We need an “email” for videocalling

There is email (several specifications in RFC), which is open and free to implement. User can create his own mail server, or use mailboxes from other companies.

I was wondering, why there isn't similar thing for voice and video calling yet? Cell phones and landline are always bound to some extra service provider and phonen numbers are hard to memorize. We need something that works purely over TCP/IP and is completely free, when two parts have access to the internet (just like email is).

There are several proprietary solutions (MS Skype, Google Hangouts, Viber), but since they are proprietary, user becomes dependent on them and can not use any other program for such service. User never knows, if his data are being stored / analyzed / sold etc.

The new service could use "email-like" addresses. Current email providers will be able to integrate such videocalls, and use the same email address for both email and videocalls. People with Gmail would call people with Skype, anybody will be able to switch to another client program or make his own. There will be "email redirection", user can have several addresses and use them at the same place.

What do you think about such idea?