You can use video or compositions as an Environment map like you would a regular material. You would load it into the Custom Texture maps slot in the Element effects panel (see Animated Video Textures
for similar info), go to the Scene Interface and click the Environment map button at the top. There is a drop-down next the current map name, and you can change it to one of the Custom Layer slots.
Check out this video tutorial for more advanced environment options
• Create custom Environments maps
• Learn how to separate the environment map
• Learn places to find your own and make maps