Firefox freezes after Worker is created and loaded

[caugner]

Describe the bug
Firefox freezes after worker is created and loaded.

To Reproduce
Steps to reproduce the behavior:

1. See repository: https://github.com/caugner/vue-ffmpeg-worker-firefox-freeze
2. git clone https://github.com/caugner/vue-ffmpeg-worker-firefox-freeze
3. cd vue-ffmpeg-worker-firefox-freeze
4. yarn install
5. yarn serve
6. Open http://localhost:8080 in Firefox.
7. Notice how the UI freezes (the website itself does not always freeze).

See also: https://bugzilla.mozilla.org/show_bug.cgi?id=1608440

Expected behavior
Since ffmpeg is run in a worker, it should not freeze the browser.

Screenshots
(Not applicable.)

Desktop (please complete the following information):

• OS: Windows 10
• Browser Firefox Nightly
• Version 74.0.a1 (2020-01-09)

Smartphone (please complete the following information):
(Not applicable)

Additional context

• I'm using Webpack's worker-loader with Vue.
• videoconverter.js does not have this issue (same approach).

[jeromewu]

This issue is more like a bug in Firefox, right now I won't do anything to fix this.

[jeromewu]

Close for now.