PeerTube is a video sharing platform, sort of like a Fediverse alternative to YouTube. It also has support for livestreaming. People from Mastodon can follow and interact with PeerTube accounts and videos.
You can find more info about PeerTube, including answers to common questions and links to step-by-step guides, on this page:
➡️ https://fedi.tips/peertube-video-hosting-on-the-fediverse
If you have any questions not covered by the guide, feel free to ask in the replies or DM me 🙂