Your browser doesn't support SharedArrayBuffer

From: https://ffmpegwasm.github.io/#demo

Using Firefox 81.02 on Fedora 32.

Your browser doesn't support SharedArrayBuffer, thus ffmpeg.wasm cannot execute. Please use latest version of Chromium or any other browser supports SharedArrayBuffer.

[Ian321]

Should work.

I just tested it with the following and it worked:

const express = require('express');
const app = express();

app.use((req, res, next) => {
  res.header('Cross-Origin-Opener-Policy', 'same-origin');
  res.header('Cross-Origin-Embedder-Policy', 'require-corp');
  next();
});

app.use(express.static('build'));

app.listen(8080);

The downside it that you can’t use scripts hosted on other domains, so Google Analytics won’t work and ffmpeg-core can’t be loaded from https://unpkg.com/.

[jeromewu]

This is an expected result as Firefox doesn’t have the full support for SharedArrayBuffer now.