You can import any URL <x id="START_LINK"/>supported by youtube-dl<x id="CLOSE_LINK"/> or URL that points to a media file. You should make sure you have diffusion rights over the content it points to, otherwise it could cause legal trouble to yourself and your instance.
We recommend you to not use the <x id="START_TAG_STRONG"/>root<x id="CLOSE_TAG_STRONG"/> user to publish your videos, since it's the super-admin account of your instance. <x id="LINE_BREAK"/> Instead, <x id="START_LINK"/>create a dedicated account<x id="CLOSE_LINK"/> to upload your videos.