Reclaiming my content from the depths of the Twitter Archives.

I've improved reCAPTCHA.

You're welcome.

So it seems if your video file has an audio track it appears as an embedded MP4, but if it's missing one you get a much richer autoplaying gif instead.
@defaced yeah, this thread gets in to a bit more detail, but video without sound seems to be the gist https://mastodon.art/@edlundart/109506302602068722
Bård Edlund / EDLUNDART (@[email protected])

🧵 3 Of course, you CAN upload actual GIF files, and they loop perfectly here as they do anywhere else that accepts GIFs. But obviously GIF is a very limiting format. So the answer is, render out your video file as an h.264 mp4 WITHOUT SOUND. As long as it is soundless, and below 40MB, AND not too huge in resolution (1080 wide works, 1920 wide does not), Mastodon will treat it exactly like an animated GIF (you may know that social media platforms actually convert GIFs to MP4 videos anyway).

Mastodon.ART