You can play videos only on certain domains using Gumlet. Here are the steps to follow:
Go to the Video Collections.
Edit your collection and navigate to Video Protection
Enter the domain that you want to allow to play your Collection of videos under the WhiteWhitelist Referrers.
Read more about video protection here Video Protection
After that what will happen, the referer header will allow a server to recognize the page from where people visit it. With allowed referer settings, you can also ensure that your video is only accessible from a specific server/host. You can add multiple referrers using which you wish your video to be accessible.