It serves two purposes on a PeerTube instance: it ensures all videos can be played optimally in the web interface, and it generates different resolutions for the same video.
It's based on <a target="_blank" rel="noopener noreferrer" href="https://activitypub.rocks">ActivityPub</a> to connect with tools <a target="_blank" rel="noopener noreferrer" href="https://peertube.cpy.re/videos/watch/da2b08d4-a242-4170-b32a-4ec8cbdca701">like Mastodon</a> for example.
It's based on <a target="_blank" rel="noopener noreferrer" href="https://en.wikipedia.org/wiki/WebRTC">WebRTC</a>, a free and open-source project for web browsers.
It's the reason why we encourage developers to use the <a target="_blank" rel="noopener noreferrer" href="https://docs.joinpeertube.org/contribute/plugins">PeerTube plugin API</a> to create their own monetization system.
