That sounds like a good idea. I hope you understand that a decent video is around 100 MB these days. 10 views will cost you 1 GB of bandwidth.
As for mp3, I don't think there will be a lot of load on your server. I recently read about lbry . It comes without any ads.
Meet LBRY, a content sharing and publishing platform that is decentralized and owned by its users.
They made it sound like it is the DuckDuckGo for YouTube.