The problem is directly related to this other one EE question:
but the solution presented there is "not enough" for my purposes...
I have created a channel in YouTube and I want to upload small videos that should be seen ONLY by my customers that login in my website. They may or may not be YouTube users, they may or may not have a Google account.
I know how to upload the YouTube video, put it as unlisted and see it through my site. It works perfectly and the user cannot download the video through my website, what is also good. On the other hand, as Gary put it in the other EE post, people could get the link for the video and pass this link to friends, for instance.
To avoid the passing-link thing, I thought about changing the video type to "private" but, when I do so, the video embedded does not appear, only a message saying "this video is private"... how should I proceed?
In other words, I would like to "tell YouTube" that my site is always able to "see all videos" embedded in my website, even the private ones (especially those), and all my customers, logged-in in my website, should be able to see these videos, but they could not see the same videos in the YouTube channel, and they should not be able to let their friends see the videos (If their friends are not my students, too. The videos are webinar math exercise problems/solutions.)
Is that possible? If yes or no, how should I proceed to be able to do something like that, please?