Architecture

Vocabulary

Fediverse: several servers following one another, several users following each other. Designates federated communities in general.
Vidiverse: same as Fediverse, but federating videos specifically.
Instance: a server which runs PeerTube in the fediverse.
Origin instance: the instance on which the video was uploaded and which is seeding (through the WebSeed protocol) the video.
Cache instance: an instance that decided to make available a WebSeed of its own for a video originating from another instance. It sends a ptCache activity to notify the origin instance, which will then update its list of WebSeeds for the video.
Following: the action of a PeerTube instance which will follow another instance (subscribe to its videos).

All the communication between the instances are signed with Linked Data Signatures with the private key of the account that authored the action.
We use the ActivityPub protocol (only server-server for now). Object models could be found in shared/models/activitypub directory.
All the requests are retried several times if they fail.

An instance has a websocket tracker which is responsible for all videos uploaded by its users.
An instance has an administrator that can follow other instances.
An instance can be configured to follow back automatically.
An instance can blacklist other instances (only used in "follow back" mode).
An instance cannot choose which other instances follow it, but it can decide to reject all followers.
After having uploaded a video, the instance seeds it (WebSeed protocol).
If a user wants to watch a video, they ask its instance the magnet URI and the frontend adds the torrent (with WebTorrent), creates the HTML5 video player and streams the file into it.
A user watching a video seeds it too (BitTorrent). Thus another user who is watching the same video can get the data from the origin server and other users watching it.