You need a Video Mixer Hardware or some software plugins can do this. I use a plugin called show logo, while I'm using virtual DJ software. with this plugin, I can put my own logo on any live playing video. It allows me to create my own TV channel from the secondary display. Moreover, there are many nice plugins for Virtual DJ like adding SMS chat panels. if you have more questions, I'm very glad to help you. ... firstname.lastname@example.org
In order for you to put a logo on a live video, you will be required to import it using the track motion on the still track. You will also re-size the image and move it anywhere you want by using key-frames.