I'm looking for adding advertising in my application. I must realize a button "watch the video if you want to download the content". In this way a user will watch the ad before continue with the download. I know that many services (for example admob) don't permit this behaviour, it's written in their terms of service:

Publishers may not ask others to click their ads or use deceptive implementation methods to obtain clicks. This includes, but is not limited to, offering compensation to users for viewing ads or performing searches, promising to raise money for third parties for such behavior or placing images next to individual ads.

So, my question is, someone know valid alternatives that haven't this limitation and permit to achieve my goal?

Please don't tell me that this way of operating isn't good for the user experience, because I haven't decision power for this project.

Thank you, Nico