Hey, I am currently trying to understand a bit better what the Activity Pub allows and what it doesn’t as I am preparing a presentation on that topic.
On Lemmy I can join other servers without having to recreate an account. Does that also work for across Activity Pub supporting software? Could I join a PeerTube page and then post there? Could I upload videos? Could I join Mastodon or Pixelfed and post images?
I’m not sure that would be the correct metaphore. Lemmy can send video attachement. But your lemmy account is not allowed to upload video to peertube so you can’t send any video.
There is also an economical reason : a video is ressource hungry.
So it is limited to watching peertube video. Let’s imagine 1000 lemmy users uploading video to peertube…
But this is a peertube limitation, right? Activity Pub itself provides the video information and peertube - due to whatever reasons (most likely the economical reasons you mention) - decides to not use that information / reject “the mail”. Is a message sent is only stored on the receiving end or also on the node I am sending it from?
Images and videos on Activity Pub are sent as direct links to the host.
So you can send text comments from Lemmy to peertube that will be replicated, and watch the video by “following” direct links to the host (it is done automagically in your browser or app).
This explanation on how images and videos are embedded while text messages are copied is really helpful!