With Dimdim Free, the host’s video is shown to all the participants of the meeting. It is not possible to see anybody else's video.
With Dimdim Pro, the first attendee who joins the meeting will be assigned an additional camera automatically. Host can enable this feature by going to the “Features” tab and selecting “Camera and Microphone” feature from the Audio/Video pop up. If host wants to assign camera to another attendee he have to disable the camera as shown below and then assign camera to other attendee .