You can use the video envelope to create your fade in. The envelope is on the timeline and you can then create handle points and ramp in or out the video over time in any fashion you choose. Select a track go to the pull down menu insert video envelope. A line appears on the video track add handle point by clicking on the line in the normal edit mode.Put 1 handle at at the begining point one at the end point and pull up and down the video tracks brightness. This is another way to fade in or out and is handy for compositing tracks together.