MobiTV, a heavily funded provider of white-label streaming video services, says it is adding a million subscribers every six months. The Emeryville, Calif.-based company offers video streaming to any internet-connected device, but focuses on working with carriers and operators to provide professionally-produced television on mobile devices.

Now it’s just raised $5 million from Leader Ventures — on top of $125 million it has already raised from venture firms Gefinor Ventures, Menlo Ventures, Redpoint Ventures, private equity firm Oak Investment Partners and strategic investors Adobe Systems Inc. and Hearst Corp.

The money is intended to pay for equipment costs.

While MobiTV already offers hosted services — chiefly for streaming mobile TV programs from ESPN, NBC, FOX Business Network and other broadcasters — it also recently launched another service that gives partners direct access to its server technology through a licensing program.

Of course, users are able to access streaming video onto many different devices, using a variety of types of video streaming services. On the web, there are consumer-facing sites (like YouTube) that offer infrastructure to other services, and also a whole range of video streaming provider companies (like Move Networks, Brightcove, Maven Networks, Joost and others). On the mobile side, where MobiTV is focusing now, there are even mobile-browser-based video sharing sites, like MyWaves.