There sort of is, RTP/RTSP, and in fact it's been around since the earliest pre-web days of the Internet. The problem is that it's a protocol with a ton of war

There sort of is, RTP/RTSP, and in fact it's been around since the earliest pre-web days of the Internet. The problem is that it's a protocol with a ton of warts -- having two connections, one UDP and one TCP, has been a massive headache for decades now. But it's not awful enough to get ripped up and redone. The Asterisk VOIP platform had a really awesome protocol called IAX that was basically RTP with the two streams merged into a single UDP connection (and a bare-bones TCP-like reliability layer for the control frames inside of UDP). IAX was never meant for anything other than VOIP, but I wish it had been turned into a wholesale replacement for RTP. If that had happened, it would have been wonderful.