How to upload from youtube?

Is it even possible at all? I know video is possible, but I don't know the detail other than that

Doubtful. In addition, the support has limited features.
forum #205252

The problem is the video is in a format not currently supported by Danbooru.

I don't think we want to encourage an increase in the uploading of videos. This is primarily an image website. There are much better websites for this, such as the aforementioned website.