Youtube:
Also simple thing to set the video Not public.
Not listed - can watch only if they owned the link - though in this way the video still could spread.
Private - could be good, only those have rights to watch the video who you give license.
I did this when some band wanted to check the video before I shared at our concert photo/video site. And some asked to delete...
so this prevented others to see it if it wasnt good enough for the band...
There are several programs to download any videos from the sites, so I'd accept that download protect does not exist.
Sending samples at the beginning of the work is always good! Once I "Almost" made a little video clip... but it didnt really fit the bands taste, so I was only the cameraman and half-director, was finished by somebody else.
Stupid
https://www.youtube.com/watch?v=do-CkrZP4Sg