Backstory: YouTube is huge. Their amount of ads is getting ridiculous. Anytime there's a free piece of software, the user is the product and they are fed ads.
The Idea: An independent film platform.
Deep Dive: You would build a similar platform to netflix but niche into only independent films. As the platform is focused on only indie films, you would be able to sell space on the platform to film makers rather than litter the site with ads.
Validation: There are huge followings for indie films and there is enough "internet angst" against youtube where you may have a chance to attract a small following.
Monetization: Rather than relying solely on ads for unrelated products/services, you could sell space on the site to film makers trying to promote their videos.