === 'undefined') {
+    log('info', 'fetch ffmpeg-core.worker.js script');
+    const workerBlob = await (await fetch(corePath.replace('ffmpeg-core.js', 'ffmpeg-core.worker.js'))).blob();
+    window.FFMPEG_CORE_WORKER_SCRIPT = URL.createObjectURL(workerBlob);
+    log('info', `worker object URL=${window.FFMPEG_CORE_WORKER_SCRIPT}`);
     log('info', `download ffmpeg-core script (~25 MB) from ${corePath}`);
-    const script = document.createElement('script');
-    const eventHandler = () => {
-      script.removeEventListener('load', eventHandler);
-      log('info', 'initialize ffmpeg-core');
-      window.Module.onRuntimeInitialized = () => {
-        log('info', 'ffmpeg-core initialized');
-        resolve(window.Module);
+    return new Promise((resolve) => {
+      const script = document.createElement('script');
+      const eventHandler = () => {
+        script.removeEventListener('load', eventHandler);
+        log('info', 'initialize ffmpeg-core');
+        window.Module.onRuntimeInitialized = () => {
+          log('info', 'ffmpeg-core initialized');
+          resolve(window.Module);
+        };
       };
-    };
-    script.src = corePath;
-    script.type = 'text/javascript';
-    script.addEventListener('load', eventHandler);
-    document.getElementsByTagName('head')[0].appendChild(script);
-  } else {
-    log('info', 'ffmpeg-core is loaded already');
-    resolve(window.Module);
+      script.src = corePath;
+      script.type = 'text/javascript';
+      script.addEventListener('load', eventHandler);
+      document.getElementsByTagName('head')[0].appendChild(script);
+    });
   }
-});
+  log('info', 'ffmpeg-core is loaded already');
+  return Promise.resolve(window.Module);
+};

tests/constants.js

@@ -2,7 +2,7 @@ const TIMEOUT = 60000;
 const BASE_URL = 'http://localhost:3000/tests/assets';
 const IS_BROWSER = typeof window !== 'undefined' && typeof window.document !== 'undefined';
 const OPTIONS = {
-  corePath: '../node_modules/@ffmpeg/core/ffmpeg-core.js',
+  corePath: 'http://localhost:3000/node_modules/@ffmpeg/core/ffmpeg-core.js',
 };
 
 if (typeof module !== 'undefined') {