Depending on the specifics of your app, the best monetization model might be:
ads
subscriptions
pay-per-title
Twitch uses a combination of ads and subscriptions; Netflix and most music/movie/TV streaming services go for subscriptions. Pay-per-title subscription is good for niche platforms with limited selection of titles. You’ll need to make a decision based on your audience and whether you need to pay for the content you’ll host or you’ll be streaming your own video.