VivoActive is an old video compression format. The company that developed it was bought by RealNetworks in 1998 and no further development is being done.
File extension: .viv
There are two ways to play VivoActive movies if you find yourself in possesion of some. One is to get RealPlayer Plus, which isn't really an option if you're short on cash, or if it's not really worth money to be able to see them. The other option is a Netscape plugin, also available from RealNetworks.
I have no experience with RealPlayer Plus, but the Netscape plugin is extremely annoying. The movie is restricted to playing at its original size, no enlargement allowed. The only controls are pause and play, so you can't fast forward or rewind if you want to skip or go back. If you missed a scene, too bad. Either deal with it or start over from the beginning.