To share a video library from one site to another, click on the SETTINGS link under your selected site-name and you should see the SHARE VIDEO LIBRARY option to the bottom right.
Enable it and select the site(s) to which you want to share videos to. Below this input field you should see 2 permission options:
- Edit permission will give your admins edit video permissions for shared videos
- Delete permission will give delete permissions for shared library videos.