You need to figure out how the theme is adding the video player to the pages. (Maybe through page.php or post.php or index.php in the theme.) Add some code around where the video player is output to only output it for members.
//the theme code to output the video player goes here
You can also redirect all non-members to the homepage or login page instead of just blocking out the content. Here is some code for that that you can tweak and add to your functions.php.