A new video codec has been made available for Video Streaming and Playback services to use over H.264 and H.265 or HEVC. This new codec is being called AV1. It is an open and royalty free video coding format, mainly to be used in video transmissions over the Internet. It is made to succeed VP9 coding format. It is intended to be used along with OPUS in an upcoming update to WebM container format for HTML5 web video and WebRTC technologies. This codec promises the same quality of stream but with a dip in the size of the file. Also, no patent holders will be paid any money for the usage of this codec. You can if you want to, enable this AV1 video codec on YouTube.
How to enable AV1 support on YouTube
If you are using Mozilla Firefox, you will need to get the latest stable version of Firefox for your device. If you are using Google Chrome, you need to get the latest Beta version for this to work. It will be rolled out to Chrome Stable shortly.
1. Mozilla Firefox
Open this URL about:config and look up for an option labeled as media.av1.enabled.
Double click on it to toggle its value to True.
Once you are done, just Restart your Mozilla Firefox browser.
2. Google Chrome
First of all, start by visiting this URL: chrome://flags/#enable-av1-decoder
Then, toggle the appropriate entry to Enabled.
Restart Google Chrome for the changes to take effect.
Check if AV1 codec is enabled on YouTube
To check if the changes that you just made are reflected in your YouTube video playback, it is really simple.
You just need to play any random video on YouTube on any of the configured browsers.
Then, while the video is playing, right click on the playback at any moment of time.
And then click on Stats for nerds.
If you have not enabled AV1, you will see something like this-
And, if AV1 is enabled and working fine, you will see something like this-
Make sure you read the line for Codecs. In the first image, it says VP9 while on the second image it says AVC1.
Hope this helps!