Missing Video Codecs

[fringe agate]

I am missing video codecs for playing web media through a web browser.
Here is one example of a video I cannot play: https://html5videoplayer.net/html5video/mp4-h-264-video-test/
Hoping for a result of: Suggestion of which codecs I need to install.
Codecs already installed: gst-libav, gst-plugins-bad, gst-plugins-bad-libs, gst-plugins-base, gst-plugins-base-libs, gst-plugins-good, gst-plugins-openh264, gst-plugins-ugly, lib32-plugins-base-libs

[dense dirge]

@fringe agate what browser

[fringe agate]

I've tried: Firefox, Tor, and Vivaldi.

[dense dirge]

Vivaldi: https://wiki.archlinux.org/title/Vivaldi#Media_playback

idk how firefox