I believe Firefox will support H.264 for videos only using the operating system's own support (so on Linux, if you have it supported in gstreamer and/or ffmpeg then it's supported in Firefox).

Linux firefox Plugins tab, though I'm not sure if it's used beyond webrtc:

> OpenH264 Video Codec provided by Cisco Systems, Inc.

> This plugin is automatically installed by Mozilla to comply with the WebRTC specification and to enable WebRTC calls with devices that require the H.264 video codec. Visit https://www.openh264.org/ to view the codec source code and learn more about the implementation.

Nope, it isn't used beyond WebRTC, and in Windows it even autodetects if the computer has a capable enough hardware encoder and use that instead (and decoding through native Windows libraries if there isn't a suitable hardware decoder).

If you’re using YouTube, it supports other formats than just H.264. So, in that instance, lack of H.264 isn’t noticeable.

Unless you don't have hardware accelerated decoding for VP8/9. Then it is very noticeable, especially on a laptop.

This completely killed my Tegra K1-based chromebook. What good is a Google laptop with a full HD display, if it can't play Youtube videos in any resolution higher than 480p?

That would be very odd because YouTube definitely supports H.264 videos in higher than 480p resolutions. VP9 is only exclusively used for some formats/resolutions (e.g., HDR is VP9-only, I think).

It's been a while since I sold it, but it would just choke on anything 720p or higher.

this!

h264 is the most widely supported codec to decode in hardware, so the inclusion of a software decoder in the browser is kinda moot.