Embed codes can be secured to limit hot-linking, and give fine grained permissions to share to Administrators.
Two protection are available :
Ensuring that the site that embed a video has the proper right to do it, by checking a token before delivering the asset : Asset protection through Tokenisation
Limiting the domains that are authorize to host a video : Asset protection through Domain control
Both protections can be used simultaneously.
We recommend using tokenization when possible, but tokenizing a video suppose you have control over the code of the web application that is hosting the video.
If you need a more immediate and straightforward solution, authorizing hosts is the way to go.