Ask HN: How to best estimate potential [video] ad revenue?

Hi HN!

I am working on a startup idea and live in a country where you need a well-written business plan for investors to take you seriously. Part of that is having a 3-year plan for revenue estimation. The idea is that revenue would be generated from video advertisements that load before a video stream is played on the website (or letting users subscribe for a small fee to opt out of ads). The video content itself would be the core value of the website (like Twitch or Youtube) so I thought playing ads would be the natural answer to how it makes money.

Could someone point out a place to get started in making revenue estimations? Something like, if n users watch a video ad it makes p dollars.

Thanks for any help!