In musical/audio terms, a fade in is a gradual increase in the level of an audiosignal up from silence. In video, a fade in indicates a scene that gradually fades up from "black," the video equivalent of silence.
“My Sales Engineer has always been really knowledgeable; he's right there with all the information I need. I've been very happy dealing with Sweetwater in general - there haven't been any negatives.” Ted Kynard, Charlotte, NC