Dont forget everything you upload stays written forever on blockchain so its a hard game to play.The author still have all the copyrights and can sue you for abusing it and you just gave him an immutable evidence.Think about that
It would be stupid if they were actually uploading all their videos to the blockchain today. Each video can range from hundreds of megabytes to gigabytes. That will cost a lot and nobody is paying for that fee. How much did you pay to upload your video to Streamanity? So unless streamanity is subsidizing their user transactions like a communist (as they like to say), I don't think it's happening.