Look here in order to find use on your video stream algorithms like: motion extraction, feature tracking and foreground extractions.
Note
Unfortunetly we have no tutorials into this section. And you can help us with that, since OpenCV is a community effort. If you have a tutorial suggestion or you have written a tutorial yourself (or coded a sample code) that you would like to see here, please contact follow these instructions: How to write a tutorial for OpenCV and How to contribute.